U-shaped LV electrical activation in LBBB has been shown to predict favorable response to CRT. It is not known if the degree of electromechanical coupling is such that the same is true for LV contraction patterns.
A total of 52 patients (48 % ischemic) scheduled for CRT implantation prospectively underwent pre-implantation CMR cine analysis using endocardial contour tracking software to generate time?volume curves and contraction propagation maps. These were analyzed to assess the contraction sequence of the LV. The effect of contraction pattern on CRT response in terms of reverse remodeling (RR) and clinical parameters (New York Heart Association functional class, 6-min walk distance and Heart Failure Questionnaire score) was assessed at 6 months.
Two types of contraction pattern were identified; homogenous spread from septum to lateral wall (type I, n?= 27) and presence of block with a subsequent U-shaped contraction pattern (type II, n?= 25). Rates of RR in those with a type 2 pattern were significantly greater at 6 months (80 % vs. 26 % , p < 0.001) as was mean increase in 6-min walk distance (126 ¡À 106 m vs. 55 ¡À 60 m; p?= 0.004).
Cine CMR can identify a U-shaped pattern of contraction which predicts increased echocardiographic and clinical response rates to CRT in patients with LBBB.