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Prognostic value of radionuclide ventriculography after myocardial infarction
Insights
Left ventricular ejection fraction (EF) is often reduced after myocardial infarction, especially with anterior infarction or complications. Persistently low EF increases cardiac failure risk, while exercise-induced EF decline predicts angina.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Diagnostic Imaging
Background:
- Myocardial infarction (MI) significantly impacts cardiac function.
- Assessing left ventricular (LV) performance is crucial for prognosis after MI.
- Radionuclide ventriculography offers a noninvasive method to evaluate LV function.
Purpose of the Study:
- To assess left ventricular ejection fraction (EF) in patients post-myocardial infarction.
- To correlate EF with infarction location, early complications, and long-term outcomes.
- To evaluate the impact of exercise on EF and its relationship with angina development.
Main Methods:
- Studied 50 consecutive patients after their first myocardial infarction.
- Measured left ventricular ejection fraction (EF) using radionuclide ventriculography at rest and during exercise.
- Evaluations were performed before hospital discharge, and at one and four months post-MI.
Main Results:
- 42 out of 50 patients had below-normal EF.
- Anterior MI patients had significantly lower mean EF (0.33 +/- 0.13) than inferior MI patients (0.43 +/- 0.09).
- Reduced EF correlated with early complications (arrhythmia, heart failure) and regional wall motion abnormalities.
- Persistently low EF (<=0.30) predicted further cardiac failure.
- Inability to increase EF during exercise at one month post-MI was associated with subsequent angina development in 10 patients.
Conclusions:
- Poor left ventricular performance is common after anterior MI, particularly with acute complications.
- Persistently low EF indicates an increased risk of recurrent cardiac failure.
- A decline in EF during exercise post-MI is a predictor of future angina.
Abstract:
We have studied 50 consecutive patients who had sustained their first myocardial infarction. Using the noninvasive technique of radionuclide ventriculography, ventricular performance, as assessed by left ventricular ejection fraction (EF), was measured at rest just before discharge from hospital when patients were well and free from cardiac failure and then at one and four months after infarction, at rest and during submaximal supine exercise. Left ventricular ejection fraction was below normal in 42 patients (normal range 0.43-0.71). Mean EF for those patients recovering from inferior infarction was 0.43 +/- 0.09 (mean +/- 1 S.D.), whereas for those who had sustained anterior infarction mean EF was significantly lower, 0.33 +/- 0.13 (p less than 0.01). EF was significantly reduced (p less than 0.01) in those patients whose early progress was complicated either by serious arrhythmia or left ventricular failure. There was only poor correlation between EF and radiographically determined heart size but global left ventricular performance correlated well with the presence of abnormalities of regional wall movement. Over the first four months low EF failed to improve in seven patients with areas of dyskinesis (EF less tha 0.30) and despite diuretic therapy five suffered further episodes of cardiac failure. Excluding those with dyskinesis there were 18 patients who were unable to increase EF on exercise on month after infarction. Of these four already had symptoms of angina but a further 10 patients developed angina in the subsequent three months. Poor left ventricular performance is common after anterior myocardial infarction, complicated in the acute phase by serious arrhythmia or left ventricular failure. Patients with persistently low EF had an increased risk of further episodes of cardiac failure, whereas a fall in EF on exercise was associated with subsequent angina.