Blood pressure and left ventricular dysfunction in the spontaneously hypertensive rat

Area of Science:

• Cardiovascular Physiology
• Hypertension Research
• Cardiac Function

Background:

• Systemic hypertension is often linked to heart dysfunction.
• Left ventricular hypertrophy can precede left ventricular dysfunction.

Purpose of the Study:

• To investigate the role of the heart in the manifestation and maintenance of systemic hypertension.
• To examine the impact of left ventricular dysfunction on blood pressure in spontaneously hypertensive rats (SHR).

Main Methods:

• Observation of left ventricular hypertrophy and dysfunction progression in female SHR over time.
• Induction of left ventricular dysfunction via experimental myocardial infarction in young SHR.
• Correlation of blood pressure changes with the extent of left ventricular damage.

Main Results:

• Female SHR developed overt left ventricular dysfunction and dilatation at 24 months, with a loss of manifest systemic hypertension despite increased vascular resistance.
• Experimental induction of left ventricular dysfunction in young SHR led to a fall in systemic arterial pressure.
• The reduction in blood pressure was directly proportional to the degree of histologic damage in the left ventricle.

Conclusions:

• The heart plays a permissive role in the expression and maintenance of systemic hypertension.
• Left ventricular dysfunction can abolish established hypertension, even with maintained vascular resistance.
• Cardiac integrity is essential for the sustained elevation of blood pressure in hypertension.