Evaluation of cardiac ischaemia in cardiac asymptomatic newly diagnosed untreated patients with primary hypothyroidism

Background: Hypothyroidism is regarded as a risk factor for coronary artery disease. Possible factors involved in this association are hyperlipidaemia and hypertension, both occurring with increased frequency in hypothyroid patients. The aim of our study was to evaluate signs/symptoms of cardiac ischaemia in untreated hypothyroid patients without angina pectoris, since this has never been performed before.

Methods: 51 consecutive cardiac asymptomatic patients (mean age 47, range 22 to 86 years) were studied by dobutamine stress echocardiography and bicycle ergometry.

Results: Mean values of body mass index, resting heart rate and blood pressure were 28.5 kg/m(2), 68 beats/min and 129/81 mmHg, respectively. Median TSH was 51.9 mU/l, mean FT47.3 +/- 2.9 pmol/l (mean +/- SD), TT31.6 +/- 0.6 nmol/l and total cholesterol was 5.8 +/- 1.6 mmol/l. None of the patients had symptoms of angina pectoris during dobutamine stress echocardiography or bicycle ergometry and no evidence of myocardial ischaemia was demonstrated. Exercise tolerance, assessed by dividing the maximum achieved workload by the target performance (depending on body height, sex and age), was diminished in 38% of patients, and significantly related to the degree of hypothyroidism.

Conclusion: No angina pectoris or cardiac ischaemia at exercise or stress was found in cardiac asymptomatic hypothyroid patients. The precise role of hypothyroidism as a risk factor for coronary artery disease should be further elucidated.