Jacky Ollitrault

Basal Asynchrony and Resynchronization with Biventricular Pacing Predict Long-Term Improvement of LV Function in Heart Failure Patients

Biventricular pacing (BiV) is emerging for patients with dilated cardiomyopathy (DCM) and asynchrony. We measured basal asynchrony and early resynchronization by radionuclide angioscintigraphy (RNA) in order to predict long‐term evolution of ventricular function after BiV. Thirty‐four patients (NYHA Class III–IV, 65.4 ± 11 years ) with large QRS (179 ± 18 ms) were implanted with BiV and studied by RNA before (D0), at day 8 (D8), and during follow‐up (20 ± 7 months) . We calculated left and right ejection fractions, the interventricular dyssynchrony (TRVLV), and the apicobasal dyssynchrony (Tab). LVEF improved from 20.2 ± 8.1% (D0) to 27.1%± 12.6% (follow‐up, P < 0.003 vs D0) and RVEF from 28.6%± 13% (D0) to 34.3 ± 11.5% (follow‐up, P < 0.03 vs D0). Inter‐ (ΔTRVLV) and intraventricular resynchronization was immediate and remained stable: TRVLV decreased from 68.3 ± 38 ms (D0) to 13.4 ± 48.5 ms (D8) and 1.8 ± 39.2 ms (follow‐up, P < 0.0001 vs D0); and Tab from 45.8 ± 64.1 ms to −18 ± 68 (D8) and −28.3 ± 53.6 ms (follow‐up, P < 0.0001 vs D0). Early inter‐ and intraventricular resynchronization (ΔTab) at D8 were related to late LVEF and RVEF improvement. Together, an LVEF > 15% and a significant interventricular dyssynchrony (TRVLV > 60 ms) at D0 have a sensitivity of 79% and a positive predictive value of 83% to predict an improvement of LVEF superior to 5% at follow‐up. In DCM patients, BiV resynchronizes ventricles early and in the long‐term, while RVEF and LVEF improve progressively. Patients with large electromechanical dyssynchrony benefit most from BiV. (PACE 2003; 26:1815–1823)

Physiological relationship between AV interval and heart rate in healthy subjects: applications to dual chamber pacing.

The purpose of this paper is to specify the mathematical relationship between spontaneous AV interval (AVI) and heart rate (HR), the amplitude and rate of variation of AVI, and the physiological factors likely to affect these characteristics. Ten patients with healthy hearts were studied. Two catheter electrodes were positioned in the right atrium and at the tip of the right ventricle respectively, allowing the detection of endocardial signals. The AV and AA intervals for each heart cycle were digitized to on accuracy of ± 1 msec. Measurements were made at rest, then during a stress test on an exercise bicycle, and finally during the recovery phase. The results show that adaptation is very precise and takes place instantly. Any variation in heart rate causes an immediate, inversely proportional variation in AVI. Adaptation follows a linear pattern, generally with relatively low amplitude and an average AVI reduction of 27.5 ±11.2 msec for an average HR increase of 78.7 ± 22.5 bpm, i.e., a decrease of 4 ± 2.1 msec for an HR variation 0f 10 bpm. The amplitude and variation rate of AVI seem to be independent 0f the age and base value of the PR interval. These observations may be useful for designing new VDD or DDD pacemakers that automatically adapt the AV interval to the instantaneous heart rate. The hemodynamic benefits 0f this adaptation were also demonstrated.

Failure of the Exercise Test to Predict the Anterograde Refractory Period of the Accessory Pathway in Wolff Parkinson White Syndrome

Modifications of the delta wave on the surface ECG during an exercise stress test were compared to electrophysiological variations in accessory pathway (AP) refractoriness and in AV node conduction, during intravenous isoproterenol infusion in ten patients with WPW syndrome. In one patient, the delta wave persisted unchanged at the end of exercise and, with isoproterenol, there was a greater reduction in the AP anterograde effective refractory period (AEHP) than in AV node conduction time. In three patients, the delta wave became less and less apparent but without completely disappearing; in these patients, the slight reduction of the AERP in the accessory pathway with isoproterenol was comparable to the reduction in AV node conduction time, explaining the progressive fusion between the two activation fronts. In the six other patients, the delta wave completely disappeared during exercise: in two cases, suddenly from one cycle to the next with strong concordance between the measured (isoproterenol) and the estimated (exercise test) AERP in the AP; in four cases, the disappearance was progressive with a significantly greater reduction in the AV node conduction time than in the measured AEHP of AP which was nonetheless very short, 190 to 225 ms, during isoproterenol infusion. These findings confirm the limitations of the exercise test to predict the AERP of the AP. In addition, they demonstrate that modifications in the delta wave during exercise result from a balance between the relative effects of sympathetic stimulation on refractoriness of AP and normal AV conduction.

Determinants of Mortality in Patients Undergoing Cardiac Resynchronization Therapy: Baseline Clinical, Echocardiographic, and Angioscintigraphic Evaluation Prior to Resynchronization

Background: In dilated cardiomyopathy (DCM) patients (pts) with cardiac resynchronization therapy (CRT) for ventricular dyssynchrony, long‐term predictors of mortality and morbidity remain poorly investigated.

Temporary transvenous VDD pacing as a bridge to permanent pacemaker implantation in patients with sepsis and haemodynamically significant atrioventricular block

AIMS Permanent pacemaker (PM) implantation is temporarily contraindicated in patients (pts) with sepsis. In patients with symptomatic atrioventricular (AV) block and infection, prolonged VVI pacing is therefore usually ensured by a ventricular pacing lead (PL) connected to an external PM generator. In patients with normal sinus function and heart failure, the VVI mode can exacerbate haemodynamic dysfunction. A single AV PL can be attractive to achieve physiological pacing. This study was designed to assess the efficacy and safety of temporary VDD pacing as a bridge to permanent PM implantation in patients with complete AV block until control of infection. METHODS AND RESULTS This study included eight patients with complete AV block and sepsis with negative blood culture. Due to the presence of congestive heart failure, a single bipolar AV PL connected to an external VDD PM generator. At VDD implantation, P-wave amplitude was 1.9 ± 1.6 mV and R-wave was 11.3 ± 5.2 mV. The ventricular pacing threshold was 0.53 ± 0.1 V for a 0.5 ms pulse. Antibiotic therapy was instituted in all patients. A permanent VDD or DDD PM was implanted after 8 ± 2.5 days of temporary VDD pacing. At permanent PM implantation, the mean brain natriuretic peptide level had decreased and sepsis was controlled in all patients. No recurrence of sepsis was observed with a mean follow-up of 15.8 ± 5.3 months. CONCLUSION Temporary VDD pacing is a safe and effective method to achieve prolonged AV physiological pacing in patients with AV block until infection has been controlled.

Long-Term Experience with a Preshaped Left Ventricular Pacing Lead

OLLITRAULT, J., et al.: 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 Ω . Between implant (n = 38) and M7 (n = 15) , pacing threshold rose from0.73 ± 0.54to1.57 ± 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. (PACE 2003; 26[Pt. II]:185–188)

Initial and Long-Term Evaluation of Escape Rhythm After Radiofrequency Ablation of the AV Junction in 50 Patients

Between 1986 and 1994, 50 patients (mean age 63 ± 13 years), 25 of whom had organic heart disease and presenting with atrial arrhythmias refractory to 5.6 ± 1.6 antiarrhythmic drugs, underwent radiofrequency ablation (5 ± 3 pulses by procedure; duration of pulses 50.5 ± 32 s) of the proximal AV junction to create complete and permanent AV block. The escape rhythm was studied immediately after the procedure and during long‐term follow‐up. Immediately after the procedure, an escape rhythm was observed in 80% of the patients (junctional in 92%). Over a mean follow‐up of 36 ± 16 months in 47 patients (2 patients died before assessment of escape rhythm and 1 was lost to follow‐up), an escape rhythm was present in 39 patients (83%) and absent in the remaining 8 (17%). The only significant difference between the two groups was the initial presence of an escape rhythm (P = 0.008). However, three patients with an initial escape rhythm had none during long‐term follow‐up. The initial presence of an escape rhythm as a predictive factor of its presence during follow‐up had a sensitivity of 87%, specificity of 63%, positive predictive value of 92%, and negative predictive value of 50%. Thus, the absence of an escape rhythm during long‐term follow‐up causing pacemaker dependency was noted in 1 of 6 patients. This represents a limitation to this palliative treatment, which should be reserved for patients suffering from supraventricular tachycardias refractory to other treatments.

Temporal and Geographical Trends in Indications for Implantation of Cardiac Defibrillators in Europe 1993–1998

Despite the demonstrated efficacy of implantable cardioverter defibrillators (ICDs) in reducing sudden and total mortality in selected populations, their implantation rates vary greatly between countries. The aim of our study was to analyze temporal and geographical trends in ICD implantations in countries with similar health related expenditure in Western Europe. A total of 2,257 patients from ten European evaluation studies of Medtronic defibrillators and defibrillation electrodes, conducted between 1993 and 1998, representing 12 countries, was included in this analysis. Rates of implantation and clinical characteristics were compared between countries and years of implantation. Rates of implantation differed greatly between Western European countries and did not correlate with indices of health related expenditure (i.e., number of patients per physician and number of patients per hospital bed). However, there was a strong and statistically significant negative correlation between the use of amiodarone and the rates of implantation (r =−0.66, P = 0.02). Temporal trends showed a significant increase in the age of the patients receiving an ICD between 1993 and 1998(57 ± 14 vs 61 ± 12years, mean ± SD, P < 0.001). There was also a temporal trend towards an increased incidence of coronary artery disease and a significant decrease in the incidence of cardiomyopathy. There was a temporal increase in implantations in patients with a history of ventricular tachycardia. Despite a general scientific agreement that ICDs are a first line treatment for patients at high risk of sudden cardiac death, their acceptance remains low in several developed countries. This low acceptance may not be entirely related to budget constraint but may also be related to their perceived efficacy by physicians and health authorities.