Abnormal signal-averaged electrocardiogram (SAECG) in obesity

Area of Science:

• Cardiology
• Electrophysiology
• Public Health

Background:

• High-frequency electrocardiogram (ECG) potentials, known as late potentials, occurring at the end of the QRS complex and into the ST segment are associated with an elevated risk of ventricular arrhythmias and sudden cardiac death.
• Signal-averaged electrocardiography (SAECG) is a computer-assisted technique used to analyze these late potentials, aiding in the prediction of ventricular arrhythmias in various clinical conditions.
• Obesity is a significant risk factor for cardiovascular morbidity and mortality, with ventricular arrhythmias being a suspected underlying cause.

Purpose of the Study:

• To investigate the prevalence of late potentials in a cohort of obese individuals compared to healthy volunteers.
• To determine if obesity, as measured by body mass index (BMI), is an independent predictor of abnormal SAECG findings.
• To assess the influence of comorbidities such as hypertension and diabetes mellitus on SAECG abnormalities in obese patients.

Main Methods:

• Signal-averaged electrocardiography (SAECG) was performed on 105 subjects, including 62 obese patients (BMI >30 kg/m2) and 43 healthy volunteers (BMI <30 kg/m2).
• Exclusion criteria included a history of heart or pulmonary disease, electrolyte imbalances, recent hospitalizations, abnormal screening ECGs, or use of medications affecting the QRS interval.
• Abnormal SAECG criteria included QRS duration >114 ms, high-frequency low amplitude >38 ms, and root-mean-square voltage <20 microV. Logistic regression analysis was used to evaluate predictors of abnormal SAECG results.

Main Results:

• Obese patients exhibited a significantly higher prevalence of SAECG abnormalities (55%) compared to healthy volunteers (4.6%).
• Within the obese group, the prevalence and number of SAECG abnormalities increased progressively with higher BMI categories.
• Body mass index (BMI) was identified as an independent predictor of abnormal SAECG results in both the obese cohort and the overall study population. Hypertension was associated with prolonged QRS duration.

Conclusions:

• Obesity is strongly associated with an increased occurrence of abnormal SAECG findings, indicating a higher risk for ventricular arrhythmias.
• These SAECG abnormalities are present in obese individuals irrespective of the presence of hypertension or diabetes.
• Obesity serves as an independent predictor of abnormal SAECG results, highlighting its critical role in cardiovascular risk stratification.