ECG alterations with progressive left ventricular hypertrophy in spontaneous hypertension

Area of Science:

• Cardiovascular Research
• Animal Models of Hypertension
• Electrocardiography

Background:

• Left ventricular hypertrophy (LVH) diagnosis in hypertensive humans relies on ECG criteria, but progression patterns are unclear.
• The spontaneously hypertensive rat (SHR) model exhibits age-related increases in left ventricular mass, making it suitable for studying LVH progression.

Purpose of the Study:

• To identify specific electrocardiogram (ECG) changes associated with the progression of left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHR).
• To establish a better understanding of evolving ECG changes in LVH using a validated animal model.

Main Methods:

• Electrocardiograms were recorded from four age groups of spontaneously hypertensive rats (SHR) and two normotensive Wistar strains (NR and WKY).
• Statistical analysis using analysis of variance (ANOVA) was performed to assess the impact of rat strain and age on ECG parameters.

Main Results:

• Progressively increased QRS duration, P-wave duration, and delayed intrinsicoid deflection were observed in SHR compared to controls (p < 0.001).
• Bipeak P-wave notching, resembling left atrial abnormality in hypertensive humans, was identified in SHR.

Conclusions:

• Specific ECG indices in SHR are directly associated with the progressive increase in left ventricular mass.
• These findings provide a valuable animal model for understanding the evolution of ECG changes in left ventricular hypertrophy (LVH) during hypertension.