J Interv Card Electrophysiol (2014) 41:23–29 DOI 10.1007/s10840-014-9920-0
Implantable cardioverter-defibrillators in patients with arrhythmogenic right ventricular cardiomyopathy: the course of electronic parameters, clinical features, and complications during long-term follow-up Giacomo Mugnai & Ruggero Tomei & Clementina Dugo & Luca Tomasi & Giovanni Morani & Corrado Vassanelli
Received: 19 March 2014 / Accepted: 13 May 2014 / Published online: 14 June 2014 # Springer Science+Business Media New York 2014
Abstract Purpose Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive cardiomyopathy characterized by myocardial atrophy and fibro-fatty replacement of the right ventricle (RV) and ventricular tachyarrhythmias in young patients. Our aim was to evaluate clinical course and electronic parameters in patients with implantable cardioverter-defibrillator (ICD) and ARVC, during longterm follow-up. Methods and results We report on 12 patients with ARVC (mean age 40±13 years) who were treated with ICD implantation in our center. Although several RV sites were tested for proper lead positions, the amplitude of R-wave at implantation was quite low (7.4±3.0 mV). After a mean follow-up of 91± 28 months, R-wave amplitude significantly decreased to a mean value of 5.4±2.5 mV (p=0.03). We also found a noticeable, nearly significant increase in pacing threshold (p=0.052) and a moderate increase in defibrillation impedance (p=0.07). Six patients (46 %) experienced at least one appropriate ICD therapy; three patients (23 %) experienced inappropriate ICD shocks secondary to the supraventricular tachycardia, T-wave oversensing, and electromagnetic interference. Conclusions ICD in patients with ARVC has been demonstrated to be feasible and safe. In our case series, we found low R-wave amplitudes at implantation and a significant R-wave decrease during follow-up; a considerable and nearly significant increase in pacing threshold was G. Mugnai (*) : R. Tomei : C. Dugo : L. Tomasi : G. Morani : C. Vassanelli Division of Cardiology, Azienda Ospedaliera Universitaria Integrata, Piazzale Stefani 1, 37126 Verona, Italy e-mail:
[email protected]
also observed. These findings may be related to the progressive fibro-fatty replacement of RV myocardium. Multiple sites should be tested in the right ventricle if sensing or pacing values are not optimal, and all the electronic parameters should be carefully monitored throughout the entire follow-up. Keywords Arrhythmogenic right ventricular cardiomyopathy . Implantable cardioverter-defibrillator . Electronic parameters . R-wave amplitude . Complications
1 Introduction Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disorder accounting for ventricular tachyarrhythmias and sudden death in young patients [1–5]. ARVC is characterized by progressive myocardial atrophy and fibro-fatty replacement of the right ventricle free wall [2, 3]. Therapy for AVRC aims to reduce and treat ventricular arrhythmias and may include antiarrhythmic drugs, catheter ablation, and implantable cardioverter-defibrillators (ICD). Although in the last decades, ICDs have been increasingly used both as prevention and as treatment of life-threatening ventricular arrhythmias; published data on the long-term results of ICDs in patients with ARVC are still limited [6–10]. The diseased right ventricle may result in additional risks during endocardial lead implantation, such as perforation, and also in inadequate pacing, sensing, and defibrillation functions in the long-term. We report on the ICD therapy, electronic parameters, and clinical follow-up of 13 patients with ARVC who underwent ICD implantation as both primary and secondary prevention.
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J Interv Card Electrophysiol (2014) 41:23–29
2 Methods
2.2 Device implantation
2.1 Patient population
All patients received transvenous endocardial defibrillation leads. In eleven patients, ICDs were placed in the prepectoral region via a subclavian vein access; one patient was implanted using a subaxillary approach with axillary vein puncture and under general anesthesia, for aesthetic reasons. All procedures were left-sided. Five dual-chamber (38 %) and eight single-chamber (62 %) ICD implantations were performed. The implanted devices were made by Medtronic Inc. (Minneapolis, MN, USA), Boston Scientific (Natick, MA, USA), and St. Jude (St. Paul, MN, USA). Three active fixation and five passive fixation leads were implanted at the right ventricular (RV) apex; four screw-in leads were positioned on the right ventricular septal wall (Table 2). Five passive fixation leads were also placed in the right atrial (RA) appendage. After the leads were placed, sensing, pacing, impedance values, and defibrillation thresholds were assessed. Particular attention was paid to achieving an R-wave amplitude >4.0 mV and a pacing threshold
