Abnormal course, abnormal flow, and systolic compression of the septal perforator associated with impaired myocardial perfusion in hypertrophic cardiomyopathy

Background The septal perforators in hypertrophic cardiomyopathy (HCM) show systolic compression. The compression is thought to be related to the malp ositioned septal perforators, but its relation to the development of myocar dial ischemia remains controversial. Methods We examined echocardiogrophically the blood flow and course of the major septal perforator in 142 consecutive patients with HCM; of these, 94 underwent coronary angiography to assess systolic compression of the septal perforators and 110 had thallium-201 scintigraphy. We then analyzed the re lation of the findings in comparison with the results in 15 patients with v olvular aortic stenosis (AS). Results The major septal perforator was visualized in 82 patients with HCM and in 8 patients with AS. The visualization did not depend on the pressure gradient between the left ventricle and aorta in the HCM patients, but did in the AS patients. In AS the perforator always showed a normal course nea r to, and convexly toward, the right ventricle. in 71 of the 82 HCM patient s, the perforator was distant from the right-sided endocardium of the ventr icular septum and often convex toward the left. The greater the leftward de viation, the higher was the grade of compression. In 48 of the 82 patients with HCM and in all of the 8 patients with AS who showed the flow signal, t he septal perforator showed systolic retrograde flow; in the patients with HCM there was a significant correlation (r = 0.54, P < .05) between the pea k velocity and the degree of leftward deviation. Furthermore, higher degree s of the leftward deviation and higher degrees of the systolic compression of the major perforator were each associated with a higher incidence of exe rcise-induced defect of thallium-201. Conclusion The echocardiographic, angiographic, and scintigraphic findings in HCM may be closely related to one another. We speculate that the series of abnormalities is initiated by a high intramural pressure and impedance o n the septal perforators due to their deviation toward the left.