Unmasking of Exercise-Induced Diastolic Dysfunction in Symptomatic Post Coronary Angiogram Patients with Normal Coronaries

Background: Diastolic dysfunction is the cause in nearly half of cases of heart failure, the hemodynamic equivalent of which is elevated cardiac filling pressures. However, owing to its ubiquity, it is often diagnosed as an incidental finding, but an association with symptoms is not established in many of the patients. Most patients with hypertension or left ventricular (LV) hypertrophy have evidence of impaired diastolic function as a finding on Doppler echocardiography, but do not have any symptoms of heart failure at rest. However, these patients do have symptoms related to diastolic dysfunction only during exercise. In this study, we have contemplated to assess invasively, left ventricular filling pressures in patients with unexplained shortness of breath with normal systolic and diastolic function on echocardiography, on exercise and compare the level of rise in patients with established diastolic dysfunction. Methods: This is an observational prospective study, done over a span of 3 months, wherein patients with typical symptoms such as chest pain and shortness of breath, after ruling out systemic causes, and were subjected to coronary angiogram. If no coronary lesion identified, patients were subjected to invasive cardiac catheterization during coronary angiogram. Patients were divided into two groups, one without diastolic dysfunction and the other with established diastolic dysfunction. Simultaneous left ventricular end diastolic pressures (LVEDP) were measured at rest and after 3-minute manual handgrip exercise and readings were noted. Results: The mean age of the population (n = 30) was 55.8 ± 7.538 and 20 were males. The mean value of LVEDP in patients with no diastolic dysfunction at resting was 4.4 ± 3.169 and after exercise was 8.40 ± 4.169. The mean value of LVEDP in patients with established diastolic dysfunction at resting was 5.30 ± 3.948 and after exercise was 8.75 ± 4.506. Paired t-test among two groups revealed a significant p-value of 0.001 after exercise among both groups, suggesting a significant increase in LVEDP in patients with exercise. Unpaired t-test comparing both groups revealed that the elevation of LVEDP in no diastolic dysfunction group was comparable with patients with diastolic dysfunction (p = 0.432). Conclusion: The increase in LVEDP with exercise is a well-established fact in patients with diastolic dysfunction. Our study adds to the fact that patients with unexplained shortness of breath can have raised LVEDP after exercise, thereby unmasking the underlying diastolic dysfunction. Our study stresses the importance of inclusion of exercise as a provocative test for the assessment of diastolic function, either invasively or non-invasively, in patients presenting with exertional dyspnea.