High-grade premature ventricular contractions during exercise recovery tied to CV mortality
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Among asymptomatic patients without a history of CVD, high-grade premature ventricular contractions during the recovery period following exercise stress testing were predictive of long-term CV mortality, researchers reported.
However, high-grade premature ventricular contractions (PVCs) observed during the exercise period were associated with neither all-cause nor CV mortality, according to data published in the Journal of the American College of Cardiology.
“Currently, most clinicians tend to ignore PVCs that occur during stress testing, but here we showed that PVCs that occurred in recovery — in particular if they are two or more in a row, frequent, multifocal, or R-on-T — identified higher-risk asymptomatic individuals who may benefit from further intensifying preventive efforts,” Samia Mora, MD, MHS, associate professor at Harvard Medical School and director of the Center for Lipid Metabolomics at Brigham and Women’s Hospital, told Healio. “Importantly, the risk carried by these high-grade PVCs — approximately 80% higher CV mortality risk — was independent of standard risk factors or even other exercise testing variables, and mostly identified individuals who were more likely to die from CVD after 10 years of follow-up. This was in contrast to PVCs that occurred only during exercise, which were not associated with increased risk after accounting for other CV or exercise test variables.”
The researchers evaluated 5,486 asymptomatic participants in the Lipid Research Clinics prospective cohort. The mean age was 45 years, 42% were women and mean follow-up was 20 years.
Premature ventricular contractions and mortality
Researchers identified high-grade PVCs — defined as frequent (> 10 per minute), multifocal, R-on-T type or more than two PVCs in a row — in 1.8% of participants during exercise, in 2.4% of participants during recovery from exercise, and in 0.8% of participants during both exercise and recovery, according to the results.
The probabilities of all-cause and CV mortality diverged in the presence of high-grade PVCs during the exercise recovery period, Refaat and colleagues wrote.
Researchers reported that high-grade PVCs observed during recovery were associated with CV mortality (adjusted HR = 1.59; 95% CI, 1.09-2.3; P = .015), but the same association was not observed for high-grade PVCs during exercise (aHR = 1.16; 95% CI, 0.73-1.85; P = .527).
The association between high-grade PVCs during recovery and CV mortality remained significant after adjustment for age, sex and traditional risk factors (aHR = 1.82; 95% CI, 1.19-2.79; P = .006) as well as adjustment for exercise duration, heart rate recovery, achieving target heart rate and ST segment depression (aHR = 1.68; 95% CI, 1.09-2.6; P = .02).
In subgroup analyses, there was no significant difference in the association between recovery high-grade PVCs and CV mortality among men or women and patients with or without diabetes, hyperlipidemia or hypertension (P for interaction > .05 for all).
“These results support conclusions from earlier studies in higher risk populations, as prior studies in more symptomatic populations and a study in asymptomatic French policemen also found that high grade recovery PVCs carried increased risk,” Mora told Healio. “We think that these PVCs could be indicative of insufficient vagal reactivation post-exercise, as it is known that the parasympathetic system kicks in right after stopping exercise in order to counteract the sympathetic system of the autonomic nervous system.
“From a practical perspective, it would be important for exercise test reports to add in their summary statements a comment about high grade recovery PVCs, in addition to reporting METs, exercise BP, and heart rate recovery post-exercise. This would be most helpful for busy clinicians who often only have time to read the summary statement of a stress test, as these stress test measures have been shown to each carry independent prognostic information,” Mora told Healio.
Stress testing in a low-risk population
“The current study shows for the first time that high-grade exercise-induced PVCs during recovery — but not during exercise — is associated with a higher risk of CV death in asymptomatic adults without previous CV disease, even after adjustment for demographic and clinical variables and nonischemic parameters of exercise performance,” Sandeep A. Saha, MD, MS, cardiologist at the Oregon Heart Center, wrote in a related editorial.
“The current study did not show any prognostic value of exercise-induced PVCs for all-cause mortality, and was not able to demonstrate the utility of using exercise-induced PVCs during recovery in reclassification of long-term CV mortality risk in this population,” Saha wrote. “Therefore, these findings support the current guidelines that do not recommend exercise stress testing as a screening test in patients at low risk for CAD.”
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