Cardiomyocyte functions couple with left ventricular geometric patterns in hypertension

Area of Science:

• Cardiovascular Physiology
• Hypertension Research
• Cellular Biology

Background:

• Left ventricular (LV) geometric patterns are known prognostic indicators in essential hypertension.
• The link between cardiomyocyte functional alterations and LV geometric patterns in hypertension remains unclear.

Purpose of the Study:

• To investigate morphological and functional changes in isolated cardiomyocytes from rats with different LV geometric patterns induced by hypertension.
• To correlate cardiomyocyte function with specific LV geometric patterns in a hypertensive model.

Main Methods:

• Dahl salt-sensitive (DS) rats were fed a high-salt diet to induce hypertension and classified into concentric hypertrophy, eccentric hypertrophy, and concentric remodeling groups based on echocardiography.
• Ventricular myocytes were isolated and subjected to electrical pacing to assess the force-frequency relationship (contraction and relaxation) at various stimulation rates.
• In vivo LV function was evaluated using echocardiographic measurements.

Main Results:

• Concentric and eccentric hypertrophy increased myocyte width without affecting length.
• Concentric hypertrophy and concentric remodeling groups exhibited in vivo LV dysfunction.
• DS rats, particularly those with concentric hypertrophy, showed impaired cardiomyocyte contraction and relaxation, especially at higher frequencies, indicating a disrupted force-frequency relationship.

Conclusions:

• Structural and functional cardiomyocyte changes are closely associated with specific LV geometric patterns in hypertension.
• These myocyte alterations may explain the varying prognoses observed across different LV geometric patterns in hypertensive individuals.