Gaël Jauvert

Echocardiographic Modeling of Cardiac Dyssynchrony Before and During Multisite Stimulation: A Prospective Study

CAZEAU, S., et al.: Echocardiographic Modeling of Cardiac Dyssynchrony Before and During Multisite Stimulation: A Prospective Study. Multisite biventricular pacing therapy offers significant clinical improvement in some stimulated patients with electrocardiographic criteria of cardiac dyssynchrony. However, observational data increasingly suggest that patients suffering from congestive heart failure in presence of modest QRS widening may also derive benefit from cardiac resynchronization therapy (CRT), and that some patients can be significantly improved clinically after system implantation despite no apparent change in QRS width. This pilot study explored the value of an echocardiographic model to identify cardiac electromechanical dyssynchrony parameters (EDP) in candidates for CRT, and their potential correction after implantation. The study included 66 consecutive CRT recipients of CRT in NYHA functional class III or IV who had one or more atrioventricular, interventricular or intraventricular dyssynchrony criteria. An immediate improvement was observed in 85% of the population with a partial or total correction of their EDP. However, the modifications in EDP differed considerably between recipients of de novo CRT systems and patients with previously implanted standard pacing systems upgraded with the implantation of a left ventricular lead. EDP measurements appear to identify potential candidates for CRT, and to confirm the success of system implantation. (PACE 2003; 26[Pt. II]:137–143)

Intra- and interatrial conduction delay: Implications for cardiac pacing

Atrial conduction disorders are frequent in elderly subjects and/or those with structural heart diseases, mainly mitral valve disease, hyperthrophic cardiomyopathies, and hypertension. The resultant electrophysiological and electromechanical abnormalities are associated with a higher risk of paroxysmal or persistent atrial tachyarrhythmias, either atrial fibrillation, typical or atypical flutter or other forms of atrial tachycardias. Such an association is not fortuitous because intra‐ and interatrial conduction abnormalities delays disrupt (spatial and temporal dispersion) electrical activation, thus promoting the initiation and perpetuation of reentrant circuits. Preventive therapeutic interventions induce variable, sometimes paradoxical effects as with the proarrhythmic effect of class I antiarrhythmic drugs. Similarly, atrial pacing may promote proarrhythmias or an antiarrhythmic effect according to the pacing site(s) and mode. Multisite atrial pacing was conceived to correct, as much as possible, abnormal activation induced by spontaneous intra‐ or interatrial conduction disorders or by single site atrial pacing, which are situations responsible for commonly refractory arrhythmias. Atrial electrical resynchronization can also be used to correct mechanical abnormalities like left heart AV dyssynchrony resulting from intraatrial conduction delays. (PACE 2004; 27:507–525)

Long‐Term Effects of Biatrial Synchronous Pacing to Prevent Drug‐Refractory Atrial Tachyarrhythmia: A Nine‐Year Experience

Biatrial Pacing for Atrial Tachyarrhythmia Prevention. Introduction. Results of previous studies suggest that atrial resynchronization by multisite atrial pacing may coutribute to prevention of recurrences in patients with drug‐refractory atrial tachyarrbythmias and significant intra‐atrial conduction delay.

Comparison between radiofrequency with contact force-sensing and second-generation cryoballoon for paroxysmal atrial fibrillation catheter ablation: a multicentre European evaluation

AIMS Whether pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) using contact force (CF)-guided radiofrequency (RF) or second-generation cryoballoon (CB) present similar efficacy and safety remains uncertain. METHODS AND RESULTS We performed a multicentre study comparing procedural safety and arrhythmia recurrence after standardized PVI catheter ablation for PAF using CF-guided RF ablation (Thermocool(®) SmartTouch™, Biosense Webster; or Tacticath™, St Jude Medical) (CF group) with second-generation CB ablation (Arctic Front Advance™, Medtronic) (CB group). Overall, 376 patients (mean age 59.8 ± 10.4 years, 280 males) were enrolled in 4 centres: 198 in CF group and 178 in CB group. Procedure was shorter for CB group than for CF group (109.6 ± 40 vs. 122.5 ± 40.7 min, P = 0.003), but fluoroscopy duration and X-ray exposure were not statistically different (P = 0.1 and P = 0.22, respectively). Overall complication rate was similar in both groups: 14 (7.1%) in the CF group vs. 13 (7.3%) in the CB group (P = 0.93). However, transient right phrenic nerve palsy occurred only in CB group (10 patients, 5.6%; P = 0.001 vs. CF group) and severe non-lethal complications (embolic event, tamponade, or oesophageal injury) occurred only in CF group (5 patients, 2.5%; P = 0.03 vs. CB group). No periprocedural death occurred in either group. Single-procedure freedom from any atrial arrhythmias at 18 months post-ablation was comparable in CF group and CB group (76 vs. 73.3%, respectively, log rank P = 0.63). CONCLUSION Pulmonary vein isolation using CF-guided RF and second-generation CB leads to comparable single-procedure arrhythmia-free survival at up to 18 months with similar overall complication rate.

Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial.

BACKGROUND Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP). METHODS The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year. RESULTS Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF. CONCLUSIONS In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.

Relationship between cardiac arrhythmias and sleep apnoea in permanently paced patients with type I myotonic dystrophy

The long-term relationship between cardiac arrhythmias and sleep apnoea in myotonic dystrophy (DM1) is unknown. Pacemakers enabling the long-term monitoring of electrocardiographic and ventilation parameters were implanted in 20 patients with DM1 (mean age = 42+/-11.6 years), followed 40+/-12.3 months. Arrhythmias were recorded by the pacemaker in 17 patients (85%): 14 developed arrhythmic episodes that occurred either in absence or in presence of concomitant sleep apnoea. Conversely, among these 14 patients, the majority of sleep apnoea episodes were not associated with concomitant arrhythmias. In the other three patients who developed arrhythmias, simultaneous sleep apnoea was never observed. Episodes of sleep apnoea were observed in all patients, though only 85% presented with sleep apnoea syndrome. In conclusion, a high incidence of arrhythmias and sleep apnoea was observed. While arrhythmias are generally attributable to an organic substrate, they are sometimes precipitated by functional triggers, as in the case of sleep apnoea.

Endocardial acceleration (sonR) vs. ultrasound-derived time intervals in recipients of cardiac resynchronization therapy systems

AIMS Optimization of cardiac resynchronization therapy (CRT) requires the gathering of cardiac functional information. An accurate timing of the phases of the cardiac cycle is key in the optimization process. METHODS AND RESULTS We compared Doppler echocardiography to an automated system, based on the recording of sonR (formerly endocardial acceleration), in the detection of mitral and aortic valves closures and measurements of the duration of systole and diastole. We prospectively studied, under various conditions of cardiac stimulation, 75 recipients of CRT systems (69% men), whose mean age was 72 ± 9.2 years, left ventricular ejection fraction 35 ± 11%, baseline QRS duration 154 ± 29 ms, and New York Heart Association functional class 3.0 ± 0.7. We simultaneously recorded (i) sonR, detected by a non-invasive piezoelectric micro-accelerometer sensor clipped onto an electrode located in the parasternal region, (b) electrocardiogram, and (c) Doppler audio signals, using a multichannel data acquisition and analysis system. The correlation between timing of mitral and aortic valve closure by sonR vs. Doppler signals was examined by linear regression analysis. Correlation coefficients and the average absolute error were calculated. A concordance in the timing of the mitral (r = 0.86, error = 9.7 ms) and aortic (r = 0.93, error = 9.7 ms) valves closure was observed between the two methods in 94% of patients. Similarly, sonR and the Doppler-derived measurements of systolic (r = 0.85, error = 13.4 ms) and diastolic (r = 0.99, error = 12 ms) interval durations were concordant in 80% of patients. CONCLUSION A high concordance was found between sonR and the cardiac ultrasound in the timings of aortic and mitral valve closures and in the estimation of systolic and diastolic intervals durations. These observations suggest that sonR could be used to monitor cardiac function and adaptively optimize CRT systems.

Analysis of cardiac micro-acceleration signals for the estimation of systolic and diastolic time intervals in cardiac resynchronization therapy

Heart sounds, measured via cardiac micro-acceleration (CMA), carry valuable information about the mechanical and hemodynamic function of the heart. The aim of the present study is to estimate systolic and diastolic time intervals from CMA features, extracted by segmentation of the first two heart sounds, i.e. onset, maximum energy and end instants. CMA, ECG and echocardiographic audio signals were acquired simultaneously on 60 patients under different hemodynamic conditions. Linear models, fitted between CMA features and echo timings, were evaluated with their correlation coefficient, model error and coefficient stability. Models for mitral valve closing, aortic valve closing and opening instants showed satisfactory results, whereas the estimation of the opening instant of the mitral valve was more difficult. This work suggests the potential utility of CMA for monitoring cardiac function and defining optimal, adaptive pacing configurations.

Comparison of a Radiofrequency Powered Flexible Needle with a Classic Rigid Brockenbrough Needle for Transseptal Punctures in Terms of Safety and Efficacy

INTRODUCTION This study aimed to evaluate the safety and efficacy of utilising an innovative radiofrequency (RF) powered flexible needle to achieve transseptal puncture (TSP). METHODS AND RESULTS A RF powered flexible needle (Toronto catheter, Baylis Medical Company Inc.) associated with a stiffer dilator (Torflex Superstrong, Baylis Medical Company Inc.) was used in 125 consecutive patients referred for left sided ablations (mean age=55.6, male=86.5%) and compared with a standard transseptal set (BRK needle, SL0 sheath and dilator, St Jude Medical, Inc.) used in the previous 100 patients (mean age=56, male 82%). TSP was achieved in 95/100 patients in the Brockenbrough group and in all 125 patients in the Toronto group (p=0.01) despite an equivalent proportion of difficult situations (8 and 9% respectively) and patients with a prior TSP (17% vs 24%). 7/100 needle related events (failure, aborted attempt or pericardial effusion) occurred in the Brockenbrough group and none in the Toronto group (p=0.01). The Toronto needle crossed the septum at the first attempt in 123/125 (98.4%) patients and the Brockenbrough needle in 84/95 (88%) patients (p<0.001). CONCLUSION Our data suggest that the Toronto RF powered flexible needle is safer and more efficient than a standard Brockenbrough needle and can be used not only in difficult situations but routinely to achieve TSP.

Clinical testing of a new pacemaker function to monitor ventricular capture.

Automatic beat‐by‐beat capture functions are designed to minimize the pacing energy delivered, while maintaining the highest safety by delivering an immediate back‐up stimulus in case of loss of capture. The objective of this study was to estimate the lowering of ventricular pacing amplitude allowed by such a function, compared to amplitudes usually set manually in routine practice. An automatic ventricular pacing threshold test is launched every 6 hours to measure the automatic capture threshold (AT). From AT the function calculates: (1) the“capture amplitude”(Vc) = AT + 0.5 V at a minimum output of 1 V and (2) the“safety amplitude” (Vs) = twice AT at a minimum output of 2.5 V. The function preferentially uses Vc and verifies capture after each paced beat. In case of loss of capture, a back‐up spike is delivered and Vs is implemented until the next threshold measurement. We estimated the ventricular amplitude delivered by the pacemaker from data stored in the pacemaker memory. We compared these values with the pacing amplitude typically programmed manually (MPA) by physicians at twice AT and a minimum of 2.5 V. Data from 57 recipients of Talent 3 DR pacemakers were analyzed. Complete data sets were available in 25 patients at 1 day, 28 at 1 month, and 39 between 1 day and 1 month. No loss of capture or ventricular pause was observed on 53 ambulatory electrocardiograms (ECG); and pulse amplitude automatically delivered by the device was significantly lower than the MPA at each of the three time points analyzed. This new beat‐by‐beat capture function allows a significant lowering of the pacing amplitude compared to manual settings, while preserving a 100% safety.