bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decrease in Patient Radiation Exposure by a Tantalum Filter during Electrophysiological Procedures
Authors: ROSSI PIER LUCA , MARISELLI MATTEO , CORAZZA IVAN , BIANCHINI DAVID , BIFFI MAURO , MARTIGNANI CRISTIAN , ZANNOLI ROMANO , BORIANI GIUSEPPE 
Published: February 2009

Aim: Minimization of X‐ray exposure remains a primary issue in cardiac electrophysiology. The effectiveness of X‐ray beam filtration during cardiac electrophysiological procedures was therefore studied, using a 0.05‐mm‐thick tantalum (Ta) foil, as a filter on the primary X‐ray beam, to reduce the patient dose without degradation of image quality.
Method: Preliminary tests were made on a phantom developed with polymethylmethacrylate, catheters, and guide wires. The filter was then used in patients during cardiac procedures. Identical patient images were obtained with and without the Ta filter insertion and the ratio between image quality and patient dose was evaluated. Changes in patient dose and signal‐to‐noise ratio, as image quality index were measured on the phantom and in patients.
Results and Conclusions: When the Ta filter was used, the mean effective individual patient dose decreased by 3 to 40% (mean reduction = 27%), with no perceivable difference in image quality estimated by electrophysiologists. This Ta filter may be useful to limit the radiation exposure of patients and operators during cardiac procedures.
Variable Effects of Physical Training of Heart Rate Variability, Heart Rate Recovery, and Heart Rate Turbulence in Chronic Heart Failure
Authors: PIOTROWICZ EWA , BARANOWSKI RAFAŁ , PIOTROWSKA MAŁGORZATA , ZIELIŃSKI TOMASZ , PIOTROWICZ RYSZARD 
Published: February 2009

Background: Heart rate variability (HRV), heart rate turbulence (HRT), and heart rate recovery (HRR), indices that reflect autonomic nervous system (ANS) activity, are outcome predictors in patients with chronic heart failure (CHF). It is not clear, however, whether they reflect the same components of ANS activity. No study has examined the effects of physical training (PT) training on HRV, HRT, and HRR in CHF.
Study Objective: To examine the responses of HRV, HRT, and HRR to a PT program in patients presenting with CHF.
Methods: In 41 patients (mean age = 58.7 ± 10.2 years) in New York Heart Association CHF functional classes II or III, and with a left ventricular ejection fraction <40%, HRV, HRT, and HRR were measured before and after 8 weeks of PT.
Results: The training was clinically effective in all patients. Before versus after PT, standard deviation of all normal RR intervals increased from 107 ± 30 to 114 ± 32 ms (P = 0.047), high frequency increased from 210 ± 227 to 414 ± 586 ms2/Hz (P = 0.02), and the low/high frequency ratio decreased from 1.8 ± 1.55 to 1.1 ± 1.2 (P = 0.002). HRT and HRR did not change significantly after PT.
Conclusions: In patients with CHF, the positive effects of PT were limited to HRV indices, which reflect parasympathetic activity, without significantly changing HRR and HRT. These observations indicate that different mechanisms modulate HRV, HRR, and HRT, which provide complementary information regarding ANS activity. The 8‐week PT program failed to completely normalize ANS function.
Cavotricuspid Isthmus Ablation with Large‐Tip Gold Alloy Versus Platinum‐Iridium‐Tip Electrode Catheters
Authors: KARDOS ATTILA , FOLDESI CSABA , MIHALCZ ATTILA , SZILI‐TOROK TAMAS 
Published: February 2009

Background: Gold has excellent electrical conductive properties and creates deeper and wider lesions than platinum‐iridium during radiofrequency (RF) ablation in vitro. We tested the maximum voltage‐guided technique (MVGT) of cavotricuspid isthmus (CTI) ablation using two 8‐mm tip catheters containing gold (group G) or platinum‐iridium (group PI).
Methods: We enrolled 31 patients who underwent CTI ablation. In group G (n = 15) CTI ablation was performed with a gold‐tip ablation catheter, while in group PI (n = 16) a platinum‐iridium tip was used. Ablation was guided by CTI potentials with the highest amplitude until achievement of bidirectional block (BIB). If BIB was not achieved after 10 RF applications, RF was delivered via a 3.5‐mm irrigated‐tip catheter. Success rate, procedure duration, duration of fluoroscopic exposure, and number of RF applications were measured.
Results: BIB was achieved in all patients in group G, while in group PI an irrigated tip was used in four patients (0% vs 25%, P < 0.001). These four patients required a total of 21 additional RF applications (5.25 ± 2.22). Procedure time (56.4 ± 12 vs 73.1 ± 15 minutes P < 0.05) and fluoroscopic explosure (4.9 ± 2.3 vs 7.1 ± 3.8 minutes, P < 0.01) were shorter in group G than in group PI. Mean number of RF applications was lower (4.6 ± 1.9 vs 6.6 ± 3.1 P < 0.001) and total RF duration shorter (280 ± 117 vs 480 ± 310 seconds) in group G than in group PI. No difference was observed in the number of recurrences at a 6 month‐follow up (1 in group G vs 1 in group PI).
Conclusion: Using the MVGT of CTI ablation, gold‐tip catheters were associated with shorter procedural and fluoroscopic times, and fewer RF applications.
Diabetes Does Not Affect Ventricular Repolarization and Sudden Cardiac Death Risk in Patients with Dilated Cardiomyopathy
Authors: VRTOVEC BOJAN , FISTER MISA , POGLAJEN GREGOR , STARC VITO , HADDAD FRANCOIS 
Published: February 2009

Background: We studied the effects of diabetes on ventricular repolarization parameters and sudden cardiac death in patients with dilated cardiomyopathy (DCM).
Methods: We enrolled 132 consecutive patients in New York Heart Association (NYHA) heart failure functional classes II or III and left ventricular ejection fraction <40% without evidence of coronary artery disease. In 45 patients (34%), diabetes was diagnosed according to standard criteria (study group), and the remaining 87 (66%) had no diabetes (controls). All patients underwent a 5‐minute high‐resolution electrocardiogram recording for determination of QT variability (QTV) index and were followed for 1 year thereafter.
Results: At baseline, the two groups did not differ in age, gender, left ventricular ejection fraction, NYHA functional class, or plasma brain natriuretic peptide levels. Similarly, QTV index did not differ between the study group (−0.51 ± 0.55) and controls (−0.48 ± 0.51; P = 0.48). During follow‐up, 18 patients (14%) died of cardiac causes. Of the 18 deaths, eight were attributed to heart failure, and 10 to sudden cardiac death. Mortality was higher in the study group (10/45, 20%) than in controls (8/87, 10%) (P = 0.03). The same was true of the heart failure mortality (6/45 [13%] vs 2/87 [2%], P = 0.01), but not of the sudden cardiac death rate (3/45 [7%] vs 7/87 [8%], P = 0.78). By multiple variable analyses, diabetes predicted total and heart failure mortality, and a high QTV predicted sudden cardiac death.
Conclusions: Diabetes appears to increase the risk of heart failure in patients with DCM without affecting ventricular repolarization parameters and sudden cardiac death risk.
Gender Effects on Novel Time Domain Parameters of Ventricular Repolarization Inhomogeneity
Authors: KRAUSS THOMAS TIMOTHY , MÄUSER WANDA , REPPEL MICHAEL , SCHUNKERT HERIBERT , BONNEMEIER HENDRIK 
Published: February 2009

Introduction: Parameters of ventricular repolarization variability are increasingly being used in an attempt to understand better and predict the occurrence of ventricular tachycardia. Nevertheless, some of the measures used have thus far not been analyzed regarding gender differences in a large group of healthy subjects. Furthermore, new parameters might give further insight.
Methods and Results: We investigated 139 healthy volunteers (mean age 41.6 ± 15.3 years, range 20–77, median 40.0 years, 76 women) without evidence of organic cardiac disease. Mean RR interval and established time domain parameters of heart rate variability (rMSSD; SDNN) were measured for each subject. Beat‐to‐beat QT interval and time‐domain QT interval variability were analyzed. Characteristics of the QT interval and QT interval variability were determined as hourly mean values. The standard deviation of all QT intervals/hour (SDQT) and the standard deviation of all QTc intervals/hour (SDQTc) were used to measure QT interval variability. Four novel ratios of repolarization inhomogeneity (VRI: SDQT/SDNN; VR II: SDQT/rMSSD; VR III: SDQTc/SDNN; VR IV: SDQTc/rMSSD) were introduced. Female subjects exhibited significantly higher values in all four ratios of variability.
Conclusion: The obvious gender differences in repolarization inhomogeneity found in this study might be valuable in better understanding differences between men and women in the genesis of ventricular tachycardia.
Cardiac Resynchronization Therapy in Patients with Mildly Impaired Left Ventricular Function
Authors: FOLEY PAUL W.X. , STEGEMANN BERTHOLD , SMITH RUSSELL E.A. , SANDERSON‡ JOHN E. , LEYVA FRANCISCO 
Published: February 2009

Aims: We sought to determine the unknown effects of cardiac resynchronization therapy (CRT) in patients with a left ventricular ejection fraction (LVEF) >35%. Because of its technical limitations, echocardiography (Echo) may underestimate LVEF, compared with cardiovascular magnetic resonance (CMR).
Methods: Of 157 patients undergoing CRT (New York Heart Association [NYHA] functional class III or IV, QRS ≥ 120 ms), all of whom had a preimplant Echo‐LVEF ≤35%, 130 had a CMR‐LVEF ≤35% (Group A, 19.7 ± 7.0%[mean ± standard deviation]) and 27 had a CMR‐LVEF >35% (Group B, 43.6 ± 7.7%). All patients underwent a CMR scan at baseline and a clinical evaluation, including a 6‐minute walk test and a quality of life questionnaire, at baseline and after CRT.
Results: Both groups derived similar improvements in NYHA functional class (A =−1.3, B =−1.2, [mean]), quality of life scores (A =−21.6, B =−33.0; all P < 0.0001 for changes from baseline), and 6‐minute walking distance (A = 64.5, B = 70.1 m; P < 0.001 and P < 0.0001, respectively). Symptomatic response rates (increase by ≥1 NYHA classes or 25% 6‐minute walking distance) were 79% in group A and 92% in group B. Over a maximum follow‐up period of 5.9 years for events, patients in group A were at a higher risk of death from any cause, hospitalization for major cardiovascular events (P = 0.0232), or cardiovascular death (P = 0.0411). There were borderline differences in the risk of death from any cause (P = 0.0664) and cardiovascular death or hospitalization for heart failure (P = 0.0526).
Conclusions: This observational study suggests that the benefits of CRT extend to patients with a LVEF > 35%.
Prevalence of Cancelled Shock Therapy and Relationship to Shock Delivery in Recipients of Implantable Cardioverter‐Defibrillators Assessed by Remote Monitoring
Authors: VARMA NIRAJ , JOHNSON MARK A. 
Published: February 2009

Background: Cancelled shock therapy (CxTx) may presage shock delivery and shorten battery longevity of implantable cardioverter‐defibrillators (ICDs). However, it is silent and has received little attention. Remote home monitoring (HM) with continuous surveillance and automatic daily data archiving allows investigation of CxTx.
Methods and Results: We retrospectively analyzed a database of 4,960 recipients of HM ICD, from 2002 to 2007. Over a mean follow‐up of 445 ± 253 days, CxTx occurred in 1,392 (28%) patients, mostly as single episodes (n = 1,120). However, 142 patients (10% of patients with CxTx, 2.9% of the whole ICD population) had >10 CxTx. CxTx was followed by shock delivery in 432 patients, in 239 (55%) of whom CxTx occurred >10 days prior to shock delivery. In 113 patients (26%), CxTx occurred in the 72‐hour period preceding the shock. A single CxTx preceded the shock in 74 of these 113 patients, and only eight patients had >3 CxTx.
Conclusion: CxTx was highly prevalent in unselected ICD recipients, though the intraindividual density of episodes was low. In 2.9% of the overall population, the number of CxTx was sufficient to shorten the battery longevity. A high number of CxTx usually did not predict the delivery of shocks.
Long‐Term Effects of Dynamic Atrial Overdrive Pacing on Sleep‐Related Breathing Disorders in Pacemaker or Cardioverter Defibrillator Recipients
Authors: SINHA ANIL‐MARTIN , BAUER ALEXANDER , SKOBEL ERIC C. , MARKUS KAI‐U , RITSCHER GUIDO , NOELKER GEORG , BREITHARDT OLE‐ALEXANDER , BRACHMANN JOHANNES , STELLBRINK CHRISTOPH 
Published: February 2009

Introduction: Sleep‐related breathing disorders occur in 20–30% of Europeans and North Americans, including 10% of sleep apnea syndrome (SAS). A preliminary study suggested that atrial overdrive pacing with a fixed heart rate might alleviate SAS. However, it is not known whether dynamic atrial overdrive pacing alleviates SAS.
Methods: Patients with indications for a dual chamber pacemaker or implantable cardioverter‐defibrillator (ICD) were screened for SAS using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. If PSQI was >5, cardio‐respiratory polygraphy was performed before and 4 and 7 months after device implantation. Patients were randomized to algorithm ON–OFF (group A) or OFF–ON (group B) and the apnea‐hypopnea index (AHI) was measured.
Results: Out of 105 consecutive patients, 46 (44%) had a positive PSQI. This analysis included 12 patients (mean age = 61 ± 10 years, body mass index 28.9 ± 6.5 kg/m2, left ventricular ejection fraction = 38.3 ± 13.6%; 10 men). All patients suffered from obstructive or mixed SAS. There were no significant differences in PSQI or AHI between baseline and follow‐up or between the two study groups. Therefore, the study was terminated ahead of schedule.
Conclusions: The prevalence of obstructive or mixed SAS was high in pacemaker or ICD recipients and reduced left ventricular ejection fraction. In these patients, long‐term dynamic atrial overdrive pacing using did not improve PSQI or SAS. Therefore, patients with relevant obstructive or mixed SAS should not be offered atrial pacing therapy.
Stepwise Evaluation of Unexplained Syncope in a Large Ambulatory Population
Authors: IGLESIAS JUAN F. , GRAF DENIS , FORCLAZ ANDREI , SCHLAEPFER JUERG , FROMER MARTIN , PRUVOT ETIENNE 
Published: February 2009

Background: Up to 60% of syncopal episodes remain unexplained. We report the results of a standardized, stepwise evaluation of patients referred to an ambulatory clinic for unexplained syncope.
Methods and Results: We studied 939 consecutive patients referred for unexplained syncope, who underwent a standardized evaluation, including history, physical examination, electrocardiogram, head‐up tilt testing (HUTT), carotid sinus massage (CSM) and hyperventilation testing (HYV). Echocardiogram and stress test were performed when underlying heart disease was initially suspected. Electrophysiological study (EPS) and implantable loop recorder (ILR) were used only in patients with underlying structural heart disease or major unexplained syncope. We identified a cause of syncope in 66% of patients, including 27% vasovagal, 14% psychogenic, 6% arrhythmias, and 6% hypotension. Noninvasive testing identified 92% and invasive testing an additional 8% of the causes. HUTT yielded 38%, CSM 28%, HYV 49%, EPS 22%, and ILR 56% of diagnoses. On average, patients with arrhythmic causes were older, had a lower functional capacity, longer P‐wave duration, and presented with fewer prodromes than patients with vasovagal or psychogenic syncope.
Conclusions: A standardized stepwise evaluation emphasizing noninvasive tests yielded 2/3 of causes in patients referred to an ambulatory clinic for unexplained syncope. Neurally mediated and psychogenic mechanisms were behind >50% of episodes, while cardiac arrhythmias were uncommon. Sudden syncope, particularly in older patients with functional limitations or a prolonged P‐wave, suggests an arrhythmic cause.
Impact of AV Conduction Disorders on SafeR Mode Performance
Authors: THIBAULT BERNARD , SIMPSON CHRISTOPHER , GAGNÉ CARL‐ÉRIC , BLIER LOUIS , SENARATNE MANOHARA , McNICOLL SERGE , STUGLIN CARLO , WILLIAMS RANDY , PINTER ARNOLD , KHAYKIN YAARIV , NITZSCHE REMI 
Published: February 2009

Purpose: CAN‐SAVE R is a Canadian multicenter study that compares the effects of a new pacing mode algorithm designed to minimize right ventricular (V) pacing versus DDD mode with a long atrioventricular (AV) delay in a general population of pacemaker (PM) recipients.
Study Participants: Patients with permanent atrial fibrillation (AF) or high‐degree AV block (AVB) were excluded. We present preliminary data collected in 208 patients (mean age=71 ± 11 years, 68% men), for the 2‐month baseline period during which all PM were programmed in the new pacing mode. The pacing indications were sinus node disease (SND) without AVB in 39%, AVB without SND in 30%, SND and AVB in 16%, and miscellaneous in 15% of patients.
Results: The mean percent V pacing in the overall population was 9.5 ± 23.8% (range=0–100%, median <1%), ranging between 0.5 ± 1.5% (median=0) in patients without AVB and 18.7 ± 31.2% in patients (median = 1) with AVB. Adverse events potentially related to the new pacing mode were observed in two patients with AVB.
Conclusions: A new pacing mode was effective and safe in a general population of PM recipients without permanent AVB and was associated with an overall <1% median V pacing. CAN‐SAVE R will compare the long‐term effects of the new pacing mode with DDD with a long AV delay on clinical outcomes and cardiac function.
Prevention of Venous Thrombosis by Warfarin after Permanent Transvenous Leads Implantation in High‐Risk Patients
Authors: COSTA ROBERTO , DA SILVA KÁTIA REGINA , RACHED ROBERTO , FILHO MARTINO MARTINELLI , CARNEVALE FRANCISCO CÉSAR , MOREIRA LUIZ FELIPE PINHO , STOLF NOEDIR ANTONIO GROPPO 
Published: February 2009

Background: The incidence of venous lesions following transvenous cardiac device implantation is high. Previous implantation of temporary leads ipsilateral to the permanent devices, and a depressed left ventricular ejection fraction have been associated with an increased risk of venous lesions, though the effects of preventive strategies remain controversial. This randomized trial examined the effects of warfarin in the prevention of these complications in high‐risk patients.
Method: Between February 2004 and September 2007, we studied 101 adults who underwent a first cardiac device implantation, and who had a left ventricular ejection fraction ≤0.40, or a temporary pacing system ipsilateral to the permanent implant, or both. After device implantation, the patients were randomly assigned to warfarin to a target international normalized ratio of 2.0–3.5, or to placebo. Clinical and laboratory evaluations were performed regularly up to 6 months postimplant. Venous lesions were detected at 6 months by digital subtraction venography.
Results: Venous obstructions of various degrees were observed in 46 of the 92 patients (50.0%) who underwent venography. The frequency of venous obstructions was 60.4% in the placebo, versus 38.6% in the warfarin group (P = 0.018), corresponding to an absolute risk reduction of 22% (relative risk = 0.63; 95% confidence interval = 0.013–0.42).
Conclusions: Warfarin prophylaxis lowered the frequency of venous lesions after transvenous devices implantation in high‐risk patients.
Early Conduction Disorders Following Percutaneous Aortic Valve Replacement
Authors: CALVI VALERIA , PUZZANGARA EUGLENA , PRUITI GIUSI PAOLA , CONTI SERGIO , DI GRAZIA ANGELO , USSIA GIAN PAOLO , CAPODANNO DAVIDE , TAMBURINO CORRADO 
Published: February 2009

Background: Percutaneous aortic valve replacement (PAVR) may be an alternative therapy for patients with severe aortic stenosis who are denied valve surgery because of age and comorbidity. Data are few regarding the incidence of early conduction disorders (CD) after PAVR. We examined the incidence and characteristics of CD in the immediate postoperative period after PAVR, and the need for permanent pacemaker (PPM) implantation.
Methods and Results: Between June 2007 and June 2008 30 patients (mean age = 82.1 ± 8.5 years) underwent PAVR in our institution. The incidence of new, postoperative CD, diagnosed by 12‐lead or 24‐hour Holter electrocardiogram, was 68.0%. Left bundle branch block was the most common conduction abnormality, with an incidence of 45.8%. The incidence of complete atrioventricular block requiring PPM implantation was 20%.
Conclusions: We observed a higher incidence of early conduction disorders and need for PPM implantation after PAVR than generally reported after surgery. Whether this observation is clinically important requires larger prospective studies and follow up.
Self‐reported occupational skin contact with cleaning agents and the risk of disability pension
Authors: Feveile Helene , Christensen Karl Bang , Flyvholm Mari‐Ann 
Published: February 2009

Background:  Occupational skin diseases often affect the hands and can lead to consequences at both the individual and the social level.Objectives:  To investigate and quantify the association between self‐reported occupational skin contact with cleaning agents and subsequent transition to disability pension.Methods:  A sample of 8337 employees between 18 and 59 years of age participated in the Danish Work Environment Cohort Study in 1990, 1995, or 2000. They were followed up regarding disability pension until 2006 using the DREAM register on social transfer payments for all inhabitants in Denmark. The Cox proportional hazards model was used to estimate the impact of occupational exposure to cleaning agents on subsequent disability pension.Results:  Among women, 11% of the disability pension cases were attributable to exposure to cleaning agents and/or disinfectants.Conclusions:  The study suggests a potential for prevention of work‐related disabilities among job groups exposed to cleaning agents.
Cobalt‐containing alloys and their ability to release cobalt and cause dermatitis
Authors: Julander Anneli , Hindsén Monica , Skare Lizbet , Lidén Carola 
Published: February 2009

Background:  Cobalt, nickel, and chromium are important skin sensitizers. However, knowledge about cobalt exposure and causes of cobalt sensitization is limited.Objectives:  To study release of cobalt, nickel, and chromium from some cobalt‐containing hard metal alloys and to test reactivity to the materials in cobalt‐sensitized patients.Methods:  Discs suitable for patch testing were made of some hard metal alloys. Cobalt, nickel, and chromium release from the materials was determined by immersion in artificial sweat (2 min, 1 hr, 1 day, and 1 week). Patch test reactivity to the discs and to serial dilutions of cobalt and nickel was assessed in previously patch‐tested dermatitis patients (19 cobalt positive and 18 cobalt‐negative controls).Results:  All discs released cobalt, nickel, and chromium. Some discs released large amounts of cobalt (highest concentration: 290 μg/cm2/week). Seven discs elicited three or more positive test reactions.Conclusions:  The concentration of released cobalt was high enough to elicit allergic contact dermatitis in cobalt‐sensitized patients. As the materials in the discs are used in wear parts of hard metal tools, individuals with contact allergy to cobalt may develop hand eczema when handling such materials.