P1634Clinical significance of the incidental detection of non-sustained ventricular tachycardia with remote monitoring of the pacemaker

Abstract

Background: Asymptomatic non-sustained ventricular tachycardia (NSVT) is often incidentally detected by the diagnostic function of modern pacemakers (PM). NSVT prognostic role has already been studied in patients with implantable cardioverter- defibrillators, who are often affected by structural heart disease, but it is still unknown in the more heterogeneous and older population of PM patients. Purpose: To evaluate the prevalence of NSVT in PM patients, to compare the clinical characteristics of patients with and without NSVT and to assess the prognostic role of NSVT in terms of total mortality, cardiovascular mortality and cardiovascular hospitalizations. Methods: We retrospectively included consecutive patients followed with PM remote monitoring from September 2010 to December 2015. During the first 12-15 months of remote monitoring, the first three transmissions were analyzed and the patients were divided in two groups: group A) included patients presenting NSVT, group B) patients without NSVT. The two groups were compared in terms of age, sex, prevalence of ischemic and non-ischemic heart disease, non-cardiac comorbidities and in terms of total mortality, cardiovascular mortality and cardiovascular hospitalizations on the basis of the administrative data provided by the regional administration of the national health system. Results: We enrolled 444 patients (mean age 76,2±10,9 yo, males 60,8%). At least one run of NSVT was recorded in 26,6% of patients (median length of the longest NSVT 148 cycles; median rate of the fastest NSVT 205 bpm). The two groups did not differ for age (p0,554), left ventricular ejection fraction (LVEF) (60,6±10,4% vs 60,7±10,0%; p0,910) nor for prevalence of hypertension (p0,112), diabetes mellitus (p0,324), hypercholesterolemia (p0,205), chronic renal failure (p0,2±9), ischemic cardiomyopathy (p0,213), atrial fibrillation (p0,078), hyperthyroidism (p0,190), cancer (p0,512). Conversely, patients with NSVT had more frequently atrioventricular conduction disorders (76,3 vs 54,6%; p<0,001) with higher percentage of ventricular pacing (71±41 vs 54±45%; p<0,001), history of heart failure (20,3 vs 12,3%; p0,025) and valvular heart disease (29,7 vs 18,4%; p0,003). At baseline patients with NSVT were more treated with beta-blockers (47,7 vs 34,8%; p0,013) but less treated with sotalol (9,3 vs 16,9%; p0,039) and amiodarone (0,9 vs 8,1%; p0,004). Median length of follow up (FU) was 51,0 months (IR 34,2). Data on FU is currently being analyzed. Conclusion: In this large series, patients with NSVT detected incidentally with PM remote control are more frequently affected by heart failure and valvular heart disease, without significant differences in LVEF. However, differences in chronic antiarrhythmic therapy usage and ventricular pacing percentage may partially justify these data. The real clinical significance of NSVT could be better explained by the forthcoming analysis of mortality and hospitalizations.