Risk Stratification in Hypertrophic Cardiomyopathy: Is Two-Dimensional Echocardiographic Strain Ready for Prime Time?

Incremental value of left atrial active function measured by speckle tracking echocardiography in patients with hypertrophic cardiomyopathy

PURPOSE

Hypertrophic cardiomyopathy (HCM) impairs left ventricular (LV) diastolic function leading to left atrial (LA) dilatation. Because Doppler echocardiography cannot accurately assess LV diastolic function in hearts with heterogeneous hypertrophy, assessment of LA function might be useful for risk stratification of patients with HCM. This study aimed to elucidate the impact of LA function on outcome in patients with patients.

METHODS

Seventy-six patients with HCM who underwent echocardiographic and cardiac magnetic resonance imaging were retrospectively enrolled. Twenty-six control subjects were also included. Using speckle tracking echocardiography, LA function was divided into active and passive strain indices based on the timing of the second positive peak of LA strain rate that occurred during LV systole.

RESULTS

Left atrial strain indices of active and passive function were significantly impaired concomitantly with increased LA volume index in HCM patients compared with controls. During follow-up (2.6 ± 1.7 years), 14 patients with HCM developed cardiac events (heart failure hospitalization or atrial fibrillation). The association of LA active strain with cardiac events was independent of and incremental to clinical and echocardiographic parameters (age, gender, E/e', LV global longitudinal strain, and LA volume index) in sequential models. Cardiac events were more frequent in HCM patients with LA active strain <20.3% than with active strain ≥20.3% (P = .01).

CONCLUSION

Loss of LA active function was associated with increased cardiac events in patients with HCM.

Characterization of hypertrophic cardiomyopathy according to global, regional, and multi-layer longitudinal strain analysis, and prediction of sudden cardiac death

To evaluate the severity of hypertrophic cardiomyopathy (HCM) according to global, regional, and multi-layer longitudinal strain (LS) analysis using speckle-tracking echocardiography. From February 2007 to November 2014, we prospectively evaluated 375 consecutive HCM patients referred to our specialized cardiomyopathy center. Demographics, clinical, and rest and exercise echocardiographic parameters were collected according to a completely standardized protocol. Global, regional, and multilayer strain analyses were performed. Correlations between LS and other characteristics were evaluated, and we assessed their prognostic value to predict sudden cardiac death (SCD) or appropriate implantable cardioverter defibrillator (ICD) shocks during follow-up, using Cox proportional hazards analyses. We finally included 217 patients (50.1 ± 15.6 years, 67% male) but only 179 (82%) had LS analysis of sufficient quality. An inverse relation was observed between the mean basal left ventricular (LV) LS and diastolic parameters [E/Ea (r = - 0.30) and left atrium indexed volume (r = - 0.23)], as well as between the resting LV outflow-tract maximal gradient (r = - 0.26) or during peak exercise (r = - 0.20). Mean LS in the LV hypertrophic area was particularly related with maximal wall thickness (r = - 0.47) and transmural global LS with the degree of myocardial fibrosis in cardiac magnetic resonance (r = - 0.32). During a median follow-up of 2.8 ± 1.5 years, mean transmural LS in the hypertrophic area was predictor of SCD and appropriate ICD shock (10 events/179 patients, hazard ratio = 0.83 [95% CI 0.72-0.95], p = 0.01). Basal LS and hypertrophic area LS are valuable parameters to evaluate HCM severity. Mean hypertrophic area LS particularly seems predictive of SCD occurrence and appropriate ICD shocks.