Electrocardiographic and vectorcardiographic findings in asymptomatic young men with primary T‐wave abberations in the electrocardiogram. Relationship to sympatho‐adrenal activity at rest and during different stress tests

Summary. Twelve asymptomatic men aged 18–19 years with flat, notched or inverted precordial T waves without concomitant ST depression (group T) were compared to thirteen age‐matched controls with normal electrocardiograms (group C). Orthogonal leads, spatial vectorcardiography and sympatho‐adrenal activity, as reflected by plasma catecholamines, were studied at rest and during mental stress (Stroop's colour word conflict test), isometric exercise (hand grip) and a cold pressor test. The groups had similar heart volumes and physical work capacity. Group T showed higher resting supine systolic blood pressure (140±15 mmHg vs. 121±8 mmHg, P<0·001) and plasma noradrenaline (1·82±0·79 nmol 1 ‐1 vs. 1·25±0·49 nmol 1<sp> ‐1 , P<0·05) whereas heart rate, diastolic blood pressure and plasma adrenaline were similar in the two groups at rest. Increases in diastolic blood pressure and plasma adrenaline were larger in group T in connection with each of the stressful provocations. The magnitude of the T‐wave aberrations in the electrocardiogram and the orthogonal leads in the vectorcardiogram as well as the spatial QRS‐T angle were positively correlated to the plasma noradrenaline levels at rest. Changes of the T‐wave aberrations in connection with stress were variable. The changes were positively correlated to heart rate and adrenaline during mental stress, to adrenaline during isometric exercise and to heart rate and noradrenaline during cold provocation. The present study demonstrates increased sympathetic tone at rest and increased reactivity in connection with stress in otherwise healthy young subjects selected on the basis of T‐wave aberrations often considered as indicative of organic heart disease. The findings suggest that the T‐wave aberrations were caused by increased sympathetic discharge.