Exercise electrocardiogram in patients with normal and abnormal coronary arteriogram

ST depression and left ventricular haemodynamics during exercise in patients with angina pectoris

The mechanism of ischaemic ST depression and the cause of its low sensitivity to coronary artery stenosis are not well understood. Of 30 patients with severe stable effort angina, 19 (63%) showed ischaemic ST depressions after exercise (the STAE group) and 11 did not. The highest load during the symptom-limited exercise test and the heart rate on that load did not differ between the two groups. The clinical characteristics and angiographic findings were also similar, but the findings at heart catheterization differed during exercise (in supine). Although the load was similar, the stroke index was significantly lower (38 vs. 53 ml/m2 BSA) and the left ventricular end-diastolic pressure rose to a significantly higher value in the STAE group (40 vs. 32 mmHg). When STAE occurred, they were exclusively or concomitantly present in chest lead 5. These findings suggest that ischaemic STAE may not reflect regional ischaemia but the consequent left ventricular dysfunction. The mechanism may, for example, be that a sufficiently elevated left ventricular diastolic pressure causes a global subendocardial ischaemia.

Prediction of left main coronary artery stenosis by exercise electrocardiography

The possibilities of predicting left main coronary artery stenosis (LMCAS) by the T wave pattern in exercise ECG were studied in a consecutive series of patients with stable angina pectoris and were compared to the predictive ability of ST criteria. After exclusion of patients with interfering diagnoses and digitalis treatment, 146 patients remained; 16 of them had LMCAS. Appearance or increase of a biphasic or negative T wave in leads V2-6 2 min after exercise detected 63% of the LMCAS, and the predictive value of a positive test was 36%. The sensitivity of the ST criteria was only 38% and the predictive value 26%. The observer concordance was 98% for the T wave and 84% for the ST criteria. These T wave criteria are at least as sensitive and predictive as the ST criteria and easier to apply.

Post exercise T wave changes in patients with normal and abnormal coronary arteriogram

The pre- and postexercise ECGs of those with normal (n = 15) and those with abnormal (n = 66) coronary arteriogram (diameter reduction greater than or equal 50% regarded as significant) were compared in a series of 81 patients with effort angina. ECGs with other known causes of ST-T changes had been excluded. The ECGs 2 and 4 min after a bicycle exercise test were studied for an abnormal ST reaction, and the change in the T wave amplitude in lead V2 from before to 2 min after exercise was measured when there was no q wave, QS complex or negative T at rest in this lead. None of the 15 patients in the normal arteriogram group had abnormal ST reaction post exercise and 1 of 13 evaluable ECGs showed a reduction of T in V2 greater than or equal to 20%. In the abnormal arteriogram group, 37 of the 66 patients had an abnormal reaction and 17 of the remaining 26 evaluable ECGs showed a reduction of T in V2 greater than or equal to 20%. The sensitivity of an abnormal ST reaction for significant coronary obstructions was 56% at specificity of 100%. Addition of an alternative criterion of a reduction of the T amplitude in lead V2 greater than or equal to 20% from before to 2 min post exercise increased the sensitivity to 82% and decreased the specificity to 92%. Thus, it seems worthwhile to study the T V2 reaction in angina patients who do not show an abnormal ST reaction post exercise.

Usefulness of the postexercise response of systolic blood pressure in the diagnosis of coronary artery disease

The normal decline in systolic blood pressure (SBP) during the recovery phase of treadmill exercise does not occur in some patients with coronary artery disease (CAD). In others the recovery values of SBP exceed the peak exercise values. To examine the diagnostic value of this observation, we studied 31 normal subjects and 56 patients undergoing treadmill exercise before coronary cineangiography. Because of large differences in peak exercise pressures between the two groups, recovery ratios were derived by dividing the SBP at 1, 2, and 3 min after exercise by the peak exercise SBP. The 1, 2, and 3 min ratios in the normal subjects declined steadily from 0.85 +/- 0.07 (SD) to 0.79 +/- 0.06 and to 0.73 +/- 0.06, respectively, while the ratios in the patients with CAD remained elevated at 0.97 +/- 0.12 to 0.97 +/- 0.11 to 0.93 +/- 0.13. With use of the upper limits defined by two SDs of the normal value, recovery ratios were compared with the occurrence of angina and with ST segment depression on the exercise electrocardiogram in the patients with CAD. Abnormal ratios were more frequent in patients with CAD (53/56, 95%) than in those with ST segment depression (33/56, 59%), angina (37/56, 66%), and either ST segment depression or angina (42/56, 75%). Twenty of the patients with CAD who were on no medication underwent an additional treadmill exercise test on a separate day and no significant differences were found in the ratios from the two tests. Ten additional patients with CAD underwent treadmill exercise testing while on placebo and while on a beta-blocker.(ABSTRACT TRUNCATED AT 250 WORDS)