Back to Search
Start Over
Effects of diltiazem on left ventricular systolic and diastolic function in hypertrophic cardiomyopathy.
- Source :
-
The American journal of cardiology [Am J Cardiol] 1996 Aug 15; Vol. 78 (4), pp. 451-7. - Publication Year :
- 1996
-
Abstract
- Hypertrophic cardiomyopathy (HC) is characterized by impaired diastolic function, and left ventricular (LV) outflow tract obstruction in about one-fourth of patients. Verapamil improves diastolic properties, but may have dangerous adverse effects. This study investigates the effects of diltiazem on hemodynamics and LV function in 16 patients with HC who were studied with cardiac catheterization and simultaneous radionuclide angiography. Studies were performed during atrial pacing (15 beats above spontaneous rhythm) at baseline and during intravenous diltiazem administration (0.25 mg x kg(-1) over 2 minutes, and 0.014 mg x kg(-1) x min(-1). Diltiazem induced a systemic vasodilation (cardiac index: 3.4 +/- 1.0 to 4.0 +/- 1.0 L x min(-1) x m(-2), p = 0.003; aortic systolic pressure: 116 +/- 16 to 107 +/- 19 mm Hg, p = 0.007; systemic resistance index: 676 +/- 235 to 532 +/- 193 dynes x s x cm(-5) x m(-2), p = 0.006), not associated with changes in the LV outflow tract gradient. The end-systolic pressure/volume ratio decreased (30 +/- 42 to 21 +/- 29 mm Hg x ml(-1) x m(-2); p = 0.044). Pulmonary artery wedge pressure (11 +/- 5 to 15 +/- 6 mm Hg, p = 0.006), and peak filling rate increased (4.1 +/- 1.3 to 6.0 +/- 2.4 stroke counts x s(-1), p = 0.004). The time constant of isovolumetric relaxation tau decreased (74 +/- 40 to 59 +/- 38 ms, p = 0.045). The constant of LV chamber stiffness did not change. Thus, active diastolic function is improved by the acute administration of diltiazem by both direct action and changes in hemodynamics and loading conditions. LV outflow tract gradient does not increase despite systemic vasodilation. In some patients, however, a marked increase in obstruction and a potentially harmful elevation in pulmonary artery wedge pressure do occur. Passive diastolic function is not affected.
- Subjects :
- Adult
Blood Pressure drug effects
Calcium Channel Blockers administration & dosage
Cardiac Catheterization
Cardiac Output drug effects
Cardiac Pacing, Artificial
Cardiac Volume drug effects
Cardiomyopathy, Hypertrophic physiopathology
Cardiovascular Agents administration & dosage
Diastole
Diltiazem administration & dosage
Female
Heart Atria
Heart Rate drug effects
Humans
Injections, Intravenous
Male
Middle Aged
Myocardial Contraction drug effects
Pulmonary Wedge Pressure drug effects
Radionuclide Angiography
Systole
Vascular Resistance drug effects
Vasodilator Agents administration & dosage
Vasodilator Agents therapeutic use
Ventricular Outflow Obstruction drug therapy
Ventricular Outflow Obstruction physiopathology
Calcium Channel Blockers therapeutic use
Cardiomyopathy, Hypertrophic drug therapy
Cardiovascular Agents therapeutic use
Diltiazem therapeutic use
Ventricular Function, Left drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9149
- Volume :
- 78
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- The American journal of cardiology
- Publication Type :
- Academic Journal
- Accession number :
- 8752192
- Full Text :
- https://doi.org/10.1016/s0002-9149(96)00336-0