The relationship between exertional chest pain/dyspnoea--heart rate in patients with coronary artery disease using Exercise ToleranceTest.

Objectives: To observe the relationship between chest pain/dyspnoea-heart rate during exertion in patients with angiographically proved Coronary artery disease compared to patients having negative Exercise Tolerance Test in a private and public sector hospital.

Methods: This is an observational two centre study from Karachi in which 150 patients referred for Exercise ToleranceTest (ETT) at Ziauddin University Hospital, Clifton campus and National Institute of Cardiovascular Diseases Karachi were included. The period of study extended from September 2008 to March 2010. All patients performed a maximal progressive exercise on Bruce protocol. Age, Body Mass Index, target heart rate and risk factors of Coronary artery disease were noted for each patient. The resting heart rate and resting systolic Blood Pressure (BP) were noted. The maximum systolic BP, maximum heart rate, total exercise time and Multiples of resting oxygen consumption (METS) were recorded at the end of exercise. The chest pain and dyspnoea score were plotted against maximum heart rate.

Results: Out of 136, 51 were ETT positive and 76 were ETT negative. The ETT positive were older in age, had lesser maximal heart rate, lesser total exercise time and lesser METS than ETT negative. Out of 51 ETT positive patients, 20 had chronotropic incompetence.

Conclusion: In patients having positive ETT and referred for angiography, the chest pain-heart rate relationship correlated well with number of vessel disease. The dyspnoea-heart rate relationship was not different in the two groups.