Apical sequestration in hypertrophic cardiomyopathy: its clinical features and pathophysiology]

The clinical and pathophysiological significance of apical sequestration, in which an apical cavity was sequestered from the remainder of the left ventricle by cavity obliteration was investigated in patients with hypertrophic cardiomyopathy (HCM). Among 196 consecutive patients, 24 with apical sequestration and 70 control subjects proven to have no sequestration with left ventriculography were selected for this study using echocardiography combined with Doppler color flow imaging. Various cardiac disorders occurred significantly more frequently in patients with apical sequestration than in the 70 controls: NYHA > or = II, 83% vs 51%; thromboembolism, 17% vs 3%; ventricular tachycardia, 47% vs 11%; and apical asynergy, 75% vs 4%. Continuous Doppler ultrasound revealed that all 24 patients with sequestration had a high systolic blood flow velocity across the obliterated cavity (2.7 +/- 0.9 m/s). During isovolumic relaxation or early diastolic filling or both, 21 of them had paradoxical jet flow directed toward the basal cavity away from the apex, with the peak flow velocity ranging from 1.0 m/s to 3.5 m/s (mean 1.9 +/- 0.7). The maximal diastolic pressure gradient across the obliterated cavity ranged between 4 mmHg and 49 mmHg using the simple Bernoulli's equation, which suggested a significantly higher pressure in the sequestered apical chamber during early diastole. Patients with sequestration were classified into 2 groups; 17 with (group A) and 7 without (group B) apical hypertrophy. The time interval from the closing of the aortic valve to the onset of filling into the sequestered cavity was longer in group A than in group B (401 +/- 191 vs 131 +/- 145 ms, p < 0.01) as assessed by the pulsed Doppler technique. Angiographic asynergy of the apex was more frequent in group A than in group B (100 vs 29%, p < 0.01). In group B, the midventricular cavity was incompletely obliterated throughout the cardiac cycle; whereas, in group A, it was obliterated completely in systole and partially in diastole. Apical sequestration is not uncommon in HCM; it is accompanied by abnormal segmental wall motion, which may be related to ventricular arrhythmias and thromboembolism. Prolonged cavity obliteration with a higher systolic apical pressure and a persistent diastolic intraventricular gradient may play a pathogenic role in apical aneurysmal formation in the absence of fixed coronary artery disease, particularly in patients with apical hypertrophy.     

Apical hypertrophic cardiomyopathy

We describe a patient with asymptomatic apical hypertrophic cardiomyopathy(AHCM)who later developed cardiac arrhythmias,and briefly discuss the diagnostic modalities,differential diagnosis and treatment option for this condition.AHCM is a rare form of hypertrophic cardiomyopathy which classically involves the apex of the left ventricle.AHCM can be an incidental finding,or patients may present with chest pain,palpitations,dyspnea,syncope,atrial fibrillation,myocardial infarction,embolic events,ventricular fibrillation and congestive heart failure.AHCM is frequently sporadic,but autosomal dominant inheritance has been reported in few families.The most frequent and classic electrocardiogram findings are giant negative T-waves in the precordial leads which are found in the majority of the patients followed by left ventricular(LV)hypertrophy.A transthoracic echocardiogram is the initial diagnostic tool in the evaluation of ACHM and shows hypertrophy of the LV apex.AHCM may mimic other conditions such as LV apical cardiac tumors,LV apical thrombus,isolated ventricular non-compaction,endomyocardial fibrosis and coronary artery disease.Other modalities,including left ventriculography,multislice spiral computed tomography,and cardiac magnetic resonance imagings are also valuable tools and are frequently used to differentiate AHCH from other conditions.Medications used to treat symptomatic patients with AHCM include verapamil,beta-blockers and antiarrhythmic agents such as amiodarone and procainamide.An implantable cardioverter defibrillator is recommended for high risk patients.     

Apical hypertrophic cardiomyopathy: clinical and two-dimensional echocardiographic assessment

Of 965 patients with hypertrophic cardiomyopathy evaluated by echocardiography at the National Institutes of Health during a 7-year period, 23 (2%) had a nonobstructive morphologic form, in which wall thickening occurred predominantly in the apical (distal) portion of the left ventricle. The patients ranged in age from 15 to 69 years (mean, 37) and were predominantly male (14 patients) and white (only 1 was of oriental descent). Fifteen patients had significant functional limitation, which was usually caused by exertional dyspnea and fatigue. Several electrocardiographic patterns were identified in the study group, but only 4 of these patients showed "giant" negative T waves. Only 3 patients had a morphologic expression of apical hypertrophy that closely resembled that described in Japanese patients--that is, hypertrophy that was particularly localized and confined to the true left ventricular apex (2 of these patients had giant negative T waves). Hence, hypertrophy located predominantly in the distal left ventricle was uncommon in our primarily North American patient population with hypertrophic cardiomyopathy. Most of our patients showed morphologic and clinical features that were dissimilar to those found previously in Japanese patients with apical hypertrophy.     

Apical hypertrophic cardiomyopathy: clinical follow-up and diagnostic correlates

To determine the clinical course of apical hypertrophic cardiomyopathy, 26 patients (mean age 45 years) with asymmetric apical hypertrophy diagnosed by echocardiography or angiography were followed up for an average of 7.3 years (range 1 to 22). Presenting symptoms included atypical chest pain (n = 10), typical angina (n = 6), dyspnea (n = 5) and palpitation (n = 8). Ten patients were asymptomatic. At follow-up all patients had inverted precordial T waves, and 14 had the syndrome of "giant T wave negativity" (greater than or equal to 10 mm). In six patients with electrocardiographic follow-up of greater than 10 years (mean 13.4), precordial T wave inversion had progressed from -0.8 +/- 3.9 to -11.2 +/- 8.0 mm in lead V4 in association with increased QRS amplitude. Episodic atrial fibrillation occurred in 4 of 10 patients with echocardiographic left atrial enlargement. Although left ventricular systolic function was normal, diastolic relaxation was impaired in comparison with values in 10 healthy control subjects: in all 18 patients studied peak filling rate was decreased (4.44 +/- 0.44 versus 6.13 +/- 1.54 stroke volumes/s); time to peak filling was increased (174 +/- 40 versus 147 +/- 32 ms); and atrial systolic contribution to ventricular end-diastolic volume was increased (21.5 +/- 6.8 versus 11.5 +/- 4.6 stroke volume %). During follow-up, 21 of the 26 patients remained in stable condition or were asymptomatic. One patient with normal coronary arteries had an apical myocardial infarction with development of a discrete apical aneurysm and loss of "giant T wave negativity." This patient was the only one to have documented life-threatening ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)     

Apical hypertrophic cardiomyopathy in association with Takayasu's arteritis

We describe an interesting case of a patient who had Takayasu's arteritis and apical hypertrophic cardiomyopathy. Electrocardiogram, and transthoracic and transesophageal echocardiograms showed classical features of apical hypertrophic cardiomyopathy which is particularly uncommon outside Japan. To the best of our knowledge, the presence of apical hypertrophic cardiomyopathy in patients with Takayasu's arteritis has not been reported till date.