The Incremental Value of Magnetic Resonance Imaging for Identification of Apical Pouch in Patients with Apical Variant of Hypertrophic Cardiomyopathy

High-risk imaging characteristics in left ventricular apex for the life-threatening arrhythmic events in Japanese hypertrophic cardiomyopathy patients

Left ventricular (LV) apical aneurysm is known to be associated with the life-threatening arrhythmic events in hypertrophic cardiomyopathy (HCM). However, the current 2014 ESC guideline has not included apical aneurysm as a major risk factor for sudden cardiac death and 2018 JCS guideline includes it only as a modulator, while it has been included as a new major risk marker in 2020 AHA/ACC guideline. Therefore, we sought to identify high-risk imaging characteristics in LV apex which is associated with a higher occurrence of ventricular tachycardia/fibrillation (VT/VF). In 99 consecutive Japanese HCM patients (median age, 65 years; 59 males) undergoing implantable cardioverter-defibrillator (ICD) implantation for primary prevention following cardiac magnetic resonance including late gadolinium enhancement (LGE), the occurrence of appropriate ICD interventions for VT/VF was evaluated for 6.2 (median) years after ICD implantation. Overall, appropriate ICD interventions occurred in 43% with annual rates of 7.0% for appropriate interventions. Kaplan-Meier analysis demonstrated that the presence of LV apical aneurysm was significantly associated with a higher occurrence of appropriate interventions (annual rates 18.9% vs. 6.4%, P = 0.013). Similarly, patients with high LV mid-to-apex pressure gradient (annual rates 14.9% vs. 6.2%, P = 0.022) and presence of apical LGE (annual rates 10.9% vs. 4.0%, P = 0.001) experienced appropriate interventions more frequently. An aneurysm, high-pressure gradient, and LGE in an apex are associated with VT/VF. These characteristics in apex should be kept in mind when implanting ICD in Japanese HCM patients as a primary prevention.

Multimodality imaging of hypertrophic cardiomyopathy

The diagnosis and management of hypertrophic cardiomyopathy (HCM) requires multimodality imaging. Transthoracic echocardiogram (TTE) remains the first-line imaging modality to diagnose HCM identifying morphology and obstruction, which includes left ventricular outflow obstruction, midcavitary obstruction and systolic anterior motion. Cardiac magnetic resonance imaging (CMR) can adjudicate equivocal cases, rule out alternative diagnoses and evaluate for risk factors of sudden cardiac death. Imaging with TTE or transesophageal echocardiogram can also guide alcohol septal ablation or surgical myectomy respectively. Furthermore, TTE can guide medical management of these patients by following peak gradients. Thus, multimodality imaging in HCM is crucial throughout the course of these patients' care.

Left ventricular morphologic progression in apical hypertrophic cardiomyopathy

BACKGROUND

Left ventricular (LV) morphologic progression in apical hypertrophic cardiomyopathy (AHC) has not been well studied. We evaluated serial echocardiographic changes in LV morphology.

METHODS

Serial echocardiograms in AHC patients were assessed. LV morphology was categorized according to the presence of an apical pouch or aneurysm, and LV hypertrophic severity and extent; relative, pure, and apical-mid type defined as mild (<15 mm thickness) apical hypertrophy, significant (≥15 mm) apical hypertrophy, and both apical and midventricular hypertrophy, respectively. Adverse clinical events and late gadolinium enhancement (LGE) extent on cardiac magnetic resonance were evaluated for each morphologic type.

RESULTS

In 41 patients, 165 echocardiograms (maximal interval: 4.2 [IQR, 2.3-11.8] years) were evaluated. Morphologic changes were observed in 19 (46%) patients. Eleven (27%) patients displayed the progression of LV hypertrophy toward pure or apical-mid type. Five (12%) and 6 (15%) patients developed new pouches and aneurysms. Patients with progression tended to be younger (50 ± 15.6 vs 59 ± 14.4 years, P = 0.058) and had a longer period of follow-up (12 [5-14] vs 3 [2-4] years, P < 0.001). During a follow-up of 7.6 (IQR 3.0-12.1) years, 21 (51%) experienced clinical events. The relative, pure, and apical-mid types showed different LGE extents (2%, 6%, and 19%, P = 0.004). Patients with severe hypertrophic and apical involvement showed higher clinical event rates.

CONCLUSIONS

About half of AHC patients had a progression of LV morphology to more hypertrophic involvement and/or an apical pouch or aneurysm formation. Advanced AHC morphologic types were associated with higher event rates and scar burdens.

Apical aneurysm formation in apical hypertrophic cardiomyopathy: Pilot study with cardiac magnetic resonance

BACKGROUND

The dynamic changes and apical aneurysm formation in apical hypertrophic cardiomyopathy (HCM) have not been specifically described. This study aimed to describe these changes to better understand the progression of apical HCM.

METHODS AND RESULTS

Seventy-two patients with apical HCM who underwent at least two cardiac magnetic resonance (CMR) examinations were retrospectively included in this study. The mean interval between the first and last CMR examinations was 50.1 ± 26.8 months (ranging from 4 to 118 months). Compared with the initial values, the left atrial diameter, maximum left ventricular wall thickness and late gadolinium enhancement extent significantly increased (all P < 0.05), while the left ventricular ejection fraction significantly decreased (P < 0.05), at the latest CMR examination. More importantly, the dynamic process of apical aneurysm formation in apical HCM was observed in a subset of patients, which may follow these four stages: starting with systolic apical cavity obliteration, then broadening of the apical slit in systole, further developing into an apical outpouching, and finally forming an apical aneurysm. Eleven patients experienced adverse cardiovascular events, including new-onset or progressive atrial fibrillation (n = 7), hospitalization with heart failure (n = 3) and implantable cardioverter defibrillator intervention (n = 1), at the time of the latest CMR examination.

CONCLUSIONS

In the progression of apical HCM, cardiac structure and function will change accordingly. Apical aneurysm formation in apical HCM is a chronic and continuous dynamic process that may follow a 4-step pathway of disease progression.

Different characteristics of apical aneurysm in hypertrophic cardiomyopathy are related to difference in long-term prognosis

BACKGROUND

Data regarding long-term cardiac and cerebrovascular adverse events in patients with hypertrophic cardiomyopathy (HCM) and apical aneurysm (AAn) are scarce and specific treatment strategies that include the use of anticoagulants have not yet been established. We aimed to evaluate the prevalence and long-term prognostic implication based on characteristics of AAn in patients with HCM.

METHODS

A total of 458 consecutive patients diagnosed with HCM underwent cardiovascular magnetic resonance imaging and echocardiography from August 1, 2008 to December 31, 2015. AAn was classified into Grade 1 and Grade 2 based on size and morphology. The patients were followed up for a median duration of 6.3 years (range, 4.2-8.7 years) for major adverse cardiac and cerebral events (MACCEs); a composite of cardiac death, HCM-related hospitalization, cerebrovascular accident (CVA), heart transplantation, myocardial infarction, and implantable cardiac defibrillator/cardiac resynchronization therapy.

RESULTS

AAn was detected in 9.2%. MACCEs developed more frequently in patients with AAn than in those without AAn (30.1% vs. 20.7%, P = 0.015), with the rate of CVA as the main difference (9.7% vs. 5.3%, P = 0.011). Grade 2 AAn group showed significantly higher MACCE than Grade 1 AAn group (41.8% vs. 21.9%, P < 0.001). In multivariate analysis, the presence of AAn was independently associated with increased risk of MACCEs (adjusted hazard ratio: 1.95; 95% confidence interval, CI: 1.16-3.28; P = 0.012).

CONCLUSIONS

AAn is independently associated with increased risk of HCM-related adverse events, especially cerebral infarction, with significant relationship between aneurysm size and adverse events.

Apical hypertrophic cardiomyopathy with left ventricular apical aneurysm: prevalence, cardiac magnetic resonance characteristics, and prognosis

Aims

Hypertrophic cardiomyopathy (HCM) with left ventricular apical aneurysm (LVAA) is associated with an increased risk of adverse cardiovascular events. However, the clinical significance of LVAA in apical HCM (ApHCM) has not been reported. This study aimed to investigate the prevalence, cardiac magnetic resonance (CMR) characteristics, and prognosis of LVAA in ApHCM patients.

Methods and results

A total of 1332 consecutive ApHCM patients confirmed by CMR in our hospital were retrospectively analysed. LVAAs were identified in 31 patients of all ApHCM patients (2.3%, 31/1332). Besides, 31 age- and gender-matched ApHCM patients without LVAA were used for comparison. Of the 31 aneurysm patients (mean age, 53.8 ± 15.1 years old), 28 (90.3%) had clinical symptoms, and 3 (9.7%) had a family history of HCM. The rate of missed diagnosis of echocardiography for detecting LVAA was 64.5% (20/31), most (90%, 18/20) of unidentified LVAAs by echocardiography were small aneurysms (&lt;20 mm). Compared with ApHCM patients without LVAA, the proportion of systolic mid-cavity obstruction and late gadolinium enhancement (LGE) presence, and the LGE extent in ApHCM patients with LVAA were significantly higher (all P&lt;0.05). The Kaplan–Meier curves showed that the event-free survival rate in ApHCM patients with LVAA was significantly lower than that in ApHCM patients without LVAA (log rank, P = 0.010).

Conclusion

ApHCM with LVAA is a very rare condition, which is often missed by echocardiography and could be reliably detected with CMR and is associated with a higher risk of adverse cardiovascular events compared with ApHCM without LVAA.

Call a Spade a Spade: Missed Diagnosis of Apical Hypertrophic Cardiomyopathy

Apical hypertrophic cardiomyopathy is a variant of hypertrophic cardiomyopathy characterized by apical hypertrophy, deep T-wave inversions in precordial electrocardiogram (EKG) leads, and a ventriculogram shaped like the "Ace of Spades." Patients are often asymptomatic but sometimes present with atypical chest pain, angina, or atrial fibrillation. The deep T-wave inversions on EKG often mimic acute coronary syndrome. Coronary angiogram in these patients is unrevealing, but the characteristic left ventriculogram establishes this diagnosis. The deep T-wave inversions can appear suddenly or deepen over years, making the diagnosis difficult to establish early in the disease. Transthoracic echocardiogram may miss the hypertrophied apex, but echo contrast imaging or cardiac magnetic resonance imaging can reliably confirm the diagnosis and detect apical aneurysms. We present a case of apical hypertrophic cardiomyopathy which was not evident despite many admissions, EKGs, cardiac catheterizations and echocardiograms until the diagnosis was confirmed with left ventriculogram and cardiac magnetic resonance imaging 20 years after initial presentation.

Hypertrophic Cardiomyopathy With Left Ventricular Apical Aneurysm: Implications for Risk Stratification and Management

BACKGROUND

A previously under-recognized subset of hypertrophic cardiomyopathy (HCM) patients with left ventricular (LV) apical aneurysms is being identified with increasing frequency. However, risks associated with this subgroup are unknown.

OBJECTIVES

The authors aimed to clarify clinical course and prognosis of a large cohort of HCM patients with LV apical aneurysms over long-term follow-up.

METHODS

The authors retrospectively analyzed 1,940 consecutive HCM patients at 2 centers, 93 of which (4.8%) were identified with LV apical aneurysms; mean age was 56 ± 13 years, and 69% were male.

RESULTS

Over 4.4 ± 3.2 years, 3 of the 93 patients with LV apical aneurysms (3%) died suddenly or of heart failure, but 22 (24%) survived with contemporary treatment interventions: 18 experienced appropriate implantable cardioverter-defibrillator discharges, 2 underwent heart transplants, and 2 were resuscitated after cardiac arrest. The sudden death (SD) event rate was 4.7%/year, which includes sudden death, successful resuscitation from cardiac arrest or appropriate ICD interventions triggered by VF or rapid VT. Notably, recurrent monomorphic ventricular tachycardia requiring ≥2 implantable cardioverter-defibrillator shocks occurred in 13 patients, including 6 who underwent successful radiofrequency ablation of the arrhythmic focus without ventricular tachycardia recurrence. Five non-anticoagulated patients experienced nonfatal thromboembolic events (1.1%/year), whereas 13 with apical clots and anticoagulation did not incur embolic events. There was no consistent relationship between aneurysm size and adverse HCM-related events. Rate of HCM-related deaths combined with life-saving aborted disease-related events was 6.4%/year, 3-fold greater than the 2.0%/year event rate in 1,847 HCM patients without aneurysms (p < 0.001).

CONCLUSIONS

HCM patients with LV apical aneurysms are at high risk for arrhythmic sudden death and thromboembolic events. Identification of this phenotype expands risk stratification and can lead to effective treatment interventions for potentially life-threatening complications.

Update on hypertrophic cardiomyopathy and a guide to the guidelines

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disorder, affecting 1 in 500 individuals worldwide. Existing epidemiological studies might have underestimated the prevalence of HCM, however, owing to limited inclusion of individuals with early, incomplete phenotypic expression. Clinical manifestations of HCM include diastolic dysfunction, left ventricular outflow tract obstruction, ischaemia, atrial fibrillation, abnormal vascular responses and, in 5% of patients, progression to a 'burnt-out' phase characterized by systolic impairment. Disease-related mortality is most often attributable to sudden cardiac death, heart failure, and embolic stroke. The majority of individuals with HCM, however, have normal or near-normal life expectancy, owing in part to contemporary management strategies including family screening, risk stratification, thromboembolic prophylaxis, and implantation of cardioverter-defibrillators. The clinical guidelines for HCM issued by the ACC Foundation/AHA and the ESC facilitate evaluation and management of the disease. In this Review, we aim to assist clinicians in navigating the guidelines by highlighting important updates, current gaps in knowledge, differences in the recommendations, and challenges in implementing them, including aids and pitfalls in clinical and pathological evaluation. We also discuss the advances in genetics, imaging, and molecular research that will underpin future developments in diagnosis and therapy for HCM.