Mechanical contraction to guide CRT left-ventricular lead placement instead of electrical activation in myocardial infarction with left ventricular dysfunction: An experimental study based on non-invasive gated myocardial perfusion imaging and invasive electroanatomic mapping
Whether the region of the latest electrical activation (LEA) corresponds with the segment of the latest mechanical contraction (LMC) in ischemic cardiomyopathy (ICM) is uncertain. We aimed to investigate the relationship between the left-ventricular (LV) viable segments with LEA and with LMC after myocardial infarction (MI) and analyze the acute hemodynamic responses (dP/dtmax) after cardiac resynchronization therapy (CRT) pacing at different LV sites.
Methods and results
Bama suckling pigs (n = 6) were subjected to create MI models. Both gated myocardial perfusion imaging (GMPI) and electroanatomic mapping (EAM) were performed successfully before MI and 4 weeks after MI. LMC was assessed by phase analysis of GMPI, while LEA was evaluated by EAM. The dP/dtmax was measured before CRT and when the CRT LV electrode was implanted in viable segments of LMC, viable segments of lateral wall and scar, respectively. The viable segments of LEA were consistent with the sites of LMC for five in six cases. The dP/dtmax increased significantly compared with that before CRT when the CRT LV electrode was implanted in viable segments of LMC (1103.33 ± 195.76 vs 717.83 ± 80.74 mmHg·s−1, P = .001), which was also significantly higher than in viable segments of lateral wall (751.17 ± 105.62 mmHg·s−1, P = .000) and scar (679.50 ± 60.87 mmHg·s−1, P = .001).
Non-invasive GMPI may be a better option than invasive EAM for guiding LV electrode implantation for CRT in ICM.
KeywordsCardiac resynchronization therapy gated SPECT dyssynchrony myocardial infarction latest mechanical contraction
Cardiac resynchronization therapy
Left ventricular mechanical dyssynchrony
Latest electrical activation
Gated myocardial perfusion imaging
Left ventricular electrical dyssynchrony
Single photon emission computed tomography
The project was supported by the National Natural Science Foundation of China (81471690, PI: Yuetao Wang), Youth Science Fund Project of National Natural Science Foundation of China (81701737, PI: Jianfeng Wang; 81701734, PI: Xiaoliang Shao), Jiangsu Province Science and Technology Program-Project of Standardized Diagnosis and Treatment of Key Diseases (BE2015635, PI: Yuetao Wang), and Key Project of Changzhou Municipal Health Bureau (ZD201409, PI: Xiaosong Wang). It was also supported by a Grant from the American Heart Association (17AIREA33700016, PI: Weihua Zhou).
The authors declare that they have no conflict of interest.
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