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Correspondence to Dr Jasmine Grewal, Division of Cardiology, St. Paul’s Hospital, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada; [email protected]
Introduction
Premature ventricular contractions (PVCs) in individuals with a structurally normal heart are usually considered benign.1 2 However, very frequent PVCs, defined as greater than 10% of all QRS complexes on standard 24-hour Holter monitoring, have been found to be associated with the presence or subsequent development of left ventricular dilatation and dysfunction.3–5 Treatment of frequent PVCs in patients with impaired ventricular function can result in improvement or normalisation of ventricular function.
PVCs are becoming increasingly recognised during pregnancy and it may be that pregnancy unmasks pre-existing PVCs or that they are occurring de novo. PVCs in pregnancy pose an additional challenge, as the maternal and fetal implications are not known in this already cardiac overloaded state. There is minimal data published in this area. Small studies have suggested that the incidence of PVCs decreases during the postpartum period in women with new onset of ventricular arrhythmia during pregnancy.6 7 Beta-blockers such as metoprolol have resulted in a significant decrease in PVC burden during pregnancy.8 The objective of this study was to determine the rate of maternal cardiac and fetal/neonatal adverse events among pregnant women with PVCs and compare with relevant control groups.
Methods
Study design and population
This is a prospective case–control study of consecutive pregnancies referred to the St. Paul’s Hospital Cardiac Obstetrics Clinic. The cases were consecutive patients referred for findings of or complaints secondary to PVCs between January 2010 and December 2016. All patients with greater than 1% PVC burden on at least one Holter monitor in pregnancy were eligible. Exclusion criteria were (1) women with palpitations but no documented PVCs, (2) pregnancy that resulted in spontaneous abortion <20 weeks, (3) documented structural cardiac disease and/or (4) history of cardiovascular events. The first control group consisted of the first 53 consecutive age-matched women referred to the same clinic between January 2010 and December 2016 for a history of supraventricular tachycardia (SVT) or SVT in the current pregnancy with a PVC burden of <1% on Holter monitoring. The second control group consisted of women considered to have a low-risk normal pregnancy with no cardiac diagnosis and consisted...