A Practical Scoring System for Estimating Ventricular Arrhythmia Events in Patients with Cardiac Resynchronization Therapy for Primary Prevention

The prognostic value of defibrillators in cardiac resynchronization therapy (CRT) for primary prevention remains debatable. Predicting ventricular arrhythmias (VAs) before implantation is useful for deciding whether to add a defibrillator to a CRT device. This study aimed to determine the risk factors for VA events after CRT device implantation and to construct a scoring model. A total of 153 patients who underwent CRT device implantation, with no history of sustained ventricular tachycardia or ventricular fibrillation (including 25 patients with CRT pacemakers) and with follow-up period >1 year after implantation were included. We assessed VA events requiring implantable cardioverter-defibrillator therapy and sustained VA events requiring clinical treatment. During a mean follow-up of 6.3 years, 24 patients (16%) received therapy for VA. Multivariate analysis revealed age ≤ 70 years (hazard ratio [HR] 2.936, P = 0.037), administration of tolvaptan (HR 11.259, P < 0.001), and coronary artery disease (HR 2.444, P = 0.045) were independent predictors for VA events. Risk scores were assigned based on the HR for each predictor, and the population was divided into 3 risk groups (low: 0 points; moderate: 1-3 points; high: 4-5 points). VAs occurred less frequently in the low-risk group than in the other risk groups (low: 8.1%; moderate: 18%; high: 21%) (log-rank, P < 0.001). No significant differences in mortality were observed between the groups, whereas hospitalization for heart failure occurred more frequently in the high-risk group than in the other groups. In conclusion, a scoring system using specific background information may help predict VA events in prophylactic CRT recipients.