Long-term outcome in patients with apical hypertrophic cardiomyopathy

Long-Term Outcomes of Patients With Apical Hypertrophic Cardiomyopathy Utilizing a New Risk Score

Background

Apical hypertrophic cardiomyopathy (aHCM) is a distinct variant characterized by predominant hypertrophy of the left ventricle apex.

Objectives

This study sought to describe aHCM patients' characteristics and develop a risk score for aHCM patients.

Methods

A total of 462 patients (age 58 ± 15 years, 68% male) diagnosed with aHCM were included. The primary endpoint was death, appropriate defibrillator discharge, or need for cardiac transplantation. Variables showing potential association with the composite endpoint were considered to develop an aHCM-specific risk score.

Results

At baseline, 67% patients were asymptomatic and 69% had no risk factors for sudden death. On echocardiography, the mean left ventricle ejection fraction, left atrial volume index, and right ventricular systolic pressure were 64% ± 8%, 36 ± 15 ml/m2, and 32 ± 10 mm Hg, respectively, with 51(11%) demonstrating an apical aneurysm. Baseline cardiac magnetic resonance, performed in 246 (53%) patients, demonstrated delayed gadolinium enhancement in 170 (71%) patients (mean percentage of 4.9% ± 6.6%). At age 6.3 ± 4.8 years, the composite events occurred in 80 (17%, death in 62 [13%]) patients. The aHCM-specific risk score, incorporating age, apical aneurysm, left atrial volume index, serum creatinine, and right ventricular systolic pressure, demonstrated good discrimination (C-statistic = 0.75) with an expected to observed ratio of 1.02 and a calibration slope of 0.91. The risk score ranged between 0 and 8 points, with a higher score associated with higher composite events.

Conclusions

aHCM constituted 6.8% of our overall HCM cohort with a composite event rate of 2.8%/year. The aHCM risk score provided good discrimination in predicting the composite primary endpoint, with a higher score associated with a higher rate of events.

Clinical, echocardiographic and cardiac MRI predictors of outcomes in patients with apical hypertrophic cardiomyopathy

Recent studies have found that some adverse cardiovascular events could also occur in patients with apical hypertrophic cardiomyopathy (ApHCM), which is different with previous studies suggesting benign nature of this condition. Therefore, the present study aimed to observe the clinical prognosis of ApHCM and to identify the predictors of poor prognosis in clinical, echocardiography and cardiac magnetic resonance (CMR). A total of 126 ApHCM patients with both echocardiography and CMR were identified retrospectively from January 2008 to December 2018. Adverse clinical events were defined as a composite of cardiac death, progressive heart failure, myocardial infarction, thromboembolic stroke, appropriate implantable cardioverter-defibrillator (ICD) interventions for ventricular tachycardia or ventricular fibrillation, and new-onset atrial fibrillation (AF). During a mean follow-up of 96.8 ± 36.0 months, clinical events were observed in 34 (27.0%) patients. As compared with patients without clinical events, patients with clinical events were older and had a higher incidence of heart failure. Moreover, patients with clinical events had a higher incidence of non-sustained ventricular tachycardia (NSVT) and had larger left atrial volume index (LAVI), thicker apical thickness, lower peak systolic mitral annular velocity (S') than those without clinical events. In addition, late gadolinium enhancement (LGE) in CMR were more frequently observed in patients with clinical events. Five predictors of poor prognosis were identified: age ≥ 55 years, LAVI ≥ 36.7 ml/m², S' ≤ 6.7 cm/s, NSVT and LGE. ApHCM was not as benign as expected. Age ≥ 55 years, LAVI ≥ 36.7 ml/m², S' ≤ 6.7 cm/s along with NSVT and LGE were independent predictors for poor prognosis of ApHCM.

Comprehensive left ventricular outflow tract management beyond septal reduction to relieve obstruction

The surgical management of patients with hypertrophic obstructive cardiomyopathy can be extremely challenging. Relieving the left ventricular outflow tract obstruction in these patients is often achieved by performing a septal myectomy. However, in many instances, septal reduction alone is not enough to relieve the obstruction. Interventions on the sub-valvular apparatus, including the anomalous chordae tendineae and the abnormal papillary muscles, are often required. In this review, we summarize the embryology and the pathophysiology of the different elements that may contribute to the left ventricular outflow tract obstruction in the setting of hypertrophic obstructive cardiomyopathy. In addition, we highlight the different surgical procedures that a surgeon may adopt to relieve the left ventricular outflow tract obstruction, beyond the septal myectomy.

Apical Hypertrophic Cardiomyopathy: A Case Report

Apical hypertrophic cardiomyopathy (ApHCM) is a rare variant of hypertrophic cardiomyopathy, characterized by a spade-like left ventricular cavity. A 58-year-old African-American female with past medical history of hypertension presented for evaluation of recurrent exertional chest tightness, palpitations and headache. Prior workup including multiple stress tests and angiogram was non-conclusive. Electrocardiogram (EKG) showed characteristic marked T-waves inversions in inferior leads and left ventriculography revealed left ventricle apical hypertrophy with spade like left ventricular cavity that was typical of Yamaguchi syndrome. This case highlights the rare incidence of the disease among African American as well as the challenging diagnostic and presentation features of the disease.

Risk of death in long-term follow-up of patients with apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (HC) has been considered a "benign" form of HC, with limited data on long-term outcome. We compared apical HC patients with a non-HC, age- and gender-matched Minnesota white population to identify outcomes and prognostic factors. Between 1976 and 2006, 193 patients (62% men) with apical HC were seen at our clinic. Their most recent echocardiographic examinations were reviewed. Mean ± SD age at first presentation was 58 ± 17 years. A family history of HC or sudden cardiac death (SCD) was reported by 43 patients (22%); coronary artery disease was known in 22 (11%). An apical pouch was present in 29 patients, including an apical aneurysm in 6 and apical dilatation with hypokinesis in 23. Median follow-up (187 patients [97%]) was 78 months (range, 1-350). Death from all causes occurred in 55 patients (29%; 33 women) at a mean age of 72 years (range, 20-92). During follow-up, more women had heart failure (p = 0.001), atrial fibrillation (p = 0.009), or died (p <0.001) than men. Survival was worse than expected (p = 0.001); the observed versus expected 20-year survival was 47% versus 60%. SCD, resuscitated cardiac arrest, and/or defibrillator discharge was observed in 11 patients (6%) during follow-up. Multivariate predictors of decreased survival were higher age at baseline (p <0.001), female gender (p <0.001), and atrial fibrillation at baseline (p = 0.06). In conclusion, apical HC in this population was associated with increased mortality, especially in women. Because apical HC is less benign than previously suspected, careful longitudinal care is warranted.

Pseudonormalization of negative T wave during stress test in asymptomatic patients without ischemic heart disease: a clue to apical hypertrophic cardiomyopathy?

INTRODUCTION

Generally, apical hypertrophic cardiomyopathy (ApHCM) shows a negative T wave on an electrocardiogram (ECG), which waxes and wanes during the clinical course. However, some patients with ApHCM just have negative T waves and show no obvious diagnostic evidence on their echocardiography, so the diagnosis of ApHCM cannot be confirmed or is delayed for several years in many cases.

CASE REPORT

In our study, 2 males in their 50s showed negative T waves on their ECG precordial leads, but no diagnosis was confirmed for over 10 years, despite all efforts. Both patients showed pseudonormalization of the negative T wave during a stress test using a treadmill and dobutamine. They were finally diagnosed with ApHCM confirmed by cardiac magnetic resonance (MR).

DISCUSSION

Pseudonormalization of the negative T wave during a stress test is a quite rare phenomenon, particularly in the general population, and cardiac MR is very costly and inaccessible. Thus, when such an ECG pattern is observed without evidence of other pathology, the possibility of ApHCM should be kept in mind and the performance of cardiac MR may be considered. Furthermore, this pseudonormalization pattern could also be one possible explanation for the waxing and waning of the negative T wave during the course of ApHCM.

Severe symptoms in mid and apical hypertrophic cardiomyopathy

BACKGROUND

We analyzed the clinical and quantitative echocardiographic characteristics of patients with sub-basal hypertrophic cardiomyopathy (HCM) to define the characteristics of patients (pts) with severe symptoms.

METHODS

Of 444 pts in a referral-based HCM program, 22 (5%) had midventricular or apical HCM. Quality of life (QoL) questionnaire was administered as an independent confirmer of symptomatic state.

RESULTS

Ten pts were NYHA III and IV, and 12 pts were NYHA I and II; QoL scores (41 +/- 26 vs. 10 +/- 13, P = 0.001) confirmed a priori division of two groups based on NYHA classification. Pts with more severe symptoms were more likely female (70% vs. 25%, P = 0.001) with atrial fibrillation (40% vs. 0%, P = 0.02). They more frequently had midventricular HCM 60% versus 8% (P = 0.01) (mid-LV thickness 17 +/- 6 vs. 12 +/- 2 mm, P = 0.03) and had much smaller LV diastolic volumes 68 +/- 12 versus 102 +/- 22 ml (39 +/- 4 vs. 53 +/- 12 ml/m(2), P = 0.001). Septal E/E' was higher in the severely symptomatic pts (15 +/- 5 vs. 7 +/- 3, P = 0.001) indicating higher estimated LV filling pressure. Midobstruction with apical akinetic chamber was noted in 4/10 pts who developed refractory symptoms. Cardiac mortality was higher in the severely symptomatic patients, 4/10 who had midventricular HCM as compared to 0/12 in the mildly symptomatic apical HCM group (P = 0.03).

CONCLUSIONS

In subbasal HCM, pts with severe symptoms have midventricular hypertrophy, with encroachment of the LV cavity and consequent very small LV volumes that may be complicated by mid-LV obstruction. Pts with mid-LV hypertrophy are more symptomatic than those with apical HCM, are often refractory to therapy, and have higher mortality.