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A normal electrocardiogram precludes the need for left ventriculography in the assessment of coronary artery disease
Insights
A normal electrocardiogram (ECG) reliably identifies good left ventricular function in patients with suspected coronary artery disease. This finding suggests routine left ventriculography may be unnecessary, saving significant time and resources.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Clinical Medicine
Background:
- Coronary artery disease (CAD) diagnosis often involves invasive procedures.
- Left ventricular function is a key indicator of cardiac health.
- Left ventriculography is a standard but resource-intensive method for assessing left ventricular function.
Purpose of the Study:
- To determine if a normal electrocardiogram (ECG) can accurately predict good left ventricular function.
- To assess if a normal ECG can eliminate the need for routine left ventriculography in patients with suspected CAD.
- To evaluate the diagnostic performance of ECG criteria in identifying preserved left ventricular function.
Main Methods:
- Prospective study of 391 patients undergoing cardiac catheterization for suspected CAD.
- ECGs were assessed using a 29-point QRS scoring system and by clinical judgment.
- Left ventricular function was evaluated using digital ventriculography, with ejection fraction > or = 50% defining good function.
Main Results:
- A normal ECG, as judged by cardiologists, demonstrated high sensitivity (94.4%-96.3%) and negative predictive value (97.2%-98.6%) for good left ventricular function.
- The QRS score of 0 (normal complexes) showed similar diagnostic accuracy.
- Specificity for identifying good left ventricular function was moderate (37.4%-49.6%).
Conclusions:
- A normal ECG assessment by a cardiologist is sufficient to identify good left ventricular function.
- Routine left ventriculography can be obviated in patients with a normal ECG, simplifying diagnostic pathways.
- Implementing this strategy can lead to substantial cost savings and reduced procedural time in cardiac catheterization laboratories.
Objective:
To assess whether a normal electrocardiogram can identify good left ventricular function and obviate the need for routine left ventriculography in patients undergoing cardiac catheterization for suspected coronary artery disease.
Design:
A prospective study of patients undergoing cardiac catheterisation.
Setting:
A regional cardiac centre.
Patients:
The electrocardiograms, coronary angiograms, and left ventriculograms of 391 consecutive patients undergoing investigations for suspected coronary artery disease were entered into the study. Patients with arrhythmias and cardiac pathologies other than coronary artery disease were excluded.
Main Outcome Measures:
The electrocardiogram was assessed using a 29 point QRS scoring system, and classified by two cardiologists and a trainee cardiologist as normal or abnormal. Left ventricular function was assessed by digital ventriculography.
Results:
The sensitivity, specificity, and negative predictive value of a QRS score of 0 (normal QRS complexes) for discriminating good left ventricular function (ejection fraction > or = 50%) were 92.6%, 41.5%, and 97.2%, respectively. The figures for a normal electrocardiogram as assessed by a doctor were 96.3%, 40.4%, and 98.6% for cardiologist A; 96.3%, 37.4%, and 98.4% for cardiologist B; and 94.4%, 49.6%, and 98.2% for the cardiology trainee.
Conclusions:
If a cardiologist judges the ECG to be normal, left ventriculography is unnecessary and a formal QRS score does not improve reliability of this clinical judgment. Adopting this strategy would save 30-40,000 Pounds in consumables and 65-87 hours of catheter laboratory and staff time for a department catheterising 3000 patients with suspected coronary artery disease annually.