Emerging Role of Three‐Dimensional Speckle Tracking Strain for Accurate Quantification of Left Ventricular Dyssynchrony

A case was 53‐year‐old female with dilated‐phase hypertrophic cardiomyopathy. She was classified as New York Heart Association functional class III heart failure despite receiving optimal medical therapy. The electrocardiogram taken showed intraventricular conduction delay with a QRS width of 194 msec. The left ventricular (LV) end‐diastolic and systolic volumes, and ejection fraction (EF) were 101 mL, 68 mL, and 32%, respectively. The patient showed no significant mechanical LV dyssynchrony as evidenced by two‐dimensional (2D) speckle tracking radial strain, which is defined as the time difference between anterior‐septum and posterior wall, of 105 msec (