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Diastolic function of the heart in untreated primary hypertension
Insights
Prolonged left ventricular (LV) relaxation time may indicate early cardiac changes in hypertension. This study found prolonged LV relaxation in hypertensive men, suggesting it
Area of Science:
- Cardiology
- Hypertension Research
- Vascular Medicine
Background:
- Hypertension is a major risk factor for cardiovascular disease.
- Early detection of cardiac involvement in hypertension is crucial for timely intervention.
- Understanding the relationship between blood pressure and cardiac/vascular changes is essential.
Purpose of the Study:
- To investigate left ventricular (LV) diastolic function in relation to blood pressure (BP).
- To assess cardiac and peripheral vascular changes in hypertensive individuals.
- To determine if prolonged LV relaxation is an early indicator of hypertensive heart disease.
Main Methods:
- Studied four groups of untreated 49-year-old men based on BP levels: normotensive, borderline, mild, and moderate to severe hypertension.
- Measured isovolumic relaxation time and early diastolic filling using phonocardiography and echocardiography.
- Assessed LV wall thickness and peripheral vascular resistance in hypertensive groups.
Main Results:
- Isovolumic relaxation time and early diastolic filling tended to increase with BP.
- The A2O interval (aortic closure to apexcardiogram O point) was significantly prolonged in mild and moderate to severe hypertension groups.
- Prolonged LV relaxation was observed even without increased LV wall thickness in some hypertensive subjects.
- Moderate to severe hypertension showed increased LV wall thickness and calf vascular resistance.
Conclusions:
- Prolonged LV relaxation time may serve as an early sign of cardiac involvement in primary hypertension.
- Cardiac structural changes in hypertension may occur concurrently with peripheral vascular structural changes.
- Early diastolic dysfunction is a potential marker for hypertensive cardiac alterations.
Abstract:
To study left ventricular (LV) diastolic function of the heart in relation to blood pressure (BP) and other signs of hypertensive cardiac and peripheral vascular changes, isovolumic relaxation time and early diastolic filling were determined in four BP groups of untreated 49-year-old men: normotensive subjects (n = 20), men with borderline hypertension (n = 30), mild hypertension (n = 45), and moderate to severe hypertension (n = 24). Isovolumic relaxation time, measured as the distance between aortic closure (A2, phonocardiography) and mitral valve opening (echocardiography), and early diastolic filling, measured as the distance between mitral valve opening and the O point of the apexcardiogram, tended to increase with BP level, and the total interval from aortic closure to the O point (A2O interval) was significantly prolonged in the two groups with mild and moderate to severe hypertension. A prolonged A2O interval (greater than or equal to 117% of expected value at observed heart rate) was seen in several hypertensives, who had no obvious increase in LV wall thickness on M mode echocardiography. This suggests that a prolonged LV relaxation time may be an early sign of cardiac involvement in primary hypertension. In the group with moderate to severe hypertension, an increase in LV wall thickness was seen together with an increase in resistance at maximal dilation in the calf. This supports the theory that when changes in cardiac structure develop they occur in parallel with structural changes also in the periphery.