Abnormal Heart Rate Recovery as a Predictor of Coronary Artery Disease in Patients Undergoing Exercise Stress Myocardial Perfusion Imaging: A 4-Year Retrospective Study in Chong Hua Hospital

Abstract

Background: Abnormal heart rate recovery (HRR) after exercise is associated with an increase in all-cause mortality in both asymptomatic individuals and patients with established heart disease. In clinical practice, myocardial perfusion imaging (MPI) is used to establish the diagnosis and prognosis of coronary artery disease (CAD). This study aimed to determine the relationship between the HRR and the MPI findings of patients who underwent exercise stress test using sestamibi MPI. Methods: This was a four-year retrospective chart review study that included all patients who underwent exercise stress test using the sestamibi MPI at Chong Hua Hospital from January 2014 through December 2017. HRR was computed as the difference between peak HR and HR at the 60th second. Abnormal HRR was defined as either <12 beats per minute (bpm) from the peak HR after one minute with post-exercise cooldown. Patient demographics and clinical factors were reviewed and analyzed using parametric and nonparametric statistical tools. Results: A total of 304 patients were included in the study: 68% were male, 86% were aged >40 years. The most common comorbidity was combined hypertension and dyslipidemia (35%). The mean HRR was 31 bpm, and the mean percentage of chronotropic response (PCR) was 86. Eighty-eight percent of the patients had normal HRR. Eighty-six percent had MPI results within normal ranges. The chi squared test results showed no significant relationship between HRR and the diagnosis of inducible ischemia (p=0.141). Conclusion: About 88% of the study subjects were identified with normal HRR, while only 12% were classified as having abnormal HRR. There was no significant correlation between HRR and MPI findings of inducible ischemia among Filipino who underwent exercise stress MPI in this study.