bluuebunny/crossref_metadata_2025 huggingface dataset:
Wavelength Index at Three Atrial Sites in Patients with Paroxysmal Atrial Fibrillation
Authors: PADELETTI LUIGI , MICHELUCCI ANTONIO , GIOVANNINI TIZIANA , PORCIANI MARIA CRISTINA , BAMOSHMOOSH MOHAMED , MEZZANI ALESSANDRO , CHELUCCI ANDREA , PIERAGNOLI PAOLO , GENSINI GIAN FRANCO
Published: October 2007

PADELETTI, L., et.al.: Wavelength Index at Three Atrial Sites in Patients with Paroxysmal Atrial Fibrillation. The purpose of this study was to evaluate the wavelength index (WLI) at three atrial sites in a group of 23 patients with recurrent episodes of lone paroxysmal atrial fibrillation (LPAF) and a control group (n = 20). All patients underwent programmed atrial stimulation (paced cycle length = 600 ms) at high, medium, and low lateral right atrial wall. P wave duration, sinus cycle length, and corrected sinus node recovery time were not significantly different between the two study groups. WLI was calculated according to the following formulas: atrial effective refractory period (AERP)/duration of atrial extrastimulus electrogram (A2) or AERP/A2+ atrial latency; and atrial functional refractory period (AFRP)/A2. WLI was significantly shorter in LPAF than in the control group at each of the paced atrial sites independently of the formula used. Duration of premature atrial electrogram appeared to play the major role in determining the difference in WLI between patients with paroxysmal atrial fibrillation and the control group.
Familial Atrioventricular Heart Block of Adult Onset: Electrocardiogram and HLA Typing Analysis
Authors: EBISAWA KATSUTO , NAKAYAMA TOSHIO , TANAKA KOUZOU , SHIMADA KAZUYUKI
Published: October 2007

EBISAWA, K., et.al.: Familial Atrioventricular Heart Block of Adult Onset: Electrocardiogram and HLA Typing Analysis. A family was investigated because of heart block and sinus arrhythmia. The electrical characteristics were: (1) adult onset in all members; (2) complete heart block with atrial fibrillation in 2, and first‐ or second‐degree heart block in 7 members; and (3) sinus arrhythmia in 3 members. Human leukocyte antigen (HLA) typing was performed. HLA A2, B39, Cw7, and DR12 were positive in 4 of 5 members in the heart block group. In the sinus arrhythmia group, HLA DR12 was positive in all members. In the normal group, none of these HLA typings was positive except one. These findings indicate a tighter relationship between heart block and the HLA locus than previously thought.
Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: A Review
Authors: MARCUS FRANK I. , FONTAINE GUY
Published: October 2007

MARCUS, F.I., et.al.: Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy: A Review. Right ventricular dysplasia is being recognized with increasing frequency. It should be considered as a cause of ventricular tachycardia of left bundle branch block configuration and/or sudden unexpected death particularly during exercise in young men. The electrocardiogram (ECG) may show anterior precordial T wave inversion, particularly in lead V2 and/or a QRS complex duration ≥ 110 ms in the right precordial leads. Echocardiographic studies focusing on the size and wall‐motion abnormalities of the right ventricle are useful in confirming the diagnosis. Radionuclide angiography usually shows a moderately or markedly depressed right ventricular ejection fraction with normal or relatively well preserved left ventricular function. Cinemagnetic resonance imaging demonstrates abnormal fatty infiltration of the right ventricular myocardium and can show increased right ventricular dimensions as well as wall‐motion abnormalities. Contrast ventricular angiography remains the gold standard to establish the diagnosis but must be performed with appropriate views and with care to avoid ventricular premature beats. Quantitative analysis of right ventricular dimensions can be performed in selected centers. Three‐dimensional echocardiography is a promising approach to evaluate right ventricular wall‐motion abnormalities as well as to demonstrate enlargement. The etiology and pathogenesis of this condition is not clear. A familial incidence has been well‐documented in certain areas and an abnormal gene has been identified. Sporadic cases are the most common. In contrast to Uhl's anomaly, characterized pathologically by areas of paper thin myocardium, the right ventricular free wall is minimally decreased in thickness. Histologically there appears to be a replacement of musculature by fatty tissue. Medical therapy with sotalol or amiodarone, or combination therapy (Class Ic drugs plus beta‐blocking drugs, or amiodarone plus beta‐blocking drugs) is frequently effective in preventing recurrent ventricular tachycardia. Ablation using radiofrequency (RF) or direct current (DC) energy is reserved for patients who are unresponsive or intolerant of antiarrhythmic drugs. Ventricular arrhythmia recurrence of different morphology is not uncommon after apparent successful ablation. There appears to be a lower rate of successful ablation using RF energy. However, patients with this condition who have been resuscitated from sudden cardiac death or those refractory to medical treatment are candidates for ablation, implantation of an automatic cardioverter defibrillator, or cardiac transplantation. Surgery consisting of total disconnection of the right ventricle is a promising therapeutic modality.
Identification of Atrial Fibrillation Episodes in Ambulatory Electrocardiographic Recordings: Validation of a Method for Obtaining Labeled R‐R Interval Files
Authors: MURGATROYD FRANCIS D. , XIE BAIYAN , COPIE XAVIER , BLANKOFF IVAN , CAMM A. JOHN , MALIK MAREK
Published: October 2007

MURGATROYD, F.D., et.al.: Identification of Atrial Fibrillation Episodes in Ambulatory Electrocardiographic Recordings: Validation of a Method for Obtaining Labeled R‐R Interval Files. Current systems for analyzing ambulatory electrocardiograms (ECGs) are unable to distinguish precisely between sinus rhythm and atrial fibrillation (AF) episodes, and are unable to produce RR interval listings that distinguish AF from sinus rhythm on a beat‐to‐beat basis. We describe a method for obtaining such a computerized listing (“Composite Rhythm” file) from ambulatory recordings containing episodes of AF. The file lists the rhythm of each beat, its real time, and the QRS complex morphology. A visual inspection is made of a full printout of the recording to identify the precise time of onset and termination of each episode of AF. These times are entered into a computer and identified with the corresponding beats on a conventional RR interval file generated by Holter analysis. The method was validated using 1‐hour segments from 20 ambulatory ECGs containing 145 episodes of AF. These were visually identified by four independent observers with a mean sensitivity of 99.1%. The first beat of AF was identified concordantly in 96% of episodes, with a discrepancy of ≤ 3 beats in the other episodes. The times of 200 selected QRS complexes were then entered into the computer by each observer; 91.1 % of these complexes were identified exactly and 100% were identified to within one beat. The Composite Rhythm files have several potential applications for testing AF detection algorithms and studying the mode of onset of AF.
Sensing Failure in a Tiered Therapy Implantable Cardioverter Defibrillator: Role of Auto Adjustable Gain
Authors: WASE ABDUL , NATALE ANDREA , DHALA ANWER A. , DESHPANDE SANJAY , SRA JASBIR S. , BLANCK ZALMEN , MAGLIO CHERYL , JAZAYERI MOHAMMAD R. , AKHTAR MASOOD
Published: October 2007

WASE A., et.al.: Sensing Failure in a Tiered Therapy Implantable Cardioverter Defibrillator: Role of Auto Adjustable Gain. Implantable cardioverter defibrillators have an established role in the management of life‐threatening tachyarrhythmias. These devices use sophisticated sensing circuitry to detect and promptly treat a vast majority of these arrhythmias. However, they are not foolproof. We report one case where the device failed to sense every other QRS complex during induced ventricular fibrillation due to marked electrical alterans. Thus, undersensing can be a potentially fatal problem despite the use of auto adjustable gain.
Long‐Term Follow‐Up of Patients Treated By Radiofrequency Ablation of the Atrioventricular Junction
Authors: JENSEN STEEN M. , BERGFELDT LENNART , ROSENQVIST MÅRTEN
Published: October 2007

JENSEN, S.M., et al.: Long‐Term Follow‐Up of Patients Treated By Radiofrequency Ablation of the Atrioventricular Junction. Radiofrequency ablation of the AV conduction tissue (His‐bundle ablation) is an accepted treatment for therapy resistant atrial fibrillation/flutter. However, data on the long‐term effects of the procedure are limited. We followed 50 patients for a mean of 17 months after AV junction ablation. The indication was treatment resistant atrial fibrillation or flutter. The patients underwent a standardized interview performed by two nurses. Health care was studied via the in‐patient register. Subjective improvement was reported by 88% and the number of days in hospital per year was reduced from 17 to 7. The use of antiarrhythmic drugs was reduced by 75%. If the reduction in costs of drugs and days in hospital is compared with the cost of the ablation and the pacemaker implantation, breaking even is achieved after 2.6 years. We could not confirm that patients with paroxysmal atrial fibrillation note less improvement than those with chronic fibrillation. Conclusion: Ablation of the AV junction is a cost effective treatment with good long‐term results and relatively few complications. Recommendations: Chronic atrial fibrillation: If sinus rhythm cannot be established and in cases in which heart rate regulating drugs have been ineffective, ablation of the AV junction with implantation of a VVIR pacemaker is recommended. Paroxysmal atrial fibrillation: If the patient despite treatment with antiarrhythmic drugs continues to have symptomatic episodes of atrial fibrillation, then AV junction ablation with implantation of a permanent pacemaker is recommended. Patients who have self‐limiting episodes of atrial fibrillation should be given a DDDR pacemaker with an automatic mode switch. Patients who do not have self‐limiting attacks and require DC conversion, should receive a VVIR pacemaker
A Fast and Reliable Algorithm to Localize Accessory Pathways Based on the Polarity of the QRS Complex on the Surface ECG During Sinus Rhythm
Authors: D'AVILA ANDRE , BRUGADA JOSEP , SKEBERIS VASSILIS , ANDRIES ERIK , SOSA EDUARDO , BRUGADA PEDRO
Published: October 2007

d'AVILA, A., et al.: A Fast and Reliable Algorithm to Localize Accessory Pathways Based on the Polarity of the QRS Complex on the Surface ECG During Sinus Rhythm. Background: Many criteria have been published to localize accessory pathways from the 12‐lead EGG during sinus rhythm. This study analyzed whether the localization of an accessory pathway could be predicted by using the polarity of the QRS complex during sinus rhythm on the surface ECG, instead of the delta wave polarity as used in many reports. Methods: The ECGs of 140 patients with an overt and single accessory pathway were evaluated. Eight localizations were taken into account. The precise location was previously known from successful radiofrequency ablation sites. Results: In 128 patients (92%), the new algorithm allowed an accurate diagnosis of the site of implantation of the accessory pathway. Conclusion: Analysis of the polarity of the QRS complex on five electrocardiographic leads provides an easy, fast and reliable way to localize accessory pathways during sinus rhythm.
Effects of Atrial, Ventricular, and Atrioventricular Sequential Pacing on Coronary Flow Reserve
Authors: KOLETTIS THEOFILOS M. , KREMASTINOS DIMITRIOS T. , KYRIAKIDES ZENON S. , TSIRAKOS ANASTASIOS , TOUTOUZAS PAVLOS K.
Published: October 2007

KOLETTIS, T.M., et al.: Effects of Atrial, Ventricular, and Atrioventricular Sequential Pacing on Coronary Flow Reserve. Experimental animal data have indicated that altered left ventricular depolarization sequence as a result of right ventricular pacing may diminish coronary blood flow in the distribution of the left anterior descending coronary artery. To further investigate this, we compared the effects of atrial, ventricular, and atrioventricular (AV) sequential pacing on coronary flow reserve. Twenty‐seven patients (24 male, mean age 55 ± 7 years) with normal left anterior descending coronary arteries were studied. Coronary flow reserve was calculated as the ratio of mean flow velocity at maximal coronary vasodilatation to mean flow velocity at baseline. The study consisted of two parts. In the first part, AV sequential pacing was compared to atrial pacing at the same rate; coronary flow reserve did not differ significantly between the two pacing modes (14 patients, 4.85 ± 1.88 vs 5.47 ± 1.55, respectively, P > 0.05). In the second part, all three pacing modalities were compared; coronary flow reserve was significantly higher during ventricular compared to AV sequential pacing, but not significantly different compared to atrial pacing (3.69 ± 1.42 vs 2.90 ± 0.86 vs 3.11 ± 0.89, respectively, P < 0.05). This difference was secondary to a significant decrease in mean baseline velocity during ventricular pacing, while mean velocity during hyperemia was comparable between the three pacing modes. It is concluded that AV sequential pacing does not appear to exert a significant effect on coronary flow reserve. Ventricular pacing, however, may lower resting coronary blood velocity in some patients, without affecting maximal coronary blood velocity, resulting in a higher coronary flow reserve.
Effects of Electroporation on Transmembrane Potential Induced by Defibrillation Shocks
Authors: KRASSOWSKA WANDA
Published: October 2007

KRASSOWSKA, W.: Effects of Electroporation on Transmembrane Potential Induced by Defibrillation Shocks. This study uses a one‐dimensional model of cardiac strand to investigate the effects of electroporation on transmembrane potential (Vm) induced by defibrillation shocks. The strand is stimulated at the ends by extracellular electrodes. Its membrane, when exposed to large Vm, increases its conductance in a manner consistent with reversible electrical breakdown. Numerical simulations indicate that Vm increases proportionally to the shock strength only until the ends of the strand electroporate. Beyond this point, further increases in shock strength result in only a minor change in Vm. This arrest in the growth of Vm is caused by pores that develop in the cells immediately adjacent to the electrodes and that shunt part of the stimulating current directly into intracellular space. Consequently, only a fraction of the delivered current, Icr gives rise to Vm; the current in excess of Icr. divides itself proportionally between intra‐ and extracellular space and does not contribute to macroscopic Vm. Thus, electroporation has a beneficial effect: the formation of pores prevents the development of an excessively high Vm and limits the damage to the tissue. In contrast, electroporation does not affect the “sawtooth” component of Vm that reflects polarization of individual cells by electric field. These results indicate that electroporation does not impair the ability of the shock to reach the distant myocardium and may actually aid defibrillation by reducing nonuniformity of electrical conditions between regions close to the electrodes and in the bulk of tissue.
Computer Analysis of Monophasic Action Potentials: Manual Validation and Clinically Pertinent Applications
Authors: FRANZ MICHAEL R. , KIRCHHOF PAULUS F. , FABRITZ C. LARISSA , ZABEL MARKUS
Published: October 2007

FRANZ, M.R., et al.: Computer Analysis of Monophasic Action Potentials: Manual Validation and Clinically Pertinent Applications. Monophasic action potential (MAP) recordings are increasingly being used in a variety of clinical and experimental situations but their manual measurement is cumbersome, especially when hundreds or thousands of beats must be analyzed to monitor the exact time course of action potential duration (APD) changes following heart rate alterations, during surveillance of APD alternans, or during the onset and stabilization of Class III drug effects. To facilitate this task we developed a computer program that automates programmed electrical stimulation, digitizes at 1‐kHz sampling frequency MAP recordings up to 8 channels simultaneously, analyzes all APDs at repolarization levels from 10%–90% in 10% decrements (APD10–90), and automatically outputs the analyzed numerical data into spreadsheets for graphical display or statistical analysis. To validate the computer algorithm, two independent observers manually analyzed 585 concurrent MAP recordings at a paper speed of 100 mm/s. Cycle length measurements by the computer were precise to 0.4 ± 0.5 ms as compared to the computer determined paced cycle length. Computer measurements of APD20, 50, and 90 differed from manual measurements by 2.0 ± 8.8 ms, 0.7 ± 7.9 ms, and 0.2 ± 8.5 ms, respectively, for observer 1; and by 12.2 ± 8.3 ms, 5.8 ± 7.5 ms, and 1.4 ± 10.1 ms, respectively, for observer 2. Inter‐observer variability (IOV) was 10.3 ± 11.1 ms (APD20), 5.1 ± 9.0 ms (APD50), and 1.2 ± 7.8 ms (APD90), which was similar to computer/observer‐2 differences and significantly greater (0.001) than computer/observer‐1 differences. This indicates that the computer analysis was at least as precise as manual measurements when compared to IOV, and more precise when comparing computer/observer‐1 differences to IOV. While providing equal or greater precision, computer‐aided analysis of 100 MAP signals took approximately 1 minute while manual analysis of the same data set took between 2.5 and 4 hours. The pacing and analysis software was subsequently applied to experiments that mimic clinically pertinent examples of MAP recordings: (1) automatic generation, analysis, and graphical display of electrical restitution curves at multiple ventricular sites simultaneously; (2) evaluation of myocardial pharmacokinetics by monitoring the progression of Class III antiarrhythmic drug effects by continuous MAP recordings, and displaying differences in drug action between multiple sites; (3) depiction of the adaptation time course of APD to abrupt changes in paced cycle length; and (4) quantitative analysis of APD alternans during myocardial ischemia. The results show that our computerized algorithm greatly facilitates the generation of cardiac electrophysiological, and clinically important, data.
Atrial Pressure and Experimental Atrial Fibrillation
Authors: SIDERIS DIMITRIS A. , TOUMANIDIS SAVVAS T. , TSELEPATIOTIS EVANGELOS , KOSTOPOULOS KOSTIS , STRINGLI TINA , KITSIOU TATIANA , MOULOPOULOS SPYRIDON D.
Published: October 2007

SIDERIS, D.A., et al.: Atrial Pressure and Experimental Atrial Fibrillation. A possible profibrillatory effect on the atria of an elevated atrial pressure and the site of atrial stimulation was examined. In 15 anesthetized dogs, right or left atrial or biatrial pacing was applied at a high rate (300–600/min) for 5 seconds at double threshold intensity under a wide range of atrial pressures achieved by venous or arterial transfusion or bleeding. Induction of atrial fibrillation in 236 of 1,971 pacing runs was associated with a significantly higher (P < 0.001) atrial pressure (21.6 ± 12.2 mmHg, mean ± SD) than maintenance of sinus rhythm (16.8 ± 11.1 mmHg in 1,735 of 1,971 pacing runs). Stimulation of the right atrium resulted in atrial fibrillation more frequently than left atrial or biatrial stimulation, with biatrial stimulation less frequent than right or left atrial stimulation. The induction of atrial fibrillation was related to the atrial pressure and to the site of stimulation but not to the pacing rate or the prepacing heart rate. The prepacing heart rate, associated with failure to induce sustained atrial fibrillation, was higher than that associated with atrial fibrillation in 12 of 15 experiments (significantly in 6) and not significantly lower in 3 of 15. Atrial fibrillation lasting 1 minute or more was more frequently associated with simultaneous stimulation of both atria than of either atrium alone. Thus, an elevated atrial pressure may facilitate the induction of atrial fibrillation. The site of stimulation also plays an important role for both the induction and maintenance of atrial fibrillation in this model.
Successful Radiofrequency Catheter Ablation for Macroreentrant Ventricular Tachycardias in a Patient with Tetralogy of Fallot After Corrective Surgery
Authors: CHINUSHI MASAOMI , AIZAWA YOSHIFUSA , KITAZAWA HITOSHI , KUSANO YORIKO , WASHIZUKA TAKASHI , SHIBATA AKIRA
Published: October 2007

CHINUSHI, M., et al.: Successful Radiofrequency Catheter Ablation for Macroreentrant Ventricular Tachycardias in a Patient with Tetralogy of Fallot After Corrective Surgery. Radiofrequency (RF) catheter ablation was applied to two macroreentrant ventricular tachycardias (VTs) documented after corrective operation for tetralogy of Fallot. The activation wavefront of VT with a right bundle branch block pattern was found to revolve in a clockwise manner around a presumed myotomy scar in the right ventricle, and VT with a left bundle branch block pattern revolved around the same anatomical obstacle in a counterclockwise manner. In both VTs, the biggest conduction delay was confirmed at the right ventricular outflow tract. RF applications to the slow conduction area terminated each VT within a few seconds but were insufficient to cure the VTs. RF lesions were then applied to the, slow conduction area in a line to intersect the macroreentrant circuit, and both VTs became noninducible.
Cardiac Involvement in Emery‐Dreifuss Muscular Dystrophy: Role of a Diagnostic Pacemaker
Authors: RAKOVEC PETER , ZIDAR JANEZ , ŠINKOVEC MATJAŽ , ZUPAN IGOR , BRECELJ ALEŠ
Published: October 2007

RAKOVEC, P., et al.: Cardiac Involvement in Emery‐Dreifuss Muscular Dystrophy: Role of a Diagnostic Pacemaker. Emery‐Dreifuss muscular dystrophy is an X‐linked recessive myopathy. Its progression is slow, and it rarely leads to cessation of walking; therefore, it has often been called “benign.” On the other hand, cardiac involvement is often severe and sudden death is not uncommon. We describe a family with four affected males, two of whom died suddenly. The case of an affected man with first‐degree AV block, incomplete right bundle branch block, and left anterior fascicular block is described in detail. The prophylactic insertion of a diagnostic pacemaker enabled us to follow the progress of conduction disturbances without leaving the patient unprotected. While AV and intraventricular conduction defects were more prominent before pacemaker implantation, sinus node dysfunction became more important during the follow‐up.
Preliminary Results of a Limited Thoracotomy: New Approach to Treat Atrial Fibrillation
Authors: MCCLELLAND JAMES H. , DUKE DAVID , REDDY RAMAKOTA
Published: October 2007

Objective: To determine efficacy of a new procedure combining epicardial bipolar radiofrequency (RF) pulmonary vein (PV) antrum isolation and ganglionated plexus (GP) ablation for treatment of atrial fibrillation (AF).

Background: PV antrum electrical isolation and GP ablation have each been associated with elimination of AF. Both of these can be performed epicardially in a single combined surgical procedure, which may have advantages over endocardial ablation.

Methods and Results: Twenty‐one subjects entered a prospective evaluation of limited thoracotomy epicardial bipolar PV antrum isolation, verified by PV recordings, with GP ablation, guided by GP mapping. Procedural success was defined as freedom from AF and antiarrhythmic agents during 1 year of follow‐up, including evaluation by prolonged continuous monitoring capable of detecting asymptomatic arrhythmias. All subjects had recordable PV potentials and GP activity prior to ablation. Circumferential epicardial bipolar RF eliminated PV potentials in 18 of 20 right and 14 of 20 left PV antra. This concurrently eliminated 79% of GP activity (125 of 159 active sites); nearly all remaining GP activity could then be eliminated using epicardial bipolar RF forceps. Fifteen of 20 (75%) subjects overall, and 14 of 16 (87.5%) subjects with paroxysmal or persistent AF had a successful procedure.

Conclusion: Limited thoracotomy epicardial bipolar RF antrum isolation, verified by PV recordings, with GP ablation, guided by GP mapping, is effective treatment for AF and should be considered in patients with paroxysmal or persistent AF.
ORIGINAL INVESTIGATIONS: Tissue Harmonic Imaging in Echocardiography: Better Valve Imaging, But at What Cost?
Authors: Hawkins Karin , Henry John S. , Krasuski Richard A.
Published: October 2007

Background: Tissue harmonic imaging (THI) improves echocardiographic image quality and is widely utilized. Unfortunately it also makes structures appear artificially thickened. We sought to examine its impact on the imaging of left‐sided heart valves. Methods: A large echocardiographic database was searched for full, standard transthoracic echocardiographic exams performed 12‐month periods before (n = 3,786) and after (n = 3,914) transition to THI at a single institution. Patients with prosthetic valves were excluded. Results: The mean age of patients was 63 ± 17 years and 65% were men. No appreciable difference in demographics was observed between time periods. While inadequate visualization of the mitral valve was reduced by 30% using THI (P = 0.014), reports of leaflet thickening increased by 28% (P = 0.005). Similarly, inadequate aortic valve visualization was reduced by 53% with THI (P < 0.001), at the expense of more aortic sclerosis (+6%, P = 0.034). Among the 480 patients with echocardiograms using each modality (time interval between studies: 370 ± 143 days), THI did not appreciably improve visualization of the either valve. Although no significant increase in mitral thickness was seen with THI, aortic sclerosis was increased by at least one grade in 24.5% (P < 0.006). Conclusion: This study suggests that while THI enhances imaging of difficult to visualize valves, it may overestimate mitral and aortic valve thickness. This could lead to overdiagnosis and unnecessary follow‐up studies. Cardiologists interpreting THI echocardiograms should become familiar with the modality's shortcomings.
Left Ventricular versus Biventricular Pacing: A Randomized Comparative Study Evaluating Mid‐Term Electromechanical and Clinical Effects
Authors: Valzania Cinzia , Rocchi Guido , Biffi Mauro , Martignani Cristian , Bertini Matteo , Diemberger Igor , Biagini Elena , Ziacchi Matteo , Domenichini Giulia , Saporito Davide , Rapezzi Claudio , Branzi Angelo , Boriani Giuseppe
Published: October 2007

Background: Although left ventricular (LV) pacing has been proposed as an alternative to biventricular (BIV) pacing for heart failure (HF) patients, few comparative data are available on the electromechanical effects of these pacing modalities at mid‐term follow‐up. Aim: To investigate the clinical and echocardiographic effects of LV versus BIV pacing in a mid‐term randomized study. Methods: After implantation of a device with LV/BIV pacing capabilities, 22 patients with chronic HF and left bundle branch block were randomized to LV or BIV pacing. Patients were assessed both preimplantation and after 3 months by clinical examination, ECG and echocardiography with pulsed tissue Doppler imaging. Results: At 3 months LV pacing improved clinical parameters, LV ejection fraction (+5%, range 5–8%, P = 0.007) and intraventricular dyssynchrony (−40 ms, range −50 to −15 ms, in septal to lateral delay, P = 0.008) to a similar extent to BIV pacing. A decrease in interventricular mechanical delay (−25 ms, range −40 to −5 ms, P = 0.008) and QRS duration (−28 ms, range −40 to −5 ms, P = 0.008) was observed in BIV, but not in LV patients. Conclusion: In this pilot evaluation, LV pacing appeared to be associated with clinical benefits similar to BIV pacing at mid‐term follow‐up, and this was combined with an improvement in intraventricular dyssynchrony, regardless of variations in interventricular dyssynchrony and QRS duration. Echocardiographic evaluation of intraventricular dyssynchrony seems to be an appropriate method for assessing the chronic response to LV pacing.
VO2 Max and Anaerobic Threshold in Hypertension: A Tissue Doppler Study
Authors: Danciu Sorin C. , Krause Steven W. , Wagner Chris , Gonzalez Joaquin , Brenchley Jackie , Clark Clifton , Herrera Cesar J.
Published: October 2007

Background: Hypertension can impair left ventricular (LV) relaxation causing shortness of breath and reduced exercise capacity, which may affect the clinical evaluation of the symptomatic hypertensive patient. In this study we used tissue Doppler imaging (TDI) to identify correlates of anaerobic threshold (AT) and maximum oxygen uptake (VO2 Max). Our goal was to assess the feasibility of TDI as a surrogate of functional capacity in hypertensive individuals. Methods: We studied subjects without metabolic syndrome and with normal LV function (ejection fraction (EF) >50%)
. Traditional echocardiographic variables were obtained before and after a cardiopulmonary exercise test. Systolic (S) and diastolic (E′and A′) myocardial velocities were measured at the basal septal (bs) and posterior (bp) walls. Results: After multivariate analysis, resting E′bp (r =0.56, P < 0.002) and isovolumic relaxation time (IVRT) (r =−0.49, I < 0.03) correlated with VO2 Max, while A Valsalva correlated with AT (r =−0.46, P < 0.03). Peak stress E′/A′bp correlated with age and gender corrected METs (r =−0.63, P < 0.0004) and VO2 Max (r =−0.39, P< 0.04). Conclusions: Resting E′bp and peak stress E′/A′bp correlate with VO2 Max in hypertensive patients. TDI may be an important tool when assessing symptoms in this population.
The Effect of Isolated Left Bundle Branch Block on the Myocardial Velocities and Myocardial Performance Index
Authors: Akif Duzenli Mehmet , Ozdemir Kurtulus , Soylu Ahmet , Aygul Nazif , Yazici Mehmet , Tokac Mehmet
Published: October 2007

Objectives: This study was planned in order to investigate the effect of left bundle branch block (LBBB) on myocardial velocities obtained by tissue Doppler echocardiography (TDE) and myocardial performance index (MPI). Methods: Subjects with LBBB (n = 61) and age‐matched healthy subjects (n = 60) were enrolled in the study. Left ventricular (LV) ejection fraction (EF), mitral inflow velocities (E‐wave and A‐wave), isovolumetric contraction and relaxation time (ICT and IRT), ejection time (ET), and flow propagation velocity (Vp) were measured by conventional echocardiography. Systolic velocity (Sm), early and late diastolic velocities (Em and Am) and time intervals were measured by TDE. MPI was calculated by the formula (ICT + IRT)/ET. Results: LVEF and mitral E/A ratio were similar in both groups. Vp was lower in the LBBB group than in the control group, whereas the E/Em and the E/Vp ratio was higher. LV Sm and Em/Am ratio were lower in LBBB group. Right ventricular Sm and Em/Am ratio were similar in both groups. LV mean and RV MPI were significantly increased in LBBB group. Conclusion: These findings obtained by TDE show that isolated LBBB impairs the ventricular functions. Both of the LV and RV dysfunctions shown by the new parameters may contribute to increased morbidity and mortality in cases with isolated LBBB.
Effect of Preload Reduction by Hemodialysis on Conventional and Novel Echocardiographic Parameters of Left Ventricular Structure and Function
Authors: Palecek Tomas , Skalicka Lenka , Lachmanova Jana , Tesar Vladimir , Linhart Ales
Published: October 2007

Background: Available studies of the effect of hemodialysis (HD) on left ventricular (LV) performance brought ambiguous results. Therefore we aimed to investigate the effect of acute preload reduction induced by HD on conventional and novel parameters of LV structure and function. Methods: Thirty‐six patients underwent echocardiography 1 hour prior to and 1 hour following regular HD. M‐mode, two‐dimensional, and Doppler echocardiography were used to analyze conventional LV structural and functional parameters. Systolic and diastolic mitral annular velocities assessed by pulsed‐wave tissue Doppler echocardiography (PW‐TDE) and flow propagation velocity (Vp) of early LV inflow were measured as novel indices of LV systolic and diastolic function. Results: After HD, all heart chambers including LV significantly reduced in their size. The reduction in LV mass was also observed. Parameters of LV systolic function—ejection fraction and systolic mitral annular velocity, significantly improved, whereas fractional shortening did not. As for LV diastolic function, conventional Doppler parameters and Vp were substantially changed after HD. Conversely, PW‐TDE diastolic velocities were not significantly affected. Conclusions: The fluid removal induced by HD leads to a substantial decrease in LV size and mass. The improvement of LV longitudinal contraction documented by PW‐TDE seems to be responsible for the increase in global LV systolic function after HD. While standard Doppler parameters of LV diastolic function and Vp are significantly affected by preload reduction, PW‐TDE diastolic indices appears to be less load dependent. Therefore, PW‐TDE represents a promising method for the LV diastolic function assessment in patients on HD.
Sleep apnea and dialysis therapies: Things that go bump in the night?
Authors: UNRUH Mark L.
Published: October 2007

Sleep apnea has been linked to excessive daytime sleepiness, depressed mood, hypertension, and cardiovascular disease in the general population. The prevalence of severe sleep apnea in the conventional thrice‐weekly hemodialysis population has been estimated to be more than 50%. Sleep apnea leads to repetitive episodes of hypoxemia, hypercapnia, sleep disruption, and activation of the sympathetic nervous system. The hypoxemia, arousals, and intrathoracic pressure changes associated with sleep apnea lead to sympathetic activation, endothelial dysfunction, oxidative stress, and inflammation. Because sleep apnea has been shown to be widespread in the conventional dialysis population, it may be that sleep apnea contributes substantially to the sleepiness, poor quality of life, and cardiovascular disease found in this population. The causal links between conventional dialysis and sleep apnea remain speculative, but there are likely multiple factors related to volume status and azotemia that contribute to the high rate of severe sleep apnea in dialysis patients. Both nocturnal automated peritoneal dialysis and nocturnal hemodialysis have been associated with reduced severity of sleep apnea. Nocturnal dialysis modalities may provide tools to increase our understanding of the uremic sleep apnea and may also provide therapeutic alternatives for end‐stage renal disease patients with severe sleep apnea. In conclusion, sleep apnea is an important, but overlooked, public health problem for the dialysis population. The impact of sleep apnea treatment in this high‐risk population may include reduced sleepiness, better mood and blood pressure, and lowered risk of cardiovascular disease.
Nonconvulsive status epilepticus: High incidence in dialysis‐dependent patients
Authors: IFTIKHAR Sheikh , DAHBOUR Said , NAUMAN Siddiqi
Published: October 2007

Nonconvulsive status epilepticus is defined as a mental status change from baseline of at least a 30‐min duration associated with constant or near‐continuous ictal discharges on an electroencephalogram (EEG). Nonconvulsive status epilepticus is an often‐overlooked diagnosis as a cause of acute confusional state. There are few case reports in dialysis patients. We are reporting 5 patients on chronic dialysis treatment who presented with an acute confusional state. Nonconvulsive status epilepticus was diagnosed by EEG and response to intravenous benzodiazepines. We recommend early EEG to be considered in the evaluation of dialysis patients with an acute confusional state.
Ectopic mediastinal parathyroid carcinoma as a cause of dialysis‐dependent renal failure
Authors: TKACZYK Marcin , CZUPRYNIAK Aneta , NOWICKI Michał
Published: October 2007

Carcinoma of the parathyroid gland is infrequent in patients with secondary hyperparathyroidism. Typical clinical symptoms are related to the presence of a neck mass and hypercalcemia. We describe a case of a 55‐year‐old man in whom primary parathyroid carcinoma led most likely to the development of end‐stage dialysis‐dependent renal failure, and the diagnosis of the cancer was delayed due to ectopic localization of the tumor, and dramatic complications in the clinical course of the disease, including acute pancreatitis and peritionitis. However, 6 months after successful surgery and subsequent radiotherapy, the patient is well and free from recurrences but remains chronically dialysis‐dependent.
Secondary sternal Aspergillus osteomyelitis in a diabetic hemodialysis patient with previous allograft rejection
Authors: NATESAN Sinthumathi , ABRAHAM Georgi , MATHEW Milly , LALITHA M.K. , SRINIVASAN C.N.
Published: October 2007

A 29‐year‐old diabetic woman who had a previously failed renal allograft on maintenance hemodialysis developed sternal aspergillosis with Aspergillus terreus following a pericardiectomy. She was successfully treated with surgical debridement and a combination of antifungal agents including amphotericin B, caspofungin, and voriconizole. The diagnostic difficulties and management are discussed.
Comparison of calcium phosphate product values using measurement of plasma total calcium and serum ionized calcium
Authors: TERTTI Risto , HARMOINEN Aimo , LESKINEN Yrjö , METSÄRINNE Kaj P. , SAHA Heikki
Published: October 2007

Calcium phosphate product (Ca × Pi) is a clinically relevant tool to estimate the cardiovascular risk of patients with renal failure. In reports, mostly total serum calcium has been used. As measurement of serum ionized calcium has some benefits and is being used increasingly, we estimated the respective levels of calcium phosphate product using both total (t‐Ca × Pi) and ionized calcium (ion‐Ca × Pi). Fifty‐eight healthy individuals and 180 hemodialysis (HD) patients from 2 centers were studied. Diagnostic accuracies for corresponding values of the t‐Ca × Pi and ion‐Ca × Pi were calculated using a GraphROC program. Of HD patients, 64% had t‐Ca × Pi <4.4 mmol2/L2 regarded as a desirable goal, and 10% had values over 5.6 mmol2/L2 associated with a high cardiovascular risk. Based on GraphROC analysis, t‐Ca × Pi of 4.4 mmol2/L2 corresponded to a value of 2.2 mmol2/L2 of ion‐Ca × Pi and, respectively, t‐Ca × Pi of 5.6 mmol2/L2 corresponded 2.8 mmol2/L2 of ion‐Ca × Pi. Owing to the good agreement between the results in the 2 centers, these values for risk levels can be used in both centers. When measurement of ionized calcium is used, Ca × Pi values of 2.2 and 2.8 mmol2/L2 can be used instead of generally used values of 4.4 and 5.6 mmol2/L2 with total calcium.
Effect of pharmacological suppression of secondary hyperparathyroidism on cardiovascular hemodynamics in predialysis CKD patients: A preliminary observation
Authors: SINGH Narinder P. , SAHNI Vaibhav , GARG Dheeraj , NAIR Mohan
Published: October 2007

Cardiovascular events are the principal cause of mortality in patients with chronic kidney disease (CKD). Secondary hyperparathyroidism (SHPT), a common complication of CKD, contributes to cardiac dysfunction. This study is an attempt to demonstrate the effects of parathyroid hormone suppression with oral calcitriol on cardiovascular hemodynamics. Twenty predialysis CKD patients with SHPT were given calcitriol therapy for 12 weeks. Ten similar patients received placebo. Echocardiographic assessment of cardiac function was performed at baseline and after 12 weeks of treatment. Calcitriol therapy effectively suppressed SHPT. Baseline left ventricular (LV) end diastolic diameter and LV end systolic diameter were 4.86±0.48 and 2.86±0.33 cm, and the mean FS was 41.02±4.79%. Left ventricular end systolic and end diastolic volumes were normal (42.30±9.07 and 91.40±19.68 mL). The ejection fraction was slightly reduced (53.54±3.57%). Pretreatment Doppler indices including E velocity (0.816±0.087 m/s), A velocity (0.696±0.089 m/s), and E/A ratio (1.193±0.210) were significantly impaired. After 12 weeks of calcitriol therapy, there was no significant change in the LV dimensions or ejection fraction, but there was a significant improvement in the diastolic parameters, namely the A velocity (0.680±0.084) and E/A ratio (1.238±0.180). Secondary hyperparathyroidism is an important factor in the pathogenesis of cardiovascular complications in CKD. There is evidence to support that correction of hyperparathyroidism can improve the systolic dysfunction seen in advanced kidney disease. This study shows that diastolic dysfunction seen in predialysis CKD patients may also be possibly improved with calcitriol therapy.
Inadvertent postdialysis anticoagulation due to heparin line locks
Authors: PEPPER Ruth J. , GALE Daniel P. , WAJED Julekha , BOMMAYYA Girish , ASHBY Damien , MCLEAN Adam , LAFFAN Mike , MAXWELL Patrick H.
Published: October 2007

Large‐bore dual lumen in‐dwelling venous catheters are used in hemodialysis. These catheters are usually locked with heparin after the treatment. This study addressed the underappreciated postdialysis coagulopathy that can result. Thirty‐six patients were included: 7 dialyzed through arterio‐venous fistulae, 29 through in‐dwelling venous catheters. The latter group was further subdivided according to whether they received heparin or heparin‐free dialysis. To assess the heparin lock, a full‐dose heparin lock as well as a much weaker heparin lock and a citrate lock were used. To assess the coagulopathy, blood was taken 1 hr after dialysis. The activated partial thromboplastin time (APTT) and anti‐Xa level was measured. Additionally, 6 venous catheters were removed and the amount of fluid expelled upon locking with saline was measured. Clotting from the patient group with arterio‐venous fistulae was normal following dialysis. The patients with in‐dwelling venous catheters and heparin locks had significantly deranged clotting; 6 out of 10 patients had abnormal APTT results. All patients with catheters, heparin‐free dialysis, and heparin locks had deranged clotting (7 out of 7). The rate decreased significantly when heparinized saline was used as a lock. A subset of patients had a citrate lock rather than a heparin lock; the clotting results normalized in all but one patient. An in vitro study demonstrated immediate leakage of fluid from the end of the ports upon locking. Significant postdialysis anticoagulation can occur after dialysis, which can be attributed to the heparin line locks. This risk is considerably reduced when a citrate lock is used instead.
Sleep apnea in hemodialysis patients: Risk factors and effect on survival
Authors: ARGEKAR Pushkar , GRIFFIN Valerie , LITAKER David , RAHMAN Mahboob
Published: October 2007

Sleep disorders are common in patients with end‐stage renal disease (ESRD). Using a simple questionnaire, we estimate the probability of sleep apnea in ESRD patients, determine the factors associated with a higher probability of sleep apnea, and determine the association between the probability of sleep apnea and cardiovascular and all‐cause mortality. Study design: Prospective cohort study. Setting and participants: prevalent hemodialysis patients (n=270) in 7 urban outpatient hemodialysis units. Predictor: Probability of sleep apnea as quantified by the Flemons questionnaire. Outcomes and measurements: Clinical, demographic, and dialysis‐related characteristics were obtained at baseline. Total and cardiovascular mortality was ascertained after a median follow‐up of 34 months. The probability of sleep apnea was low in 79 (29%) patients, moderate in 116 (43%) patients, and high in 75 (28%) patients. Male gender (odds ratio [OR] 5.13, p<0.001), obesity (BMI >30, OR 7.58, p<0.01), and interdialytic weight gain (OR 1.72/kg change, p<0.004) were independently associated with a high probability of sleep apnea. A high probability of sleep apnea at baseline did not predict total (hazard ratio [HR] 0.81, p=NS) or cardiovascular mortality (HR 0.9, p=NS). The Flemons questionnaire is validated in the general population, but has not been tested specifically in hemodialysis patients. The study may not be adequately powered to detect a difference in mortality. A high proportion of hemodialysis patients are likely to have sleep apnea; a simple bedside questionnaire can be used for screening to identify these patients. Excessive interdialytic weight gain is a potentially modifiable factor that increases the likelihood of sleep apnea. Despite the presence of a strong association between sleep apnea and mortality in the general population, a similar association could not be demonstrated in ESRD patients with a high prevalence of this condition.
Relative blood volume measurements during hemodialysis: Comparisons between three noninvasive devices
Authors: DASSELAAR Judith J. , HUISMAN Roel M. , DE JONG Paul E. , FRANSSEN Casper F.M.
Published: October 2007

The monitoring of relative blood volume changes (ΔRBV) has been advocated for the prevention of hemodialysis (HD) hypotension. Stand‐alone devices (Crit‐Line) or devices incorporated into the HD apparatus (blood volume monitor [BVM], Hemoscan) are widely used for this purpose. Comparisons between devices are scarce. The aim of this study was, first, to compare ΔRBV results from these 3 devices with ΔRBV calculated from changes in laboratory‐derived hemoglobin (ΔRBV‐lab‐Hb) and, second, to compare ΔRBV results between the different devices. Fourteen patients received 2 HD treatments in a randomized order: one with the Hemoscan and Crit‐Line combination and one with the BVM and Crit‐Line combination. ΔRBV‐lab‐Hb was measured at 2 and 4 hr into the HD session. Bland‐Altman analyses showed that ΔRBV results from the 3 devices differed systematically from ΔRBV‐lab‐Hb, i.e., the difference between the 3 devices and ΔRBV‐lab‐Hb varied significantly (p<0.05) with the magnitude of the measurement. The interdevice comparison showed considerable differences in ΔRBV results. At the end of the treatment, a significant difference (p<0.05) between ΔRBV measured by the Hemoscan and Crit‐Line device (−9.8±2.7% and −11.5±4%, respectively) was found. In most patients, a systematic difference between Crit‐Line and Hemoscan and between Crit‐Line and BVM was observed. Relative blood volume change measurements by Crit‐Line, Hemoscan, and BVM yield results that differ systematically from the results obtained from laboratory‐derived Hb changes. Furthermore, there are substantial differences in ΔRBV results between the 3 ΔRBV devices.
Aging veterans and the end‐stage renal disease management dilemma in the millennium
Authors: VACHHARAJANI Tushar J. , ATRAY Naveen K.
Published: October 2007

The population of aging veterans with complex multiple medical problems is increasing steadily in developed nations. The life expectancy in an aging population with end‐stage renal disease (ESRD) is often compared with terminal malignancy. Renal failure in elderly patients often generates a myriad of complicated issues and the nephrologists are faced with the dilemma of conveying the prognosis of renal failure in elderly patients and also explain the pros and cons of offering a renal replacement therapy. Our objectives were to assess the cumulative survival in veterans with ESRD over 70 years of age and to evaluate the factors considered for either not initiating or withdrawing from dialysis. All veterans above age 70 years, who were being evaluated for possible dialysis therapy over a 5‐year period, were included in the study. The cumulative survival rates at 1 year, 3 years and 5 years were 60%, 37%, and 20%, respectively. Tunneled cuffed catheter was the dialysis access in a third of these patients on dialysis adding to the morbidity. Twenty‐four patients considered either not initiating or withdrawing from dialysis therapy after consensus agreement from either the patient or the power of attorney. The decision to initiate dialysis therapy should be made considering the social, ethical, and associated comorbid conditions. A decision to not initiate or withdraw dialysis is possible in critically ill elderly patients and if taken judiciously can reduce physical and mental stress of both the patient and their family members.