bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporary Atrial Pacing in the Prevention of Postoperative Atrial Fibrillation
Authors: NETO VICENTE ÁVILA , COSTA ROBERTO , DA SILVA KÁTIA REGINA , MARTINS ANDRÉ LUIZ MENDES , ESCOBAR LUIZ FERNANDO , MOREIRA LUIZ FELIPE PINHO , COSTA REGINA VALÉRIA , SANTOS LETÍCIA BEZERRA , MELO RICARDO FERNANDES AZEVEDO 
Published: January 2007

Background: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG.
Methods: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event.
Results: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P=0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005–0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024–1.12) and no pacing as independent risk factors of postoperative AF.
Conclusions: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence.
Prevalence and Characteristics of Left Atrial Tachycardia Following Left Atrial Catheter Ablation
Authors: HASHIMOTO TORU , TADA HIROSHI , NAITO SHIGETO , MIYAJI KOHEI , YAMADA MINORU , TADOKORO KAZUYOSHI , KASENO KENICHI , OSHIMA SHIGERU , TANIGUCHI KOICHI 
Published: January 2007

Background: Left atrial tachycardia (AT) is a complication of left atrial catheter ablation (LACA) of atrial fibrillation (AF). However, its prevalence and characteristics have not been sufficiently clarified.
Methods: We divided 121 patients who underwent LACA into 2 groups based on the results of AT occurrence after LACA (follow‐up period; 12 ± 7 months): an AT+ group and AT– group.
Results: New‐onset left AT occurred in 30 patients (25%) 31 ± 51 days after LACA. Among the 26 patients with an early onset of AT, 4 underwent a second ablation for AT, and 21 became free of AT within 6 months without a repeat ablation procedure. Among the 4 patients with a late onset of AT (>2 months after the LACA), the tachycardia remitted without a repeat ablation procedure in a single patient within 6 months. Among 71 patients who underwent LACA with additional ablation lines, 22 (31%) developed new‐onset left AT. Among 50 patients who underwent LACA alone, 8 (16%) developed new‐onset left AT (P = 0.02).
Conclusions: New‐onset left AT is a frequent complication of LACA for AF, especially in men and in patients with a low left ventricular ejection fraction. Early (<2 months) onset AT does not require a repeat ablation because it often represents a transient phenomenon and disappears spontaneously.
Left Atrial Catheter Ablation Promotes Vasoconstriction of the Right Coronary Artery
Authors: YAMASHITA EIJI , TADA HIROSHI , TADOKORO KAZUYOSHI , HASHIMOTO TOHRU , KASENO KENICHI , MIYAJI KOHEI , NAITO SHIGETO , OSHIMA SHIGERU , TANIGUCHI KOICHI 
Published: January 2007

Background: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA.
Methods: We studied 20 patients with drug‐refractory AF who underwent LACA, performed to encircle the left‐ and right‐sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance. Quantitative coronary angiography was performed before and after LACA, and we analyzed the minimal lesion diameter (MLD) of the proximal segment of the coronary arteries, and the basal tone, the baseline percent constriction versus maximal dilation after nitroglycerin administration.
Results: No significant difference was observed in MLD or basal tone of the left coronary arteries after LACA. However, in the right coronary artery (RCA), the basal MLD was smaller (P < 0.01) and the basal tone was greater (P< 0.05) after than before LACA. No correlation was found between the baseline MLD or tone of the RCA and total amount of radiofrequency energy delivered or procedure duration. In 75% of RCA, the baseline MLD was smaller after than before LACA, which was significantly higher (P < 0.01) than observed in the left coronary arteries (38%).
Conclusion: Vasoconstriction was promoted in the RCA shortly after LACA, which may explain the variant angina reported after LACA.
Clinical Predictors of Appropriate Implantable‐Cardioverter Defibrillator Discharge
Authors: CATANZARO JOHN N. , MAKARYUS AMGAD N. , SISON CRISTINA , VAVASIS CHRISTOS , DONALDSON DAVID , BELDNER STUART , BOAL BERNARD , JADONATH RAM 
Published: January 2007

Background: The implantable cardioverter‐defibrillator (ICD) is the mainstay of treatment for ventricular tachyarrhythmias due to its impact on mortality. ICD discharges may be appropriate or inappropriate, and identification of patients at risk for ICD discharge is essential. We sought to determine the predictors of appropriate ICD discharge.
Methods: We analyzed data from 591 ICD recipients (mean age 67.9 ± 13.0 years; 474 men; mean follow‐up 10.9 ± 13.8 months). The association between ICD discharges and multiple clinical variables, including age, gender, hypertension, diabetes, coronary artery bypass graft (CABG) surgery, syncope, atrial fibrillation (AF), prior coronary intervention, left ventricular ejection fraction (LVEF), left ventricular end diastolic dimension, left ventricular end systolic dimension (LVESD), and ambient drug therapy was examined.
Results: The rates of appropriate or inappropriate discharges, delivered to 155 patients, were 0.49 per follow‐up year (F/Y). The median time‐to‐first appropriate discharge was 3.4 years. Among the discharges delivered, 97(63%) were appropriate and 58(37%) were inappropriate. Risk factors associated with a trend toward earlier appropriate discharges included age ≤65 years, and diuretic and digitalis use. By multiple variable analysis, no history of CABG and an enlarged LVESD were independent predictors of earlier appropriate ICD discharge.
Conclusions: Patients who did not have CABG revascularization were 2.8‐fold more likely than those who underwent CABG, and patients with enlarged LVESD were 2.5‐fold more likely than those with normal LVESD to receive appropriate ICD discharges. These patients deserve special vigilance and management in order to prevent the occurrence of ventricular tachyarrhythmias triggering ICD discharges.
A Comparison of ICD Implantations in the United States Versus Italy
Authors: GREENBERG STEVEN M. , EPSTEIN ANDREW E. , DEERING THOMAS , GOLDMAN DANIEL S. , GHIDINA MARCO , NEASON CURTIS , PROCLEMER ALESSANDRO 
Published: January 2007

Background: The benefits conferred by implantable cardioverter defibrillators (ICDs) have expanded to primary prevention. The advancements in ICD therapy (ACT) registry in the United States and the Italian ICD registry (IIR) examine changing trends in ICD implantation in their respective countries. Data from these registries may be useful for comparison of transcontinental differences in ICD utilization.
Methods: This study includes initial implantations in patients enrolled in ACT and IIR. A comparative analysis was performed for device indications based on primary or secondary prevention. Sub‐group analyses by device types (single, dual chamber, or cardiac resynchronization) were performed.
Results: This analysis included 4,547 primary implantations in ACT and 6,491 in IIR. The groups were similar with respect to age. There were 82% primary and 18% secondary prevention indications in ACT, versus 42% primary and 58% secondary prevention indications in IIR (P < 0.001). There was a significantly higher rate of dual chamber ICD implants in ACT than in IIR for both primary (35.7% vs 23.7%, P < 0.001) and secondary prevention (52.3% vs 36.9%, P < 0.001). Conversely, more CRT‐D were implanted in IIR than in ACT (primary prevention 46.5% vs 32.0%; secondary prevention 29.0% vs 13.0%, P < 0.001).
Conclusions: Significant differences were observed in the types of indications for ICDs between ACT and IIR. Device prescription differed significantly between countries. The specific reasons for differences in ICD implantation patterns in these two countries are unclear. These observations warrant further investigations to determine if these differences are associated with different qualities of life and clinical outcomes.
Left Atrial Remodeling: Assessment of Size and Shape to Detect Vulnerability to Atrial Fibrillation
Authors: COZMA DRAGOS , POPESCU BOGDAN A. , LIGHEZAN DAN , LUCIAN PETRESCU , MORNOS CRISTIAN , GINGHINA CARMEN , DRAGULESCU STEFAN‐IOSIF 
Published: January 2007

Background: The ellipse formula often underestimates left atrial (LA) dilation. Complete echocardiographic analysis of LA shape in relation to electrical remodeling has not been performed.
Aim of the Study: To analyze the relation between LA shape/surface and vulnerability to atrial fibrillation (AF).
Methods: We studied 112 patients aged 43 ± 16 years, and referred for electrophysiological study. LA surface (LAS) was measured at end‐systole (maximal). Trapezoidal LA shape was defined if the transverse dimension was less than the basal dimension. Decremental index (DI) was calculated as the maximal percentage prolongation of interatrial conduction time during atrial extrastimulation. The LA was considered vulnerable if AF was inducible. DI >50%, repetitive atrial activity, and fragmented electrograms defined susceptibility to vulnerability.
Results: LAS ranged between 10.5 and 36.6 cm2; 77 patients had a trapezoidal LA. By simple regression analysis LAS correlated with DI (r2= 0.38, P = 0.0001). LAS predicted susceptibility to vulnerability better than vulnerability to AF (area under the ROC curve: 0.93 vs 0.81). The best cut‐off value for LAS as predictor of susceptibility to vulnerability was 19.5 cm2 (sensitivity: 89%; specificity: 90.5%; positive predictive value: 93.4%; negative predictive value: 84.4%). Using LAS >25 cm2 as a cut‐off value, LA vulnerability to AF was detected with a sensitivity of 56.2% and a specificity of 95% (positive predictive value: 81.8%; negative predictive value: 83.3%). LA shape was trapezoidal in 72% patients with LAS >25 cm2 and in 30% patients with LAS <19.5 cm2 (P < 0.0001).
Conclusions: LA dilation and electrical remodeling are related. Progressive LA dilation is accompanied by shape remodeling. Appropriate characterization of LA remodeling should therefore include LAS measurement and LA shape assessment.
G‐CSF‐Induced Mobilization of CD34+ Progenitor Cells and Proarrhythmic Effects in Patients with Severe Coronary Artery Disease
Authors: WOLFRAM OLIVER , JENTSCH‐ULLRICH KATHLEEN , WAGNER ANDREA , HAMMWÖHNER MATTHIAS , STEINKE RAINER , FRANKE ASTRID , ZUPAN IGOR , KLEIN HELMUT U. , GOETTE ANDREAS 
Published: January 2007

Aim: Granulocyte colony stimulating factor (G‐CSF) therapy has been reported to be proarrhythmic. The in vivo mobilization of endothelial progenitor cells (EPCs) and the possible proarrhythmic effects in patients with severe coronary artery disease (CAD) and inducible ischemia have not been described.
Methods: We treated 8 patients (mean age = 69 ± 10) suffering from severe CAD and angina pectoris (CCS 3 ± 0.5) despite optimal medical therapy with subcutaneous G‐CSF over 7 days to mobilize EPCs (CD34+, CD117+). ECG monitoring was performed throughout the treatment period. A 24‐hour ECG was recorded before and after G‐CSF application. Mobilization of EPCs was monitored by fluorescent activated cell sorter (FACS‐Calibur®, Becton‐Dickinson, Franklin Lakes, NJ, USA) analysis. Other medications remained unchanged.
Results: G‐CSF therapy significantly increased peripheral leukocyte count from 7.45 ± 2.4 to a peak of 42.2 ± 10.9 × 103/μL with a parallel rise in CD34+ EPCs from 4.35 ± 1.94 to 33.0 ± 22.8/μL. The percentage of CD34+/CD117+ cells changed from 0.32 ± 0.25 to 0.24 ± 0.28% (day of discharge, P = ns). During continuous ECG monitoring, no significant bradycardia, tachycardia, or changes in conduction were observed. Holter data collected after 7 days of G‐CSF therapy showed no significant differences from baseline. A linear correlation (r = 0.76) was observed for the absolute values of ΔP wave duration and ΔCD34+ concentration on day 2 compared to follow‐up at 142 ± 33 days, though it did not reach statistical significance (P = 0.29).
Conclusion: This is the first study showing that mobilization of CD34+ EPCs is safe in patients with severe CAD. The accompanying leukocytosis did not appear proarrhythmic. Changes in P wave duration might be attributable to G‐CSF therapy.
Heart Rate Turbulence after Ventricular Pacing Trains During Programmed Ventricular Stimulation
Authors: HAVRANEK STEPAN , STOVICEK PETR , PSENICKA MIROSLAV , WICHTERLE DAN , LINHART ALES 
Published: January 2007

Background: This study tested the hypothesis that heart rate turbulence (HRT) following ventricular pacing trains depends on train cycle length, presence of retrograde ventriculoatrial (VA) conduction, and left ventricular (LV) function.
Methods: We analyzed digital recordings of programmed ventricular stimulation (PVS) performed in 82 patients (57 men) referred for electrophysiologic studies of ventricular arrhythmias, whose mean age was 64 ± 12 years and LV ejection fraction (EF) was 47 ± 15%. Profiles of sinus RR intervals after all available 8‐beat ventricular pacing trains (600‐and 400‐ms) were averaged. Heart rate turbulence slope (HRTS) was analyzed as the maximum positive slope of a regression line through a sequence of 2–5 (HRTS2 ‐ HRTS5) consecutive RR intervals within the first 5 RR intervals after the pacing train.
Results: Dynamics of RR intervals had biphasic and monophasic patterns, in patients with and without VA conduction, respectively. Sinus nodal response was less prominent after 600‐ms than 400‐ms pacing trains. After 400‐ms pacing trains, HRTS was significantly shallower in patients with LVEF ≤40% than in those with LVEF >40%. HRTS4 was the best discriminator between the two groups (6.8 ± 8.6 ms/RR vs 19.6 ± 26.0 ms/RR, P = 0.017).
Conclusion: In patients with VA conduction, HRT after ventricular pacing trains reflects a combination of vagal withdrawal due to transient hypotension and suppression of sinus node automaticity. Attenuation of vagal modulation was detected in patients with LV dysfunction during standard PVS.
Heart Rate Turbulence after Atrial Premature Complexes Depends on Coupling Interval and Atrioventricular Nodal Conduction
Authors: WICHTERLE DAN , BULKOVA VERONIKA , FIKAR MIROSLAV , HAVRANEK STEPAN , STOVICEK PETR 
Published: January 2007

Background: Positive Turbulence onset (TO) after atrial premature complexes (APCs) was found temporally related to spontaneous episodes of atrial fibrillation. This study tested the hypothesis that heart rate turbulence (HRT) after APCs is influenced by APC prematurity independently of the prematurity of conducted ventricular complexes.
Methods: We studied 33 patients (mean age = 58 ± 16 years, 19 men), 11 of whom had structural heart disease, who were referred for electrophysiological studies of supraventricular or ventricular arrhythmias. Sequences of single right atrial extrastimuli were delivered with coupling intervals adjusted to reach 60% prematurity of conducted ventricular complexes. Descriptors of HRT were compared between patients with slow versus fast atrioventricular (AV) conduction of APCs.
Results: The early RR interval dynamics after APCs was prominently modulated by the suppression of sinus node automaticity by the direct effect of APCs. This effect was significantly greater after earlier APCs with longer AV conduction times than after later coupled APCs with shorter AV conduction times.
Conclusions: The early phase of HRT is strongly influenced by the coupling interval of APCs, independently of the prematurity of conducted ventricular complexes. Consequently, the more positive TO preceding spontaneous atrial fibrillation episodes might be an epiphenomenon of incidental short‐coupled APCs with delayed AV conduction, likely to trigger atrial fibrillation.
Ventricular Repolarization Dynamics During Different Sleep Stages in the Subacute Phase of Myocardial Infarction
Authors: BONNEMEIER HENDRIK , NÖTGES JANA K. , MAJUNKE BENINA , STRASSBURG ALAN , ORTAK JASMIN , KOTHE HENNING , WEITZ GUNTHER , SCHUNKERT HERIBERT 
Published: January 2007

Background: Ventricular arrhythmias after myocardial infarction (MI) are often nocturnal. However, the arrhythmogenic effects of sleep after MI are unknown. We examined the effects of sleep stages on QT dynamicity and tested the hypothesis of a differential effect of sleep stage on the QT/RR relationship after recent MI, versus in healthy controls (HC).
Methods: Polysomnography and electrocardiograms were simultaneously recorded in 21 men in the subacute phase of a first uncomplicated MI, and in 10 age‐matched, male HC. QT dynamicity (QT/RR slope) and parameters of QT interval were measured during wakefulness, stages 1–4 of nonrapid eye movement (non‐REM) sleep, and REM sleep.
Results: Mean QT and RR intervals increased through all sleep stages in both MI survivors and HC. The Bazett‐corrected QT interval remained stable from wakefulness throughout all sleep stages. QT/RR slopes remained stable from wakefulness to stage 3 in both groups. However, unlike in MI survivors, the QT/RR slopes decreased and remained significantly lower during deep sleep and REM sleep in HC.
Conclusion: An abnormal QT/RR relationship in deep sleep and REM sleep was observed after a recent MI, reflecting an insufficient shortening of ventricular repolarization with increasing heart rates, which might have important implications in the nocturnal distribution of ventricular arrhythmias after MI.
Effects of Aging on Reflex Autonomic Nervous Response Induced by Orthostatic Maneuvers
Authors: BARANTKE MELANIE , ORTAK JASMIN , LIEB WOLFGANG , WILKE IRIS K. , SCHUNKERT HERIBERT , BONNEMEIER HENDRIK 
Published: January 2007

Background: Baroreflex sensitivity (BRS), exercise pressor reflex (EPR), and aging influence the autonomic nervous response associated with orthostatic maneuvers. Standing significantly increases heart rate (HR), with an initial increase (1.ΔHR) due to EPR and a secondary, more gradual increase (2.ΔHR) due to BRS. HR then decreases (3.ΔHR), which is also attributable to BRS. Thus far, however, few data are available regarding the interdependence of these variables.
Methods and Results: Ninety‐five healthy volunteers (mean age 37 ± 11 years, range 10–70 years; 50 women) underwent continuous noninvasive measurements of beat‐to‐beat blood pressure, HR, and spontaneous BRS in the supine (10 minutes) and upright (10 minutes) positions. After tilt, 1.ΔHR, 2.ΔHR, and 3.ΔHR were calculated from the HR recording. From the 1st to the 6th decade BRS, 2.ΔHR and 3.ΔHR decreased with normal aging ([BRS 11.88 ± 7.97 ms/mmHg to 1.81 ms/mmHg, P = 0.006], 2.ΔHR [16.75 ± 3.40 beats to 5.33 ± 2.52 beats, P = 0.002], 3.ΔHR [52.25 ± 5.91 beats to 11.33 ± 4.04 beats, P < 0.001]). However, no such association was noted between 1.ΔHR and age (21.25 ± 9.35 beats to 12.00 ± 7.21 beats, ns). BRS while standing was correlated with 1.ΔHR (r = 0.432, P < 0.001).
Conclusions: EPR, in contrast to BRS, was not significantly influenced by normal aging. Furthermore, not only was BRS influenced by EPR, as is generally acknowledged, but EPR and BRS were interrelated. These observations offer new insights into the complex interactions of orthostasis‐induced physiological autonomic reflexes associated with normal aging.
Modulation of Cardiac Autonomic Nervous Activity Early after Cardioversion of Atrial Fibrillation by Biphasic Waveform
Authors: ORTAK JASMIN , KURTZ FRANZISKA , KRENZIEN ANN‐SOPHIE , JANCA NINA , WILKE IRIS , BARANTKE MELANIE , EBERHARDT FRANK , WIEGAND UWE K.H. , SCHUNKERT HERIBERT , BONNEMEIER HENDRIK 
Published: January 2007

Background: Imbalance of cardiac autonomic nervous modulation might prominently contribute to early relapses of atrial fibrillation (AF) after cardioversion (CV). The biphasic (Bi) waveform is more effective than the monophasic (Mo) waveform in CV of AF. Whether these waveforms have different effects on autonomic modulation early after CV is unknown.
Methods: We investigated 171 consecutive patients after successful electrical CV (mean age 65.4 years, 82% male, 80% structural heart disease). Bi waveform was used in 89, Mo waveform in 82. Heart rate variability (HRV) was analyzed from 24‐hour Holter recordings, started directly after CV.
Results: Mean delivered total energy was significantly lower in the Bi group (Bi 223 ± 163 W, Mo 355 ± 211 W, P < 0.001). Mean RR interval decreased within 5 hours after CV and increased again within the remaining hours, without significant differences between Bi and Mo groups. Time courses of time domain parameters of HRV revealed Bi profiles with the lowest levels 6 hours after CV in both groups. However, the hourly values of HRV were significantly higher in the Bi subgroup.
Conclusion: Our study indicates that waveform and total delivered energy significantly influence autonomic modulation of the sinus node in the early phase after CV of AF. In contrast to Bi CV, Mo CV is characterized by a significant decrease of cardiac vagal modulation, which may have an arrhythmic effect by increasing the degree of early electrical stunning after CV of AF.
Lead Design and Initial Applications of a New Lead for Long‐Term Endovascular Vagal Stimulation
Authors: NABUTOVSKY YELENA , FLORIO JOSEPH , MORGAN KEVIN , GRILL WARREN M. , FARAZI TARANEH G. 
Published: January 2007

Background: Vagal nerve stimulation (VNS) has negative chronotropic and dromotropic effects. We developed and tested an endovascular spiral vagal stimulation lead (ESVL) designed to follow the projection of the cardiac branches of the vagus nerve around the superior vena cava (SVC) to optimize VNS.
Methods: ESVL contained six 5‐mm coil electrodes, spaced 5‐mm apart with a spiral guidewire to provide shape. The tightness and diameter of the guidewire were changed before each placement to simulate different lead designs. Various 2‐, 3‐, and 4‐electrode combinations were used and several lead positions were tested each time. Each VNS protocol included 2–12 V, 15‐second pulse trains at 20 Hz, with 2 ms pulse duration. A basket catheter (BC) was used as control and to approximate the initial VNS location. The VNS protocol was performed at the optimal location, using first the BC and then several ESVL configurations.
Results: VNS caused a voltage‐dependent decrease in heart rate (HR). Using the optimal ESVL configuration at 7 V, HR decreased by 30.4% (37.2 bpm) in dog no. 1 and 12.4% (16.6 bpm) in dog no. 2, versus 15.5% (16.6 bpm) and 16.7% (19.5 bpm) with the BC.
Conclusions: A new endovascular spiral lead that takes advantage of the anatomy of the cardiac branches of the vagus nerve in the SVC was developed. VNS using ESVL produced significant HR slowing at voltages slightly below the highest pulse generator output of 7.5 V, which may be suitable for long‐term implantation.