Óscar Alcalde

Spatial Resolution of Defibrillator Electrograms to Detect Distinct Exit Sites of Scar-Related Ventricular Tachycardia

Analysis of implantable cardioverter‐defibrillator electrograms (IEGMs) with pacing along the scar edge is often used to approximate distinct exit sites of scar‐related ventricular tachycardia (VT). We evaluated the spatial resolution of IEGMs in identifying distinct exit sites of scar‐related VT.

Atypical pacemaker-mediated tachycardia from the atrial channel: What is the mechanism?

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Wide QRS complex tachycardia followed by 2:1 atrioventricular block: What is the mechanism?

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Not Enough QRS Shortening? Keep Calm and Add Another Lead

ElectrophysiologyUnit, CardiovascularDivision, Department ofMedicine, Hospital delMar, Universitat AutònomadeBarcelona, Barcelona, Spain Correspondence Jesús JiménezLópez,MD,Hospital delMar,CardiovascularDivision, ElectrophysiologyUnit, 25–27PasseigMarítim,Barcelona08003Spain. Email: jejilo78@gmail.com All authors contributed to the critical revisionof thearticle and take responsibility for all aspects of the reliability and freedomfrombiasof thedatapresentedand their discussed interpretation.

Implantable Cardioverter-defibrillator Therapy for Hypertrophic Cardiomyopathy: Usefulness in Primary and Secondary Prevention.

Cardiac resynchronization therapy (CRT) diminishes symptoms and reduces hospitalization and mortality in patients with heart failure, LV dysfunction and left bundle branch block. However, up to one third of patients do not respond to CRT. In that regard, few initial studies presenting multisite pacing have shown encouraging results, demonstrating both feasibility and safety in placing a second CS lead in >80% of patients intended, with further QRS shortening, which is the most powerful predictor of LV reverse remodelling.

Sudden Change in R-Wave Amplitude. Is It a Device Malfunction?

INTRODUCTION AND OBJECTIVES Hypertrophic cardiomyopathy is a frequent cause of sudden death. Clinical practice guidelines indicate defibrillator implantation for primary prevention in patients with 1 or more risk factors and for secondary prevention in patients with a history of aborted sudden death or sustained ventricular arrhythmias. The aim of the present study was to analyze the follow-up of patients who received an implantable defibrillator following the current guidelines in nonreferral centers for this disease. METHODS This retrospective observational study included all patients who underwent defibrillator implantation between January 1996 and December 2012 in 3 centers in the province of Barcelona. RESULTS The study included 69 patients (mean age [standard deviation], 44.8 [17] years; 79.3% men), 48 in primary prevention and 21 in secondary prevention. The mean number of risk factors per patient was 1.8 in the primary prevention group and 0.5 in the secondary prevention group (P=.029). The median follow-up duration was 40.5 months. The appropriate therapy rate was 32.7/100 patient-years in secondary prevention and 1.7/100 patient-years in primary prevention (P<.001). Overall mortality was 10.1%. Implant-related complications were experienced by 8.7% of patients, and 13% had inappropriate defibrillator discharges. CONCLUSIONS In patients with a defibrillator for primary prevention, the appropriate therapy rate is extremely low, indicating the low predictive power of the current risk stratification criteria.

Terapia con desfibrilador automático implantable en la miocardiopatía hipertrófica: utilidad en prevención primaria y secundaria

An 85-year-old man with chronic ischemic heart disease, carrying a single-chamber implantable cardioverter defibrillator (ICD; Lumax R ©, Biotronik, Berlin, Germany) was scheduled for surgical electrode inspection and defibrillation test due to a sudden decrease in the sense Rwave amplitude. The ICD was implanted for secondary prophylaxis due to symptomatic ventricular tachycardia (VT) in 2004. During followup, several episodes of VT occurred that required direct current (DC) shocks. Hence, antiarrhythmic drug therapy with sotalol was started and the patient remained asymptomatic and free of VT recurrences. The device and the electrode were replaced in 2010 due to elective indication for battery consumption and suspicion of electrode dysfunction due to conductor fracture with high pacing impedances and detection of electrical noise. After the reoperation a home monitoring system (Home Monitoring R ©, Biotronik) was given to the patient and sotalol therapy was withdrawn due to significant bradycardia. A year later, a new episode of VT requiring defibrillation was noticed so oral amiodarone was started. The patient remained asymptomatic but through remote monitoring some weeks later, a transient but significant and sharp decline in sensed R wave was documented. The results were confirmed with the programmer at the ambulatory visit and a new surgical revision of the electrode was indicated consequently. In the check-up of the electrode at the operating room, sudden changes in the value of the sensed R wave were observed repeatedly following a pattern of alternance of two different values every few minutes (Fig. 1), which was unrelated to position, hyperventilation, and effort.