Progression of hypertrophic cardiomyopathy into a hypokinetic left ventricle: Higher incidence in patients with midventricular obstruction

Abstract

The development of segmental or generalized left ventricular hypokinesia is an unusual occurrence in patients with hypertrophic cardiomyopathy. To determine the incidence and possible pathophysiologic mechanisms responsible for this process, the serial clinical and laboratory data of 62 patients with the diagnosis of hypertrophic cardiomyopathy were analyzed. During a mean follow-up period of 8 years (range 2 to 21), 5 patients (Group A) developed left ventricular hypokinesia, whereas the remaining 57 patients (Group B) continued to exhibit the clinical and laboratory findings of hypertrophic cardiomyopathy. Three patients developed a dilated left ventricle with generalized hypokinesia; two other patients had segmental left ventricular wall motion abnormalities. None of these five patients who developed left ventricular hypokinesia had fixed coronary artery disease. The mean age, sex, mean duration of follow-up, presence of coronary myocardial bridges and angina pectoris, and an interventricular gradient were all similar in Groups A and B. Midventricular obliteration was seen in 4 (80%) of the 5 patients in Group A and in 4 (7%) of the 57 patients in Group B (p less than 0.001). Findings from this study reveal that segmental or generalized left ventricular hypokinesia can develop in patients with hypertrophic cardiomyopathy in the absence of fixed coronary artery disease. Such hypokinesia can occur after an acute myocardial infarction or it can develop gradually without clinical or electrocardiographic evidence of infarction. Patients with the mid-ventricular obliteration variant of hypertrophic cardiomyopathy are at a higher risk of developing segmental or diffuse left ventricular hypokinesia.

Beneficial Effect of Dual-Chamber Pacing for a Left Mid-Ventricular Obstruction With Apical Aneurysm.

“…An asynergic or aneurysmal apical chamber in the absence of fixed coronary artery disease has been previously described in a patient with MVO, [8][9][10] and it has been suggested that the development of apical aneurysm may be secondary to increased afterload and high apical pressure resulting from a systolic MVO. 8,10 Therefore, relief of the high apical pressure may be necessary to preventing further asynergy.…”

“…8,10 Therefore, relief of the high apical pressure may be necessary to preventing further asynergy. It has been considered that drug-refractory patients with MVO are candidates for cardiac surgery, 11,12 but recently, pacing therapy for pressure gradient reduction in patients with MVO has been reported, 6 as is the case for patients with hypertrophic LVOT obstruction.…”

Midventricular Hypertrophic Obstructive Cardiomyopathy with Left Ventricular Aneurysm and Clot: The Role of Transesophageal Echocardiogram in Assessment and Management of Myomectomy

“…The dyskinetic/akinetic apical aneurysm can provide the structural basis for intracavitary thrombus formation. 6 Other possible cause of LV aneurysm include post myocardial infarction. Our patient had no history of angina or myocardial infarction.…”

Hypertrophic Cardiomyopathy With Midventricular Obstruction and Apical Aneurysm. A Case Report.

“…Fighali et al showed that segmental or generalized left ventricular hypokinesis could develop in patients with HCM and midventricular obliteration without a fixed coronary artery obstruction, 7 and they speculated that a possible cause of such hypokinesis was that the large pressure gradient at the midventricular level might lead to further compensatory apical hypertrophy, which could in turn make the flow obstruction more severe and the pressure in the apical chamber higher. The pressure overload on the apical wall might eventually lead to myocardial dysfunction with dilation of the apical chamber.…”