bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Pulmonary Vein Isolation on the Morphology of P Waves: The Contribution of Pulmonary Vein Muscle Excitation to the Formation of P Waves
Authors: DATE TARO , YAMANE TEIICHI , INADA KEIICHI , MATSUO SEIICHIRO , KANZAKI YASUKO , MIYANAGA SATORU , SHIBAYAMA KENRI , MIYAZAKI HIDEKAZU , SUGIMOTO KEN‐ICHI , TANIGUCHI IKUO , MOCHIZUKI SEIBU
Published: January 2007

Background: Although the pulmonary veins have been demonstrated to play an important role in initiating and perpetuating atrial fibrillation, the role that cardiac muscle tissue in the pulmonary veins plays regarding the formation of P wave remains to be elucidated. We sought to clarify the contribution of pulmonary vein cardiac muscles to the formation of P waves by analyzing the P loops/waves in patients with atrial fibrillation.

Methods: The subjects in this study consisted of 21 patients (mean age, 57 ± 10 years) with drug‐refractory, paroxysmal atrial fibrillation who had undergone a segmental ostial isolation of all four pulmonary veins from the left atrium. Vectorcardiograms, intracardiac electrograms, and electrocardiograms (ECGs) were recorded before and after pulmonary vein isolation.

Results: The morphology of P waves changed after pulmonary vein isolation procedures with a significant increase in the maximal amplitude of both the leftward force in lead x and the anterior force in lead z (P < 0.05). The middle part (second one of three parts) of P loop on the horizontal plane shifted anteriorly and leftward after pulmonary vein isolation. Intracardiac electrograms in the pulmonary veins demonstrated the averaged activation times of all four pulmonary veins to range from 40% to 84% of the P duration.

Conclusions: The excitation of cardiac muscle tissue, which has migrated to the pulmonary veins, was thus found to play an important role in the formation of the middle part of the P wave/loop.
Dual‐Site Right Atrial Pacing Increases Left Atrial Appendage Flow in Patients with Sick Sinus Syndrome and Paroxysmal Atrial Fibrillation
Authors: STOCKBURGER MARTIN , BARTELS RALF , GERHARDT LARS , BUTTER CHRISTIAN
Published: January 2007

Background: Dual‐site right atrial pacing has been proposed as a promising concept for prevention of paroxysmal atrial fibrillation (PAF). Effects of this pacing configuration on left atrial appendage (LAA) flow and transmitral flow may be of prognostic and hemodynamic relevance. This study aims to characterize acute changes in left atrial flow depending on dual‐site right atrial pacing.

Methods: In 12 patients (66 ± 8.8 years, 4 women) with PAF and sinus bradycardia a pacemaker with a right atrial dual‐site lead configuration (right atrial lateral and coronary sinus ostium) was implanted. Flow velocities in the left pulmonary vein (LPV), LAA, and across the mitral valve were assessed by transesophageal echocardiography and compared during sinus rhythm (SR) and dual‐site (DS) pacing.

Results: Dual‐site pacing resulted in higher maximum (SR: 0.57 m/s; pacing: 0.77 m/s; P < 0.02) and mean (SR: 0.33 m/s; DS: 0.47 m/s; P < 0.01) LAA emptying flow when compared with SR. The passive transmitral flow component (maximum E‐wave velocity) was lower during dual‐site pacing (SR: 0.53 m/s vs DS: 0.44 m/s, P < 0.02). The E/A ratio tended to be lower during dual‐site pacing (SR: 1.21 vs DS: 1.01, P = 0,10). LPV flow velocities during SR and DS pacing did not differ.

Conclusion: DS right atrial stimulation in patients with PAF increases the LAA emptying flow velocity and shifts the transmitral flow pattern towards a lower passive component when compared with sinus rhythm. The change in LAA flow may contribute to a lower incidence of thromboembolism and merits further investigation.
The Salty Dog: Serum Sodium and Potassium Effects on Modern Pacing Electrodes
Authors: McVENES, B.A. RICK , HANSEN NANCY , LAHTINEN STUART P. , STOKES KEN
Published: January 2007

Background: This study was conducted to characterize the behavior of chronic modern endocardial electrodes with capacitively coupled constant voltage pulse generators in canines.

Methods: Five animals were studied with chronic paired unipolar microporous platinum, and porous steroid‐eluting electrodes in the ventricle. Screw‐in and passive fixation electrodes were also implanted in the atrium. IV infusions of 500–800 mL of 50 meq KCl in 500 mL Ringer's solution, and 3% NaCl were given over periods of 120 and 80 minutes, respectively, during separate anesthetized monitors.

Results: Mean maximum Na+ and K+ achieved was 158 and 8.3 meq/L, respectively. During KCl infusion, ventricular threshold, current, and energy decreased. In the atrium, half the leads went to exit block at ∼7.0 meq/L K+. Others continued to perform acceptably. The atrial electrogram decreased 70% with no change in the ventricular signal. No change in impedance occurred. During NaCl infusion, no changes in atrial or ventricular threshold occurred while current increased 21%–32%. This resulted in a 40%–55% increase in energy due to a 20% decrease in impedance. The atrial electrogram decreased 32%–36% while the ventricular amplitude decreased 25%. Slew rate decreased 19%–27%. Control studies for effects of heart rate, fluid volume, and anesthesia duration did not cause any changes.

Conclusion: These data support the conclusion that threshold is a voltage mediated response. Thus, voltage thresholds, not energy, current or pulse duration is the most relevant parameter for safety margin determination. Atrial parameters should be followed during electrolyte imbalances. Correlation in humans is needed.
Pacemaker Endocarditis: Clinical Features and Management of 60 Consecutive Cases
Authors: MASSOURE PIERRE‐LAURENT , REUTER SYLVAIN , LAFITTE STEPHANE , LABORDERIE JULIEN , BORDACHARD PIERRE , CLEMENTY JACQUES , ROUDAUT RAYMOND
Published: January 2007

Background: The incidence of endocarditis related to pacemakers is increasing, while the diagnosis and management remain difficult. The objective of this study was to evaluate the clinical features and management of endocarditis after implantation of pacemakers (PM) or cardioverter defibrillators (ICD).

Methods: We analyzed the hospital course of 60 consecutive patients (48 men, mean age 68 ± 12 years) admitted to our center for PM (n = 59) or ICD (n = 1) endocarditis between 1998 and 2004.

Results: Fever (78%), asthenia (65%), and local symptoms (35%) were common. Positive cultures were obtained in 53 cases (Staphylococcus 89%). Sixteen patients (27%) had pulmonary embolism. Vegetations (mean size 15.2 ± 8 mm, range 5 to 35 mm) were found in 54 cases (90%), with transthoracic echocardiography in 26 cases (43%), and transesophageal echocardiography (TEE) in 50 cases (89% of the 56 patients who had TEE). Devices were removed surgically (n = 20) or percutaneously (n = 37). In the surgical group, vegetations were larger (17.9 ± 7 mm vs 13.2 ± 7 mm, P = 0.01). After removal, 42 patients (70%) had a new PM. Mortality factors (6 deaths – follow up 3.4 ± 2 years) were the number of vegetations and absence of extraction of the device (P < 0.02). Clinical features and management of the 37 patients with early onset endocarditis (within 1 year after implantation) did not differ from those with late onset.

Conclusions: PM endocarditis was essentially staphylococcal. TEE was required for the diagnosis of vegetations. Complete removal of the device is required and associated with a favorable outcome.
Prevalence and Characterization of Asymptomatic Pacemaker and ICD Lead Perforation on CT
Authors: HIRSCHL DAVID A. , JAIN VINEET R. , SPINDOLA‐FRANCO HUGO , GROSS JAY N. , HARAMATI LINDA B.
Published: January 2007

Background: Pacemakers and implantable cardiac defibrillators (ICDs) are widely used for the management of cardiac arrhythmias and congestive heart failure (CHF). Acute implantation complication rates range from 3% to 7%. The aim of this study is to describe the incidence of lead perforation on computed tomography (CT), and correlate these findings with electrophysiologic data.

Methods: Images of 100 consecutive patients with permanent pacemakers (n = 72) or ICDs (n = 28) who underwent multidetector CTs of the chest were identified. Cases were reviewed by 2 cardiothoracic radiologists, and a third if there was disagreement. Each CT was reviewed for device and fixation type, tip position, and presence of pericardial effusion. Results were correlated with lead impedance and pacing threshold, when available [79% (79/100)]. A cardiac electrophysiologist interpreted device data.

Results: All 100 patients had right ventricular leads (58 passive, 42 active) and 61 had right atrial leads (12 passive, 49 active). 15% (15/100) of patients had a lead perforation. Perforation rates were 15% (9/61) for atrial and 6% (6/100) for ventricular leads (P < 0.05, chi square). Four of 28 (14%) right ventricular ICD leads and 2 of 72 (3%)
right ventricular pacemaker leads were perforated (P < 0.05, chi square). 12% (6/49) of active right atrial leads, and 25% (3/12) of passive right atrial leads perforated (P = NS, chi square). 7% (3/42) of active right ventricular leads, and 5% (3/58) of passive ventricular leads perforated (P = NS, chi square). Electrophysiologic parameters did not differ significantly between perforated and nonperforated leads.

Conclusion: Asymptomatic perforation is a common phenomenon and rarely resulting in electrophysiologic consequences. Atrial leads perforated more frequently than ventricular leads, and ventricular ICD leads perforated more frequently than ventricular pacemaker leads.
Economic Analysis of a Randomized Trial of Biventricular Pacing in Canada
Authors: BENTKOVER JUDITH D. , DORIAN PAUL , THIBAULT BERNARD , GARDNER MARTIN
Published: January 2007

Background: Congestive heart failure (CHF) has been shown to affect 5% of the Canadian adult population, and leads to 9.5 deaths per 100 cardiac‐related hospitalizations in Canada. The economic outcomes from biventricular pacing for heart failure are not well understood. This study analyzes resource utilization and related costs associated with CHF for patients who receive standard implantable cardiac defibrillators (ICDs) versus those who receive ICD plus biventricular pacing or cardiac resynchronization therapy (CRT).

Methods: The Canadian analysis of resynchronization therapy in heart failure (CART‐HF) study included 72 patients with New York Heart Association class II‐IV CHF requiring an ICD. Patients were randomized to receive either ICD + CRT treatment or ICD treatment alone. Medical resource utilization data were collected for 6 months following treatment and were applied to representative costs for the provinces of Quebec and Ontario. Resource utilization was subcategorized into pharmacological therapy, physician visits, hospitalizations, adverse events, and productivity losses.

Results: Post‐treatment, per patient costs for the CRT + ICD treatment group were less than the follow‐up costs for patients receiving ICD treatment only in each province. Mean savings for patients receiving biventricular therapy were CAD$2,420 in Quebec and CAD$2,085 in Ontario during the 6‐month follow‐up.

Conclusions: These analyses indicate that savings in post‐implant health‐care utilization (hospitalizations and pharmacological therapy) can offset some of the device and procedural costs associated with CRT devices.
Implantation of Active Fixation Leads in Coronary Veins for Left Ventricular Stimulation: Report of Five Cases
Authors: HANSKY BERT , VOGT JUERGEN , GUELDNER HOLGER , SCHULTE‐EISTRUP SEBASTIAN , LAMP BARBARA , HEINTZE JOHANNES , HORSTKOTTE DIETER , KOERFER REINER
Published: January 2007

Background: Securing transvenous left ventricular (LV) pacing leads without an active fixation mechanism in proximal coronary vein (CV) segments is usually challenging and frequently impossible. We investigated how active fixation leads can be safely implanted in this location, how to avoid perforating the free wall of the CV, and how to recognize and respond to perforations.

Materials and Methods: In five patients with no alternative to LV pacing from proximal CV segments, 4 Fr SelectSecure (Medtronic, Minneapolis, MN, USA) leads, which have a fixed helix, were implanted through a modified 6 Fr guide catheter with a pre‐shaped tip (Launcher, Medtronic).

Results: Active fixation leads were successfully implanted in proximal CVs in five patients. There were no complications. Acute and chronic pacing thresholds were comparable to those of conventional CV leads. The pre‐shaped guide catheter tip remains in close proximity to the myocardial aspect of the CV, directing the lead helix toward a safe implantation site.

Conclusions: If only proximal CV pacing sites are available, 4 Fr SelectSecure leads can be safely implanted through a modified Launcher guide catheter, avoiding more invasive implantation techniques. Other than venous stenting or implantation of leads with retractable tines, SelectSecure leads are expected to remain extractable.
Cardiac Resynchronization Therapy Optimization by Ultrasonic Cardiac Output Monitoring (USCOM) Device
Authors: SIU CHUNG‐WAH , TSE HUNG‐FAT , LEE KATHY , CHAN HON‐WAH , CHEN WAI‐HONG , YUNG CINDY , LEE STEPHEN , LAU CHU‐PAK
Published: January 2007

Objectives: We investigated the accuracy and feasibility of a 2D echo‐independent ultrasonic continuous wave Doppler cardiac output monitoring device (USCOM) operated by trained nurse for the atrio‐ventricular interval (AVI) optimization in cardiac resynchronization therapy (CRT).

Background: CRT is of proven benefit in patients with advanced chronic heart failure and ventricular conduction delay. Appropriate AVI selection is critical to optimize hemodynamic in CRT. Currently, most non‐invasive methods for AVI optimization are often complicated and labor‐intensive.

Methods: USCOM method, Ritter method, and aortic outflow cardiac output method were used to determine the optima AVI in 20 patients with CRT. The accuracy and time for measurement of each method were determined.

Results: The optimal AVI determined by USCOM method had good correlation with Ritter's method and aortic outflow estimated cardiac output method (r2= 0.78, P < 0.01 and r2= 0.73, P < 0.01, respectively). The optimal AVI determined USCOM method showed good agreement (within 10 msec range) with Ritter's method (85% patients) and aortic outflow estimated cardiac output method (80%). The mean time for determining AVI using USCOM method was shorter than that with aortic outflow method (7.1 ± 0.7 min vs 12.7 ± 1.1 min, P < 0.01), whereas the mean time was shortest for Ritter method (4.7 ± 1.6 min vs 7.1 ± 0.7 min, P < 0.01).

Conclusion: USCOM device operated by trained nurse can provide a simple, accurate, and fast non‐invasive method for the AVI optimization in CRT population.
Activation Sequence Modification During Cardiac Resynchronization by Manipulation of Left Ventricular Epicardial Pacing Stimulus Strength
Authors: TEDROW USHA B. , STEVENSON WILLIAM G. , WOOD MARK A. , SHEPARD RICHARD K. , HALL KIM , PELLEGRINI CHRISTINE P. , ELLENBOGEN KENNETH A.
Published: January 2007

Background: Success of cardiac resynchronization therapy (CRT) depends on altering electrical ventricular activation (VA) to achieve mechanical benefit. That increases in stimulus strength (SS) can affect VA has been demonstrated previously in cardiomyopathy patients undergoing ablation.

Objective: To determine whether increasing SS can alter VA during CRT.

Methods: In 71 patients with CRT devices, left ventricle (LV) pacing was performed at escalating SS. Timing from pacing stimulus to right ventricular (RV) electrogram, ECG morphology, and maximal QRS duration on 12 lead ECG were recorded.

Results: Demographics: Baseline QRS duration 153 ± 25 ms, ischemic cardiomyopathy 48%, ejection fraction 24%± 7%. With increased SS, conduction time from LV to right ventricle (RV) decreased from 125 ± 56 ms to 111 ± 59 ms (P = 0.006). QRS duration decreased from 212 ± 46 ms to 194 ± 42 ms (P = 0.0002). A marked change in QRS morphology occurred in 11/71 patients (15%). The RV ring was the anode in 6, while the RV coil was the anode in 5. Sites with change in QRS morphology showed decrease in conduction time from LV to RV from 110 ± 60 ms to 64 ± 68 ms (P = 0.04). Twelve patients (16%) had diaphragmatic stimulation with increased SS.

Conclusions: Increasing LV SS reduces QRS duration and conduction time from LV to RV. Recognition of significant QRS morphology change is likely clinically important during LV threshold programming to avoid unintended VA change.
Changes in Heart Rate Variability, Quality of Life, and Activity in Cardiac Resynchronization Therapy Patients: Results of the HF‐HRV Registry
Authors: GILLIAM F. ROOSEVELT , KAPLAN ANDREW J. , BLACK JAMES , CHASE KELLIE J. , MULLIN CHRISTOPHER M.
Published: January 2007

Background: Cardiac resynchronization therapy (CRT) is a viable therapy in the treatment of heart failure (HF). Heart rate variability (HRV) is a prognostic marker of HF and mortality and is a sign of autonomic dysfunction. Acute improvements in measures of HRV have been demonstrated after CRT in small clinical studies. The purpose of the present study was to evaluate changes in HRV and patient outcomes over time and the relationship between these changes in a large generalized sample of patients who received CRT with defibrillator (CRT‐D).

Methods: The Heart Failure‐Heart Rate Variability (HF‐HRV) registry enrolled 1,421 patients who received a CRT‐D device capable of measuring HRV. Patients were followed for a 1‐year period. Device diagnostics, including HRV footprint; standard deviation of averaged normal R to R intervals (SDANN); and mean, minimum, and maximum heart rate were measured at each visit, in addition to activity log, New York Heart Association (NYHA) class, and quality of life (QOL) data.

Results: This large sample of HF patients showed an overall improvement in SDANN (69.2 ± 25.5, 78.5 ± 27.8, 79.4 ± 27.2, 80.7 ± 28.2) and HRV footprint (31.5 ± 11.8, 33.4 ± 12.3, 34.2 ± 12.2, 34.5 ± 12.3) at the 2 week, 3 month, 6 month, and 12 month visits, respectively (both P < 0.001). There were also significant changes over time in clinical status (improved QOL, increased activity, and improved NYHA, all P < 0.0001), with the greatest changes occurring between the 2 week and 3 month visits.

Conclusion: In conclusion, these study results demonstrate that device measured HRV parameters and patient outcomes significantly improve after receipt of CRT.
Unusual Pacing Observed in a Biventricular Pacemaker with Epicardial Pacing Leads
Authors: SAUER WILLIAM H. , GARCIA FERMIN C. , VERDINO RALPH J. , COOPER JOSHUA M.
Published: January 2007

In this case report, we describe inappropriate pacing in a patient with a newly implanted biventricular pacing system with three epicardial leads. Very high pacing thresholds resulted from the use of nonsteroid eluting leads, and unusual pacing behavior was due to the chosen implant locations for the right atrial and right ventricular epicardial leads. The interplay between the programmed pacemaker parameters, the very late ventricular sensing in the setting of intrinsic right bundle branch block, and atrial lead oversensing led to ineffective biventricular pacing. The persistently elevated pacing thresholds and sensing problems led to very early battery depletion and the need to replace the epicardial system with three new endocardial leads.
Brugada Electrocardiographic Pattern Induced During Febrile State with Marked Leukocytosis
Authors: GAVRIELATOS GERASIMOS , LETSAS KONSTANTINOS P. , PAPPAS LOUKAS K. , EFREMIDIS MICHALIS , SIDERIS ANTONIOS , KARDARAS FOTIS
Published: January 2007

Several agents and conditions have been reported to unmask or accentuate the electrocardiographic pattern of Brugada syndrome including fever. At a molecular level, sodium channels have been showed to be temperature dependent. Herein, we describe a case of Brugada electrocardiographic pattern unmasked during febrile state and marked leukocytosis.
Remote, Wireless, Ambulatory Monitoring of Implantable Pacemakers, Cardioverter Defibrillators, and Cardiac Resynchronization Therapy Systems: Analysis of a Worldwide Database
Authors: LAZARUS ARNAUD
Published: January 2007

Study Objective: To describe the daily routine application of a new telemonitoring system in a large population of cardiac device recipients.

Methods: Data transmitted daily and automatically by a remote, wireless Home Monitoring™ system (HM) were analyzed. The average time gained in the detection of events using HM versus standard practice and the impact of HM on physician workload were examined. The mean interval between device interrogations was used to compare the rates of follow‐up visits versus that recommended in guidelines.

Results: 3,004,763 transmissions were made by 11,624 recipients of pacemakers (n = 4,631), defibrillators (ICD; n = 6,548), and combined ICD + cardiac resynchronization therapy (CRT‐D) systems (n = 445) worldwide. The duration of monitoring/patient ranged from 1 to 49 months, representing 10,057 years. The vast majority (86%) of events were disease‐related. The mean interval between last follow‐up and occurrence of events notified by HM was 26 days, representing a putative temporal gain of 154 and 64 days in patients usually followed at 6‐ and 3‐month intervals, respectively. The mean numbers of events per patient per month reported to the caregivers for the overall population was 0.6. On average, 47.6% of the patients were event‐free. The mean interval between follow‐up visits in patients with pacemakers, single‐chamber ICDs, dual chamber ICDs, and CRT‐D systems were 5.9 ± 2.1, 3.6 ± 3.3, 3.3 ± 3.5, and 1.9 ± 2.9 months, respectively.

Conclusions: This broad clinical application of a new monitoring system strongly supports its capability to improve the care of cardiac device recipients, enhance their safety, and optimize the allocation of health resources.
Upgrading from Single Chamber Right Ventricular to Biventricular Pacing in Permanently Paced Patients with Worsening Heart Failure: The RD‐CHF Study
Authors: LECLERCQ CHRISTOPHE , CAZEAU SERGE , LELLOUCHE DAVID , FOSSATI FABIEN , ANSELME FRÉDERIC , DAVY JEAN‐MARC , SADOUL NICOLAS , KLUG DIDIER , MOLLO LUCA , DAUBERT JEAN‐CLAUDE
Published: January 2007

Background: Biventricular (BiV) stimulation lowers morbidity and mortality in patients with drug‐refractory congestive heart failure (CHF), depressed left ventricular (LV) function, and ventricular dyssynchrony in absence of indication for permanent cardiac pacing. This pilot, single‐blind, randomized, cross‐over study examined the safety and efficacy of upgrading conventional pacing systems to BiV stimulation in patients with advanced CHF.

Methods: We included 56 patients in New York Heart Association (NYHA) functional classes III or IV despite optimal drug treatment and ventricular dyssynchrony (interventriclar delay >40 ms or LV preejection delay >140 ms) in need of pacemaker replacement. We compared the patients' functional status, arrhythmias, and standard echocardiographic measurements during 3 months of conventional, single right ventricular (RV) versus 3 months of BiV stimulation.

Results: There were 44 patients in the cross‐over phase. QRS duration was shortened by 23% and LV preejection delay by 16% with BiV stimulation. NYHA functional class, 6‐minute hall walk and quality of life score were significantly improved with BiV stimulation compared with single RV pacing by 18%, 29%, and 19%, respectively. No significant difference was observed in the ventricular arrhythmia burden or LV reverse remodeling between the 2 periods.

Conclusions: This pilot study showed that upgrading from RV pacing to BiV pacing significantly improves symptoms and exercise tolerance in chronically paced patients with advanced CHF and mechanical dyssynchrony.
Long‐Term Follow‐Up of Biventricular Pacing Using a Totally Endocardial Approach in Patients with End‐Stage Cardiac Failure
Authors: PASQUIÉ J.L. , MASSIN F. , MACIA J.C. , GERVASONI R. , BORTONE A. , CAYLA G. , GROLLEAU R. , LECLERCQ F.
Published: January 2007

Background: Besides standard left ventricular (LV) stimulation via the coronary sinus, a transseptal approach allows left ventricular endocardial stimulation. We report our long‐term observations with biventricular stimulation, using a strictly endocardial system for patients presenting with severe congestive heart failure.

Methods: Six patients with nonischemic cardiomyopathy (mean age = 60 ± 9.6 years, women) in New York Heart Association (NYHA) functional class III (n = 5) or IV, despite optimal drug therapy, and a mean LV ejection fraction of 24 ± 3%, underwent implantation of biventricular stimulation systems between April 1998 and March 1999. All presented with left bundle branch block and an increased LV end‐diastolic diameter (mean = 66 ± 5 mm). In all patients, a bipolar pacing lead was implanted in the lateral LV wall using a direct transseptal approach. After implantation, all patients received oral anticoagulation.

Results: QRS duration decreased from 184 ± 22 ms to 108 ± 11 ms. NYHA functional class decreased to II in all patients within 1 month. Over a 85 ± 5 month follow‐up, two patients underwent cardiac transplantation, 2 and 4 years after device implantation, respectively; two patients died of end‐stage heart failure 4 years after system implantation; and two patients were alive in functional class II. One patient, who experienced syncope due to fast ventricular, underwent implantation of an ICD. One transient ischemic attack occurred in a patient whose anticoagulation was temporarily interrupted.

Conclusions: Long‐term endocardial biventricular stimulation via a transseptal approach was safe and effective in this small population. This approach needs to be further compared with conventional epicardial pacing via the coronary sinus
Three Years of Cardiac Resynchronization Therapy: Could Superior Benefits be Obtained in Patients with Heart Failure and Narrow QRS?
Authors: GASPARINI MAURIZIO , REGOLI FRANÇOIS , GALIMBERTI PAOLA , CERIOTTI CARLO , BONADIES MARIKA , MANGIAVACCHI MAURIZIO , ANDREUZZI BRUNO , BRAGATO RENATO , PINI DANIELA , KLERSY CATHERINE , GRONDA EDOARDO
Published: January 2007

Aim of the study: To examine the long‐term effects of cardiac resynchronization therapy (CRT) in patients presenting with heart failure (HF) and QRS ≤120 ms.

Methods: This was a prospective, longitudinal study of 376 patients [mean age = 65 years, mean left ventricular (LV) ejection fraction (EF) = 29%, mean QRS duration =165 ms, mean distance covered during a 6‐minute hall walk (6‐MHW) = 325 m], who underwent successful implantation of CRT systems. The QRS duration at baseline was ≤120 ms in 45 patients (12%) who were not pre‐selected by echocardiographic criteria of dyssynchrony, and >120 ms in the remaining 331 patients. The baseline characteristics of the 2 groups were similar. We evaluated indices of cardiac function, percentage of responders, and survival rates over a mean 28‐month follow‐up.

Results: Both groups experienced similar long‐term increases in 6‐MHW, and decreases in New York Heart Association functional class and LV end‐systolic volume (all comparisons P < 0.0001 in both groups). Time interaction of changes in LVEF and percentage of responders were significantly different (P = 0.03 and P = 0.004, respectively), in favor of the narrow QRS group, where the changes were sustained and persisted at 2 and 3 years. The long‐term death rate from HF was lower in the group with narrow than in the group with wide QRS complex (P = 0.04; log‐rank test).

Conclusions: CRT confers considerable long‐term clinical, functional, and survival benefits in patients presenting with HF and narrow QRS, not preselected by echocardiographic criteria of dyssynchrony. Caution is advised before denying CRT to these patients on the basis of QRS width only.
Long‐Term Performance of Coronary Sinus Leads Used for Cardiac Resynchronization Therapy
Authors: IULIANO ASSUNTA , SHOPOVA GERGANA , DE SIMONE ANTONIO , SOLIMENE FRANCESCO , TURCO PIETRO , MARRAZZO NATALE , LA ROCCA VINCENZO , CIARDIELLO CARMINE , AGRUSTA MARCO , STABILE GIUSEPPE
Published: January 2007

Background: Little is known regarding the long‐term performance of coronary sinus (CS) leads, which have an effect on the longevity of cardiac resynchronization therapy (CRT) systems.

Methods: This study included 109 patients (79 men) whose mean age was 68 ± 9 years, New York Heart Association (NYHA) functional class 3.2 ± 0.5, and left ventricular ejection fraction 25.6 ± 6.6%, and who underwent CRT (n = 45) or CRT‐D (n = 64) systems implants for management of idiopathic (53%), ischemic (40%), or miscellaneous (7%) dilated cardiomyopathy. Unipolar (n = 57) or bipolar (n = 52) leads were placed into the CS venous system.

Results: At implant, no significant difference was observed between unipolar and bipolar leads with respect to mean sensing performance (14 ± 6 mV vs 14 ± 8 mV, P = 0.97), pacing impedance (875 ± 234 ohms vs 943 ± 331 ohms, P = 0.24), and stimulation energy threshold (2 ± 3.2 μJ vs 1.13 ± 1.5 μJ, P = 0.08). At a median follow‐up of 33 months, a significant decrease in stimulation impedance and increase in stimulation energy threshold was observed with unipolar (689 ± 122 vs 875 ± 234 ohms, P < 0.01, and 8.34 ± 10.4 μJ vs 2 ± 3.2 μJ, P < 0.001, respectively) as well as with bipolar (735 ± 268 ohms vs 943 ± 331 ohms, P < 0.01, and 4.81 ± 9.92 vs 1.13 ± 1.5 μJ, P = 0.02, respectively) leads. No significant difference in sensing performance was observed with either type of lead (10 ± 5 mV vs 14 ± 6 mV and 10 ± 6 mV vs 14 ± 8 mV, respectively). At long‐term follow‐up, no significant difference among any sensing or stimulation parameter was observed between unipolar and bipolar leads.

Conclusions: At long‐term follow‐up, a significant increase in the energy required for stimulation was observed, whereas sensing performance remained unchanged. The increase in energy capture threshold was less marked with bipolar than with unipolar leads.
Segmental Wall Motion Abnormality Analyzed by Equilibrium Radionuclide Angiography and Improvement in Ventricular Function by Cardiac Resynchronization Therapy
Authors: EDER VERONIQUE , FAUCHIER LAURENT , COURTEHOUX MAXIME , BONNET PIERRE , BABUTY DOMINIQUE
Published: January 2007

Introduction: The purpose of this study was to determine the impact of the left ventricular (LV) segmental wall motion abnormalities detected by equilibrium radionuclide angiography (ERNA) on the improvement in LV and right ventricular (RV) function during biventricular (BIV) stimulation.

Results: We studied 28 patients in NYHA functional classes III or IV and QRS duration >150 ms on resting electrocardiogram. ERNA was performed before and during BIV stimulation at a 6‐month follow‐up. A significant shortening of QRS duration was observed during BIV stimulation (165 ± 5 ms before vs 133 ± 6 ms during, P < 0.01). Wall motion abnormalities (WMA) were observed in 16 patients (10 with nonischemic cardiomyopathies). In this group, LV and RV ejection fractions (EF) did not increase during BIV stimulation (LVEF=22 ± 2% vs 20 ± 1.6%, ns; RVEF=34 ± 3% vs 37 ± 3.8%, ns). Significant increases in RVEF (23 ± 3.2%→38 ± 2.9%, P=0.001) and LVEF (20 ± 2.5%→30 ± 3%, P=0.01) were observed in the group of patients without segmental WMA and with global hypokinesia (GH). In this group, a significant decrease in the dispersion in the phase of RV contraction was observed (SD=39 ± 5 vs 26 ± 2 ms; P < 0.01). WMA predicted an increase in LVEF, in contrast to a baseline 6‐minute‐walk test, maximal oxygen consumption and LVEF, or amount of QRS shortening.

Conclusions: BIV stimulation increased in LV and RV EF in patients with ventricular dyssynchrony in absence of segmental WMA. ERNA was reliable in the selection of candidates for CRT.
Acute Left Ventricular Dyssynchrony Improvement Predicts Long‐Term Benefit from Cardiac Resynchronization Therapy
Authors: CAPASSO FABIO , GIUNTA ANNA , DE SIMONE ANTONIO , TURCO PIETRO , LA ROCCA VINCENZO , GRIMALDI M. GABRIELLA , IULIANO ASSUNTA , STABILE GIUSEPPE
Published: January 2007

Study Objective: To evaluate the relationship between acute response to cardiac resynchronization therapy (CRT) and long‐term clinical outcome in patients with drug refractory heart failure.

Methods and Results: In 28 patients undergoing CRT implant, left ventricular (LV) dyssynchrony was evaluated by tissue Doppler imaging (TDI)‐derived longitudinal strain by mean of septum‐lateral basal asynchrony index (S‐Li) and basal delayed longitudinal contraction (DLC). TDI measurements were made before, and 30 minutes and 1 year after implant. Baseline and 1‐year follow‐up New York Heart Association (NYHA) functional class, 6‐minute walking test (6‐MWT) distance, and quality of life (QoL) score were measured. Responders (n=22) were defined by a ≥ 1 decrease in NYHA functional class and 6‐MWT ≥25% at 1 year. At baseline, no differences were observed between responders and nonresponders in clinical and echocardiographic measurements. LV dyssynchrony acutely recovered only in responders 30 minutes after implantation, with a significant reduction in S‐Li and DLC. Moreover, the percent decreases in S‐Li and DLC were highly correlated with those observed in NYHA class (r=0.70, and r=0.81, respectively, P < 0.001), 6‐MWT (r=0.59, and r=0.57, respectively, P < 0.001 and P < 0.01), and QoL score (r=0.71, and r=0.83, respectively, p < 0.001) at 1‐year follow‐up.

Conclusions: Acute recovery of LV intraventricular dyssynchrony is a major discriminator between responders and nonresponders to CRT, which strongly correlates with a favorable long‐term clinical outcome.
AAIsafeR Limits Ventricular Pacing in Unselected Patients
Authors: PIOGER GUY , LENY GÉRARD , NITZSCHÉ RÉMI , RIPART ALAIN
Published: January 2007

Introduction: Dedicated pacing modes, such as AAIsafeR, prevent ventricular (V) pacing in selected patients. We report our experience in consecutive unselected patients.

Methods: All data collected in recipients of Symphony DR 2550 pacemakers (ELA Medical, Montrouge, France) were retrospectively analyzed. At each visit, the percentage of V and atrial (A) pacing and the number of endless‐loop tachycardia (ELT) episodes detected by the device were retrieved. Data were pooled according to pacing mode and compared with non‐paired Student's t‐test.

Between April 2004 and July 2005, our center recruited 147 patients (mean age=80 ± 9 years, 54% men) treated for AV block (n=58), sinus node dysfunction (n=48) or other indications (n=41). Mean age at implant was 80 ± 9 years, and 54% were men. AAIsafeR(R) was programmed in 96 patients, DDD(R) in 43, DDI in 7, and DDD/AMC in 1 patient. In DDD mode, the mean resting AV delay was set at 150 ± 17 ms. Patients were seen 1 month after implantation of the pacing system to verify its proper function, and every 6 months thereafter. At each follow‐up, the percentage of ventricular and atrial pacing, and the number of ELT detected by the device, were recorded.

Results: The mean follow‐up was 7 ± 6 months (range 1–21). No device was reprogrammed from AAIsafeR(R) to DDDI(R) because of permanent AF. Only 6 devices (6.25%) were automatically reprogrammed from AAIsafeR(R) to DDD(R) during follow‐up due to permanent AV block. An empirical choice of AAIsafeR pacing mode at the time of implantation was effective in 94% of patients, allowing a significant decrease in the percentage of V pacing. AAIsafeR versions 1 or 2 significantly decreased the percentage of V pacing (9 ± 21%) compared with DDD (95 ± 14%), DDD/AMC (31 ± 34%), and DDI (87 ± 20%) pacing (P < 0.00001). The mean percentage of V pacing was 12 ± 24% (median 0%, range 0–94) in AAIsafeR1 versus 4 ± 12% (median 0%, range 0–52) in AAIsafeR2 (P=0.055). In 16 devices upgraded from AAIsafeR version 1 to version 2, with follow‐up analyzable in both modes, the mean percentage of V pacing decreased from 6.4 ± 15.1% to 2.6 ± 9.7% (ns). No adverse effect related to the AAIsafeR modes was observed. No patient reported palpitation, dyspnea, or lightheadedness attributable to overdrive pacing by the AF prevention algorithms, and there was no rehospitalization, need for cardioversion, device‐related complication, or death.

Conclusions: In unselected pacemaker recipients, AAIsafeR reliably prevented V pacing compared with other pacing modes. No adverse effects were reported by any patient. Furthermore, maintaining spontaneous AV conduction protected the patients against ELT episodes.
Dynamic and Dual‐Site Atrial Pacing in the Prevention of Atrial Fibrillation: The STimolazione Atrial DInamica Multisito (STADIM) Study
Authors: DE SIMONE ANTONIO , SENATORE GAETANO , DONNICI GIOVANNI , TURCO PIETRO , ROMANO ENRICO , GAZZOLA CARLO , STABILE G.
Published: January 2007

Objectives: The impact of new algorithms to consistently pace the atrium on the prevention of atrial fibrillation (AF) remains unclear. Our randomized, crossover study compared the efficacy of single‐ and dual‐site atrial pacing, with versus without dynamic atrial overdrive pacing in preventing AF.

Methods: We studied 72 patients (mean age=69.6 ± 6.5 years, 34 men) with sick sinus syndrome (SSS) and paroxysmal or persistent AF, who received dual‐chamber pacemakers (PM) equipped with an AF prevention algorithm and two atrial leads placed in the right atrial appendage (RAA), by passive fixation, and in the coronary sinus ostium (CS), by active fixation, respectively. At implant, the patients were randomly assigned to unipolar CS versus RAA pacing. The PM was programmed in DDDR mode 1 month after implant. Each patient underwent four study phases of equal duration: (1) unipolar, single site (CS or RAA) pacing with the AF algorithm ON (atrial lower rate=50 ppm); (2) unipolar, single site pacing with the AF algorithm OFF (atrial lower rate=70 bpm); (3) bipolar, dual‐site pacing with AF algorithm ON; (4) bipolar, dual‐site pacing with the AF algorithm OFF.

Results: Among 40 patients (56%), who completed the follow‐up (15 ± 4 months) no difference was observed in the mean number of automatic mode switch (AMS) corrected for the duration of follow‐up, in unipolar (5.6 ± 22.8 vs 2.6 ± 5.5) or bipolar mode (3.3 ± 12.7 vs 2.1 ± 4.9) with, respectively, the algorithm OFF or ON. With the AF prevention algorithm ON, the percentage of atrial pacing increased significantly from 78.7 ± 22.1% to 92.4 ± 4.9% (P < 0.001), while the average ventricular heart rate was significantly lower with the algorithm ON (62.4 ± 17.5 vs 79.9 ± 3 bpm (P < 0.001).

Conclusions: The AF prevention algorithm increased the percentage of atrial pacing significantly, regardless of the atrial pulse configuration and pacing site, while maintaining a slower ventricular heart rate. It had no impact on the number of AMS in the unipolar and bipolar modes in patients with SSS.
Thresholds and Complications with Right Ventricular Septal Pacing Compared to Apical Pacing
Authors: BURRI HARAN , SUNTHORN HENRI , DORSAZ PIERRE‐ANDRÉ , VIERA ISABELLE , SHAH DIPEN
Published: January 2007

Background: Right ventricular septal pacing has been proposed as an alternative to apical pacing. However, data concerning thresholds and requirement for lead repositioning with this technique are scant.

Methods: We reviewed data at implantation and follow‐up of 362 consecutive recipients of the same model of active fixation lead (Medtronic 5076‐58, Minneapolis, MN, USA) to avoid differences due to lead characteristics. Patients were divided into two groups according to whether the lead was positioned on the interventricular septum (n = 157) or at the right ventricular apex (n = 205). Thresholds, lead impedance, and requirement for lead repositioning were compared between groups at implantation and follow‐up.

Results: There were no differences between the septal and apical groups in sensing and pacing thresholds or lead impedance, either at implantation or during a 24‐month follow‐up. In the septal group, the lead had to be repositioned in four patients (2.5%) due to lead dislodgement in two patients, acute threshold rise in one patient, and pericardial effusion in another patient (the lead had unintentionally been positioned on the anterior free wall in these last two patients). In the apical group, the lead had to be repositioned in eight patients (3.9%, P = 0.56) due to lead dislodgement in three patients and acute threshold rise in five patients.

Conclusions: Acute and chronic thresholds associated with septal pacing are similar to those observed with apical pacing, and risk of lead dislodgement is low. However, multiple radioscopic views must be used to avoid inadvertent positioning of the lead on the anterior free wall.
Placement of a Pacing Lead at the Inferior Portion of the Interatrial Septum Without Special Tools
Authors: ACOSTA HELBERT , POTHULA VIJAYASIMHA R. , RODRIGUEZ MARIO , RAMADAS SUMATI , CASTELLANOS AGUSTIN
Published: January 2007

Introduction: Previous studies have suggested that, among septal sites, the inferior portion of the interatrial septum (IAS) is the most likely to prevent atrial fibrillation, though inserting an active fixation lead at this site can be tedious and time consuming. We describe a relatively straightforward technique to insert a lead at this site without special tools.

Method: We studied 117 consecutive patients (mean age=76 ± 8 years, 69% men) with ACC/AHA class I and II pacing indications and histories of paroxysmal or permanent atrial fibrillation, undergoing implantation of a dual chamber pacing system. A technique using the “preshaped” stylet and fluoroscopic guidance is described.

Results: The insertion was successful in 111 patients (95%). Acute dislodgement occurred in six patients (5%). The intrinsic P‐wave duration was 117 ± 22 ms, and the paced P‐wave duration was 90 ± 20 ms (23% shortening, P < 0.001). The mean time required to insert the atrial lead was 12 ± 8 minutes. No complications occurred.

Conclusions: Insertion of an active fixation lead at the inferior portion of the interatrial septum was safe and highly successful in the majority of patients with this technique.
Atrioventricular Nodal Reentrant Tachycardia in the Elderly: Efficacy and Safety of Radiofrequency Catheter Ablation
Authors: MEILTZ ALEXANDRE , ZIMMERMANN MARC
Published: January 2007

Background: Radiofrequency (RF) catheter ablation is considered the treatment of choice for patients with atrioventricular nodal reentrant tachycardia (AVNRT). This study examined the efficacy and safety of RF ablation in patients with AVNRT ≥65 years of age.

Methods: We retrospectively analyzed data collected in 350 consecutive patients who underwent AVNRT RF ablation between 1995 and 2005. They were divided according to whether they were <65 years (Group 1, n = 280; mean age = 46 ± 13 years, 69% women) or ≥65 years (Group 2, n = 70; mean age = 72 ± 6 years, 59% women) of age.

Results: Patients in Group 2 more often had structural heart disease (12/70 vs 17/280, P = 0.002) than in Group 1, though there was no difference in the prevalence of syncope (6/70 vs 18/280, P = 0.52) or atrial fibrillation (1/70 vs 6/280, P = 0.70) between the 2 groups. Before RF ablation, patients in Group 2 had a longer mean A‐H intervals (90 ± 31 ms vs 77 ± 19 ms, P < 0.0001), H‐V intervals (44 ± 6 ms vs 41 ± 5 ms, P < 0.0001), fast pathway refractory period (358 ± 14 ms, vs 335 ± 68 ms, P = 0.01), and tachycardia cycle length (394 ± 71 ms vs. 335 ± 59 ms, P < 0.0001). A >140 ms A‐H interval was present in 3/70 patients in Group 2 versus 0/280 in Group 1 (P < 0.001). No difference was observed between the 2 groups in primary RF ablation success rate (70/70 vs 277/280, P = 0.38), overall procedure duration (75 ± 35 minute vs 78 ± 43 minute, P = 0.61), duration of fluoroscopic exposure (14 ± 12 minute vs 13 ± 12 minute, P = 0.63), or number of RF pulses (median 5 vs 4, P = 0.051). Two patients in Group 1 (0.57%) developed 3rd degree AV block requiring permanent pacing. Recurrences of AVNRT were limited to Group 1 (16/280 vs 0/70, P = 0.001).

Conclusions: RF ablation of AVNRT was highly effective and safe in patients ≥65 years of age despite a higher prevalence of structural heart disease and longer A‐H intervals at baseline. RF ablation might be considered as first‐line therapy for the elderly with AVNRT.
Significance of Late Recurrence of Atrial Fibrillation during Long‐Term Follow‐Up after Pulmonary Vein Isolation
Authors: SOLHEIM EIVIND , HOFF PER IVAR , OFF MORTEN KRISTIAN , OHM OLE‐JØRGEN , CHEN JIAN
Published: January 2007

Background and Study Objective: Patients with paroxysmal or persistent atrial fibrillation (AF) can be treated by pulmonary vein (PV) isolation. Although the recurrence rate after the procedure is relatively high, the long‐term outcomes after initially recurrence‐free procedures remains unclear. We examined the rates of recurrence of AF after PV isolation.

Methods: Our study included 278 consecutive patients with drug‐refractory AF (mean age = 53 ± 11 years, 228 men). PV isolation was based on the disappearance of PV potentials recorded from a circumferential catheter after segmental ostium ablation. Cavo‐tricuspid isthmus lines and additional atrial lines were performed in 124 and 28 patients, respectively. Patients were monitored for a mean of 26 ± 11 months (range 12–56). Recurrence was defined as ≥1 episodes of symptomatic or asymptomatic AF >1 month after the procedure.

Results: A total of 120 (34) patients had ≥1 recurrence of AF >1 month after the procedure, of whom 14 (4) had a first recurrence >6 months after the procedure. There was a significantly higher recurrence rate among patients with persistent AF.

Conclusions: A relatively high AF recurrence rate was observed after PV isolation. AF may recur late after the ablation procedure, though the majority of recurrences occurred within 6 months after the first procedure. There were no differences in incidence or time of occurrence of late recurrences between patients with paroxysmal versus persistent AF.
Antiarrhythmic Drug Therapy after Radiofrequency Catheter Ablation in Patients with Atrial Fibrillation
Authors: TURCO PIETRO , DE SIMONE ANTONIO , LA ROCCA VINCENZO , IULIANO ASSUNTA , CAPUANO VINCENZO , ASTARITA COSTANTINO , DI NAPOLI TOMMASO , MESSINA VINCENZO , BALDI SILVANO , STABILE GIUSEPPE
Published: January 2007

Objectives: The use of antiarrhythmic drugs after ablation is a controversial issue when evaluating the efficacy of atrial fibrillation (AF) ablation. This study compares in a prospective and randomized fashion the impact of an antiarrhythmic drug in preventing AF recurrence after AF ablation.

Methods: From February 2004 to May 2005, 107 consecutive patients (mean age 57 ± 10 years, 69 men), with paroxysmal (60%) or persistent (40%) drug refractory AF, were randomly assigned to ablation alone (Group A, 53 patients) or combined with the best antiarrhythmic therapy, preferably amiodarone (Group B, 54 patients). All patients underwent cavo‐tricuspid and left inferior pulmonary vein (PV)‐mitral isthmus ablation plus circumferential PV ablation, using a guided electro‐anatomical approach. Standard electrocardiograms (ECG), and ambulatory and transtelephonic ECG monitoring were used to assess AF recurrences. Recurrences during the first month after ablation were excluded from this analysis.

Results: At 12 months of follow‐up, no significant difference was observed in the rates of AF recurrences between Group A (18/53 patients, 34%) and Group B (16/54 patients, 30%). The percentage of patients with ≥1 asymptomatic AF episode was higher in Group B than in Group A (10/16 patients, 63%, vs 5/18 patients, 28%, P = 0.04).

Conclusions: Continuing antiarrhythmic drug therapy in patients who undergo catheter ablation for AF did not lower the rate of AF recurrences. Antiarrhythmic drugs increased the proportion of patients with asymptomatic AF episodes.