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Delayed untwisting: the mechanistic link between dynamic obstruction and exercise tolerance in patients with hypertrophic obstructive cardiomyopathy.
- Source :
-
Journal of the American College of Cardiology [J Am Coll Cardiol] 2009 Sep 29; Vol. 54 (14), pp. 1326-34. - Publication Year :
- 2009
-
Abstract
- Objectives: We sought to determine the mechanisms linking dynamic obstruction and exercise tolerance in patients with hypertrophic obstructive cardiomyopathy (HOCM).<br />Background: Patients with HOCM have reduced exercise tolerance. However, the association between dynamic obstruction and peak oxygen consumption (VO2max) is weak.<br />Methods: We enrolled 25 patients with HOCM, 20 with hypertrophic cardiomyopathy (HCM), and 20 normal control patients. Two-dimensional, Doppler, strain, and left ventricular (LV) twist mechanics by speckle tracking echocardiography were obtained. The 25 HOCM patients had left heart catheterization, and 16 were re-examined after septal reduction.<br />Results: Deformation measurements were the lowest in HOCM patients and increased (p<0.05) after septal reduction. Twist and untwisting rate were not different between patients with HCM and control patients, but untwisting was significantly delayed in HCM patients and longest in HOCM patients. The delay related well with LV end-diastolic pressure (r=0.76) and volume (r=-0.73), and VO2max (r=-0.75, all p<0.01). After septal reduction, untwisting occurred earlier and accounted for the increase in end-diastolic volume (r=0.65), and VO2max (r=0.74, both p<0.05).<br />Conclusions: Dynamic obstruction leads to delayed untwisting in HOCM, which accounts well for the increased LV filling pressures, the reduced LV volumes, and VO2max. After septal reduction, untwisting occurs earlier and leads to an improvement in LV filling and exercise tolerance.
- Subjects :
- Cardiac Catheterization
Cardiac Volume physiology
Diastole physiology
Echocardiography
Ethanol administration & dosage
Female
Heart Septum
Humans
Male
Middle Aged
Oxygen Consumption physiology
Torsion Abnormality physiopathology
Cardiomyopathy, Hypertrophic physiopathology
Cardiomyopathy, Hypertrophic therapy
Exercise Tolerance physiology
Torsion Abnormality diagnostic imaging
Subjects
Details
- Language :
- English
- ISSN :
- 1558-3597
- Volume :
- 54
- Issue :
- 14
- Database :
- MEDLINE
- Journal :
- Journal of the American College of Cardiology
- Publication Type :
- Academic Journal
- Accession number :
- 19778676
- Full Text :
- https://doi.org/10.1016/j.jacc.2009.05.064