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[Left ventricular hypertrophy secondary to systemic hypertension: its effect on coronary hemodynamics]
Insights
Phasic blood flow in coronary arteries is altered in patients with pressure overload hypertrophy. Increased ventricular pressure and wall thickness disrupt early diastolic inflow, potentially reducing coronary flow reserve.
Area of Science:
- Cardiology
- Physiology
Context:
- Systemic hypertension commonly leads to left ventricular hypertrophy (LVH).
- Altered coronary blood flow dynamics in LVH are not fully understood.
- Doppler catheter measurements provide insights into phasic coronary blood flow.
Purpose:
- To investigate the characteristics of phasic blood velocity patterns in the left anterior descending coronary arteries.
- To identify potential causes of these altered patterns in pressure overload hypertrophy.
- To assess the relationship between flow patterns, ventricular hypertrophy, and coronary flow reserve.
Summary:
- Doppler measurements in 16 hypertensive patients with LVH revealed decreased early diastolic inflow velocity.
- Prolongation of the time to peak diastolic velocity (TDPV) correlated with LVH severity, peak systolic pressure, and ejection fraction.
- Coronary flow reserve tended to decrease with prolonged TDPV and increased wall thickness.
Impact:
- Systolic vascular compression and strain may cause early diastolic inflow disturbances in hypertensive LVH.
- Reduced early diastolic inflow velocity might contribute to decreased coronary reserve.
- Findings enhance understanding of coronary hemodynamics in pressure overload hypertrophy.
Abstract:
To clarify the characteristics and possible causes of phasic blood velocity patterns in pressure overload hypertrophy, we measured blood flow velocities in the left anterior descending coronary arteries in 16 patients with left ventricular hypertrophy secondary to systemic hypertension. These measurements were made with a 20MHz Doppler catheter. All patients had normal coronary arteriograms. The blood flow velocity patterns were characterized by the decrease in the rise of early diastolic inflow velocity. Prolongation in the time from the onset of diastole to peak velocity (TDPV) correlated with the degree of left ventricular hypertrophy. TDPV was prolonged in proportion to the increase in the peak left ventricular systolic pressure and left ventricular ejection fraction. The flow reserve calculated from the ratio of the diastolic mean velocity after the intracoronary injection of papaverine to the resting flow showed a trend toward the decrease proportional to the prolongation in TDPV due to an increase of wall thickness. In conclusion, preceding systolic vascular compression and systolic vascular strain can be factors causing early diastolic inflow disturbance in left ventricular hypertrophy secondary to hypertension. The decrease of coronary reserve may partially be attributable to the decrease in the rise of early diastolic inflow velocity.