Prognostic Significance of Different Ventricular Ectopic Burdens During Exercise in Asymptomatic UK Biobank Subjects

Background and AimsThe consequences of exercise-induced premature ventricular contractions (PVCs) in asymptomatic individuals remain unclear. This study aimed to assess the association between PVC burdens during stress testing and major adverse cardiovascular events (MACE; myocardial infarction (MI), life-threatening ventricular arrhythmia (LTVA), and heart failure (HF)), and all-cause mortality. Additional end-points were: MI, LTVA, HF and cardiovascular mortality. MethodsA neural network was developed to count PVCs from ECGs recorded during exercise (6 min) and recovery (1 min) in 48,502 asymptomatic participants from UK Biobank. Associations were estimated using multivariable Cox proportional hazard models. ResultsMean age was 56.8 (+/-8.2 years); 51.1% were female, and median follow-up was 11.5 years. Low PVC counts during exercise and recovery were both associated with MACE risk, independently from clinical factors: adjusted hazard ratio [HR]: 1.2 (2-4 exercise PVCs, p = 0.022) and HR 1.2, (1 recovery PVC, p = 0.031). Risk increased with increasing PVC count: HR 1.8 (>25 exercise PVCs, p<0.001) and HR 1.5 ([&ge;]5 recovery PVCs, p < 0.001). A similar trend was observed for all-cause mortality, although associations were only significant for higher PVC burdens: HRs: 1.4 (11-25 exercise PVCs, p = 0.007) and 1.5 ([&ge;]5 recovery PVCs, p < 0.001). Complex PVCs rhythms were associated with higher risk compared to PVC count alone. PVCs were also strongly associated with incident HF, LTVA, and cardiovascular mortality, but not MI. ConclusionPVC count during exercise and recovery are both associated with MACE, all-cause mortality, HF, LTVAs and cardiovascular mortality, independent of clinical and exercise stress test factors, indicating a "dose response" between PVC count and risk. Complex PVCs rhythms are associated with higher risk compared to PVC count alone.