The initial stage of left ventricular hypertrophy in spontaneously hypertensive rats is manifested by a decrease in...

Area of Science:

• Cardiology
• Physiology
• Experimental Medicine

Background:

• Hypertension leads to left ventricular hypertrophy (LVH).
• The discrepancy between increased left ventricular mass (LVM) and electrocardiogram (ECG) QRS amplitudes, termed relative voltage deficit, is a known phenomenon.
• Understanding this deficit is crucial for accurate LVH diagnosis.

Purpose of the Study:

• To test the hypothesis of relative voltage deficit in spontaneously hypertensive rats (SHR).
• To investigate the relationship between systolic blood pressure (sBP), LVM, and QRS amplitudes in an experimental model.
• To correlate findings with clinical implications for ECG diagnostics of LVH.

Main Methods:

• Orthogonal electrocardiograms were recorded in male SHR at 12 and 20 weeks of age.
• Systolic blood pressure (sBP) and left ventricular mass (LVM) were measured.
• Specific potential of myocardium (SP) was calculated as the ratio of maximum QRS spatial vector magnitude (QRSmax) to LVM.

Main Results:

• SHR exhibited significantly higher LVM compared to WKY controls, correlating with sBP increase.
• QRSmax in SHR did not increase with sBP or LVM; it was lower in 20-week-old SHR compared to controls.
• SP values, indicating relative voltage deficit, were significantly lower in SHR and decreased with disease progression.

Conclusions:

• The study supports the hypothesis of a relative voltage deficit in LVH.
• Findings explain the high incidence of false negative ECG results in clinical LVH diagnosis.
• Results may aid in re-evaluating and utilizing false negative ECGs for clinical diagnosis and prognosis.