[Myocardial infarct without Q wave in the elderly: diagnostic evaluation using vectorcardiography]

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.