Post Exercise High-Grade PVCs linked to long term risk of CV Mortality: Study

Although exercise stress testing is widely used for diagnosis and risk stratification of symptomatic patients with suspected or known coronary artery disease (CAD), its prognosis in asymptomatic individuals remains uncertain. Therefore, Dr Samia Mora and her team conducted a study to investigate whether high-grade PVCs during stress testing predict mortality in asymptomatic individuals.

In this retrospective cohort study, the researchers included 5,486 asymptomatic individuals who took part in the Lipid Research Clinics prospective cohort had baseline interview, physical examination, blood tests, and underwent Bruce protocol treadmill testing. They used adjusted Cox survival models to evaluate the association of exercise-induced high-grade PVCs (defined as either frequent (>10 per minute), multifocal, R-on-T type, or ≥2 PVCs in a row) with all-cause and cardiovascular mortality.

Key findings of the study:

• Upon two decades of follow-up, the researchers observed overall 840 deaths, including 311 cardiovascular deaths.
• They found that high-grade PVCs in 1.8% of patients during exercise, in 2.4% of patients during recovery from exercise, and in 0.8% of patients during both exercise and recovery.
• They noted that 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) as well as adjustment for exercise duration, heart rate recovery, achieving target heart rate and ST-segment depression (aHR = 1.68).
• They also found similar findings in the clinical subgroups.
• They noted that the high-grade PVCs observed during recovery was associated with CV mortality (adjusted HR = 1.59). However, they did not observe a similar association for high-grade PVCs during exercise (aHR = 1.16).
• They further noted that recovery PVCs did not improve 20-year cardiovascular mortality risk discrimination beyond clinical variables.

The authors concluded, "High-grade PVCs occurring during recovery were associated with long-term risk of cardiovascular mortality in asymptomatic individuals, whereas PVCs occurring only during exercise were not associated with increased risk".

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DOI: https://doi.org/10.1016/j.jacc.2021.09.1366