Posterior Wall Thickness Associates With Survival Following Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy

Cardiac Elastography With External Vibration for Quantification of Diastolic Myocardial Stiffness

OBJECTIVES

Heart failure is an increasing global health problem. Approximately 50% of patients with heart failure have heart failure with preserved ejection fraction (HFpEF) and concomitant diastolic dysfunction (DD), in part caused by increased myocardial stiffness not detectable by standard echocardiography. While elastography can map tissue stiffness, cardiac applications are currently limited, especially in patients with a higher body mass index. Therefore, we developed cardiac time-harmonic elastography (THE) to detect abnormal diastolic myocardial stiffness associated with DD.

MATERIAL AND METHODS

Cardiac THE was developed using standard medical ultrasound and continuous external vibration for regionally resolved mapping of diastolic shear wave speed as a proxy for myocardial stiffness. The method was prospectively applied to 54 healthy controls (26 women), 10 patients with moderate left ventricular hypertrophy (mLVH; 5 women), and 45 patients with wild-type transthyretin amyloidosis (wTTR; 4 women), 20 of whom were treated with tafamidis. Ten healthy participants were reinvestigated after 2 to 6 months to analyze test-retest reproducibility by intraclass correlation coefficients.

RESULTS

Myocardial shear wave speed was measured with good reproducibility (intraclass correlation coefficient = 0.82) and showed higher values in wTTR (3.0 ± 0.7 m/sec) than in mLVH (2.1 ± 0.6 m/sec) and healthy controls (1.8 ± 0.3 m/sec, all P < .05). Area under the curve values were 0.991 and 0.737 for discriminating wTTR and mLVH from healthy controls, respectively. Shear wave speed was reduced in patients after tafamidis treatment (2.6 ± 0.6 m/sec, P = .04), suggesting the potential value of THE for therapy monitoring. Shear wave speed was quantified in the septum, posterior wall, and an automatically masked region (here stated for the septal region).

CONCLUSIONS

Cardiac THE detects abnormal myocardial stiffness in patients with DD with high penetration depth, independent of body mass index and region selection. Based on standard ultrasound components, cardiac THE is cost-effective and has the potential to become a point-of-care method for stiffness-sensitive echocardiography.

Long-term clinical outcomes after alcohol septal ablation for hypertrophic obstructive cardiomyopathy in Japan: a retrospective study

Hypertrophic cardiomyopathy is characterized by significant left ventricular wall thickening, often leading to obstructive symptoms. Alcohol septal ablation (ASA) has emerged as an effective treatment for patients with hypertrophic obstructive cardiomyopathy (HOCM) who remain symptomatic despite maximal medical therapy. However, the detailed long-term effects of ASA in Japanese patients with HOCM remain unclear. Therefore, this study aimed to investigate the long-term effects of ASA for HOCM by evaluating changes in symptoms, pressure gradient, hemodynamics, prognosis, and predictive factors for cardiovascular events over time. In this retrospective study, we examined 239 highly symptomatic patients (age, 64 ± 13 years; median follow-up, 6.9 years) treated with ASA for drug-refractory HOCM between 1998 and 2021. Patients were assessed using transthoracic echocardiography, magnetic resonance imaging, and cardiac catheterization. Follow-up evaluations included clinical assessments, electrocardiography, and echocardiography. Data analysis included descriptive statistics, Kaplan-Meier analysis, and multivariate regression. ASA reduced the left ventricular outflow tract gradient from 90.5 ± 52.8 to 14.4 ± 17.1 mmHg (P < 0.01) and New York Heart Association (NYHA) class from 3 [2.5-3] to 1 [1-2] at 10 years after ASA (P < 0.01). The 30-day mortality rate following ASA was 1%. Overall, 31 patients (13%) died during the follow-up period. The survival rates at 1, 5, 10, and 15 years after ASA were 97.4%, 89.9%, 83.7%, and 77.6%, respectively. Multivariable analysis revealed NYHA functional class before ASA (odds ratio [OR], 3.09; 95% confidence interval [CI], 1.40-6.82; P = 0.005), beta-blocker use (OR, 0.25; 95% CI, 0.07-0.91; P = 0.036), and class Ia agent use (OR, 0.31; 95% CI, 0.13-0.75; P = 0.009) as independent predictors of all-cause mortality. This study demonstrated low periprocedural and long-term mortality rates following ASA in patients with HOCM, suggesting that ASA provides durable symptomatic relief and reduces left ventricular outflow tract obstruction in selected highly symptomatic patients with HOCM.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

The Prevalence and Association of Exercise Test Abnormalities With Sudden Cardiac Death and Transplant-Free Survival in Childhood Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) can be associated with an abnormal exercise response. In adults with HCM, abnormal results on exercise stress testing are predictive of heart failure outcomes. Our goal was to determine whether an abnormal exercise response is associated with adverse outcomes in pediatric patients with HCM.

METHODS

In an international cohort study including 20 centers, phenotype-positive patients with primary HCM who were <18 years of age at diagnosis were included. Abnormal exercise response was defined as a blunted blood pressure response and new or worsened ST- or T-wave segment changes or complex ventricular ectopy. Sudden cardiac death (SCD) events were defined as a composite of SCD and aborted sudden cardiac arrest. Using Kaplan-Meier survival, competing outcomes, and Cox regression analyses, we analyzed the association of abnormal exercise test results with transplant and SCD event-free survival.

RESULTS

Of 724 eligible patients, 630 underwent at least 1 exercise test. There were no major differences in clinical characteristics between those with or without an exercise test. The median age at exercise testing was 13.8 years (interquartile range, 4.7 years); 78% were male and 39% were receiving beta-blockers. A total of 175 (28%) had abnormal test results. Patients with abnormal test results had more severe septal hypertrophy, higher left atrial diameter z scores, higher resting left ventricular outflow tract gradient, and higher frequency of myectomy compared with participants with normal test results (P<0.05). Compared with normal test results, abnormal test results were independently associated with lower 5-year transplant-free survival (97% versus 88%, respectively; P=0.005). Patients with exercise-induced ischemia were most likely to experience all-cause death or transplant (hazard ratio, 4.86 [95% CI, 1.69-13.99]), followed by those with an abnormal blood pressure response (hazard ratio, 3.19 [95% CI, 1.32-7.71]). Exercise-induced ischemia was also independently associated with lower SCD event-free survival (hazard ratio, 3.32 [95% CI, 1.27-8.70]). Exercise-induced ectopy was not associated with survival.

CONCLUSIONS

Exercise abnormalities are common in childhood HCM. An abnormal exercise test result was independently associated with lower transplant-free survival, especially in those with an ischemic or abnormal blood pressure response with exercise. Exercise-induced ischemia was also independently associated with SCD events. These findings argue for routine exercise testing in childhood HCM as part of ongoing risk assessment.