Due to the presenting symptoms of fatigue and dyspnea on exertion as well as high risk for coronary artery disease, additional tests were recommended prior to starting an exercise and nutritional therapy program for weight loss.
An echocardiogram was done to rule out any myocardial structural abnormalities. This test revealed a heart size near the upper limits of normal. Her heart appeared slightly hyperdynamic with a left ventricular ejection fraction of 71% suggesting possible mild diastolic dysfunction. There also was mild mitral valve prolapse present.
A sestamibi exercise test was performed to rule out myocardial ischemia. Resting heart rate was 92 and regular and blood pressure was 144/92 mm Hg. Results of the exercise test showed a peak heart rate of 172 (101% of age-predicted maximal heart rate), blood pressure of 208/100 mm Hg, and a perceived exertion of 17-18 or (very hard). Thus, the test was interpreted as a maximal effort. She complained of dyspnea, rated as moderate or 2 on a 0-4 scale, but she did not complain of chest pain or other unusual symptoms.
ECG showed 1.0 millimeters of flat ST segment depression in inferolateral leads during the last stage (7.5 METs) with slow recovery to baseline (greater than 3-4 minutes). Her exercise capacity was 96% of predicted for her age, sex, height, and weight. She did not have any dysrhythmias during exercise and only occasional wide-complex beats during the first 2-3 minutes of recovery. Blood pressure was 190/92 mm Hg at 3 minutes recovery for a normal peak to 3 minute systolic blood pressure ratio of 1.095 (a ratio of < 0.90 is suggestive of CAD). Over the next 3 minutes, blood pressure dropped to 136/84 mm Hg. Although it is not well documented in the literature, in our experience, this drop in blood pressure in the recovery period is predictive of a good response of blood pressure to a lifestyle management plan which includes weight loss, exercise, sodium reduction and relaxation techniques.
The sestamibi results revealed no fixed defects, but suggested a mild perfusion abnormality in the inferior wall. Ejection fraction was 68% and there were no areas of dyskinesis or hypokinesis.
Finally, although thyroid labs did not suggest an underactive thyroid, a resting metabolic study was done. The results of this test performed in the early morning (7:00 am) after an overnight 8-hour fast with expired air collection commencing after 30 minutes of supine rest revealed a slightly low resting metabolism. Twenty-four hour caloric expenditure was estimated to be 1341 calories. By the Harris-Benedict equation, based on her height, weight, sex, and age, her resting energy expenditure was predicted to be 1604 calories. Thus her measured resting energy expenditure was approximately 16.4% less than predicted.
Normal echocardiogram, suggestive sestamibi exercise test; moderately decreased resting metabolic rate (RMR).
Care in initiating exercise prescription; women often present with less severe CAD symptoms than men; decreased RMR may normalize with increased activity levels; resistance training may have a role in her management.