Normal limits of the electrocardiogram in Angolans

Area of Science:

• Cardiology
• Public Health
• Population Studies

Background:

• Limited data exists on normal electrocardiogram (ECG) limits in African populations, particularly in sub-Saharan Africa.
• No specific literature details normal ECG limits for Angolan adults.

Purpose of the Study:

• To determine the normal electrocardiogram (ECG) limits for adult Angolans.
• To stratify these normal ECG limits by gender and age in individuals without pre-existing heart disease.

Main Methods:

• A cross-sectional study of 2179 healthy adult Angolans (aged 15-74) was conducted.
• Standard 12-lead ECGs and rhythm strips were recorded and analyzed using University of Glasgow software and the Minnesota Code.
• Normal ranges were defined by the 2nd and 98th percentiles, with statistical analysis including Mann-Whitney, Kruskal-Wallis tests, Bonferroni adjustments, and GAMLSS models for age-dependent curves.

Main Results:

• Significant differences in normal ECG ranges were observed between men and women.
• Specific ranges were established for heart rate, P wave duration, PR interval, QRS duration, QT interval, P-wave axis, QRS-wave axis, T-wave axis, Sokolow-Lyon index, and Cornell index, varying by sex.
• Age-dependent variations were also identified, necessitating age-specific reference values.

Conclusions:

• The established ECG parameter ranges serve as a vital reference for Angolan adults without heart disease.
• Normal ECG ranges are influenced by both age and sex.
• ECG diagnostic criteria should be tailored to specific demographic factors (age and sex) for accurate interpretation in the Angolan population.