Background: The prevalence, clinical characteristics and natural history of patients with hypertrophic cardiomyopathy (HCM) and midventricular obstruction (MVO) have not been adequately studied. Methods and Results: A single-center cohort consisting of 423 patients (mean age, 49.3±17.2 years; 66.2% male) was thoroughly followed up for a median of 84 months (7 years; range, 6–480 months). MVO, characterized by the echocardiographic appearance of midventricular muscular apposition with a simultaneous mid-cavitary gradient ≥30mmHg, was identified in 34 patients (8%). Patients with MVO tended to be more symptomatic during their initial evaluation (>90% presented with NYHA class ≥II) compared to the rest of the HCM cohort. Apical aneurysm formation was identified in more than one-fourth of patients with MVO (26.5%), being a characteristic of the group. On multivariate Cox regression hazard analysis, presence of MVO strongly predicted progression to end-stage (burnt out) HCM and related heart failure (HF) deaths (hazard ratio, [HR], 2.62; 95% confidence interval [CI]: 1.2–8.8; P=0.047), as well as sudden death and associated lethal arrhythmic events (HR, 3.3; 95% CI: 1.26–8.85; P=0.016). Conclusions: MVO is a distinct phenotype of HCM associated with unfavorable prognosis in terms of end-stage HCM, sudden death and lethal arrhythmic events. The high adverse outcome rate necessitates early recognition of MVO and appropriate therapeutic interventions. (Circ J 2013; 77: 2366–2374)

Despite the fact that the role of left ventricular diastolic dysfunction in hypertrophic cardiomyopathy (HCM) patients' prognosis has been established, the effect of increased right ventricular (RV) diastolic filling pressures still remains unclear. The purpose of this study was to determine the prognostic significance of transthoracic echocardiographic indices of RV diastolic function (tricuspid inflow and tricuspid annulus tissue Doppler imaging) in HCM patients. We followed up 386 patients diagnosed with HCM (aged 49.3 ± 17.2 years; 65% male) for a median period of 67 months (interquartile range 26–189 months). Primary endpoints were considered mortality due to heart failure (HF) (13 patients) and total cardiovascular (TC) mortality [HF, sudden cardiac death and its equivalents (35 patients)]. Patients presenting with an increased RV E/E_r ratio (ratio of tricuspid in flow E wave to E_r wave obtained by tissue Doppler imaging at the lateral tricuspid annulus) had a 1.6 times greater risk for HF mortality [hazard ratio (HR): 1.6, 95% confidence interval (CI): 1.1–2.4, P = 0.03] while patients with shortened tricuspid E wave deceleration time (DTE) had a 1.1 greater risk for SCD (HR: 1.1, 95% CI: 1.01–1.2, P = 0.03). Following ROC analysis, the optimal RV indices' cut-off values for the recognition of our study endpoints were assessed [E/E_r = 6.88, sensitivity 75%, specificity 77.4%, area under curve (AUC) 0.847, P = 0.017 for HF mortality and DTE < 239 ms, sensitivity 62.5%, specificity 56.7%, AUC 0.642, P = 0.05 for TC mortality]. The establishment of RV restrictive physiology appears to have significant predictive value in HCM, regardless of the presence of other detrimental risk factors.

Aims: We aimed at directly comparing three-dimensional (3D) and two-dimensional (2D) deformation parameters in hypertrophic hearts and depict which may best reflect underlying fibrosis in hypertrophic cardiomyopathy (HCM), defined by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR). Methods and results: We included 40 HCM [54.1 ± 14.3 years, 82.5% male, maximum wall thickness (MWT) 19.3 ± 4.8 mm] and 15 hypertensive (HTN) patients showing myocardial hypertrophy (58.1 ± 15.6 years, 80% male, MWT 12.8 ± 1.4 mm) who have consecutively undergone 2D-, 3D-speckle tracking echocardiography and LGE CMR. Deformation parameters (2D and 3D) presented overall poor to moderate correlations, with 3D_longitudinal strain (LS) and 3D_circumferential strain (CS) values being constantly higher compared to 2D derivatives. By regression analysis, hypertrophy substrate (HCM vs. hypertension) and hypertrophy magnitude were the parameters to influence 2D–3D LS and CS strain correlations (R2 = 0.66, P < 0.001 and R2 = 0.5, P = 0.001 accordingly). Among segmental deformation indices, 2D_LS showed the best area under the curve [AUC = 0.78, 95% confidence intervals (CI) (0.75–0.81), P < 0.0005] to detect fibrosis, with 3D deformation parameters showing similar AUC (0.65) and 3D_LS presenting the highest specificity [93.1%, 95% CI (90.6–95.1)]. Conclusions: In hypertrophic hearts, 2D and 3D deformation parameters are not interchangeable, showing modest correlations. Thickness, substrate, and tracking algorithm calculating assumptions seem to induce this variability. Nevertheless, among HCM patients 2D_peak segmental longitudinal strain remains the best strain parameter for tissue characterization and fibrosis detection.