Whole-heart magnetic resonance imaging of isolated subpulmonary stenosis associated with hypertrophic cardiomyopathy.
- SourceAvailable from: ncbi.nlm.nih.govHeart (British Cardiac Society) 09/1997; 78(2):205-6. · 5.01 Impact Factor
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ABSTRACT: Hypertrophic cardiomyopathy is a diverse clinical and pathophysiologic entity that involves principally the left ventricle and is caused by asymmetric or concentric hypertrophy of unknown cause. If asymmetric, the hypertrophy is usually greates in the ventricular septum, but variations occur in which the hypertrophy may be maximal at the apex, at the midventricular level, or, rarely, in the free wall of the left ventricle. Right ventricular involvement is usually less evident.The principal abnormality in systole is the obstruction to left ventricular outflow caused by upper septal hypertrophy narrowing the outflow tract and setting the stage for Venturi forces to cause systolic anterior motion of the anterior or posterior mitral leaflets. The time of onset and duration of mitral leaflet-septal contact determine the magnitude of the pressure gradient. Mitral regurgitation invariably accompanies the obstruction to outflow. Ventriculomyotomy-myectomy surgery, by thinning the septum and widening the outflow tract, abolishes the abnormal mitral leaflet motion and, consequently, the obstruction to outflow and the mitral regurgitation. This form of surgery more dramatically relieves the systolic abnormalities and the accompanying symptoms than any form of medical therapy available today.The extent of hypertrophy is believed to be the principal determinant of the impaired left ventricular relaxation and increased chambers stiffness (decreased compliance) that characterize diastole in hypertrophic cardiomyopathy. Relaxation is impaired by the contraction load (the obstruction), by a decrease in the principal relaxation loads, by a pathologic degree of nonuniformity of contraction and relaxation, and in all likelihood, by impaired inactivation of the biochemical processes responsible for contraction (? due to primary or ischemia-induced calcium overload). Calcium channel-blocking agents may dramatically improve left ventricular relaxation by speeding up the inactivation process, by decreasing the degree of nonuniformity, or by altering the contraction and relaxation loads in a favorable manner.Atrial and ventricular arrhythmias are responsible for a significant proportion of the morbidity and mortality, and their occurrence also appears to depend on the extent of hypertrophy. Thus, the major manifestations of hypertrophic cardiomyopathy in systole and diastole as well as the disturbances of rhythm appear to be related to the site and/or extent of the hypertrophic process.We have learned a great deal about hypertrophic cardiomyopathy in the 27 years since its modern description. The techniques available to cardiology today have added tremendously to our knowledge and understanding of the pathophysiology of the systolic and diastolic abnormalities.The spectrum of hypertrophic cardiomyopathy continues to expand as the result of ongoing clinical and laboratory studies. However, our knowledge of the basic cellular defect(s) in this disease remains notably deficient. It is to be hoped that future research in hypertrophic cardiomyopathy will focus on the more basic aspects of this fascinating entity in order that our understanding and management of these patients can be based on a firmer foundation of fundamental scientific knowledge.Progress in Cardiovascular Diseases 01/1985; · 4.00 Impact Factor
- Heart 02/1966; 28(1):122-33.
Can J Cardiol Vol 25 No 10 October 2009e361
Whole-heart magnetic resonance imaging of isolated
subpulmonary stenosis associated with hypertrophic
Naoya Matsumoto MD, Yuichi Sato MD, Ken Nagao MD
Department of Cardiology, Nihon University Surugadai Hospital, Tokyo, Japan
Correspondence and reprints: Dr Yuichi Sato, Department of Cardiology, Nihon University Surugadai Hospital, Tokyo 101-8309, Japan.
Telephone 81-3972-8388, fax 81-3972-8388, e-mail email@example.com
Received for publication December 11, 2008. Accepted December 31, 2008
cardiology because of effort dyspnea. Echocardiography revealed asym-
metric hypertrophy of the interventricular septum (Figure 1; upper left
panel). There was an obstruction of the right ventricular outflow tract
during systole (Figure 1; arrow in upper right panel). Continuous wave
hole-heart magnetic resonance imaging (MRI) was performed
in a 59-year-old man who was referred to the department of
Doppler (Figure 1; lower panel) revealed a maximum velocity of
3.0 m/s, which corresponded to a pressure gradient of 36 mmHg within
the right ventricular outflow tract. A whole-heart MRI from the short-
axis view showed asymmetric hypertrophy of the interventricular sep-
tum, which protruded into the right ventricular outflow tract (Figure 2;
arrow). Cine MRI also showed asymmetric hypertrophy of the inter-
ventricular septum, which obstructed the right ventricular outflow
tract during systole (Figure 3; arrows).
Isolated subvalvular pulmonary stenosis (ISPS) – subvalvular pulmo-
nary stenosis without a ventricular septal defect – is a rare disorder that
has been shown to be associated with right ventricular outflow obstruc-
tion in patients with hypertrophic cardiomyopathy (1,2). It is usually
accompanied by left ventricular outflow obstruction, but isolated right
ventricular obstruction occurs infrequently. In contrast to conventional
MRI, which requires prospective projection settings for constructing the
multiple cross-sectional images, whole-heart MRI can retrospectively
depict arbitrary cross-sectional images from the previously acquired
three- dimensional data. In addition, whole-heart MRI allows for evalu-
ation of the anomalous coronary artery that often accompanies ISPS
(3). Thus, whole-heart MRI has the potential to become a routine diag-
nostic modality in patients with suspected ISPS.
images in cardiology
©2009 Pulsus Group Inc. All rights reserved
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cardiomyopathy: The importance of the site and the extent of
hypertrophy. A review. Prog Cardiovasc Dis 1985;28:1-83.
3. Yamamoto T, Habuchi Y, Morikawa J. Single coronary artery with
infundibular pulmonary stenosis. Heart 1997;78:205-6.