Dependency of Cardiac Resynchronization Therapy on Myocardial Viability at the LV Lead Position

OBJECTIVES: This study sought to analyze the effectiveness of cardiac resynchronization therapy (CRT) related to the viability in the segment of left ventricular (LV) lead position defined by myocardial deformation imaging. Echocardiographic myocardial deformation analysis allows determination of LV lead position as well as extent of myocardial viability.

METHODS: Myocardial deformation imaging based on tracking of acoustic markers within 2-dimensional echo images (GE Ultrasound, GE Healthcare, Horton, Norway) was performed in 65 heart failure patients (54 ± 6 years of age, 41 men) before and 12 months after CRT implantation. In a 16-segment model, the LV lead position was defined based on the segmental strain curve with earliest peak strain, whereas the CRT system was programmed to pure LV pacing. Non-viability of a segment (transmural scar formation) was assumed if the peak systolic circumferential strain was >-11.1%.

RESULTS: In 47 patients, the LV lead was placed in a viable segment, and in 18 patients, it was placed in a nonviable segment. At 12-month follow-up there was greater decrease of LV end-diastolic volumes (58 ± 13 ml vs. 44 ± 12 ml, p = 0.0388) and greater increase of LV ejection fraction (11 ± 4% vs. 5 ± 4%, p = 0.0343) and peak oxygen consumption (2.5 ± 0.9 ml/kg/min vs. 1.7 ± 1.1 ml/kg/min, p = 0.0465) in the viable compared with the nonviable group. The change in LV ejection fraction and the reduction in LV end-diastolic volumes at follow-up correlated to an increasing peak systolic circumferential strain in the segment of the LV pacing lead (r = 0.61, p = 0.0274 and r = 0.64, p = 0.0412, respectively). Considering only patients with ischemic heart disease, differences between viable and nonviable LV lead position group were even greater.

CONCLUSIONS: Preserved viability in the segment of the CRT LV lead position results in greater LV reverse remodeling and functional benefit at 12-month follow-up. Deformation imaging allows analysis of viability in the LV lead segment. 

PMID: 21492811

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One Comment

  1. Well designed study with really interesting results!

    The authors sought to determine CRT effectiveness related to the viability of the segment with the LV lead position as well as the area surrounding the LV lead segment. Viability was defined by analysis of myocardial deformation.

    It would be interesting to see how viability as assessed by MRI could be used to guide LV lead positioning.

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