Risk of Malignant Ventricular Arrhythmias in Patients with Mild to Moderately Reduced Ejection Fraction Following Permanent Pacemaker Implantation.

BACKGROUND: Many patients with mild to moderately reduced left ventricular ejection fraction (LVEF) that require permanent pacemaker (PPM) implantation do not have a concurrent indication for implantable cardioverter-defibrillator (ICD) therapy. However, the risk of ventricular tachycardia/fibrillation (VT/VF) in this population is unknown.

OBJECTIVE: To describe the risk of VT/VF following PPM implantation in patients with mild to moderately reduced LVEF.

METHODS: Retrospective analysis was performed on 243 patients with LVEF between 35-49% who underwent PPM placement, and did not meet indications for an ICD. The primary endpoint was occurrence of sustained VT/VF. Competing risks regression was performed to calculate sub-hazard ratios for the primary endpoint.

RESULTS: Median follow up was 27 months. 73% of patients were male, average age was 79±10 years, average LVEF was 42±4%, and 70% were New York Heart Association (NYHA) Class II or above. Most PPMs were implanted for sick sinus syndrome (34%) or atrioventricular block (50%). Of 243 total patients, 11 (4.5%) met the primary endpoint of VT/VF. Multivessel coronary artery disease (CAD) was associated with significantly higher rates of VT/VF, with a sub-hazard ratio of 5.4 (95% CI 1.5-20.1, p=0.01). Among patients with multivessel CAD, 8/82 (9.8%) of patients met the primary endpoint, for an annualized risk of 4.3% per year.

CONCLUSION: Patients with mild to moderately reduced LVEF and multivessel CAD undergoing PPM implant are at increased risk for the development of malignant ventricular arrhythmias. Patients in this population may benefit from additional risk stratification for VT/VF and consideration for upfront ICD implant.