Biomedical subjects

Stephane Garrigue

Publications and source records attributed to Stephane Garrigue.

At least 19 recordsLinked to original sources

PubMed2006

Dynamic ventricular dyssynchrony: an exercise-echocardiography study.

OBJECTIVES: We sought to assess the effects of exercise on ventricular dyssynchrony in patients with normal and depressed left ventricular (LV) function. BACKGROUND: Asynchronous myocardial contraction adversely influences ventricular function and is associated with a poor prognosis in heart failure. Exercise-induced changes in ventricular dyssynchrony may be an important determinant of dynamic changes in cardiac output and mitral regurgitation. METHODS: A total of 65 consecutive heart failure patients and 50 matched healthy control patients underwent exercise echocardiography. Conventional and tissue Doppler parameters were measured before and during symptom-limited exercise. Left ventricular dyssynchrony was defined as the standard deviation of 12 LV segmental electromechanical delays. Analysis of the control group allowed delimitation of normal cutoff values. RESULTS: In patients with normal left ventricular function, exercise did not modify the extent of LV asynchrony. In contrast, in heart failure patients, LV dyssynchrony increased by at least 20% in 34%, remained stable in 37%, and decreased by at least 20% in 29%. Moreover, 26% of heart failure patients had either exercise induction or normalization of ventricular dyssynchrony. A significant association was found between exercise-induced changes in dyssynchrony and the presence of ischemic cardiomyopathy (p < 0.05). Rest-exercise differences in ventricular dyssynchrony were correlated with changes in cardiac output and mitral regurgitation (r = -0.63 and 0.56, respectively). CONCLUSIONS: In heart failure patients, exercise can alter the magnitude of ventricular dyssynchrony. Some patients have a response to exertion with induction of ventricular dyssynchrony, whereas others show normalization. Changes in ventricular dyssynchrony during exercise correlate with alterations in cardiac output and mitral regurgitation.

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PubMed2006

Echocardiographic assessment during exercise of heart failure patients with cardiac resynchronization therapy.

This prospective echocardiographic study investigated the respective impacts of left ventricular (LV) pacing and simultaneous and sequential biventricular pacing (BVP) on ventricular dyssynchrony during exercise in 23 patients with compensated heart failure and ventricular conduction delays. During exercise, LV pacing and BVP significantly (p <0.05) improved mitral regurgitation and LV dyssynchrony compared with spontaneous activation. LV segmental electromechanical delays were significantly prolonged during LV pacing, leading to increased systolic time (p <0.05), decreased LV filling time (p <0.05), and decreased stroke volume (p <0.05) compared with BVP. After optimization of the interventricular delay with sequential BVP, additional benefit was obtained during exercise in terms of stroke volume and mitral regurgitation (p <0.05). The optimal interventricular delay was different at rest and during exercise in 57% of the patients. Changes from at rest to exercise in LV dyssynchrony were correlated with changes in stroke volume (r = -0.61, p <0.01) and changes in mitral regurgitation (r = 0.60, p <0.01).

Cardiac Pacing, Artificial↗

PubMed2006

Cardiovascular effects and risk of syncope related to donepezil in patients with Alzheimer's disease.

BACKGROUND: When otherwise unexplained, syncope in patients with Alzheimer's disease may be attributed to bradycardia caused by cholinesterase inhibitors. We studied prospectively the clinical events and cardiovascular changes occurring during treatment with donepezil in patients with Alzheimer's disease. METHODS: Consecutive patients presenting with mild-to-moderate Alzheimer's disease were included in the study. Their clinical characteristics, blood pressure, heart rate and electrocardiogram were recorded before (baseline) and during treatment with donepezil. The drug was administered at a dosage of 5 mg/day for 1 month and 10 mg/day for the following 7 months, as tolerated. We compared the baseline observations with those made at 1, 2 and 8 months of donepezil treatment. We also examined the effects of negatively chronotropic or dromotropic drugs concomitantly administered with donepezil. RESULTS: Thirty patients were included in the study, of whom 43% were taking negatively chronotropic or dromotropic drugs. The first month of therapy (donepezil 5 mg/day) was completed by 26 patients. During the 7-month high-dosage phase (10 mg/day), four patients dropped out of the study; thus, 22 patients completed the full 8 months of the study. The mean heart rate was 66 +/- 8 beats/min at baseline in the overall study population. This decreased significantly to 62 +/- 9, 61 +/- 7 and 62 +/- 8 beats/min at the 1, 2 and 8 month timepoints, respectively (all p = 0.002 vs baseline). Among patients not receiving negatively chronotropic or dromotropic drugs, heart rate decreased significantly over the course of the study (from 67 +/- 8 beats/min at baseline to 62 +/- 8 beats/min at 1 month, 62 +/- 7 beats/min at 2 months and 62 +/- 8 beats/min at 8 months [all p = 0.005 vs baseline]). There was no significant change in heart rate in patients who were receiving negatively chronotropic or dromotropic drugs. The PR interval increased over the course of the study in all patient groups, but these changes were only statistically significant in the group of patients who were not taking negatively chronotropic or dromotropic drugs (155 +/- 23ms at baseline vs 158 +/- 21, 160 +/- 22 and 163 +/- 24ms at the 1, 2 and 8 month timepoints; all p = 0.02 vs baseline). One patient developed syncope due to orthostatic hypotension; there were no cases of bradycardia-induced syncope. Gastrointestinal manifestations were reported in ten of the study patients. Abdominal pain and vomiting were the reasons for study termination in five of the eight patients who did not complete the trial. CONCLUSION: A donepezil-induced decrease in heart rate and increase in PR interval were observed only in patients with Alzheimer's disease who were not treated with negatively chronotropic or dromotropic drugs. These changes were not associated with bradycardia-induced syncope.

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PubMed2005

Cardiac resynchronization therapy: Part 1--issues before device implantation.

Cardiac resynchronization therapy (CRT) has been used extensively over the last years in the therapeutic management of patients with end-stage heart failure. Data from 4,017 patients have been published in eight large, randomized trials on CRT. Improvement in clinical end points (symptoms, exercise capacity, quality of life) and echocardiographic end points (systolic function, left ventricular size, mitral regurgitation) have been reported after CRT, with a reduction in hospitalizations for decompensated heart failure and an improvement in survival. However, individual results vary, and 20% to 30% of patients do not respond to CRT. At present, the selection criteria include severe heart failure (New York Heart Association functional class III or IV), left ventricular ejection fraction <35%, and wide QRS complex (>120 ms). Assessment of inter- and particularly intraventricular dyssynchrony as provided by echocardiography (predominantly tissue Doppler imaging techniques) may allow improved identification of potential responders to CRT. In this review a summary of the clinical and echocardiographic results of the large, randomized trials is provided, followed by an extensive overview on the currently available echocardiographic techniques for assessment of LV dyssynchrony. In addition, the value of LV scar tissue and venous anatomy for the selection of potential candidates for CRT are discussed.

Cardiac Output, Low↗

PubMed2005

Cardiac resynchronization therapy: Part 2--issues during and after device implantation and unresolved questions.

Encouraged by the clinical success of cardiac resynchronization therapy (CRT), the implantation rate has increased exponentially, although several limitations and unresolved issues of CRT have been identified. This review concerns issues that are encountered during implantation of CRT devices, including the role of electroanatomical mapping, whether CRT implantation should be accompanied by simultaneous atrioventricular nodal ablation in patients with atrial fibrillation, procedural complications, and when to consider surgical left ventricular lead positioning. Furthermore, (echocardiographic) CRT optimization and assessment of CRT benefits after implantation are highlighted. Also, controversial issues such as the potential value of CRT in patients with mild heart failure or narrow QRS complex are addressed. Finally, open questions concerning when to combine CRT with implantable cardioverter-defibrillator therapy and the cost-effectiveness of CRT are discussed.

Atrial Fibrillation↗

PubMed2005

Effect of catheter ablation on quality of life of patients with paroxysmal atrial fibrillation.

BACKGROUND: Although improved quality of life is one of the primary aims of catheter ablation for paroxysmal atrial fibrillation, there is a paucity of published data on this topic. OBJECTIVES: The purpose of this study was to determine the effect of curative catheter ablation on the quality of life of patients with symptomatic, drug-refractory paroxysmal atrial fibrillation. METHODS: This was a prospective nonrandomized study of 63 consecutively enrolled patients (49 men and 14 women, age 56 +/- 7 years). Patients were excluded from the study if they had significant structural heart disease. The ablation strategy consisted of systematic isolation of all pulmonary veins, followed by limited linear ablation in the atria comprising left isthmus ablation (between the left inferior pulmonary vein and lateral mitral annulus) and cavotricuspid isthmus ablation. Patients completed quality-of-life questionnaires comprising the SF-36 and Symptom Checklist at baseline and 3 and 12 months following ablation. RESULTS: Fifty-four patients (86%) were free of symptomatic recurrence at 12-month follow-up. Successful ablation resulted in a significant improvement of all eight subscales of the SF-36 and of symptom frequency and severity scores of the symptom checklist at 3 months. This improvement was maintained at 12 months. CONCLUSIONS: Combined pulmonary vein isolation and linear atrial ablation has a high success rate for cure of paroxysmal atrial fibrillation. Successful curative catheter ablation of paroxysmal atrial fibrillation significantly and persistently improved quality of life during long-term follow-up. This improvement in quality of life was accompanied by a significant reduction in arrhythmia symptom frequency and severity.

Atrial Fibrillation↗

PubMed2005

Clinical predictors of noninducibility of sustained atrial fibrillation after pulmonary vein isolation.

BACKGROUND: Noninducibility of sustained atrial fibrillation (AF) after pulmonary vein isolation (PVI) has been shown to be associated with a better clinical outcome. We evaluated the role of clinical variables that could predict noninducibility of sustained AF after PVI. METHODS AND RESULTS: Data were collected prospectively from 181 patients (153 male; age 54 +/- 9 years) referred for ablation of drug-refractory symptomatic paroxysmal AF (duration < or =7 days). Clinical variables were evaluated with regard to their ability of predicting noninducibility of sustained AF (< or =10 minutes) after PVI. Univariate analysis was performed on all collected variables followed by multivariate analysis for variables showing a P value <0.1. After PVI, sustained AF was noninducible in 97 (54%) patients. The following clinical variables showed a significant difference between the groups: body weight, longest AF episode, duration of AF history, presence or absence of structural heart disease, left ventricular (LV) hypertrophy, prior cardioversion, left atrial (LA) parasternal, and longitudinal diameters and LV diameters. On multivariate analysis, three independent predictors of noninducibility were identified: a shorter duration of AF episodes (AF <12 hours: RR 0.01 (0.002-0.06), P < 0.001; AF 12-48 hours: RR 0.07 (0.01-0.37), P = 0.001); LA longitudinal diameter <57 mm (RR 0.33 (0.13-0.82), P = 0.016); and absence of LV hypertrophy (RR 0.15 (0.04-0.63), P = 0.01). CONCLUSIONS: Shorter AF episodes, smaller LA longitudinal diameter, and absence of LV hypertrophy are independent predictors of noninducibility of sustained AF after PVI.

Adult↗

PubMed2005

Causes of syncope in patients with Alzheimer's disease treated with donepezil.

INTRODUCTION: Treatment of Alzheimer's disease (AD) with cholinesterase inhibitors carries a theoretical risk of precipitating bradycardia. Though syncope occurs in patients with AD, its aetiology is unclear. The aim of this study was to determine the causes of syncope in patients with AD who were treated with donepezil and hospitalised for evaluation of syncope. METHODS: We studied 16 consecutive patients (12 women, 4 men) with AD aged 80 +/- 4 years who were hospitalised for evaluation of syncope. All patients underwent staged evaluation, ranging from physical examination to electrophysiological testing. RESULTS: The mean dose of donepezil administered was 7.8 mg/day, and the mean duration of donepezil treatment at the time of syncope was 12 +/- 8 months. A cause of syncope was identified in 69% of patients. Carotid sinus syndrome was observed in three patients, complete atrioventricular block in two patients, sinus node dysfunction in two patients, severe orthostatic hypotension in two patients and paroxysmal atrial fibrillation in one patient. A brain tumour was discovered in one patient. No cause of syncope was found in 31% of patients despite comprehensive investigation. Repetition of the investigations after discontinuation of donepezil was noncontributory. CONCLUSION: In patients with AD treated with donepezil, a noninvasive evaluation identified a probable cause of syncope in over two-thirds of patients. Cardiovascular abnormalities were predominant. Noninvasive evaluation is recommended before discontinuing treatment with cholinesterase inhibitors in patients with AD and unexplained syncope.

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PubMed2004

Echocardiographic parameters of ventricular dyssynchrony validation in patients with heart failure using sequential biventricular pacing.

OBJECTIVES: We sought to evaluate the relationship between hemodynamic and ventricular dyssynchrony parameters in patients undergoing simultaneous and sequential biventricular pacing (BVP). BACKGROUND: Various echocardiographic parameters of ventricular dyssynchrony have been proposed to screen and optimize BVP therapy. METHODS: Forty-one patients with heart failure undergoing BVP implantation were studied. Echocardiography coupled with tissue tracking and pulsed Doppler tissue imaging (DTI) was performed before and after BVP implantation and after three months of optimized BVP. Indexes of inter- or intraventricular dyssynchrony were correlated with hemodynamic changes during simultaneous and sequential BVP (10 intervals of right ventricular [RV] or left ventricular [LV] pre-excitation). RESULTS: Variations in intra-LV delay(peak), intra-LV delay(onset), and index of LV dyssynchrony measured by pulsed DTI were highly correlated with those of cardiac output (r = -0.67, r = -0.64, and r = -0.67, respectively; p < 0.001) and mitral regurgitation (r = 0.68, r = 0.63, and r = 0.68, respectively; p < 0.001), whereas variations in the extent of myocardium displaying delayed longitudinal contraction (r = -0.48 and r = 0.51, respectively; p < 0.05) and the variations in septal-to-posterior wall motion delay (r = -0.41, p < 0.05 and r = 0.24, p = NS, respectively) were less correlated. The changes in interventricular dyssynchrony were not significantly correlated (p = NS). Compared with simultaneous BVP, individually optimized sequential BVP significantly increased cardiac output (p < 0.01), decreased mitral regurgitation (p < 0.05), and improved all parameters of intra-LV dyssynchrony (p < 0.01). At three months, a significant reverse mechanical LV remodeling was observed with significantly decreased LV volumes (p < 0.01) associated with an increased LV ejection fraction (p = 0.035). CONCLUSIONS: Specific echocardiographic measurements of ventricular dyssynchrony are highly correlated with hemodynamic changes and may be a useful adjunct in the selection and optimization of BVP. Individually optimized sequential BVP provided a significant early hemodynamic improvement compared with simultaneous BVP.

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PubMed2004

Detrimental ventricular remodeling in patients with congenital complete heart block and chronic right ventricular apical pacing.

BACKGROUND: Although dual-chamber pacing improves cardiac function in patients with complete congenital atrioventricular block (CCAVB) by restoring physiological heart rate and atrioventricular synchronization, the long-term detrimental effect of asynchronous electromechanical activation induced by apical right ventricular pacing (RVP) has not been well clarified. METHODS AND RESULTS: Twenty-three CCAVB adults (24+/-3 years) with a DDD transvenous pacemaker underwent conventional echocardiography before implantation and, after at least 5 years of RVP, an exercise test and echocardiography coupled with tissue Doppler imaging and tissue tracking. They were compared with 30 matched healthy control subjects. After 10+/-3 years of RVP, CCAVB adults had significantly higher values versus controls in terms of intra-left ventricular (LV) asynchrony (respectively, 59+/-18 versus 19+/-9 ms, P<0.001), extent of LV myocardium displaying delayed longitudinal contraction (39+/-15% versus 10+/-7%, P<0.01), and septal-to-posterior wall-motion delay (84+/-26 versus 18+/-9 ms, P<0.01). The ratio of late-activated posterior to early-activated septal wall thickness was higher after long-term RVP than before (1.3+/-0.2 vs 1+/-0.1, P=0.05) and was higher than in controls (1+/-0.1, P<0.05). The percentage of patients with increased LV end-diastolic diameter was higher after long-term RVP than before implantation and was higher than in controls (57% versus 13%, P<0.05, and 57% versus 0%, P<0.01, respectively). CCAVB patients with long-term RVP had a lower cardiac output than controls (3.8+/-0.6 versus 4.9+/-0.8 L/min, P<0.05) and lower exercise performance (123+/-24 versus 185+/-39 W, P<0.001). CONCLUSIONS: Prolonged ventricular dyssynchrony induced by long-term endovenous RVP is associated with deleterious LV remodeling, LV dilatation, LV asymmetrical hypertrophy, and low exercise capacity. These new data highlight the importance of the ventricular activation sequence in all patients with chronic ventricular pacing.

Adult↗

PubMed2004

Improvement of left ventricular wall synchronization with multisite ventricular pacing in heart failure: a prospective study using Doppler tissue imaging.

UNLABELLED: We sought to assess right, left and biventricular pacing effects on myocardial function by using pulsed-Doppler tissue imaging (DTI) and automated border detection (ABD) techniques which provide electromechanical delay (EMD) assessment of the different left ventricular walls. METHODS: 15 patients (67+/-7 years) with drug-resistant primitive dilated cardiomyopathy and QRS> or =140 ms received a pacemaker for multisite ventricular pacing. Echocardiography was performed after 1 month of biventricular pacing (BVP). Echocardiographic measurements were recorded during spontaneous rhythm (SpR), right ventricular pacing (RVP), left ventricular pacing (LVP) and BVP. RESULTS: LV ejection fraction was statistically similar between the four rhythms. BVP showed a significant EMD decrease for the lateral LV wall vs. SpR, RVP and even LVP. LVP resulted in significantly longer aortic pre-ejection time vs. BVP while the EMD temporal dispersion (time between the shortest regional EMD and the longest one) was similar in the two modes. CONCLUSIONS: BVP and LVP substantially reduce the EMD temporal dispersion of the four LV walls, but with a longer aortic pre-ejection time for LVP. In RVP, LVP and BVP, the septal LV wall is always activated later than during SpR. BVP and LVP are associated with a mitral regurgitation reduction.

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PubMed2004

Intra-left ventricular electromechanical asynchrony. A new independent predictor of severe cardiac events in heart failure patients.

OBJECTIVES: We sought to assess the electromechanical parameters, using tissue Doppler echocardiography, as potential independent predictors of heart failure (HF) worsening. BACKGROUND: Ventricular conduction disorders worsen the prognosis for HF patients. However, the relationships between the QRS width and morphology, hemodynamic parameters, and presence and magnitude of intra-left ventricular (LV) and inter-ventricular (V) asynchrony have not been well clarified. METHOD: A total of 104 patients with an LV ejection fraction (EF) </=45% and stabilized HF, without myocardial infarction (MI), underwent echocardiography coupled with tissue Doppler imaging and were followed for one year. The protocol analyzed the incidence of worsening HF (hospitalization for cardiac decompensation). Inter-V and regional electromechanical delays for the anterior, septal, inferior, and lateral LV walls were correlated with the QRS morphology and duration. The intra-LV and inter-V asynchrony values of these patients were compared with those of healthy subjects matched by gender and age criteria to determine the respective normal ranges. RESULTS: The presence of intra-LV (but not inter-V) asynchrony was identified as an independent predictor of severe cardiac events (hazard ratio 3.39, p < 0.0001), independent of the LVEF and QRS width. Of patients with a QRS width <120 ms (55%; n = 57), 56% presented with major intra-LV asynchrony and 12% with inter-V asynchrony. Intra-LV asynchrony was observed in 84% of left bundle branch block patients, but also in 83% of right bundle branch block patients (p = NS). There was a poor correlation between the QRS width and intra-LV or inter-V asynchrony (r = 0.36, p = NS and r = 0.43, p = 0.05, respectively). CONCLUSIONS: In HF patients without MI, patients with intra-LV asynchrony are those with a significantly higher risk of cardiac events, independent of the QRS width and LVEF. Accordingly, such patients should be more actively identified for early intensive treatment and survey.

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PubMed2004

Incidence, clinical implications and prognosis of atrial arrhythmias in Brugada syndrome.

AIMS: This single-centre prospective study was designed to determine the incidence, therapeutic implications and prognosis of atrial arrhythmias (AA) in patients with Brugada syndrome (BS). METHODS AND RESULTS: Fifty nine consecutive patients with BS and 31 age and gender-matched controls underwent an electrophysiological exploration and were followed-up during 34+/-13 months. The final AA incidence was 20% in BS patients vs 0% in controls (p < 0.01). Ventricular inducibility was significantly related to a history of AA (p = 0.02). The incidence of AA in patients with a spontaneous electrocardiogram of BS was 26% vs 10% in patients with a flecainide-induced electrocardiogram (p < 0.05). In patients with an indication of implantable cardioverter defibrillator (ICD), the incidence of AA reached 27% vs 13% in patients with BS but without ICD indication (p < 0.05). Inappropriate shocks due to AA episodes were observed in 14% of ICD patients vs 10.5% of appropriate shocks. Multivariate analysis identified the implantation of a single-chamber device as an independent predictive factor of inappropriate ICD discharges (p < 0.05). CONCLUSION: BS patients exhibit an abnormally high proportion of AA. Our data strongly suggest a more advanced disease process in BS patients with spontaneous AA. Careful programming of single-chamber ICD should be recommended to avoid inappropriate discharges.

Adult↗

PubMed2004

Biventricular pacing and left ventricular pacing in heart failure: similar hemodynamic improvement despite marked electromechanical differences.

INTRODUCTION: We conducted an acute echocardiographic study comparing hemodynamic and ventricular dyssynchrony parameters during left ventricular pacing (LVP) and biventricular pacing (BVP). We sought to clarify the mechanisms responsible for similar hemodynamic improvement despite differences in electrical activation. METHODS AND RESULTS: Thirty-three patients underwent echocardiography prior to implantation with a multisite pacing device (spontaneous rhythm [SR]) and 2 days after implantation (BVP and LVP). Interventricular dyssynchrony (pulsed-wave Doppler), extent of myocardium displaying delayed longitudinal contraction (%DLC; tissue tracking), and index of LV dyssynchrony (pulsed-wave tissue Doppler imaging) were assessed. Compared to SR, BVP and LVP caused similar significant improvement of cardiac output (LVP: 3.2 +/- 0.5, BVP: 3.1 +/- 0.7, SR: 2.3 +/- 0.6 L/min; P < 0.01) and mitral regurgitation (LVP: 25.1 +/- 10, BVP: 24.7 +/- 11, baseline: 37.9 +/- 14% jet area/left atria area; P < 0.01). LVP resulted in a smaller index of LV dyssynchrony than BVP (29 +/- 10 vs 34 +/- 14; P < 0.05). However, LVP exhibited a longer aortic preejection delay (220 +/- 34 vs 186 +/- 28 msec; P < 0.01), longer LV electromechanical delays (244.5 +/- 39 vs 209.5 +/- 47 msec; P < 0.05), greater interventricular dyssynchrony (56.6 +/- 18 vs 31.4 +/- 18; P < 0.01), and higher%DLC (40.1 +/- 08 vs 30.3 +/- 09; P < 0.05), leading to shorter LV filling time (387 +/- 54 vs 348 +/- 44 msec; P < 0.05) compared to BVP. CONCLUSION: Although LVP and BVP provide similar hemodynamic improvement, LVP results in more homogeneous but substantially delayed LV contraction, leading to shortened filling time and less reduction in postsystolic contraction. These data may influence the choice of individual optimal pacing configuration.

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PubMed2004

Death during polysomnography of a patient with cheyne-stokes respiration, respiratory acidosis, and chronic heart failure.

A patient with chronic heart failure and chronic respiratory failure (CRF) underwent ambulatory polysomnography at home. She was found dead on the morning after the recording. The tracings confirmed severe sleep apnea syndrome. After 8 h of incessant Cheyne-Stokes respiration during sleep, respiratory arrest occurred, followed 7 min later by asystole. This report illustrates a case of respiratory drive failure during sleep as the mode of death in a patient with heart failure, sleep apnea syndrome, and CRF.

Acidosis, Respiratory↗

PubMed2003

Comparison of permanent left ventricular and biventricular pacing in patients with heart failure and chronic atrial fibrillation: a prospective hemodynamic study.

BACKGROUND: Left ventricular pacing (LVP) and biventricular pacing (BVP) have been proposed as treatments for patients with advanced heart failure complicated by discoordinate contraction due to intraventricular conduction delay. For patients in sinus rhythm, BVP works in part by modulating the electronic atrial-ventricular time delay and thus optimizing contractile synchrony, the contribution of atrial systole, and reducing mitral regurgitation. However, little is known of the mechanisms of BVP in heart failure patients with drug-resistant chronic atrial fibrillation. HYPOTHESIS AND METHODS: LVP differs from BVP because hemodynamic and clinical improvement occurs in association with prolongation rather than shortening of the QRS duration. We sought to determine if LVP or BVP improves mechanical synchronization in the presence of atrial fibrillation. Thirteen patients with chronic atrial fibrillation, severe heart failure and QRS >or=140 ms received (after His bundle ablation) a pacemaker providing both LVP and BVP. The mean age was 62 +/- 6 years and left ventricular ejection fraction was 24 +/- 8%. After a baseline phase of one month with right ventricular pacing, all patients underwent in random order 2 phases of 2 months (LVP and BVP). At the end of each phase, an echocardiogram, a hemodynamic analysis at rest and during a 6-minute walking test and a cardio-pulmonary exercise test were performed. RESULTS: LVP and BVP provided similar performances at rest (p = ns). The 6-minute walking test revealed similar performances in both pacing modes but patients were significantly more symptomatic at the end of the test with LVP ( p = 0.035). The cardio-pulmonary exercise test showed higher performances with BVP (92 +/- 34 Watts) vs. LVP (77 +/- 23; p = 0.03). LVP was associated with significantly more premature ventricular complexes recorded during the 6 minute walking test (49 +/- 71) than BVP (10 +/- 23; p = 0.04). CONCLUSIONS: In this small series of patients with atrial fibrillation, congestive heart failure and a prolonged QRS duration, LVP and BVP provided similar hemodynamic effects at rest whereas BVP was associated with better hemodynamic effects during exercise and fewer premature ventricular complexes. Although the mechanisms for the observed differences are uncertain, it is possible that there is worsening of right ventricular function due to a rise in left-to-right electromechanical delay during exercise. Increased catecholamines release might contribute to the lower exercise tolerance and greater number of premature ventricular complexes recorded during exercise observed during LVP compared to BVP. RECOMMENDATIONS: Patients with atrial fibrillation, heart failure and QRS prolongation who are candidates for His-bundle ablation and cardiac resynchronization therapy may respond better to BVP rather than to LVP.

Atrial Fibrillation↗

PubMed2003

Optical mapping technique applied to biventricular pacing: potential mechanisms of ventricular arrhythmias occurrence.

Although it has been suggested that multisite ventricular pacing alleviates heart failure by restoring ventricular electrical synchronization, the respective roles of voltage output, interventricular delay, and pacing sites in the development of ventricular arrhythmias occurrence have not been studied during biventricular pacing or LV pacing. Voltage-sensitive dye was used in eight ischemic Langerdorff-perfused guinea pig hearts to measure ventricular activation times and examine conduction patterns during multisite pacing from three RV and four LV sites. The hearts were stained with di-4-ANEPPS and mapped with a 16 x 16 photodiode array at a resolution of 625 microns per diode. Isochronal maps of RV and LV activation were plotted. Ischemia was produced by gradually halving the perfusion output over 5 minutes. Pacing the RV apex and the base of the LV anterior wall was associated with the most homogeneous and rapid activation pattern (28 +/- 9 vs 41 +/- 12 ms with the other configurations, P < 0.01), and no inducible arrhythmia. In six hearts, ventricular tachycardia could be induced when pacing from the right and left free walls with 20 ms of interventricular delay, at six times the pacing threshold output. In four hearts, simultaneous RV and LV pacing at high voltage output induced ventricular fibrillation with complex three-dimensional propagation patterns, independently of the pacing sites. During biventricular pacing with ischemia, pacing at high voltage output with a long interventricular delay is likely to induce ventricular arrhythmias, particularly when left and right pacing results in a conduction pattern orthogonal to the ventricular myocardial fibers orientation.

Animals↗

PubMed2002

Long-term benefits of biventricular pacing in congestive heart failure: results from the MUltisite STimulation in cardiomyopathy (MUSTIC) study.

OBJECTIVES: The main objective of this study was to assess if the benefits of biventricular (BiV) pacing observed during the crossover phase were sustained over 12 months. BACKGROUND: MUltisite STimulation In Cardiomyopathies (MUSTIC) is a randomized controlled study intended to evaluate the effects of BiV pacing in patients with New York Heart Association (NYHA) class III heart failure and intraventricular conduction delay. METHODS: Of 131 patients included, 42/67 in sinus rhythm (SR) and 33/64 in atrial fibrillation (AF) were followed up longitudinally at 9 and 12 months by 6-min walked distance, peak oxygen uptake (peak VO(2)), quality of life by the Minnesota score, NYHA class, echocardiography, and left ventricular ejection fraction by radionuclide technique. RESULTS: At 12 months, all SR and 88% of AF patients were programmed to BiV pacing. Compared with baseline, the 6-min walked distance increased by 20% (SR) (p = 0.0001) and 17% (AF) (p = 0.004); the peak VO(2) by 11% (SR) and 9% (AF); quality of life improved by 36% (SR) (p = 0.0001) and 32% (AF) (p = 0.002); NYHA class improved by 25% (SR) (p = 0.0001) and 27% (AF) (p = 0.0001). The ejection fraction improved by 5% (SR) and 4% (AF). Mitral regurgitation decreased by 45% (SR) and 50% (AF). CONCLUSIONS: The clinical benefits of BiV pacing appeared to be significantly maintained over a 12-month follow-up period.

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