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[Left ventricular function in essential hypertension during isoproterenol infusion]
Insights
Essential hypertension with cardiac hypertrophy impairs left ventricular diastolic and systolic function, particularly after isoproterenol (ISP) infusion. Increased left ventricular mass (LVM) is linked to this dysfunction in hypertensive patients.
Area of Science:
- Cardiology
- Hypertension Research
- Cardiac Physiology
Context:
- Essential hypertension is a major risk factor for cardiovascular disease.
- Cardiac hypertrophy, a common complication of hypertension, can lead to impaired left ventricular function.
- Understanding the functional consequences of cardiac hypertrophy in hypertension is crucial for patient management.
Purpose:
- To investigate the effects of isoproterenol (ISP) on left ventricular function in patients with essential hypertension, stratified by the presence or absence of cardiac hypertrophy.
- To determine the relationship between left ventricular mass (LVM) and left ventricular dysfunction in hypertensive individuals.
Summary:
- M-mode echocardiograms were used to assess left ventricular function at rest and during ISP infusion in hypertensive patients with (Group HH) and without (Group NH) cardiac hypertrophy, and in normotensive controls.
- Group HH showed significantly decreased peak negative dD/dt (diastolic function) and peak positive dD/dt (systolic function) after ISP infusion, which correlated inversely with LVM.
- Hypertensive patients with cardiac hypertrophy exhibited diastolic and latent systolic left ventricular dysfunction, exacerbated by ISP and related to increased LVM.
Impact:
- This study highlights the detrimental effects of cardiac hypertrophy on left ventricular function in essential hypertension.
- Findings suggest that increased LVM contributes to both diastolic and systolic dysfunction in hypertensive patients.
- The results underscore the importance of managing cardiac hypertrophy to preserve left ventricular function in hypertension.
Abstract:
The left ventricular function of 23 patients with essential hypertension was investigated during infusion of isoproterenol (ISP). These patients consisted of 13 without cardiac hypertrophy (Group NH) and 10 with cardiac hypertrophy (Group HH). Ten normotensive subjects served as normal controls. To assess left ventricular functions, M-mode echocardiograms were recorded at rest and after ISP infusion for 5 minutes (0.005 and 0.01 microgram/kg/min). There were no significant differences in peak negative dD/dt in all groups at rest. But peak negative dD/dt of Group HH significantly decreased after an infusion of 0.005 microgram/kg/min ISP (Group N: 3.43 +/- 0.69, Group NH: 3.15 +/- 0.61, and Group HH: 2.49 +/- 0.48 cm/sec, respectively). The peak negative dD/dt of Group HH was also significantly decreased after a dose of 0.01 microgram/kg/min. Among all patients with hypertension, peak negative dD/dt correlated inversely with left ventricular mass (LVM) after the infusion of ISP (0.005 microgram/kg/min: r = -0.64, p less than 0.001, 0.01 microgram/kg/min: r = -0.68, p less than 0.001). The peak positive dD/dt of Group HH was significantly decreased only when compared with that of Group N at rest (Group N: 3.15 +/- 0.75, Group NH: 3.02 +/- 0.86, and Group HH: 1.92 +/- 0.68 cm/sec, respectively). The difference between the peak positive dD/dt of Group HH and that of Group N was more prominent after the infusion of ISP than at rest. Among all patients with hypertension, the peak positive dD/dt was inversely related to LVM at rest (r = -0.64, p less than 0.002). There was a similar relation between the two indexes after the infusion of ISP. Peak positive dD/dt was related to peak negative dD/dt after a dose of 0.01 microgram/kg/min in Group HH (r = 0.67, p less than 0.05). There was no significant difference in heart rate, change in blood pressure, or total peripheral vascular resistance after the infusion of ISP. It is concluded that diastolic left ventricular dysfunction and latent systolic left ventricular dysfunction are related to increased LVM in Group HH. It seems that after the infusion of ISP severe diastolic left ventricular dysfunction is related to latent systolic left ventricular dysfunction.