Background-Mechanical dyssynchrony is a potential means to predict response to cardiac resynchronization therapy (CRT). We hypothesized that novel echocardiographic image speckle tracking can quantify dyssynchrony and predict response to CRT. Methods and Results-Seventy-four subjects were studied: 64 heart failure patients undergoing CRT (aged 64Ϯ12 years, ejection fraction 26Ϯ6%, QRS duration 157Ϯ28 ms) and 10 normal controls. Speckle tracking applied to routine midventricular short-axis images calculated radial strain from multiple circumferential points averaged to 6 standard segments. Dyssynchrony from timing of speckle-tracking peak radial strain was correlated with tissue Doppler measures in 47 subjects (rϭ0.94, PϽ0.001; 95% CI 0.90 to 0.96). The ability of baseline speckle-tracking radial dyssynchrony (time difference in peak septal wall-to-posterior wall strain Ն130 ms) to predict response to CRT was then tested. It predicted an immediate increase in stroke volume in 48 patients studied the day after CRT with 91% sensitivity and 75% specificity. In 50 patients with long-term follow-up 8Ϯ5 months after CRT, baseline speckle-tracking radial dyssynchrony predicted a significant increase in ejection fraction with 89% sensitivity and 83% specificity. Patients in whom left ventricular lead position was concordant with the site of latest mechanical activation by speckle-tracking radial strain had an increase in ejection fraction from baseline to a greater degree (10Ϯ5%) than patients with discordant lead position (6Ϯ5%; PϽ0.05). Conclusions-Speckle-tracking radial strain can quantify dyssynchrony and predict immediate and long-term response to CRT and has potential for clinical application.

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Native T1 exhibited comparable ability as ECV measurement in the detection and quantification of histological collagen volume fraction, with high reproducibility, and therefore diffuse myocardial fibrosis in DCM may be reliably assessed by native T1 mapping without the administration of gadolinium contrast agent. In addition, cardiac magnetic resonance-derived ECV showed excellent agreement with histological extracellular space.

Background: Abnormalities in right ventricular function are known to occur in patients with pulmonary arterial hypertension.

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This analysis provides a range of normal variables of RV size and function, not previously published, that can be used in routine evaluation and follow-up of patients with PH.