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[Myocardial infarct without Q wave in the elderly: diagnostic evaluation using vectorcardiography]
M A Tedesco1, G Ratti, D Aquino
1Istituto Medico Chirurgico di Cardiologia, Cattedra di Cardiologia, Seconda Università degli Studi di Napoli.
Insights
Diagnosing previous non-Q wave myocardial infarction in elderly patients is challenging. Vectorcardiography (VCG) and echocardiography show promise in identifying cardiac electrical activation interruptions, aiding diagnosis.
Area of Science:
- Cardiology
- Medical Diagnostics
- Electrocardiography
Background:
- Standard electrocardiography (ECG) has limitations in diagnosing previous non-Q wave myocardial infarction (MI), especially in elderly patients with comorbidities.
- Accurate diagnosis of prior MI is crucial for appropriate patient management and risk stratification.
Purpose of the Study:
- To evaluate the diagnostic utility of vectorcardiography (VCG) and echocardiography in elderly patients with suspected previous non-Q wave MI.
- To assess the correlation between VCG findings, specifically 'bites criteria,' and echocardiographic evidence of regional hypokinesis.
Main Methods:
- Study included 31 elderly patients (63-72 years) diagnosed with non-Q wave MI.
- Methods included clinical examination, standard ECG, Frank system VCG, and M-mode/2D echocardiography with Doppler.
- VCG 'bites criteria' (duration ≥ 10 msec, voltage ≥ 0.1 mV in ≥ 2 planes) were specifically analyzed.
Main Results:
- Standard ECG showed ST-T anomalies in only 38.7% of patients.
- VCG revealed QRS-loop anomalies in 87% of patients, with 51.6% meeting 'bites criteria'.
- Echocardiography detected regional hypokinesis in 61.3% of patients.
Conclusions:
- VCG, particularly the presence of 'bites criteria,' demonstrates higher sensitivity than standard ECG for detecting abnormalities consistent with previous non-Q wave MI in elderly patients.
- VCG 'bites' suggest interrupted myocardial electrical activation, indicative of fibrous areas, and should be integrated with other clinical and instrumental data for diagnosis.
- Echocardiography provides complementary information on regional myocardial dysfunction.
Abstract:
The diagnosis of previous non-Q wave myocardial infarction by standard electrocardiographic investigation is uncertain, particularly in elderly patients because of concomitant disease. We have studied 31 elderly patients (aged 63-72 years) with a diagnosis of non-Q wave myocardial infarction between 1-6 months after this acute event. The patients underwent clinical-anamnestic examination, standard electrocardiography, vectorcardiography according to the Frank system and M-mode and 2-D echo-cardiography with continuous and pulsated Doppler. The ECG showed ST-T anomalies in 12 patients (38.7%) whereas the VCG showed anomalies of QRS-loop normal convexity in 27 patients (87%) and 16 of these (51.6%) showed bites criteria (duration > or = 10 msec, voltage > or = 0.1 mV, present at least on two planes). By echocardiography, regional hypo-akinesia was observed in 19 patients (61.3%). Although bites are not only present in myocardial infarction, they indicate an interruption of myocardial gradual electric activation, compatible with fibrous areas, and should be evaluated as a part of the clinical-anamnestic, laboratory and instrumental data.