Evaluation of serial QT dispersion in patients with first non-Q-wave myocardial infarction: relation to the severity of underlying coronary artery disease.

BACKGROUND: Increased QT dispersion (QTD) has been correlated with ventricular arrhythmias. Recent reports suggest that it may serve as a marker of the severity of underlying coronary artery disease (CAD). HYPOTHESIS: The aim of this study was to examine in-hospital changes of QTD and their possible correlation with the severity of underlying CAD in patients with first non-Q-wave myocardial infarction. METHODS: In 62 patients we estimated QTD, precordial QTD, as well as their values corrected for heart rate on Days 3 and 7 after admission. The severity of underlying ischemic burden was estimated by means of the number of diseased vessels as well as by the jeopardy score. RESULTS: On Day 3, patients with jeopardy score > or = 6 exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p = 0.001, p = 0.003, p = 0.02, p = 0.036, respectively); patients with multivessel disease had greater QTD (p = 0.007). On Day 7, patients with jeopardy score > or = 6 and multivessel disease exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p < 0.001 for all). Multiple regression analysis revealed a jeopardy score of > or = 6 as the most significant independent predictor for QTD variables. From Days 3 to 7, only patients with none or one diseased vessel orjeopardy score < 6 had shortened QTD (p = 0.01 and p = 0.015, respectively) and corrected QTD (p < 0.001 for both). CONCLUSIONS: In patients with first non-Q-wave myocardial infarction, QTD variables and their in-hospital changes reflect the severity of underlying CAD.

Comparative efficacy of primary angioplasty with stent implantation and thrombolysis in restoring basal coronary artery flow in acute ST segment elevation myocardial infarction: quantitative assessment using the corrected TIMI frame count.

Following thrombolysis and primary percutaneous transluminal coronary angioplasty (PTCA) for acute ST segment elevation myocardial infarction, basal flow in the culprit artery is known to influence prognosis. The purpose of this study was to determine if differences exist in basal flow in culprit and nonculprit coronary arteries in patients with acute ST segment elevation myocardial infarction who were treated with thrombolysis or primary PTCA with stent implantation. Twenty patients were randomized to thrombolysis (with recombinant tissue plasminogen activator) and 24 to primary PTCA with stent implantation within 3 hours of onset of acute ST segment elevation myocardial infarction. Coronary angiography was performed 90-120 minutes after thrombolysis or immediately after PTCA with stent implantation and again at 18-36 hours after intervention in both groups. Patients who failed to achieve thrombolysis in myocardial infarction (TIMI) grade 2 or 3 flow were excluded. The corrected TIMI frame count was used as the index of basal coronary artery flow. Early after intervention the mean corrected TIMI frame count in the culprit coronary artery was significantly lower in the primary PTCA with stent group (27.4 +/- 7.7 frames) than in the thrombolysis group (39.8 +/- 10 frames, p < 0.001). Eight thrombolysis patients (40%) and 20 primary PTCA patients (83%, p < 0.01) achieved TIMI grade 3 flow early after intervention. By 18-36 hours after intervention there were no significant differences in the mean correct TIMI frame count between the thrombolysis and primary PTCA with stent groups. There were no significant differences in the mean corrected TIMI frame count between these two groups in the nonculprit coronary artery, either early after intervention or at 18-36 hours. In successfully reperfused coronary arteries following acute ST segment elevation myocardial infarction, primary angioplasty with stent implantation reestablished TIMI grade 2 or 3 flow faster and more effectively than thrombolysis did.