Myocardial Work Index: A Novel Method for Assessment of Myocardial Function in South Asian Recreational Athletes

Abstract

Purpose: We used a novel noninvasive method based on speckle-tracking echocardiography to evaluate myocardial performance in South Asian recreational athletes who completed a half marathon. Methods: Transthoracic echocardiography was performed on 24 recreational athletes 48 hours before they took part in a half marathon (premarathon), within 2 hours of half marathon completion (postmarathon), and 72 hours after completion. Clinical, laboratory, and echocardiographic variables were collected. Speckle-tracking echocardiography was performed in all subjects to characterize myocardial mechanics. Results: Mean age of participants was 41.8 ± 7.4 years, and 23 (95.8%) were male. No subject had a prior history of coronary artery disease. Significant changes in pre- and postmarathon values suggested myocardial injury, including an increase in mean brain natriuretic peptide (BNP), an increase in left atrial volume, and an overall reduction in peak left ventricular global longitudinal strain. All subjects had a similar value of global work index, the average myocardial work, premarathon. Global work index did not change in 11 patients (Group 1), and global work index increased in 13 patients (Group 2) immediately postmarathon. Group 2 patients were noted to have higher heart rate, lower end-diastolic and end-systolic volumes, and higher BNP levels, suggesting myocardial stress. Conclusions: South Asian athletes completing a half marathon exhibited two different responses to the cardiac stress of the half marathon, as outlined by the use of myocardial work indices, a novel method for assessing cardiac performance.

Keywords

• echocardiography
• myocardial function
• athletes
• marathon
• endurance running
• heart stressors