The role of atrial sensing for new-onset atrial arrhythmias diagnosis and management in single-chamber implantable cardioverter-defibrillator recipients: Results from the THINGS registry.

INTRODUCTION: Atrial tachycardia/fibrillation (AT/AF) episodes are common in implantable cardioverter-defibrillator (ICD) recipients and can be undetected by standard single-chamber devices. This study aims to explore whether a single-lead ICD with an atrial dipole (ICD DX; BIOTRONIK SE & Co, Berlin, Germany) could improve the AT/AF diagnosis and management as compared to standard ICD (ICD VR). METHODS AND RESULTS: We selected patients without AT/AF history from the THINGS registry which included consecutive patients implanted with ICD for standard indications. The ICD VR and the ICD DX groups included 236 (62.8%) and 140 (37.2%) patients, respectively, and had no significant differences in baseline characteristics. During a median follow-up of 27 months, there were 7 AT/AF diagnoses in the ICD VR and 18 in the ICD DX group. The 2-year incidence of AT/AF diagnosis was 3.6% (95% confidence interval [CI]: 1.6%-9.6%) for the ICD VR and 11.4% (95% CI: 6.8%-18.9%) for the ICD DX group (adjusted hazard ratio [HR]: 3.85 [95% CI: 1.58-9.41]; P = .003). Initiation of oral anticoagulation (OAC) due to AT/AF diagnosis was reported in 15 patients. The 2-year incidence of OAC onset was 3.6% (95% CI: 1.6%-7.8%) for the ICD VR and 6.3% (95% CI: 3.0%-12.7%) for ICD DX group (adjusted HR: 1.99 [95% CI: 0.72-5.56]; P = .184). CONCLUSION: We observed that atrial sensing capability in single-chamber ICD patients without evidence of atrial arrhythmias at implant is associated with a greater likelihood of detecting AT/AF episodes. The management of these diagnosed arrhythmias often led to clinical interventions, mainly represented by initiation of OAC therapy.

Impact of pacemaker longevity on expected device replacement rates: Results from computer simulations based on a multicenter registry (ESSENTIAL).

BACKGROUND: The rate of device replacement in pacemaker recipients has not been investigated in detail. HYPOTHESIS: Current pacemakers with automatic management of atrial and ventricular pacing output provide sufficient longevity to minimize replacement rate. METHODS: We considered a cohort of 542 pacemaker patients (age 78 ± 9 years, 60% male, 71% de-novo implants) and combined 1-month projected device longevity with survival data and late complication rate in a 3-state Markov model tested in several Monte Carlo computer simulations. Predetermined subgroups were: age < or ≥ 70; gender; primary indication to cardiac pacing. RESULTS: At the 1-month follow-up the reported projected device longevity was 153 ± 45 months. With these values the proportion of patients expected to undergo a device replacement due to battery depletion was higher in patients aged <70 (49.9%, range 32.1%-61.9%) than in age ≥70 (24.5%, range 19.9%-28.8%); in women (39.9%, range 30.8%-48.1%) than in men (32.0%, range 24.7%-37.5%); in sinus node dysfunction (41.5%, range 30.2%-53.0%) than in atrio-ventricular block (33.5%, range 27.1-38.8%) or atrial fibrillation with bradycardia (27.9%, range 18.5%-37.0%). The expected replacement rate was inversely related to the assumed device longevity and depended on age class: a 50% increase in battery longevity implied a 5% reduction of replacement rates in patients aged ≥80. CONCLUSIONS: With current device technology 1/4 of pacemaker recipients aged ≥70 are expected to receive a second device in their life. Replacement rate depends on age, gender, and primary indication owing to differences in patients' survival expectancy. Additional improvements in device service time may modestly impact expected replacement rates especially in patients ≥80 years.

Less is more: Can we achieve cardiac resynchronization with 2 leads only?

BACKGROUND: We compared clinical and technical outcome of CRT recipients treated either with a conventional 3­leads (3L) CRTD or with the new 2­leads (DX) CRTD that enables atrial signal detection by a floating dipole built on a pentafilar RV lead. METHODS: Echocardiography and cardiopulmonary exercise tests were repeated either before CRTD implantation and between 6 and 12 months follow up in consecutively implanted patients who had a resting heart rate>40bpm at maximum tolerated beta-blocker dosage. HF status, reverse LV remodeling, exercise tolerance and chronotropic incompetence were assessed at 12 months FU. Device diagnostics were obtained twice yearly until December 2016. RESULTS: 37 patients aged 66 (58-73) years were consecutively implanted in 2013-2014 according to current guidelines, 25 with a 3L CRTD and 12 with a DX CRTD. Beta-blocker dosage was similar, and no difference between the 2 groups was observed in terms of NYHA class improvement, LV reverse remodeling, peak cardiopulmonary performance and presence of chronotropic incompetence at 12 months follow up. There was no difference in: amount delivered CRT; occurrence of VT/VF; occurrence of AT/AF. No patients developed need of atrial stimulation at 3-years FU. Atrial undersensing never occurred in any patient, whereas Far-field R-wave oversensing was more common in 3L patient than in DX patients (8/25 vs none, P<0.05). P wave amplitude was greater in DX vs 3L patients [5.1(3.7-9.2) vs 2.9(2-3.9) mV, P<0.01]. CONCLUSION: CRT can be achieved with two­leads-only in the majority of patients, provided that indication to atrial stimulation is ruled out.