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Biomedical subjects

Philippe Ritter

Publications and source records attributed to Philippe Ritter.

7 recordsLinked to original sources
PubMed2006

Left bundle branch block as a risk factor for progression to heart failure.

The prevalence of conduction disturbances, particularly left bundle branch block (LBBB), is strongly correlated with age and with the presence of cardiovascular disease. LBBB has been reported to affect approximately 25% of the heart failure (HF) population and it is likely that the deleterious role of such conduction disorders in the progression to HF has been underestimated. The purpose of this article is to review the data from the literature indicating that LBBB may have a causative role, mediated through the resulting intra-ventricular asynchrony, in the deterioration of cardiac function and the development of cardiac remodelling and HF. It also aims to address the potential for future clinical therapies for this conduction disorder.

Bundle-Branch Block↗
PubMed2005

Incidence and predictive factors of atrial fibrillation in paced patients.

We have designed a prospective observational study to analyze the incidence and predictive factors of atrial fibrillation (AF) during a long follow-up, in a large population. Atrial fibrillation episodes were documented by the fallback mode switch (FMS) provided by implanted pacemakers. We have included 377 patients (61% men). The pacing indications were atrioventricular (AV) block (49%), sinus node disease (SND, 16%), bradycardia-tachycardia syndrome (BTS, 5%), AV block + SND (19%), AV block + BTS (6%), and BTS + SND (5%). The mean age at implant was 75 +/- 12 (range 28-95). Atrial fibrillation before inclusion was documented in 10% of patients. Drug therapy at first follow-up included beta-adrenergic blockers (17% of the patients), amiodarone (13%), and others (16%). The mean follow-up was 30 +/- 24 weeks. At least one AF episode was stored during follow-up in the memory of 169 pacemakers (45%). Among patients without history of AF at implant, 46% had documented FMS during follow-up. Patients with AF received more antiplatelet medications than patients without AF (P = 0.03). In patients with AF, New York Heart Association functional class was slightly higher, amiodarone and sotalol were more often prescribed, and the proportion of hypertension was higher than in patients without AF. However, these trends were not statistically significant. A significant higher incidence of premature atrial beats was observed in patients with AF than patients without AF (P < 0.0002). Patients with AF had a lower atrial percentage of paced events (55%) than patients without AF (63%, P < 0.02). These preliminary results confirm the high incidence of AF in paced patients and suggest a preventive effect of atrial pacing. The effects of other clinical variables may be confirmed with a longer follow-up in a larger population.

Adult↗
PubMed2003

Comparative prospective randomized efficacy testing of different guiding catheters for coronary sinus cannulation in heart failure patients.

INTRODUCTION: The efficacy of different shapes of guiding catheters for coronary sinus (CS) cannulation was evaluated at implant of a cardiac resynchronization therapy device that required transvenous placement of a pacing lead in a coronary vein on the left ventricle. METHODS AND RESULTS: Comparative testing of 5 different guiding catheter shapes was attempted in 29 consecutive patients. Four newer guiding catheters were tested in a prospective randomized manner with a reference standard catheter always tested in the last place. All of the new catheters included a distal shape that consisted of a single curve or a compound set of curves at the catheter tip, followed by a catheter shaft design which fell into one of two classes: (1). straight shaft catheters and (2). curved shaft catheters. The curved shaft class of catheters, two new and one standard, achieved higher (16/23 (70%), 17/23 (74%) and 17/22 (77%)) CS cannulation success rates than the straight shaft class catheters ((13/23 (56%) and 12/23 (52%)). The pairing of two catheters, one from each class in a single patient, or both from the curved shaft class resulted in a combined CS cannulation success rate of up to 96%. Two of the catheters were more effective from a left hand insertion than from a right hand insertion site. CONCLUSIONS: The ability to switch between guiding catheters with different shapes and compound curves can improve the CS cannulation success rate. The selection of guiding catheters should be influenced by the intended use of the catheter either from the left or from the right hand side.

Cardiac Catheterization↗
PubMed2003

Long-term experience with a preshaped left ventricular pacing lead.

This study describes a long-term experience with a new LV pacing lead. The study population consisted of 62 patients (85% men, 71 +/- 10 years old) with advanced dilated cardiomyopathy, in NYHA Class III or IV despite optimal drug therapy, and a QRS duration > 150 ms. Patients in sinus rhythm were implanted with a triple chamber pacemaker to maintain atrioventricular synchrony. A dual chamber pacemaker was implanted in patients in atrial fibrillation for biventricular pacing only. A clinical evaluation and interrogation of the resynchronization pacemaker were performed at implant, at 1 week (W1), one (M1), four (M4), and seven (M7) months after implantation. A longer follow-up (2 years) is available for patients implanted at the authors institution. LV measurements were pacing threshold at 0.5-ms pulse duration and pacing impedance. R wave amplitude (mV) was measured at the time of implantation only. The system was successfully implanted in 86% of patients with the latest design of the lead. Mean R wave amplitude at implant was 15 +/- 7 mV and mean pacing impedance was 1054 +/- 254 omega. Between implant (n = 38) and M7 (n = 15), pacing threshold rose from 0.73 +/- 0.54 to 1.57 +/- 0.60 V (P < 0.001). In conclusion, the situs lead was successfully implanted in a high percentage of patients. In addition, low pacing threshold and high impedance measured during follow-up are consistent with a low pacing current drain, ensuring a durable pulse generator longevity.

Aged↗
PubMed2003

Impact and prevention of far-field sensing in fallback mode switches.

UNLABELLED: Far-field oversensing (FFOS) promoted by high atrial sensitivity and short atrial refractory periods induces false positive mode switches. We evaluated the incidence of ventricular FFOS in a population of DDD paced patients. METHODS: One hundred thirty-seven patients (71 +/- 10 years, 76 men) implanted with a Talent DR pacemaker were studied. Before discharge, an analysis of internal data stored in the memories of the PM was performed by the specific software incorporated in the programmer in parallel with a 24-hour Holter recording. Data were validated by a panel of experts. One and 4 months follow-up was based only on the data stored in the PM memories. RESULTS: Pacing indications were atrioventricular block (n = 75), sinus node dysfunction (n = 57), and other (n = 5). Sustained far-field oversensing was observed in 12/137 patients (9%). Out of a total of 3,511 triggered mode switch episodes, FFOS accounted for 20% and 7% of a 311 days cumulative time in mode switch. Inappropriate mode switch episodes induced by far-field were more numerous but shorter than episodes prompted by atrial arrhythmias. Atrial sensitivity was increased in eight patients, successfully in four. Reprogramming of the atrial refractory period (156 +/- 11 ms) was successful in five of six patients. CONCLUSIONS: A 9% rate of ventricular FFOS was observed in an unselected population, easily and automatically diagnosed using the internal memory function and the automatic analysis provided by the programmer. Prolongation of the atrial refractory period was more effective than resetting of the atrial sensitivity in eliminating FFOS.

Aged↗
PubMed2003

Programming optimal atrioventricular delay in dual chamber pacing using peak endocardial acceleration: comparison with a standard echocardiographic procedure.

Optimization of programmed atrioventricular delay in dual chamber pacing is essential to the hemodynamic efficiency of the heart. Automatic AV delay optimization in an implanted pacemaker is highly desirable. Variations of peak endocardial acceleration (PEA) with AV delay at rest correlate well with echocardiography derived observations, particularly with end-diastolic filling and mitral valve closure timings. This suggests the possibility of devicing a procedure for the automatic determination of the optimal AV delay. The aim of this study was to compare a proposed algorithm for optimal AV delay determination with an accepted echocardiographic method. Fifteen patients with high degree AV block received BEST-Living pacing systems. Automatic AV delay scans were performed at rest (60-300 ms in 20-ms steps with 60 beats per step) in DDD at 90 ppm, while simultaneously recording cycle-by-cycle PEA values, which were averaged for each AV delay to obtain a PEA versus AV delay curve. Nonlinear regression analysis based on a Boltzmann sigmoid curve was performed, and the optimal AV delay (OAVD) was chosen as the sigmoid inflection point of the regression curve. The OAVD was also evaluated for each patient using the Ritter echocardiographic method. Good sigmoid fit was obtained in 13 of 15 patients. The mean OAVD obtained by the PEA sigmoid algorithm was 146.9 +/- 32.1 ms, and the corresponding result obtained by echocardiography was 156.4 +/- 34.3 ms (range 31.8-39.7 ms). Correlation analysis yielded r = 0.79, P = 0.0012. In conclusion, OAVD estimates obtained by PEA analysis during automatic AV delay scanning are consistent with those obtained by echocardiography. The proposed algorithm can be used for automatic OAVD determination in an implanted pacemaker pulse generator.

Aged↗