Olivier Marie

Interventricular and intraventricular dyssynchrony in idiopathic dilated cardiomyopathy. A prognostic study with Fourier phase analysis of radionuclide angioscintigraphy

OBJECTIVES The study evaluated the prognostic value of interventricular and intraventricular dyssynchrony in idiopathic dilated cardiomyopathy (IDC). BACKGROUND Biventricular pacing is an emerging treatment for patients with dilated cardiomyopathy and ventricular dyssynchrony. The prognostic values of interventricular and intraventricular dyssynchrony have not been previously compared. METHODS A total of 103 patients with IDC were studied. Left bundle branch block was present in 25% of patients. Equilibrium radionuclide angiography was performed and Fourier phase analyses were examined in both ventricles. Difference between the mean phase of left ventricle (LV) and right ventricle (RV) assessed interventricular dyssynchrony, and standard deviations (SDs) of the mean phase in each ventricle assessed intraventricular dyssynchrony. RESULTS The QRS duration was related to both interventricular and intraventricular dyssynchrony. A degradation of the hemodynamic status was associated with an increase in intraventricular dyssynchrony but not in interventricular dyssynchrony. With a follow-up of 27 +/- 23 months, 18 patients had a major cardiac event (7 cardiac deaths; 11 worsening, leading to heart transplantation). The SDs of the LV and RV mean phase and QRS duration were predictors of cardiac event (all p < 0.0001), but interventricular dyssynchrony was not. Among 13 univariate predictors of cardiac event, the only independent predictors were an increased SD of LV mean phase (p = 0.0004) and an increased pulmonary capillary wedge pressure (p = 0.009). CONCLUSIONS Intraventricular dyssynchrony evaluated with phase analysis of radionuclide angiography is an independent predictor of cardiac event in IDC. The prognosis is related to intraventricular rather than to interventricular dyssynchrony in IDC.

Implantable loop recorder for recurrent syncope: influence of cardiac conduction abnormalities showing up on resting electrocardiogram and of underlying cardiac disease on follow-up developments

AIMS The implantable loop recorder is a useful diagnostic tool in dealing with recurrent syncope in patients. We tested to determine the influence of cardiac conduction abnormalities that turn up on resting electrocardiogram (ECG) and the impact of underlying cardiac disease on developments during follow-up. METHODS AND RESULTS Ninety-five consecutive patients received an implantable loop recorder to monitor recurrent syncope (n = 4.9+/-3.8) of unknown aetiology after cardiac investigations, including an electrophysiological study. Resting ECG was abnormal, suggesting an arrhythmic syncope, in 29 (30.5%) patients, while 21 (22.1%) patients had an underlying cardiac disease. During an average follow-up period of 10.2+/-5.2 months, 43 (45.2%) patients developed a new syncope associated in 27 of them (62.8%) with an arrhythmic event. Syncope was no more frequent in the subgroup of patients with cardiac conduction abnormalities on resting ECG, while the frequency of arrhythmic events was similar whether or not the ECG was normal. In the subgroup of patients with cardiac disease with normal left ventricular ejection fraction, the occurrence of syncope was less frequent, and the number of arrhythmic events was no greater in these patients. CONCLUSION Implantable loop recorder is a useful diagnostic tool for recurrent syncope of unknown aetiology.

Long-term follow-up on high-rate cut-off programming for implantable cardioverter defibrillators in primary prevention patients with left ventricular systolic dysfunction.

AIMS Implantable cardioverter defibrillators (ICDs) are efficient in reducing mortality in patients with left ventricular systolic dysfunction. High-rate cut-off programming may be effective in reducing appropriate and inappropriate therapies, but as the long-term consequences on morbidity and mortality remain unclear, it is underutilized. METHODS AND RESULTS We prospectively studied 365 consecutive patients (mean age 60 ± 10 years), with ischaemic (63%) or non-ischaemic cardiomyopathy and left ventricular dysfunction (mean ejection fraction 25 ± 7%), who were implanted with an ICD in primary prevention of sudden cardiac death (41% single chamber, 31% dual chamber, and 28% biventricular). All devices were programmed with a shock-only zone over 220 beats per minute (b.p.m.) and a monitoring zone between 170 and 220 b.p.m. During a median follow-up of 40 months, 41 patients received appropriate shocks (11.2%) and 24 inappropriate shocks (6.6%). Then, 306 patients never experienced any ICD shock (84%). Inappropriate discharges were related to supraventricular tachyarrhythmia in 10 patients, and noise/oversensing in 14 patients. Ventricular tachycardia episodes, sustained or not, were recorded in the monitoring zone in 43 patients (11.8%). Seven of these patients were symptomatic (1.9%), without lethal consequence. Sixty-two patients (17%) died: 35 from end-stage heart failure, 1 from unexplained sudden death, and 26 from a documented non-cardiac cause. CONCLUSION High-rate cut-off (220 b.p.m.) shock-only ICD programming, in primary prevention patients with reduced left ventricular ejection fraction, appeared to be safe during a long-term follow-up. It also resulted in a very low rate of discharges, which are known to be deleterious in this population.

Ventricular dyssynchrony and risk markers of ventricular arrhythmias in nonischemic dilated cardiomyopathy: a study with phase analysis of angioscintigraphy.

FAUCHIER, L., et al .: Ventricular Dyssynchrony and Risk Markers of Ventricular Arrhythmias in Nonischemic Dilated Cardiomyopathy: A Study with Phase Analysis of Angioscintigraphy. Biventricular pacing is a new form of treatment for patients with dilated cardiomyopathy and ventricular dyssynchrony. Limited information is available regarding the relationship between ventricular dyssynchrony and risk markers of ventricular arrhythmias in idiopathic dilated cardiomyopathy (IDC). In 103 patients with IDC, Fourier phase analysis of both ventricles was performed from equilibrium radionuclide angiography (ERNA). The difference between the mean phase of the LV and RV was a measure of interventricular dyssynchrony, and the standard deviations of the mean phases in each ventricle measured intraventricular dyssynchrony. There were no significant differences in inter‐ and intraventricular dyssynchrony between patients with versus without histories of sustained VT or VF, nonsustained VT, abnormal signal‐averaged ECG, or induced sustained monomorphic VT. Dyssynchrony was not related to decreased heart rate variability (HRV). LV and interventricular dyssynchrony were weakly related to QT duration and QT dispersion. During a follow‐up of 27 ± 23  months , 21 patients had major adverse cardiac events (MACE), including 7 cardiac deaths, 11 progression of heart failure leading to cardiac transplantation, and 3 sustained VT/VF. The only independent predictors of MACE were an increased standard deviation of LV mean phase (P = 0.003), a decreased HRV (standard deviation of normal‐to‐normal intervals, P = 0.004), and histories of previous VT/VF (P = 0.03) or nonsustained VT (P = 0.04). In conclusion, left intraventricular dyssynchrony evaluated with ERNA was an independent predictor of MACE in IDC and was not related to usual risk markers of ventricular arrhythmias. This may have implications for resynchronization therapy and/or the use of implantable cardioverter defibrillators in IDC. (PACE 2003; 26[Pt. II]:352–356)

Abnormal nocturnal heart rate variability and QT dynamics in patients with brugada syndrome

Background: In Brugada syndrome (BSY), most of the ventricular arrhythmic events are nocturnal, suggesting an influence of the autonomic nervous system.

Implantable Loop Recorder in Clinical Practice

Implantable Loop Recorder (ILR) or Insertable Cardiac Monitor (ICM) is a tool developed in the 1990’s which allows permanent monitoring of cardiac rhythm during a period exceeding one year. The major interest of this new tool is to establish a closed correlation between symptoms and heart rhythm. The first application of ICM was the diagnosis of recurrent syncope. Syncope is a common disorder which may recur and impair the survival and the quality of life of the patients. The objective of the investigation of syncope is to diagnose the cardiac aetiology because the mortality in this case is high. About half of the patients implanted with an ICM complains of a new syncope and about 50% of these patients had documented cardiac rhythm disturbances. The most frequent is a sinus bradycardia or sinus arrest but these results depend on the age of patients, resting ECG abnormalities and structural cardiac disease. A classification of the mechanisms of recurrent syncopes has been defined with the results of the ISSUE study separating the syncope due to primary cardiac arrhythmia from neurally-mediated syncope and from unknown syncope. The analysis of the presyncopal phase on the ICM restored ECG allows physicians to adapt the treatment (antiarrhythmic (with 2 h) agents or pacemaker) and optimize the programming of the pacemaker when necessary. It is recommended to implant the ICM early in the syncope patients with a normal physical examination, normal ECG and without structural heart disease and negative tilt testing. In the presence of cardiac disease, it is recommended to implant the ICM after performing an electrophysiological study and tilt testing. In syncope patients with depressed left ventricular ejection fraction, the implantation of an automatic implantable cardiac defibrillator is preferable. Early application of an ICM reduces the cost of the investigation of the patients suffering from syncope, especially when the electrophysiological study is avoided. The indications of the ICM tend to be extended to new syncope populations such as pediatric patients, the epileptic population and older patients suffering from unexplained falls. New algorithms are developed by the manufacturers which allow a good analysis of electrical atrial activity and open new applications of the ICM in the managements of patients treated for atrial arrhythmias.