Outcome after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: a multicenter study-part 2.

BACKGROUND: Implantable cardioverter-defibrillator indications in Brugada syndrome remain controversial, especially in asymptomatic patients. Previous outcome data are limited by relatively small numbers of patients or short follow-up durations. We report the outcome of patients with Brugada syndrome implanted with an implantable cardioverter-defibrillator in a large multicenter registry. METHODS AND RESULTS: A total of 378 patients (310 male; age, 46±13 years) with a type 1 Brugada ECG pattern implanted with an implantable cardioverter-defibrillator (31 for aborted sudden cardiac arrest, 181 for syncope, and 166 asymptomatic) were included. Fifteen patients (4%) were lost to follow-up. During a mean follow-up of 77±42 months, 7 patients (2%) died (1 as a result of an inappropriate shock), and 46 patients (12%) had appropriate device therapy (5±5 shocks per patient). Appropriate device therapy rates at 10 years were 48% for patients whose implantable cardioverter-defibrillator indication was aborted sudden cardiac arrest, 19% for those whose indication was syncope, and 12% for the patients who were asymptomatic at implantation. At 10 years, rates of inappropriate shock and lead failure were 37% and 29%, respectively. Inappropriate shock occurred in 91 patients (24%; 4±4 shocks per patient) because of lead failure (n=38), supraventricular tachycardia (n=20), T-wave oversensing (n=14), or sinus tachycardia (n=12). Importantly, introduction of remote monitoring, programming a high single ventricular fibrillation zone (>210-220 bpm), and a long detection time were associated with a reduced risk of inappropriate shock. CONCLUSIONS: Appropriate therapies are more prevalent in symptomatic Brugada syndrome patients but are not insignificant in asymptomatic patients (1%/y). Optimal implantable cardioverter-defibrillator programming and follow-up dramatically reduce inappropriate shock. However, lead failure remains a major problem in this population.

Clinical impact of the implantable loop recorder in patients with isolated syncope, bundle branch block and negative workup: a randomized multicentre prospective study.

BACKGROUND: Few studies have compared conventional testing with prolonged monitoring using an implantable loop recorder (ILR) following the first syncope episode in patients with bundle branch block (BBB) and negative workup. OBJECTIVES: To compare two syncope evaluation strategies-primary use of an ILR (Group 1) versus conventional testing (Group 2)-and to estimate the prevalence of significant arrhythmias in the ILR patient subset. METHODS: From January 2005 to December 2010, 78 patients admitted after one syncope episode were randomized to ILR (n=41) or conventional follow-up (n=37). Mean follow-up was 27 ± 12 months. RESULTS: Mean age was 76 ± 8 years and 30 patients were women (38.5%); 18 presented cardiomyopathy (23%) and 12 had a history of atrial fibrillation (15.4%). Mean left ventricular ejection fraction was 56.5 ± 11% and mean His-to-ventricle interval was 55 ± 6ms based on negative electrophysiological study (EPS). Electrocardiogram abnormalities involved: 34 left bundle branch blocks (BBBs); 11 right BBBs; and 33 bifascicular blocks. Overall, 21 patients (27%) developed significant arrhythmic events: ventricular tachycardia (n=1; 1.3%); sudden death (n=2; 2.6%); third-degree atrioventricular (AV) block (n=14; 18%); sick sinus syndrome (n=4; 5.1%). In 19 (24.4%) patients, relevant arrhythmias were detected, with a significant difference between the ILR group (n=15/41; 36.6%) and the conventional follow-up group (n=4/37; 10.8%) (P=0.02). Eighteen patients were implanted with pacemakers; one received an implantable defibrillator. No predictors of AV block were identified in the ILR group. CONCLUSIONS: In this randomized prospective study, the ILR strategy proved largely superior to conventional follow-up in detecting recurrent events, with a potential impact on therapeutic management. This observation highlights the usefulness of early monitoring in patients with BBB and negative EPS even after the first syncope episode but an empiric pacemaker strategy remains to be validated in this selected population.

Second meeting of the French CEIP (Centres d'Evaluation et d'Information sur la Pharmacodépendance). Part II: benzodiazepine withdrawal.

The aim of this meeting was to describe the news trends about abuse and addiction of anxiolytics and hypnotics. The part II of this meeting reviewed several aspects of the withdrawing benzodiazepines focusing in particular on clinical symptoms, biological patterns, and strategies for discontinuation. The discontinuation is usually beneficial due to the importance of adverse effects induced by long-term use of benzodiazepines. Several clinicals options have been described including gradual tapering of the current benzodiazepine, substitution with a long acting benzodiazepines or treating the symptoms of withdrawal. Psychological interventions range from a simple support through counselling to expert cognitive-behavioural therapy. However more controlled clinical trials are needed to promote adequate and optimal patient care in management of benzodiazepine withdrawing.

Long-term follow-up of idiopathic ventricular fibrillation ablation: a multicenter study.

OBJECTIVES: This multicenter study sought to evaluate the long-term follow-up of patients ablated for idiopathic ventricular fibrillation (VF). BACKGROUND: Catheter ablation of idiopathic VF that targets ventricular premature beat (VPB) triggers has been shown to prevent VF recurrences on short-term follow-up. METHODS: From January 2000, 38 consecutive patients from 6 different centers underwent ablation of primary idiopathic VF initiated by short coupled VPB. All patients had experienced at least 1 documented VF, with 87% having experienced > or =2 VF episodes in the preceding year. Catheter ablation was guided by activation mapping of VPBs or pace mapping during sinus rhythm. RESULTS: There were 38 patients (21 men) age 42 +/- 13 years, refractory to a median of 2 antiarrhythmic drugs. Triggering VPBs originated from the right (n = 16), the left (n = 14), or both (n = 3) Purkinje systems and from the myocardium (n = 5). During a median post-procedural follow-up of 63 months, 7 (18%) of 38 patients experienced VF recurrence at a median of 4 months. Five of these 7 patients underwent repeat ablation without VF recurrence. Survival free of VF was predicted only by transient bundle-branch block in the originating ventricle during the electrophysiological study (p < 0.0001). The number of significant events (confirmed VF or aborted sudden death) was reduced from 4 (interquartile range 3 to 9) before to 0 (interquartile range 0 to 4) after ablation (p = 0.01). CONCLUSIONS: Ablation for idiopathic VF that targets short coupled VPB triggers is associated with a long-term freedom from VF recurrence.

Sudden cardiac arrest associated with early repolarization.

BACKGROUND: Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest. METHODS: We reviewed data from 206 case subjects at 22 centers who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and assessed the prevalence of electrocardiographic early repolarization. The latter was defined as an elevation of the QRS-ST junction of at least 0.1 mV from baseline in the inferior or lateral lead, manifested as QRS slurring or notching. The control group comprised 412 subjects without heart disease who were matched for age, sex, race, and level of physical activity. Follow-up data that included the results of monitoring with an implantable defibrillator were obtained for all case subjects. RESULTS: Early repolarization was more frequent in case subjects with idiopathic ventricular fibrillation than in control subjects (31% vs. 5%, P<0.001). Among case subjects, those with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than those without early repolarization. In eight subjects, the origin of ectopy that initiated ventricular arrhythmias was mapped to sites concordant with the localization of repolarization abnormalities. During a mean (+/-SD) follow-up of 61+/-50 months, defibrillator monitoring showed a higher incidence of recurrent ventricular fibrillation in case subjects with a repolarization abnormality than in those without such an abnormality (hazard ratio, 2.1; 95% confidence interval, 1.2 to 3.5; P=0.008). CONCLUSIONS: Among patients with a history of idiopathic ventricular fibrillation, there is an increased prevalence of early repolarization.

Outcome after implantation of a cardioverter-defibrillator in patients with Brugada syndrome: a multicenter study.

BACKGROUND: Brugada syndrome is an arrhythmogenic disease characterized by an increased risk of sudden cardiac death (SCD) by ventricular fibrillation. At present, an implantable cardioverter-defibrillator (ICD) is the recommended therapy in high-risk patients. This multicenter study reports the outcome of a large series of patients implanted with an ICD for Brugada syndrome. METHODS AND RESULTS: All patients (n=220, 46+/-12 years, 183 male) with a type 1 Brugada ECG pattern implanted with an ICD in 14 centers between 1993 and 2005 were investigated. ICD indication was based on resuscitated SCD (18 patients, 8%), syncope (88 patients, 40%), or positive electrophysiological study in asymptomatic patients (99 patients, 45%). The remaining 15 patients received an ICD because of a family history of SCD or nonsustained ventricular arrhythmia. During a mean follow-up of 38+/-27 months, no patient died and 18 patients (8%) had appropriate device therapy (10+/-15 shocks/patient, 26+/-33 months after implantation). The complication rate was 28%, including inappropriate shocks, which occurred in 45 patients (20%, 4+/-3 shocks/patient, 21+/-20 months after implantation). The reasons for inappropriate therapy were lead failure (19 patients), T-wave oversensing (10 patients), sinus tachycardia (10 patients), and supraventricular tachycardia (9 patients). Among implantation parameters, high defibrillation threshold, high pacing threshold, and low R-wave amplitude occurred, respectively, in 12%, 27%, and 15% of cases. CONCLUSIONS: In this large Brugada syndrome population, a low incidence of arrhythmic events was found, with an annual event rate of 2.6% during a follow-up of >3 years, in addition to a significant risk of device-related complications (8.9%/year). Inappropriate shocks were 2.5 times more frequent than appropriate ones.

Results from the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) trial on atrial flutter, a multicentric prospective randomized study comparing amiodarone and radiofrequency ablation after the first episode of symptomatic atrial flutter.

BACKGROUND: There is no published randomized study comparing amiodarone therapy and radiofrequency catheter ablation (RFA) after only 1 episode of symptomatic atrial flutter (AFL). The aim of the Loire-Ardèche-Drôme-Isère-Puy-de-Dôme (LADIP) Trial of Atrial Flutter was 2-fold: (1) to prospectively compare first-line RFA (group I) versus cardioversion and amiodarone therapy (group II) after only 1 AFL episode; and (2) to determine the impact of both treatments on the long-term risk of subsequent atrial fibrillation (AF). METHODS AND RESULTS: From October 2002 to February 2006, 104 patients (aged 78+/-5 years; 20 women) with AFL were included, with 52 patients in group I and 52 patients in group II. The cumulative risk of AFL or AF was interpreted with the use of Kaplan-Meier curves and compared by the log-rank test. Clinical presentation, echocardiographic data, and follow-up were as follows: age (78.5+/-5 versus 78+/-5 years), history of AF (27% versus 21.6%); structural heart disease (58% versus 65%), left ventricular ejection fraction (56+/-14% versus 54.5+/-14%), left atrial size (43+/-7 versus 43+/-6 mm), mean follow-up (13+/-6 versus 13+/-6 months; P=NS), recurrence of AFL (3.8% versus 29.5%; P<0.0001), and occurrence of significant AF beyond 10 minutes (25% versus 18%; P=0.3). Five complications (10%) were noted in group II (sick sinus syndrome in 2, hyperthyroidism in 1, and hypothyroidism in 2) and none in group I (0%) (P=0.03). CONCLUSIONS: RFA should be considered a first-line therapy even after the first episode of symptomatic AFL. There is a better long-term success rate, the same risk of subsequent AF, and fewer secondary effects.

Comparison of transthoracic echocardiography using second harmonic imaging, transcranial Doppler and transesophageal echocardiography for the detection of patent foramen ovale in stroke patients.

AIMS: The comparison of three imaging methods to determine which is the most accurate and reliable for the detection of right-to-left shunt. METHODS AND RESULTS: One hundred and seven patients who were hospitalized for stroke underwent: a transthoracic echocardiography (TTE) using second harmonic, a transcranial Doppler (TCD) and a transesophageal echocardiography (TEE) from August 2003 to April 2004. All studies were recorded on a videotape and were studied by a physician blinded to the study. With TTE and TEE, we found 44 (41%) patent foramen ovales. All contrast tests were positive with TCD for these 44 patients. For two patients, the contrast test was positive only with TTE and TCD. We found four false negative contrast tests with TTE. Among the 63 patients who had a negative contrast test with TEE and TTE, the results were the same with TCD for 59 of them; we were not able to determine a cause for the four positive tests. CONCLUSION: This study confirms that transesophageal echocardiography has limitations in the diagnosis of patent foramen ovale. In this study, the negative predictive value of transcranial Doppler was excellent. Therefore, this examination is able to exclude a patent foramen ovale with a high level of confidence.

Regressive aortic valve and infundibular tumors during idiopathic hypereosinophilic syndrome.

Fibroblastic endocarditis is a classic complication of prolonged hypereosinophilic syndrome, whatever the cause. In France, it is most frequently encountered in cases of idiopathic hypereosinophilic syndrome. It commonly involves the apex of the ventricles, with a clinical picture of restrictive cardiomyopathy of unfavorable prognosis, and the auriculoventricular valves. We report the case of a 77-year-old man in whom atypical cardiac involvement disclosed idiopathic hypereosinophilic syndrome. In addition to the usual features of obliteration of the apex and restrictive cardiomyopathy, echocardiographic examination showed severe left ventricular dysfunction and intracardiac tumors, one of which was unusually localized to an aortic valve. Treatment, which comprised strict control of the eosinophilic process, standard treatment for cardiac failure, and anticoagulation therapy, produced rapid and long-lasting improvement of his clinical status and left systolic and diastolic ventricular function, and on echocardiography the intracardiac tumors had totally disappeared. The patient suddenly died of septic shock 16 months after first being seen.

Clinical experience with a new detection algorithm for differentiation of supraventricular from ventricular tachycardia in a dual-chamber defibrillator.

INTRODUCTION: Inadequate therapy for supraventricular tachyarrhythmias (SVT) is a frequent problem of implantable cardioverter defibrillators (ICD). Dual-chamber ICDs have been developed to improve discrimination of SVT from ventricular tachycardia (VT). We investigated the positive predictivity, sensitivity, and specificity of a new algorithm, the SMART detection trade mark algorithm, incorporated in the Phylax AV (Biotronik) dual-chamber ICD. METHODS AND RESULTS: Two hundred nine patients (185 men, age 64 +/- 11 years) received a Phylax AV ICD with SMART detection trade mark activated. In 138 of these patients, 1,245 sustained tachycardia episodes with a detailed electrogram were stored in the device during a follow-up period of 10 +/- 6 months. Episodes were correctly classified as ventricular fibrillation (VF, n = 178) in 52 patients, VT (n = 641) in 98 patients, and SVT (n = 385) in 48 patients by the algorithm. Forty-one true SVT episodes (3.3%) were misclassified as VT: atrial fibrillation (n = 7) and flutter (n = 1), sinus tachycardia (n = 12), and other SVT (n = 21). The positive predictivity for VF/VT was 94.5% (95% CI 92.7-95.8) uncorrected and 94.5% (95% CI 92.9-95.8%) corrected with the generalized equation estimation (GEE) method. The positive predictivity for SVT was 100%. The specificity was 88.9% (95% CI 85.6-91.6%) uncorrected and 89.0% (95% CI 85.6-91.6%) corrected with the GEE method with a sensitivity of 100%. CONCLUSION: The SMART detection trade mark algorithm was safe and reliable for the detection of all ventricular tachycardias. Although its specificity was high, it should be improved with regard to SVT to avoid inappropriate ICD therapies.

Heart rate variability before ventricular arrhythmias in patients with coronary artery disease and an implantable cardioverter defibrillator.

BACKGROUND: Changes in autonomic regulation of the heart may be responsible for the occurrence of arrhythmias. Although a decrease in 24-hour heart rate variability is a strong predictor of subsequent arrhythmias in patients with heart disease, many questions remain unanswered concerning changes in heart rate and heart rate variability in the minutes or hours preceding an arrhythmia. The aim of our study was to analyze changes in heart rate and heart rate variability occurring during the 90 minutes preceding an arrhythmia, in patients with coronary heart disease and an implantable defibrillator. MATERIALS AND METHODS: Thirty-eight patients, with a total of 93 episodes of ventricular arrhythmia, were included in the study. Heart rate and heart rate variability were measured in three 30-minute and five 2-minute periods preceding the arrhythmia. Heart rate variability was assessed using measurements of Poincaré plots. RESULTS: The results show a gradual increase in heart rate before the arrhythmia, from 73+/-13/min, to 75+/-14/min, and finally 78+/-15/min in the 90 minutes preceding the arrhythmia (P<0.05). CONCLUSION: Measurements of Poincaré plots showed a significant increase in their length and no significant change in their width. These results suggest that sympathetic activation is the predominant change in autonomic nervous system before a ventricular arrhythmia in patients with coronary heart disease. This change may occur as early as one hour and a half before the arrhythmia.

Mapping and ablation of idiopathic ventricular fibrillation.

BACKGROUND: Ventricular fibrillation is the main mechanism of sudden cardiac death. The feasibility of eliminating recurrent episodes by catheter ablation has not been reported. METHODS AND RESULTS: Twenty-seven patients without known heart disease (13 men, 14 women, 41+/-14 years of age) were studied after being resuscitated from recurrent (10+/-12) episodes of primary idiopathic ventricular fibrillation; 23 had received a defibrillator. The first initiating beat of ventricular fibrillation had an identical electrocardiographic morphology and coupling interval (297+/-41 ms) to preceding isolated premature beats typically noted in the aftermath of resuscitation. These triggers were localized by mapping the earliest electrical activity and ablated by local radiofrequency delivery. Outcome was assessed by Holter and defibrillator memory interrogation. Premature beats were elicited from the Purkinje conducting system in 23 patients: from the left ventricular septum in 10, from the anterior right ventricle in 9, and from both in 4. The interval from the Purkinje potential to the following myocardial activation varied from 10 to 150 ms during premature beat but was 11+/-5 ms during sinus rhythm, indicating location at peripheral Purkinje arborization. The premature beats originated from the right ventricular outflow tract muscle in 4 patients. The accuracy of mapping was confirmed by acute elimination of premature beats during local radiofrequency delivery. During a follow-up of 24+/-28 months, 24 patients (89%) had no recurrence of ventricular fibrillation without drug. CONCLUSIONS: Primary idiopathic ventricular fibrillation is a syndrome characterized by dominant triggers from the distal Purkinje system. These sources can be eliminated by focal energy delivery.