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Detection of left ventricular dysfunction after acute myocardial infarction: comparison of clinical,
1Department of Cardiology, Ninewells Hospital and Medical School, Dundee.
Insights
Identifying left ventricular dysfunction after myocardial infarction is crucial. Echocardiography and plasma BNP levels are more reliable than clinical assessment for detecting this condition.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Biomarkers
Background:
- Left ventricular dysfunction (LVD) post-myocardial infarction (MI) impacts mortality.
- Early identification of LVD is essential for effective treatment, as shown by the SAVE study.
- Captopril improves outcomes in post-MI patients with LVD, even without overt heart failure.
Purpose of the Study:
- To compare the accuracy of various methods for identifying LVD (left ventricular ejection fraction [LVEF] ≤ 40%) after acute MI.
- To evaluate echocardiography, clinical assessment, and natriuretic peptide levels for LVD detection.
Main Methods:
- A cross-sectional study involving 75 patients 2-8 days post-MI.
- Compared quantitative and qualitative echocardiography, clinical evaluation (subjective and scoring methods), and plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels.
- Calculated sensitivities and specificities against a reference echocardiographic LVEF algorithm.
Main Results:
- Clinical assessment showed low sensitivity (46%) for LVD detection.
- Clinical scoring (modified Peel index) improved sensitivity to 64%.
- Qualitative echocardiography (82%) and plasma BNP (84%) demonstrated higher sensitivity for LVD compared to ANP (64%).
Conclusions:
- Echocardiography (quantitative and qualitative) reliably detects LVD post-MI.
- Clinical assessment alone is insufficient for identifying LVD.
- Plasma BNP is a potentially useful biomarker for LVD, especially when echocardiography is unavailable.
Objective:
The SAVE study showed that captopril improves mortality in patients with left ventricular dysfunction after myocardial infarction and that this benefit occurred even in patients with no clinically overt heart failure. On the basis of this, it seems important to identify correctly which patients have left ventricular dysfunction after a myocardial infarction. The objective was to compare various methods of identifying patients with left ventricular dysfunction (left ventricular ejection fraction, LVEF, < or = 40%) after acute myocardial infarction. The methods compared were echocardiography (quantitative and qualitative visual assessment), clinical evaluation (subjective assessment and three clinical score methods), and measurement of plasma concentrations of cardiac natriuretic peptide hormones (atrial and brain natriuretic peptides, ANP and BNP).
Design:
Cross sectional study of left ventricular function in patients two to eight days after acute myocardial infarction.
Setting:
Coronary care unit of a teaching hospital.
Patients:
75 survivors of a recent myocardial infarction aged 40 to 88 with no history of cardiac failure and without cardiogenic shock at the time of entry to the study.
Main Outcome Measures:
Sensitivities and specificities of the various methods of detecting left ventricular dysfunction were calculated by comparing them with a cross sectional echocardiographic algorithm for LVEF.
Results:
Clinical impression was poor at identifying LVEF < 40% (sensitivity 46%). Clinical scoring improved this figure somewhat (modified Peel index sensitivity 64%). Qualitative visual assessment echocardiography was a more sensitive method (sensitivity 82%) for detecting LVEF < 40%. Plasma BNP concentration was also a sensitive measure for detecting left ventricular dysfunction (sensitivity 84%) but plasma ANP concentration was much poorer (sensitivity 64%).
Conclusion:
Left ventricular dysfunction is easily and reliably detected by echocardiographic measurement of LVEF and also by a quick qualitative echocardiographic assessment but is likely to be missed by clinical assessment alone. High concentrations of plasma BNP maybe another useful indicator of left ventricular dysfunction, particularly in hospitals where not all patients can be screened by echocardiography or radionuclide ventriculography after myocardial infarction.