Stéphane Boulé

Decreased Delivery of Inappropriate Shocks Achieved by Remote Monitoring of ICD: A Substudy of the ECOST Trial

Inappropriate shocks remain a highly challenging complication of implantable cardioverter defibrillators (ICD). We examined whether automatic wireless remote monitoring (RM) of ICD, by providing early notifications of triggering events, lowers the incidence of inappropriate shocks.

Pregnancy in women with an implantable cardioverter-defibrillator: is it safe?

AIMS To describe obstetric/neonatal and cardiac outcomes for a cohort of women carrying implantable cardioverter-defibrillators (ICDs) during pregnancy. METHODS AND RESULTS All women in routine follow-up at our institution for ICD implantation who became pregnant between 2006 and 2013 were included in this study. All ICDs were pre-pectoral devices with bipolar endocardial leads. Obstetric/neonatal and cardiac outcomes were assessed during pregnancy and post-partum. Twenty pregnancies were conceived by 12 women carrying ICD devices, 14 of which resulted in live births and none in maternal death. Seven of these women had structural cardiomyopathies and five had channelopathies. No device-related complications were recorded. Twelve shocks (nine transthoracic and three from ICDs) were experienced during pregnancy by two women, one of whom miscarried shortly afterwards at 4 weeks gestation. One stillbirth, three miscarriages and one termination were recorded for women with long QT syndrome, repaired tetralogy of Fallot and repaired Laubry-Pezzi syndrome, respectively. Intrauterine growth restriction, low birth weight, and neonatal hypoglycaemia were recorded in four, three, and five pregnancies, respectively. CONCLUSIONS Pregnancy had no effect on ICD operation and no evidence was found to link ICD carriage with adverse pregnancy outcomes, although one miscarriage may have been induced by ICD shock therapy. A worsening of cardiac condition occurs in specific cardiac diseases and β-blocker therapy should be continued for all women carrying ICDs in pregnancy as the benefits outweigh the risks of taking this medication.

Right Ventricular Pacing With Mechanical Dyssynchrony Causes Apoptosis Interruptus and Calcium Mishandling

BACKGROUND Mechanical dyssynchrony associated with rapid pacing induces cardiac cell stress and myocardial apoptotic pathway activation that has been implicated in the pathophysiology of left ventricular (LV) dysfunction. Effects of dyssynchrony per se are not fully understood. The objective of our study was to test whether ventricular dyssynchrony would elicit myocardial alterations in LV calcium handling regulation and cell survival or apoptosis signalling in right ventricular-paced swine. METHODS Implantation of pacemaker was performed under anaesthesia. Endocardial bipolar screw lead was inserted into the right jugular vein and positioned either in the right atrium or at the right ventricular (RV) apex. Swine were paced at 150 beats per minute for 3 weeks. RESULTS Compared with right atrial pacing, RV pacing led to abnormal LV sarcoplasmic reticulum calcium uptake (315 ± 65 vs 155 ± 55 nmol/min/mg, P < 0.05) and LV calcium-handling protein expression, ie, 35% reduction in ryanodine receptor 2, 25% decline in sarcoplasmic reticulum Ca(2+) ATPase, 70% increase in Na(+)/Ca(2+) exchanger, and 10% increase in phospholamban. RV pacing also elicited activation of LV apoptotic cascades without nuclear apoptosis. So-called interrupted apoptosis was the result of increased expression of X-linked inhibitor of apoptosis protein. Apoptosis and calcium mishandling were documented in absence of depressed heart function (ejection fraction 62 ± 8% vs 57 ± 12%, in right atrial- and RV-paced hearts, respectively, P > 0.05). CONCLUSIONS Slow rate RV pacing causes mechanical dyssynchrony and profound LV alterations in both apoptotic pathways and calcium handling in the early stages of pacing-induced cardiomyopathy.

Potential role of antitachycardia pacing alerts for the reduction of emergency presentations following shocks in patients with implantable cardioverter-defibrillators: implications for the implementation of remote monitoring

AIMS Despite increased use of remote monitoring (RM) to follow up implantable cardioverter-defibrillator (ICD) recipients, many patients still receive ICD shocks in the community and present to the emergency department. Our aim was to identify the best predictors of impending shock delivery that can be measured with an ICD and to identify the most appropriate activities to alert physicians to during RM follow-up. METHODS AND RESULTS All patients presenting to our institution for ICD shock, from November 2011 to November 2014, were enrolled in this prospective study. Patient characteristics, investigation results, and details of electrical activities from ICD interrogation were recorded at presentation. Presentations were classified as potentially avoidable if activities from a list of set criteria were apparent more than 48 h before index shock. Univariate and multivariate analyses were then used to identify predictors of potentially avoidable shocks. In total, 109 emergency presentations were recorded in 90 patients (male: 85%; 57 ± 16 years; ischaemic cardiomyopathy: 49%; LVEF: 34 ± 13%; electrical storm: 40%), of which 26 (24%) were potentially avoidable. Antitachycardia pacing (ATP) episodes were the most important predictor of impending shock. Potentially avoidable shocks were preceded by more episodes of ATP than unavoidable shocks (13 [3-67] vs. 3 [0-10]; P < 0.001). Patients followed up with RM systems configured to generate alerts following ATP delivery experienced significantly less ICD shocks (24 vs. 16%, P < 0.01). CONCLUSION Remote monitoring systems that generate alerts following ATP delivery could reduce emergency presentations for ICD shock by 24%, as ATP is a key predictor of impending shock delivery.

Validation of an Organizational Management Model of Remote Implantable Cardioverter-Defibrillator Monitoring Alerts

Background—Implantable cardioverter-defibrillators (ICDs) are a standard means of sudden cardiac death prevention. Compared with ambulatory visits, remote monitoring (RM) of ICD recipients has improved the quality of health care and spared its resources. Few studies have addressed the organization of RM. We optimized and validated our institutional model of RM organization for ICD recipients. Methods and Results—This observational study of 562 ICD recipients compared 2 RM periods consisting of iterative, qualitative, and quantitative (1) device diagnostic evaluations by nurses and cardiologists; and (2) selected decisional trees. The main study end points were the professional interventions prompted by, and times allocated to, RM alerts. During the first period, 1134 alerts occurred in 427 patients (286 patient-year), of which 376 (33%) were submitted to cardiologists’ reviews, compared with, 1522 alerts in 562 patients (458 patient-year), of which 273 (18%) were submitted to cardiologists’ reviews during the second period (P<0.001). An intervention was prompted by 73 of 376 (19.4%) alerts in the first versus 77 of 273 (28.2%) in the second period (P=0.009). The mean time to manage an alert was 4 minutes 31 s in the first versus 2 minutes 10 s in the second period (P<0.001). The annual numbers of alert-related hospitalizations were 10.8 versus 8.1 per 100-patient-year (P=0.230), and annual numbers of alert-related visits were 9.8 and 6.1 per 100-patient-year (P=0.081), respectively. Conclusions—An optimized RM organization based on automated alerts and decisional trees enabled a focus on clinically relevant events and a decrease in the consumption of resources without compromising the quality of ICD recipients’ care.

Catheter ablation reduces ventricular tachycardia burden in patients with arrhythmogenic right ventricular cardiomyopathy: insights from a north-western French multicentre registry

Aims Studies assessing radiofrequency ablation (RFA) of ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy (ARVC) report VT recurrences, but have not evaluated the impact of RFA on relevant clinical events during follow-up. We aimed to investigate relevant RFA outcomes in a multicentric registry. Methods and results This study included 49 patients with ARVC (46 with definite diagnosis, 3 with borderline diagnosis according to revised Task Force Criteria) who underwent 92 RFA procedures (83 endocardial, 9 combined endo-epicardial) between 1999-2015. Ventricular tachycardia recurrences and VT burden were assessed after each procedure or after the last RFA. Over a mean follow-up of 64 ± 51 months, VT-free survival was 37% at 1 year, 19% at 5 years, and 14% at 10 years. Ventricular tachycardia burden was significantly reduced after one procedure (23 vs. 11 VT episodes/year, P < 0.01) and after the last RFA (14 vs. 2 VT episodes/year, P < 0.01). Over a mean follow-up of 49 ± 52 months, clinical response after the last RFA (freedom from sudden cardiac death, VT requiring hospitalization, or heart transplantation) was 86% at 1 year, 69% at 5 years, and 60% at 10 years. Clinical response was associated with right ventricular dysfunction (RVD) and low numbers of mappable VT before the first RFA. Conclusion RFA was predominantly targeted at the endocardial surface. Ventricular tachycardia recurrences were common, but few ARVC patients experienced major clinical events during follow-up. Further studies should investigate the benefit of extensive substrate ablation combined with endo-epicardial strategies.

Long-term outcome of implantable cardioverter-defibrillator implantation in secondary prevention of sudden cardiac death.

BACKGROUND Little is known about the long-term outcomes of patients who receive an implantable cardioverter-defibrillator (ICD) for purely secondary prevention indications. AIMS To assess the rates and predictors of appropriate therapies over a very long-term follow-up period in this population. METHODS Between June 2003 and August 2006, 239 consecutive patients with structural left ventricular disease and a secondary prophylaxis indication for ICD therapy (survivors of life-threatening ventricular tachyarrhythmias) were prospectively enrolled. An extended follow-up of these patients was carried out. The primary endpoint was the occurrence of appropriate device therapy. Secondary endpoints were all-cause death, electrical storm and inappropriate therapy. RESULTS The study population consisted of 239 patients (90% men; mean age 64±12 years; 72% ischaemic cardiomyopathy; left ventricular ejection fraction 37±12%). During a median follow-up of 7.8 (3.5-9.3) years, appropriate device therapy occurred in 139 (58.2%) patients. Death occurred in 141 patients (59%), electrical storm in 73 (30.5%) and inappropriate therapy in 42 (17.6%). Multivariable analysis identified patients whose presenting arrhythmia was ventricular fibrillation as being less likely to require appropriate device therapy than those whose presenting arrhythmia was ventricular tachycardia (sub-hazard ratio 0.62, 95% confidence interval 0.40-0.97; P=0.04). Independent predictors of all-cause death were age at implantation (P<0.0001), wide QRS complexes (P=0.024), creatinine concentration (P=0.0002) and B-type natriuretic peptide at implantation (P=0.0001). CONCLUSION Secondary prevention ICD recipients exhibit a high risk of appropriate device therapy and death over prolonged follow-up. Patients who presented initially with ventricular fibrillation were less likely to require the delivery of appropriate device therapy.

Solitary atrial myocardial metastasis revealing ileal neuroendocrine carcinoma.

A previously healthy 56-year-old man presented with chest pain. Echocardiography and cardiac magnetic resonance imaging revealed minimal pericardial effusion associated with an isolated myocardial mass, protruding into the left atrium. The tumor was surgically removed. Cardiac valve morphology was strictly normal. Histology revealed a well-differentiated neuroendocrine carcinoma. Positron emission tomography scan and thin-slice abdominal computed tomography demonstrated ileal tumor, without evidence of liver metastasis. Histological study of the removed ileal tumor confirmed a neuroendocrine carcinoma, and histology of liver biopsy was negative. Somatostatin analogue treatment was started. No tumoral recurrence was observed after 1 year of follow-up. In conclusion, we report an unusual presentation of neuroendocrine carcinoma, revealed by a large solitary atrial metastasis, in the absence of liver involvement or carcinoid syndrome.

Remote monitoring of patients with implantable cardioverter-defibrillators: Can results from large clinical trials be transposed to clinical practice?

BACKGROUND Remote monitoring (RM) is increasingly used to follow up patients with implantable cardioverter-defibrillators (ICDs). Randomized control trials provide evidence for the benefit of this intervention, but data for RM in daily clinical practice with multiple-brands and unselected patients is lacking. AIMS To assess the effect of RM on patient management and clinical outcome for recipients of ICDs in daily practice. METHODS We reviewed ICD recipients followed up at our institution in 2009 with RM or with traditional hospital only (HO) follow-up. We looked at the effect of RM on the number of scheduled ambulatory follow-ups and urgent unscheduled consultations, the time between onset of asymptomatic events to clinical intervention and the clinical effectiveness of all consultations. We also evaluated the proportion of RM notifications representing clinically relevant situations. RESULTS We included 355 patients retrospectively (RM: n=144, HO: n=211, 76.9% male, 60.3±15.2 years old, 50.1% with ICDs for primary prevention and mean left ventricular ejection fraction 35.5±14.5%). Average follow-up was 13.5 months. The RM group required less scheduled ambulatory follow-up consultations (1.8 vs. 2.1/patient/year; P<0.0001) and a far lower median time between the onset of asymptomatic events and clinical intervention (7 vs. 76 days; P=0.016). Of the 784 scheduled ambulatory follow-up consultations carried out, only 152 (19.4%) resulted in therapeutic intervention or ICD reprogramming. We also found that the vast majority of RM notifications (61.9%) were of no clinical relevance. CONCLUSION RM allows early management of asymptomatic events and a reduction in scheduled ambulatory follow-up consultations in daily clinical practice, without compromising safety, endorsing RM as the new standard of care for ICD recipients.

Very Prolonged Episode of Self-Terminating Ventricular Fibrillation in a Patient With Brugada Syndrome

We report the case of a very prolonged spontaneous episode of self-terminating ventricular fibrillation in a patient with Brugada syndrome (BrS). The patient first underwent implantation of an internal loop recorder after an episode of prolonged loss of consciousness (several minutes) that was suggestive of a nonarrhythmic cause. After a second episode of prolonged syncope, subsequent interrogation of the loop recorder revealed a very prolonged episode of self-terminating ventricular arrhythmia, lasting 2 minutes and 41 seconds. This short report emphasizes the fact that an arrhythmic cause of syncope should not be ruled out in patients with BrS presenting with very prolonged loss of consciousness.