bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is PPARG the key gene in diabetic retinopathy?
Authors: Costa Valerio , Ciccodicola Alfredo 
Published: April 2011

Diabetic retinopathy, a microvascular complication of diabetes mellitus, is major cause of non‐inherited blindness among adults. Although diabetic retinopathy is a common complication of diabetes, we still know little about the underlying molecular mechanisms. In recent years, complex connections between important molecules and pathways in the onset and progression of diabetic retinopathy, such as advanced glycation end products, oxidative stress and inflammation, have been elucidated. Biochemical, genetic and functional studies strongly indicate peroxisome proliferator‐activated receptor‐γ (PPARγ), a pleiotropic transcription factor, as a primary target in the treatment of diabetic retinopathy. In this issue, Song et al. detail the role of PPARγ in diabetic retinopathy‐related disorders, illustrating PPARγ‐mediated inhibition of diabetes‐induced leukostasis and leakage, and its beneficial role in modulating inflammation, angiogenesis and apoptosis in retinal and endothelial cells. Moreover, they describe alternative treatments for diabetic retinopathy, such as plant‐derived PPARγ ligands, proposing their use – in combination with standard therapies – for modulation of diabetic retinopathy.LINKED ARTICLE This article is a commentary on Song et al., pp. 4–19 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476‐5381.2011.01411.x
Generating Radiofrequency Ablation Lesions Using Magnetically Coupled Bipolar Catheters
Authors: LEE CHOONGHEE , CHOI EUE‐KEUN , KONG HYOUN‐JOONG , CHOY YOUNG BIN , KIM HEE CHAN , OH SEIL 
Published: April 2011

Background:
Transmural lesions are difficult to produce in myocardial regions with thick walls, such as the left ventricle (LV), using conventional radiofrequency (RF) ablation catheters. This study was performed to evaluate the efficacy of magnetically coupled bipolar catheters and compare the performance with conventional unipolar and bipolar RF ablation catheters.
Methods and Results:
Neodymium magnets assembled in ablation catheters were used to facilitate tissue contact in a bipolar RF ablation system. In vitro sheets of porcine skeletal muscle, with 10‐mm thickness, were ablated with a 4‐mm‐tip unipolar RF ablation catheter (UA), a bipolar ablation system (BA) using a pair of 4‐mm‐tip catheters, and a magnetically coupled bipolar system (MB). The RF generator setting was 50 W and 90°C. RF energy was delivered for 30 or 60 seconds and five lesions were created in each ablation condition. The bottom side of the skeletal‐muscle sheet was exposed to saline at 37°C and a flow of 5.6 L/min, mimicking the LV endocardial surface. The top side was exposed to air, mimicking the epicardial surface. In the 60‐second ablation cases, the transmuralities were 0%, 0%, and 40% (UA, BA, and MB, respectively). The volumes of the lesions were 61.5 ± 8.5, 224.3 ± 51.8, and 359.3 ± 93.8 mm3 (UA, BA, and MB, respectively).
Conclusions:
The magnetically coupled bipolar RF ablation system created transmural lesions more efficiently than the conventional ablation system, primarily due to higher RF current density and stronger tissue contact. This prototype method could be applied to the development of novel ablation devices for thick areas of tissue. (PACE 2011; 34:934–938)
Complex Fractionated Atrial Electrogram or Linear Ablation in Patients with Persistent Atrial Fibrillation—A Prospective Randomized Study
Authors: ESTNER HEIDI L. , HESSLING GABRIELE , BIEGLER ROMAN , SCHREIECK JUERGEN , FICHTNER STEPHANIE , WU JINJIN , JILEK CLEMENS , ZRENNER BERNHARD , NDREPEPA GJIN , SCHMITT CLAUS , DEISENHOFER ISABEL 
Published: April 2011

Background: Catheter ablation of complex fractionated atrial electrograms (CFAE) for persistent atrial fibrillation (AF) is a promising treatment strategy. We tested the hypothesis that CFAE ablation is superior to linear ablation in patients with persistent or long‐standing persistent AF.
Methods: In this study, 116 patients with persistent AF were randomly assigned to undergo circumferential PVI plus additional lines (linear ablation group; 59 patients) or CFAE ablation plus ostial pulmonary vein isolation (PVI) (spot ablation group; 57 patients). Primary endpoint was freedom from atrial tachyarrhythmia after a single ablation procedure (clinical and repeat 7‐day Holter), 12 months after ablation without antiarrhythmic medication.
Results: The primary endpoint was reached in 22 of 59 (37%) patients of the linear ablation group and in 22 of 57 (39%) patients of the spot ablation group (P = 0.9). Freedom from atrial tachyarrhythmias, including reablations, was achieved in 54% of patients (linear ablation group) versus 56% of patients (spot ablation group; P = 0.8). The incidence of recurrent persistent AF was higher after linear ablation than after spot ablation (21/37 vs 11/35 patients; P = 0.03); atrial tachycardia (AT) was seen more often after spot ablation (10/35 vs 4/37 patients; P = 0.03).
Conclusion: In patients with persistent AF, CFAE ablation plus PVI reaches the same results as circumferential PVI plus lines, in terms of freedom from symptomatic atrial tachyarrhythmias within the first year after a single ablation procedure. Arrhythmia recurrences in patients after spot ablation were caused more often by AT, whereas recurrent persistent AF was more prevalent after the linear ablation approach. (PACE 2011; 34:939–948)
T‐Wave Alternans Testing in Pacemaker Patients: Comparison of Pacing Modes and Long‐Term Prognostic Relevance
Authors: DORENKAMP MARC , BREITWIESER CHRISTOPH , MORGUET ANDREAS J. , SEEGERS JOACHIM , BEHRENS STEFFEN , ZABEL MARKUS 
Published: April 2011

Background: T‐wave alternans (TWA) is a useful method for identifying patients who are at risk for sudden cardiac death. We aimed to determine the effects of different pacing modes on test results and long‐term prognostic relevance of TWA in patients following a dual‐chamber (DDD) pacemaker implantation.
Methods: Sixty‐three patients (mean age 68 ± 13 years) with structural heart disease and recently implanted DDD pacemakers were enrolled. Left ventricular (LV) function was normal or moderately impaired (mean LV ejection fraction 61 ± 13%). All patients underwent sequential TWA testing using atrial and ventricular pacing.
Results: During atrial pacing requiring physiologic conduction to the ventricles, 21% of TWA tests were positive, 43% negative, and 36% indeterminate. When using right ventricular (RV) pacing in the same patients, 19% of tests were positive, 40% negative, and 41% indeterminate. When positive and indeterminate tests were grouped as nonnegative, the concordance between atrial and ventricular pacing was 62% (κ= 0.22). After a mean follow‐up of 5.9 ± 1.9 years, 18 (29%) patients had died. Improved survival was predicted by a negative TWA test using atrial pacing (P = 0.028), but not with ventricular pacing (P = 0.722).
Conclusions: In patients with dual‐chamber pacemakers, there is a low concordance of TWA test results between atrial pacing with intrinsic conduction to the ventricles and apical RV pacing via pacemaker electrode. However, TWA during atrial pacing clearly exerts long‐term prognostic relevance in a patient group with preserved LV function and structural heart disease. (PACE 2011; 34:1054–1062)
Reliability of Ultra‐Short ECG Indices for Heart Rate Variability
Authors: Nussinovitch Udi , Elishkevitz Keren Politi , Katz Keren , Nussinovitch Moshe , Segev Shlomo , Volovitz Benjamin , Nussinovitch Naomi 
Published: April 2011

Background: Heart rate variability (HRV) is an accepted and reliable means for assessing autonomic nervous system dysfunction. A 5‐minute measurement of HRV is considered methodologically adequate. Several studies have attempted to use shorter recordings of 1–2 minutes or 10 seconds. The aim of this study was to determine the reliability of HRV parameters calculated from ultra‐short electrocardiogram recordings. Methods: Seventy healthy volunteers were recruited for the study. HRV was evaluated for 5 minutes according to accepted procedures. Thereafter, HRV parameters were recalculated from randomly selected 1‐minute and 10‐second intervals. The standard and ultra‐short measurements were correlated using intraclass correlation coefficients. Results: Good correlations between the 5‐minute electrocardiograms (ECGs) and both the 1‐minute and 10‐second ECGs were noted for average RR interval, and root mean square of successive differences in RR intervals (RMSSD). No correlation was noted for standard deviation of the RR interval (SDNN) and several other HRV parameters. Conclusions: RMSSD, but not SDNN, seem a reliable parameter for assessing HRV from ultra‐short (1 minute or 10 seconds) resting electrocardiographic recordings. Power spectral analysis and evaluation of other HRV parameters require longer recording periods. Further research is required to evaluate the importance of ultra‐short RMSSD for cardiovascular risk stratification. Ann Noninvasive Electrocardiol 2011;16(2):117–122
Patient with Syncope and LQTS Carrying a Mutation in the PAS Domain of the hERG1 Channel
Authors: Grilo Liliana Sintra , Schläpfer Jürg , Fellmann Florence , Abriel Hugues 
Published: April 2011

We report the case of a woman with syncope and persistently prolonged QTc interval. Screening of congenital long QT syndrome (LQTS) genes revealed that she was a heterozygous carrier of a novel KCNH2 mutation, c.G238C. Electrophysiological and biochemical characterizations unveiled the pathogenicity of this new mutation, displaying a 2‐fold reduction in protein expression and current density due to a maturation/trafficking‐deficient mechanism. The patient's phenotype can be fully explained by this observation. This study illustrates the importance of performing genetic analyses and mutation characterization when there is a suspicion of congenital LQTS. Identifying mutations in the PAS domain or other domains of the hERG1 channel and understanding their effect may provide more focused and mutation‐specific risk assessment in this population. Ann Noninvasive Electrocardiol 2011;16(2):213–218
Effects of Postectopic Heart Rate Turbulence on Measures of Heart Rate Variability in Patients after an Acute Myocardial Infarction
Authors: Peltola Mirja A. , Bloch Thomsen Poul Erik , Joergensen Rikke Moerch , Huikuri Heikki V. 
Published: April 2011

Background: Heart rate (HR) turbulence lasting up to 15 beats after ventricular premature beats (VPBs) may have profound effects on HR variability measures. Aim of this study was to examine the effects of HR turbulence on HR variability measures. Methods: We developed an algorithm, which deletes 15 consecutive RR intervals after VPBs and examined the effects of the HR turbulence removal on the HR variability measures in patients after an acute myocardial infarction (AMI). Two hundred and sixty seven patients with left ventricular ejection fraction (LVEF) ≤ 0.40 and occurrence of VPBs were included in the study. Differences (%) between original HR data and HR turbulence edited data were compared. Results: HR turbulence editing had variable effects on different HR variability indexes. Ultra low (ULF) and very low frequency (VLF) spectral components were mostly affected by the HR turbulence removal. Both ULF and VLF decreased significantly both at baseline Holter recordings (ULF: P = 0.006, VLF: P = 0.031) and at 6 weeks from AMI (ULF: P < 0.001, VLF: P = 0.001). The number of VPBs had a marked influence on results, e.g., when the number of VPBs exceeded the highest decile (≈50 VPBs/hour), the ULF and VLF spectral component were >30% lower after removal of turbulence. In addition, the prediction of arrhythmic events by ULF component improved after turbulence removal (AUC: 0.69 ‐>0.74). Conclusions: HR turbulence affects HR variability measures, especially the ULF and VFL spectral components. Editing of the HR turbulence should be considered when HR variability is measured from Holter recordings. Ann Noninvasive Electrocardiol 2011;16(2):123–130
Importance of Tachogram Length and Period of Recording during Noninvasive Investigation of the Autonomic Nervous System
Authors: Grant Catharina C. , van Rensburg Dina C. J. , Strydom Nina , Viljoen Margaretha 
Published: April 2011

Background: Various disciplines use quantification of heart rate variability (HRV) as an indicator of autonomic function without recognizing the importance of using standardized methodologies. The aim of this study was to assess the influence of tachogram length and period of recording on HRV indicator values. Methods: To test the influence of the length of the recording time, HRV indicator values calculated from 180, 300, 420, and 600 seconds recording periods (supine and standing) were compared. Also individual 3‐ minute periods (0–180 seconds, 180–360 seconds, 360–540 seconds) from 10‐minute (supine and standing) tachograms were compared. Results: In the supine position, vagal‐efferent HRV indicators were not influenced by tachogram length varying between 3 and 10 minutes (P > 0.05). Supine HRV indicator values representing combined sympathetic and parasympathetic influences were tachogram length‐dependent (P < 0.05). During orthostatic stress all HRV indicators were tachogram length‐dependent (P < 0.05). Upon standing up marked vagal withdrawal and sympathetic activation occurred. Vagal withdrawal tapered off during the 3–6‐minute period after rising while indicators representing combined vagal and sympathetic activation were totally reversed. Conclusions: During application of orthostatic stress the exact starting point of recording, as well as the length of recording, is critical due to the activation and normalization of homeostatic mechanisms. Starting the tachogram recording too late will miss out on part of the initial response to change in body position. Longer recording times will give a combination of values recorded during the stress response and values obtained after stabilization in the standing position. Ann Noninvasive Electrocardiol 2011;16(2):131–139
Automated versus Manual Measurement of the QT Interval and Corrected QT Interval
Authors: Kasamaki Yuji , Ozawa Yukio , Ohta Masakatsu , Sezai Akira , Yamaki Takashi , Kaneko Mutsuo , Watanabe Ichiro , Hirayama Atsushi , Nakayama Tomohiro 
Published: April 2011

Background: The International Conference on Harmonization E14 Guideline specifies detailed assessment of QT interval or corrected QT interval prolongation when developing new drugs. We recently devised new software to precisely measure the QT interval. Methods and Results: The QT intervals of all leads for a selected single heart beat were compared between automated measurement with the new software from Fukuda Denshi and manual measurement. With both automated and manual measurement, QT intervals obtained by the tangent method were shorter than those obtained by the differential threshold method, but the extent of correction was smaller. QT interval data obtained by the differential threshold method were more similar to values obtained by visual measurement than were data obtained by the tangent method, but the extent of correction was larger. Variability was related to the T‐wave amplitude and to setting the baseline and tangent in the tangent method, while skeletal muscle potential noise affected the differential threshold method. Drift, low‐amplitude recordings, and T‐wave morphology were problems for both methods. Among the 12 leads, corrections were less frequent for leads II and V3–V6. Conclusion: We conclude that, for a thorough assessment of the QT/QTc interval, the tangent method or the differential threshold method appears to be suitable because of smaller interreader differences and better reproducibility. Correction of data should be done by readers who are experienced in measuring the QT interval. It is also important for electrocardiograms to have little noise and for a suitable heart rate and appropriate leads to be selected. Ann Noninvasive Electrocardiol 2011;16(2):156–164
Myocardial Scar in Sarcoidosis by 12‐lead ECG and Pathology
Authors: Strauss David G. , Selvester Ronald H. , DiBernardo Louis R. 
Published: April 2011

This case demonstrates the use of QRS scoring to quantify myocardial scar in a patient with cardiac sarcoidosis and left bundle branch block who progressively received an implantable defibrillator, cardiac resynchronization therapy (CRT), left ventricular assist device and cardiac transplantation. QRS scoring has been shown to correlate with magnetic resonance imaging measurements of scar, identify arrhythmogenic substrate and predict response to CRT, but had not previously been compared to pathology‐documented scar in nonischemic cardiomyopathies. Further study is warranted to assess the ability of QRS scoring to guide therapy for individual patients. Ann Noninvasive Electrocardiol 2011;16(2):219–222
Electrocardiographic Findings at Initial Diagnosis in Children with Isolated Left Ventricular Noncompaction
Authors: Ergul Yakup , Nisli Kemal , Varkal Muhammet Ali , Oner Naci , Dursun Memduh , Dindar Aygun , Aydogan Umrah , Omeroglu Rukiye Eker 
Published: April 2011

Background: The aim of this study was to comprehensively evaluate electrocardiographic (ECG) findings of isolated left ventricular noncompaction (IVNC) patients at initial diagnosis and to explore the correlation between them and the clinical, echocardiographic, and magnetic resonance imaging (MRI) findings. Methods: Twenty‐three patients diagnosed with IVNC by echocardiography and cardiac MRI between January 2006 and June 2010 were enrolled in this study. The patients were examined with standard ECG and 24‐hour Holter ECG. For comparison purpose, ECGs of 50 healthy children of similar ages and demographic characteristics were taken. Results: In 87% of patients, ECG abnormalities were found. The most frequently seen ECG findings were left ventricular hypertrophy, ST‐segment depression, and negative T wave related to abnormal repolarization particularly in DII, DIII, and V4–6 leads, as well as prolonged PR and QTc intervals. No ECG features or patterns were found that were specific to the disease. In contrast to adult patients, while no intraventricular conduction defects (particularly in the left bundle brach) were found in any of our patients, 13% had considerable bradycardia and one required a pacemaker. The Holter ECG recordings showed supraventricular tachycardia attacks in two patients and a short ventricular tachycardia attack in one. Patients whose echocardiograms and MRI showed left ventricular systolic dysfunction and left ventricular dilatation had signs of left ventricular hypertrophy and repolarization abnormality on their ECGs, but there was no significant difference in PR, QRS, and QTc intervals. Conclusion: Regardless of how frequently left ventricular hypertrophy and repolarization abnormalities are found on IVNC patients’ initial ECGs, we think that they are not unique to the disease but are related to the severity of the cardiomyopathy. Ann Noninvasive Electrocardiol 2011;16(2):184–191
Clinical Aspects of the Early Repolarization Syndrome: A 2011 Update
Authors: Stern Shlomo 
Published: April 2011

Recent studies suggest that the electrocardiographic (ECG) finding of J‐point ST‐elevation, the early repolarization syndrome, is not as benign as earlier believed. Three important articles published in 2008/2009 suggest that this finding in the inferolateral leads of the ECG may be representing a risk for subsequent ventricular fibrillation. Although these retrospective studies do justify a careful evaluation of persons with this electrocardiographic pattern, especially of those with syncope or ventricular arrhythmias and/or family history of sudden cardiac death, it seems to be unjustified to consider it today to be a marker for high risk for sudden cardiac deaths in a general population. Even in athletes, early repolarization was found to increase only minimally their arrhythmic risk. In spite of certain similarities with the Brugada syndrome, their association is far from being proved. Prospective studies and further electrophysiological and genetic information will help to clarify the clinical significance of this syndrome. Ann Noninvasive Electrocardiol 2011;16(2):192–195
Comparison of Chronic Biphasic Pacing versus Cathodal Pacing of the Right Ventricle on Left Ventricular Function in Sheep after Myocardial Infarction
Authors: Mower Morton M. , Hepp Dennis , Hall Ralph 
Published: April 2011

Background: The physiological effects of biphasic pacing have not been studied in compromised hearts. Methods: Myocardial infarction was induced in 12 sheep by high coronary artery ligation. Perioperative mortality was 33%. The surviving eight animals exhibited increased left ventricular volume and reduced percent fractional shortening. Two weeks after the infarction, sheep were implanted with atrial‐triggered, right ventricular pacemaker systems capable of pacing with cathodal (cathodal pulse) and biphasic (anodal pulse followed by cathodal pulse) waveforms, and randomly assigned to an initial mode. At 3‐month intervals, or whenever pacing was lost for any reason, the pacing system was switched to the alternative mode. Cardiac function was assessed at 2‐ to 3‐week intervals through the use of echocardiograms. Successful pacing was confirmed over an average of 8 weeks in each mode. Results: Cathodal pulsing had neither beneficial nor deleterious effect on the diminished cardiac performance induced by myocardial infarction. When compared to the cathodal mode, biphasic pulsing improved cardiac performance as reflected by decrease of diastolic and systolic ventricular volumes, reduction in left ventricular systolic diameter, and increases in percent fractional shortening. When compared to the unpaced state after the myocardial infarction, the percent fractional shortening was significantly increased by biphasic pacing. Concordant trends in improvement in the other cardiac parameters were also observed for the biphasic mode. No ventricular tachyarrhythmias or mortality was associated with biphasic stimulation. Conclusion: When compared to cathodal pacing, myocardial biphasic pacing has no safety issues in sheep that have undergone a large myocardial infarction. Importantly, biphasic pulsing elicited significant benefits in cardiac performance. Ann Noninvasive Electrocardiol 2011;16(2):111–116
Application of uterine compression suture in association with intrauterine balloon tamponade (‘uterine sandwich’) for postpartum hemorrhage
Authors: YOONG WAI , RIDOUT ALEXANDRA , MEMTSA MARIA , STAVROULIS ANDREAS , AREF‐ADIB MERNOOSH , RAMSAY‐MARCELLE ZEUDI , FAKOKUNDE ABIODUN 
Published: April 2011

AbstractWe evaluated in a prospective observational study the use of a ‘uterine sandwich’ technique (uterine compression sutures in association with intrauterine tamponade) in women who had had unsuccessful medical treatment for postpartum hemorrhage. Ten of the 11 patients had cesarean sections (complicated by placenta previa and uterine atony) and one had a normal delivery. The median estimated blood loss and units of blood transfused were 1500ml (range 750–4000ml) and two units (range 0–9), respectively. B‐Lynch sutures were placed in two patients and Hayman's modification was used in nine. Bakri balloon tamponade was in place for a median of 22hours (range 17–27hours), while the median volume infused in the balloon was 300ml (range 150–350ml). The combined technique was successful in avoiding hysterectomy in all cases, and there was no documented postpartum morbidity. This is a simple and quick surgical technique that can be used to treat atonic postpartum hemorrhage, particularly in conjunction with placenta previa.