Left ventricular remodelling in the year after myocardial infarction: an echocardiographic, haemodynamic, and radionuclide angiographic study.

BACKGROUND: The factors that influence infarct expansion early after myocardial infarction have been identified; however, there is less information about late-phase left ventricular enlargement. This study was designed to identify the clinical, haemodynamic, echocardiographic, and radionuclide angiographic criteria that predict the progress of left ventricular dilation after discharge for a first-anterior myocardial infarction. METHODS: Sixty-seven patients with first Q-wave acute anterior myocardial infarction not treated with thrombolytic agents underwent baseline echocardiographic, haemodynamic, and radionuclide angiographic evaluation 4-7 days after the onset of symptoms. The echocardiographic and radionuclide evaluations were repeated after 1 year in the 55 patients who completed the follow-up. By multivariate stepwise linear regression analysis, left ventricular end-diastolic volume after 1 year and change from baseline were modelled as a function of baseline left ventricular end-diastolic volume and other potential predictors. RESULTS: A model including left ventricular end-diastolic pressure, global wall motion score, baseline left ventricular end-diastolic volume, and a Thrombolysis in Myocardial Infarction (TIMI) score of 0-1 was able to predict 84% of the left ventricular end-diastolic volume at the follow-up; a TIMI score of 0-1, the transverse end-diastolic diameter, global wall motion score, and the number of coronary vessels with 70% stenosis accounted for 81% of the variation in left ventricular end-diastolic volume from baseline, while the transverse end-diastolic diameter was inversely related to this parameter. CONCLUSIONS: The results of this study demonstrate that after an anterior myocardial infarction, the patency of the infarct-related artery is the major determinant of late left ventricular dilation, while left ventricular end-diastolic pressure influences early left ventricular dilation and baseline end-diastolic volume. Therefore, to improve left ventricular remodelling, it appears necessary to increase the patency of the infarct-related artery and improve the diastolic loading of the left ventricle at an early stage in the infarction. The inverse relationship between baseline left ventricular transverse diameter and the change in left ventricular volume after discharge indicates that the higher the baseline left ventricular volume, the less it changed during the follow-up. The global wall motion score appears to be a non-invasive parameter that is useful for identifying patients with a high risk of progressive left ventricular dilation.

Continuous electrocardiographic monitoring for more than one hour does not improve the prognostic value of ventricular arrhythmias in survivors of first acute myocardial infarction.

This study was designed to compare the prognostic value of predischarge ambulatory electrocardiographic monitoring for 1, 6 and 24 hours in 188 patients surviving a first acute myocardial infarction. Ventricular premature complexes (VPCs) were considered as a mean hourly rate or classified using Lown and Moss grading systems. During the 1-year follow-up 20 cardiac deaths occurred. For all 3 monitoring times, a higher number of VPCs/hour and a higher Moss grade were associated with mortality, whereas a Lown grading system gave prognostic information only for the first hour of recording. Monitoring time did not influence specificity or sensitivity in predicting mortality; > or = 3 VPCs/hour showed a higher sensitivity than > or = 10 VPCs/hour (p < 0.05) with a comparable specificity. After 1-hour data entered the model, neither the 6- or the 24-hour data entry improved the overall likelihood ratio statistic, regardless of what VPC grading system was used. These results demonstrate that continuous electrocardiographic recordings of > 1 hour are unnecessary when they are to be used for detecting ventricular arrhythmia as a predictor of mortality in patients surviving a first acute myocardial infarction.

Incremental prognostic value of thallium imaging and coronary angiography in patients with a symptom-limited ECG stress test.

BACKGROUND: This study evaluates the incremental prognostic value of qualitative thallium-201 imaging and coronary angiography in patients with suspected or known coronary artery disease. METHODS: Within 1 month, 150 patients underwent diagnostic symptom-limited ECG stress test, thallium imaging, and coronary angiography. The incremental power of sequentially performed tests was evaluated by the overall likelihood ratio statistic. RESULTS: At 3-year follow-up, 16 patients had died from a cardiac cause, 12 had suffered a nonfatal myocardial infarction, and 34 had undergone revascularization procedures more than 60 days after testing. Considering hard events, thallium imaging did not improve the prognostic information provided by clinical exercise stress test data, while coronary angiography increased the predictive power of the combined, exercise stress test, and scintigraphic data (P < 0.001). Moreover, when thallium results were added to clinical, exercise, and coronary angiographic data, the predictive power was unchanged. When the analysis was repeated including the occurrence of late revascularization procedures, each test showed additional prognostic information to that obtained by the other combined tests (P < 0.001). CONCLUSIONS: This study demonstrates that in patients with a symptom-limited ECG stress test, coronary angiography adds prognostic information to combined clinical, exercise ECG, and thallium imaging data. The incremental prognostic value of qualitative thallium imaging is demonstrable only when late revascularization procedures are included as events.