[Show abstract][Hide abstract] ABSTRACT: Corrected QT (QTc) intervals were measured retrospectively in 160 consecutive survivors of acute myocardial infarction under 66 years of age. Calculations were made the first 2 d in the coronary care unit (CCU), the first post-CCU day, at discharge, and at 1–3, 6, and 12 months after discharge. All patients were in sinus rhythm and without bundle branch block at discharge from the hospital. Sixteen patients died during the first follow-up year. Twenty patients suffered a reinfarction, five of whom died.The highest QTc values were registered in the CCU and the lowest at the 1-year control. Patients with subendocardial infarcts had longer QTc intervals than those with transmural infarcts, especially during the acute phase. Patients with inferior infarcts had shorter QTc intervals during the CCU period.Those who reinfarcted or died a cardiac death (particularly when sudden) during the follow-up year had longer QTc intervals during the post-CCU phase. A multivariate analysis of risk factors revealed that the QTc interval at discharge was of significant independent value for predicting major cardiac events after discharge from the hospital. It is concluded that repeated measurements of QTc may be of value when assessing prognosis after acute myocardial infarction.
[Show abstract][Hide abstract] ABSTRACT: QTc intervals were measured retrospectively in 46.3 survivors of AMI with a mean age of 65 years. The measurement was made one at discharge from hospital. Patients with anterior infarcts had significantly longer QTc intervals than those with inferior or uncertain infact localization. A weak but significant correlation was found between S-GOT maximum and QTc interval. Patients with ventricular arrhythmias in the CCU had longer QTc intervals. Patients with a poor long-term prognosis had significantly shorter QTc intervals. This finding was explained by digitalis therapy. Among patients without bundle branch block, digitalis and quinidine, those below 66 years of age who died within the first six months tended to have longer QTc intervals than the survivors. It is concluded that measurements of QTc interval at discharge have no long-term predictive value. This factor may, however, have some bearing on the short-term prognosis in younger patients without therapy which affects the QTc interval.
[Show abstract][Hide abstract] ABSTRACT: The effect of metoprolol on corrected QT interval (QTc) was studied retrospectively in 111 survivors of AMI below 70 years of age. Prior to discharge the patients were stratified by age, infarction size and ventricular arrhythmias and randomized. Metoprolol, 100 mg b.i.d., or placebo were given double-blindly to 59 and 52 patients, respectively. QTc intervals were measured four times prior to randomization and three times during the follow-up year. The highest QTc mean was registered on the second day in the CCU. QTc intervals subsequently decreased significantly in both groups between discharge and the three-month control (p < 0.001). Patients on metoprolol had significantly shorter QTc intervals during the follow-up year than those on placebo (0.394 +/- 0.028 vs. 0.406 +/- 0.034 sec, p < 0.001). The QTc-shortening effect of beta-receptor blockade was most marked in patients with prolonged QTc intervals at discharge. Patients who died suddenly had prolonged QTc intervals prior to discharge. In this group the proposed beneficial effect of beta-receptor blockade on QTc interval cannot be evaluated as most of these patients had died before the first control.
[Show abstract][Hide abstract] ABSTRACT: Out of a total of 947 patients admitted to the CCU at Serafimerlasarettet during 2 years, all those with AMI and vintricular fibrillation (VF) or ventricular tachycardia (VT) during the CCU stay were selected. The QT interval could be measured in 15 patients with VF and 12 with VT before the event. The QT interval was also measured in two control groups; one consisted of 27 consecutively admitted patients with AMI without ventricular arrhythmias (VA), the other of 27 non-AMI patients treated in the CCU. Most patients in the group with VA showed pathologically prolonged QT intervals and there were statistically significant differences between this group and the control groups regarding corrected mean QT intervals. If these findings are confirmed, QT measurements might be of value in the prediction of malignant VA in AMI.
[Show abstract][Hide abstract] ABSTRACT: Right heart and pulmonary artery pressures were measured in 28 patients with inferior acute myocardial infarction, 12 of whom also had ECG evidence of right ventricular involvement (RVI). Those with RVI had significantly higher mean right-sided filling pressures 9.3 mm Hg, SD +/- 4.5 than those without RVI, 4.3 mm Hg, SD +/- 1.9. A steeper relationship between right ventricular enddiastolic and mean pulmonary artery pressures was seen in patients with RVI in contrast to those without, where no marked rise in right-sided filling pressures with increasing mean pulmonary artery pressures was seen.