Is Heart Rate Recovery Really Associated with Severity of Coronary Artery Disease in Patients with Normal Exercise Treadmill Test?

Background and Objectives: Rapid diagnosis and treatment of cardiovascular diseases is really helpful in reducing further complications. There are different modalities for this goal but each has benefits and limitations. Exercise Treadmill Test (ETT) is a non-invasive, cheap and accessible test. Coronary CT Angiography (CTA) is recently considered as an applied modality for assessing severity of Coronary Artery Disease (CAD). In this study we aimed to investigate possible association between Heart Rate Recovery (HRR) in ETT and severity of CAD in CTA. Materials and Methods: In this cross-sectional, descriptive-analytic study we enrolled 70 susceptible patients for coronary artery disease. All patients underwent ETT and CTA. HRR in 1st and 2nd minute along with severity of CAD detected in CTA and patient's demographic information were recorded in a questionnaire. Finally, all data was analyzed using SPSS version 21.0 software. Results: In this study, 43 (61.4%) of patients were men. Mean HRR in 1st and 2nd minutes was 20.9 ± 7.36 and 35 ± 10.10 respectively. 27 of patients (38.5%) had abnormal HRR. We observed a statistically significant association between 1st and 2nd minute HRR and Hypertension (HTN). We also observed a significant association between severity of CAD with HTN, Diabetes Mellitus (DM) and Hyperlipidemia (HLP). A significant association was observed between severity of CAD and 1st minute (P-value=0.01) and 2nd minute (P-value=0.002) HRR in this investigation. Conclusion: Considering the association between HRR in ETT and severity of CAD in CTA along with benefits of ETT such as non-invasive entity, lower expenses and availability, it seems logical to suggest ETT for patients before CTA.