The natural history of hypertrophic cardiomyopathy in a large Mediterranean cohort

Clinical Implications of Left Ventricular Apex Mechanics in Patients With Apical Hypertrophic Cardiomyopathy

BACKGROUND

Apical hypertrophic cardiomyopathy (ApHCM) is a unique disease with pathologic hypertrophy mainly at the left ventricular (LV) apex. Although previous studies have indicated apical dysfunction in ApHCM, how apical mechanics change during disease progression has not been thoroughly examined. The aims of this study were to characterize the mechanics of the LV apex in patients with ApHCM at different disease stages and to explore the clinical significance of these alterations.

METHODS

One hundred four patients with ApHCM were divided into three subtypes on the basis of LV apical maximum wall thickness (AMWT) and extent of hypertrophy: relative type (isolated apical hypertrophy with AMWT < 15 mm), pure type (isolated apical hypertrophy with AMWT ≥ 15 mm), and mixed type (both apical and midventricular hypertrophy with AMWT ≥ 15 mm). Two-dimensional speckle-tracking echocardiography was used to analyze LV segmental strain, global strain, and twist. Comparisons of these parameters were performed among ApHCM subtypes and 30 healthy control subjects. Logistic regression and Cox proportional-hazards regression analyses were used to explore associations between myocardial mechanics and clinical indicators. A composite outcome of new-onset atrial fibrillation, heart failure hospitalization, myectomy, and all-cause mortality was assessed.

RESULTS

Even in relative ApHCM patients, apical longitudinal strain (LS), circumferential strain, and radial strain (RS) were significantly impaired compared with control subjects (LS: -14.6 ± 4.1% vs -20.0 ± 1.7% [P = .001]; circumferential strain: -19.6 ± 2.5% vs -25.6 ± 3.7% [P = .002]; RS: 26.6 ±7.4% vs 35.6 ± 11.1% [P = .026]), while apical rotation and LV twist remained unchanged. In patients with greater apical hypertrophy (mixed and pure patients), apical LS and RS were more abnormal. Moreover, apical rotation showed significant reductions compared with relative-type patients. After adjusting for clinical and myocardial mechanical parameters, apical rotation was independently associated with New York Heart Association functional class ≥ II (odds ratio, 0.81; 95% CI, 0.66-0.99; P = .036) and the composite outcome (hazard ratio, 0.82; 95% CI, 0.73-0.91; P = .001).

CONCLUSIONS

Relative ApHCM demonstrates apical dysfunction but sparing of apical rotation, which was abnormal in more extensive phenotypes. LV apex mechanics were closely related to clinical patterns, with apical rotation correlated with both New York Heart Association functional class ≥ II and clinical events.

Validation of the new American College of Cardiology/American Heart Association Guidelines for the risk stratification of sudden cardiac death in a large Mediterranean cohort with Hypertrophic Cardiomyopathy

BACKGROUND

The aim of our study was to assess the performance of the new American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines, with respect to sudden cardiac death (SCD) prevention, in comparison with the established risk score of the European Society of Cardiology (hypertrophic cardiomyopathy [HCM] Risk-SCD), in a large Mediterranean cohort of HCM patients.

METHODS

The clinical and imaging characteristics of 784 HCM patients (mean age at first evaluation 52 ± 16 years, 67.2% males) were analyzed retrospectively. The sensitivity, specificity, and negative predictive value for SCD events of the presence of ≥1 risk factor for SCD according to the ACC/AHA Guidelines 2020 and of the HCM Risk-SCD≥6% and HCM Risk-SCD≥4% were estimated during follow-up.

RESULTS

During follow-up, 47 (6%) patients suffered an SCD event. The presence of ≥1 major risk factor for SCD according to the new ACC/AHA Guidelines had 96% sensitivity (95% CI 85.5-99.5%) with modest specificity of 59% (95% CI 55-62.2%) and negative predictive value of 99.5% (95% CI 98.2-99.9%). On the contrary, HCM- Risk-SCD≥6% had a relatively low sensitivity (32%, 95% CI 19.1-47.1%) and high specificity of 95% (95% CI 93.1-96.4%), whereas, HCM-Risk-SCD≥4% had sensitivity of 60% (95% CI 44-74%) and specificity of 83.9% (95% CI 80-85.6%). Both the HCM Risk-SCD cut-off values demonstrated lower negative predictive value but higher accuracy than the ACC/AHA algorithm for SCD prediction.

CONCLUSION

The novel ACC/AHA proposed algorithm identifies most of the patients with an SCD event with the cost of numerous defibrillator implantations. HCM-Risk-SCD demonstrated higher specificity, whereas its sensitivity and negative predictive value are modest.

A simple algorithm for a clinical step-by-step approach in the management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease with an autosomal dominant pattern and a reported prevalence of about 0.2%. In this review, we present a simple algorithm for the management of first diagnosed HCM patients. Initially, the clinical examination, medical and detailed family history and the ECG are essential. The etiological diagnosis of left ventricular hypertrophy is important in order to differentiate HCM due to sarcomeric genes mutation from other phenocopies, such as cardiac amyloidosis. The next step consists of the cardiovascular imaging and ambulatory electrocardiography. Cardiopulmonary exercise testing may also be considered if available. All of the above provide evidence for the critical step of the risk stratification of patients for sudden cardiac death. The therapeutic strategy, with respect to obstructive and nonobstructive disease, arrhythmias and end-stage HCM is also described.