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Electrocardiographic appearance of old myocardial infarction in paced patients
George E Kochiadakis1, Michail D Kaleboubas, Nikos E Igoumenidis
1Cardiology Department, University Hospital of Heraklion, Crete, Greece.
Insights
Diagnosing chronic myocardial infarction using paced electrocardiograms is possible. Cabrera's and Chapman's signs show high sensitivity for detecting prior myocardial infarction but lack specificity for infarct location.
Area of Science:
- Cardiology
- Electrocardiography
- Diagnostic Medicine
Background:
- Chronic myocardial infarction diagnosis can be challenging.
- Electrocardiography is a key diagnostic tool in cardiology.
- Pacing electrocardiography offers a potential method for evaluating cardiac conditions.
Purpose of the Study:
- To assess the utility of paced electrocardiogram criteria for diagnosing chronic myocardial infarction.
- To evaluate the sensitivity and specificity of specific electrocardiographic signs during ventricular pacing.
- To determine if infarct location influences the diagnostic accuracy of these criteria.
Main Methods:
- Evaluated 45 patients with known myocardial infarction and 26 healthy controls.
- Applied right ventricular apex pacing after coronary angiography.
- Assessed five electrocardiographic criteria: Cabrera's sign, Chapman's sign, Q waves in specific leads, and QRS notching.
Main Results:
- Cabrera's and Chapman's signs demonstrated the highest sensitivity (91.1% and 86.6%) for detecting myocardial infarction.
- All individual criteria exhibited low specificity (42.3-69.2%).
- Combining Cabrera's and Chapman's signs improved specificity to 82.2% while maintaining good sensitivity (77.7%).
Conclusions:
- Paced electrocardiography, particularly using Cabrera's and Chapman's signs, aids in recognizing prior myocardial infarction.
- These criteria are effective for diagnosing myocardial infarction regardless of infarct location.
- Specificity remains a limitation, and these signs cannot reliably determine the specific infarct site.
Abstract:
This study evaluated the possibility of diagnosing chronic myocardial infarction in the presence of the pacing electrocardiogram. Forty-five patients with known myocardial infarction (anterior 23, inferior 22) and 26 healthy controls were studied. After coronary angiography, pacing was applied from the right ventricular apex, and the sensitivity, specificity, and average diagnostic accuracy of five criteria on the paced electrocardiogram were assessed: (1) Notching 0.04 second in duration in the ascending limb of the S wave of leads V3, V4, or V5 (Cabrera's sign); (2) Notching of the upstroke of the R wave in leads I, aVL, or V6 (Chapman's sign); (3) Q waves > 0.03 second in duration in leads I, aVL, or V6; (4) Notching of the first 0.04 second of the QRS complex in leads II, III, and aVF; (5) Q wave > 0.03 second in duration in leads II, III, and aVF. The most sensitive criteria, for anterior and inferior myocardial infarctions were Cabrera's and Chapman's (91.1 and 86.6%, respectively). All criteria had low specificity (range 42.3-69.2%). The combination of Cabrera's and Chapman's sign decreased the sensitivity to 77.7%, but increased specificity to 82.2%. The sensitivity and specificity of all the criteria were independent of the myocardial infarction site. In paced patients, the application of electrocardiographic criteria, and especially the combination of Cabrera and Chapman, provides useful clinical information in recognizing prior myocardial infarction but not in assigning the specific infarct site.