Accuracy of the pacemaker event recorder versus Holter-ECG to detect both symptomatic and asymptomatic ventricular arrhythmias

Although new pacemakers can register cardiac rhythm, few studies were performed evaluating their accuracy in diagnosing ventricular arrhythmias (VA). This study aimed to assess the correlation and agreement between the pacemaker's monitor and the ambulatory Holter in detecting VA. Methods/results We studied 129 patients with pacemakers, mean age 68.6±19.1 years, 54.8% female. Once Holter monitoring was connected, the pacemakers’ event counters were reset and clocks of both systems were synchronized to register ECG simultaneously. Pacemakers were programmed to detect the lowest ventricular rate and lowest number of sequential beats allowed in their event monitors. After 72 hours, Holter and pacemakers records were analyzed. VA was defined in Holter and event monitor respectively as: isolated premature ventricular complexes: “PVC”; pairs: “couplets”; nonsustained ventricular tachycardia (NSVT): “triplets”- 3 beats; “runs”- 4–8 or > 8 beats, and “HVR”- 3–4 beats. Spearman correlations evaluated whether pacemaker and Holter identified the same parameters. Intraclass correlation coefficients and respective 95% confidence intervals were calculated to assess the concordance between methods. The agreement between both systems was low, except for “triplet” and three beats NSVT (ICC = 0.984). The correlation for more than 10 PVC/h was moderate (kappa = 0.483). When the pacemaker was programmed to detect HVR sequences of three beats lower than 140 bpm (< 140/3), the correlation with NSVT was perfect (r = 1) and agreement was also quite high (ICC = 0.800). Conclusions pacemaker's event monitors underestimate the occurrence of ventricular arrhythmias detected by Holter. Standardization of pacemakers’ algorithms is required before using this function for patient's clinical follow-up. This article is protected by copyright. All rights reserved