Outcomes of untreated frequent premature ventricular complexes with normal left ventricular function.

OBJECTIVE: The natural history of frequent premature ventricular complexes (PVCs) in association with preserved left ventricular ejection fraction (LVEF) is uncertain. The optimal management of this population is thus undefined. We studied the outcomes of untreated patients with frequent PVCs and preserved LVEF. METHODS: This cohort study prospectively evaluated consecutive patients from 2012 to 2017, with asymptomatic or minimally symptomatic frequent idiopathic PVCs (≥5% PVCs in 24 hours; normal LVEF; no cause identified on comprehensive evaluation). No suppressive therapy (ablation or antiarrhythmic drugs) were used and patients were followed with serial ambulatory ECG monitoring and echocardiography. The primary arrhythmic outcome was reduction in PVC burden to <1% on serial ambulatory monitoring. The primary echocardiographic outcome was a reduction of LVEF to <50%. RESULTS: One hundred patients met inclusion criteria (mean age 51.8 years, 57% female) with a median PVC burden of 18.4%. Reduction to <1% PVCs occurred in 44 of 100 patients (44.0%) at a median of 15.4 months (range 2.6 to 64.3). Recurrence was uncommon (4/44, 9.1%). Four patients (4.3%) with a persistently elevated PVC burden developed left ventricular dysfunction (LVEF <50%) during the follow-up period at a range of 53-71 months. The initial PVC burden did not predict subsequent resolution (HR 1.00(0.97, 1.03); p=0.86). CONCLUSIONS: A strategy of active surveillance is appropriate for the majority of patients with frequent idiopathic PVCs in association with preserved LVEF, owing to the low risk of developing left ventricular systolic dysfunction and the high rate of spontaneous resolution.

Impact of frequent premature ventricular contractions on pregnancy outcomes.

OBJECTIVES: To determine cardiac and fetal/neonatal event rates among pregnant women with premature ventricular contractions (PVCs) and compare with control groups. METHODS: Prospective case-control cohort study: 53 consecutive pregnancies in 49 women referred to the St. Paul's Hospital between 2010 and 2016 with PVC burden >1% in women without underlying cardiac disease. Maternal cardiac and fetal/neonatal outcomes were compared with two pregnant control groups: (1) supraventricular tachycardia (SVT) group of 53 women referred for a history of SVT/SVT in the current pregnancy and (2) low-risk group of 53 women with no cardiac disease. RESULTS: The maximal PVC burden was 9.2% (range 1.1%-58.7%). Six of 53 (11%) pregnancies were complicated by a maternal cardiac event: heart failure n=1 and sustained ventricular tachycardia requiring therapy n=5 as compared with no cardiac events in both control groups. All women with an adverse event had a PVC burden >5%. Seven (13%) pregnancies were complicated by an adverse fetal and/or neonatal event and this was similar to the normal control group (5 (9%), P=0.45) and significantly less than the SVT group (16 (30%), P=0.03). The adverse fetal event was driven by small for gestational age neonates and preterm delivery. CONCLUSIONS: In our cohort of pregnant women with a structurally normal heart and 'high' PVC burden, we found an adverse maternal event rate of 11%, and all events were successfully managed with medical therapy. The rate of adverse fetal events in the PVC group was similar to the normal control group.

Prognostic impact of inappropriate defibrillator shocks in a population cohort.

BACKGROUND: There is a relative paucity of data linking inappropriate implantable cardioverter-defibrillator (ICD) shocks to adverse clinical outcomes. OBJECTIVE: To examine the association between inappropriate ICD shocks and mortality or heart transplantation in a large population cohort. DESIGN, SETTING, PATIENTS: A cohort study which included all subjects who underwent ICD implantation between 1998 and 2008 and were followed up at our institution. MAIN OUTCOME MEASURES: Multivariable Cox regression analyses were conducted to investigate the effect of inappropriate shocks on the risk of death and heart transplantation. Appropriate and inappropriate ICD therapies were modelled as time-dependent covariates. RESULTS: A total of 1698 patients were included. During a median follow-up of 30 months, there were 246 (14.5%) deaths and 42 (2.5%) heart transplants. The incidence of inappropriate shocks was 10% at 1 year and 14% at 2 years. In the adjusted model, inappropriate shocks were not associated with death or transplantation (HR=0.97, 95% CI 0.70 to 1.36, p value=0.873). In contrast, appropriate shocks were associated with adverse outcomes (HR=3.11, 95% CI 2.41 to 4.02, p value<0.001). The lack of association between inappropriate shocks and outcomes persisted for those with severely impaired left ventricular function (ejection fraction <30%) and for those receiving multiple inappropriate treatments. CONCLUSIONS: In this study, we observed no association between inappropriate ICD shocks and increased mortality or heart transplantation, even among those with severely impaired cardiac function. These findings question whether inappropriate ICD shocks lead to adverse outcomes.