Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping

OBJECTIVES: Few studies have evaluated cardiac electrical activation dynamics after cardiac resynchronization therapy. Although this procedure reduces morbidity and mortality in heart failure patients, many approaches attempting to identify the responders have shown that 30% of patients do not attain clinical or functional improvement. This study sought to quantify and characterize the effect of resynchronization therapy on the ventricular electrical activation of patients using body surface potential mapping, a noninvasive tool. METHODS: This retrospective study included 91 resynchronization patients with a mean age of 61 years, left ventricle ejection fraction of 28%, mean QRS duration of 182 ms, and functional class III/IV (78%/22%); the patients underwent 87-lead body surface mapping with the resynchronization device on and off. Thirty-six patients were excluded. Body surface isochronal maps produced 87 maximal/mean global ventricular activation times with three regions identified. The regional activation times for right and left ventricles and their inter-regional right-to-left ventricle gradients were calculated from these results and analyzed. The Mann-Whitney U-test and Kruskall-Wallis test were used for comparisons, with the level of significance set at p≤0.05. RESULTS: During intrinsic rhythms, regional ventricular activation times were significantly different (54.5 ms vs. 95.9 ms in the right and left ventricle regions, respectively). Regarding cardiac resynchronization, the maximal global value was significantly reduced (138 ms to 131 ms), and a downward variation of 19.4% in regional-left and an upward variation of 44.8% in regional-right ventricular activation times resulted in a significantly reduced inter-regional gradient (43.8 ms to 17 ms). CONCLUSIONS: Body surface potential mapping in resynchronization patients yielded electrical ventricular ...

The Effect of Coronary Stenting on Ventricular Activation Time in Coronary Artery Disease

BACKGROUND AND OBJECTIVES: The ventricular activation time (VAT) is increased in both ventricular hypertrophy and bundle branch block. It is also known that the VAT is increased in myocardial ischemia due to the development of depolarization abnormality. However, little is known about the changes in the VAT on body surface electrocardiography following coronary stenting in patients with ischemic heart disease. The purpose of this study was to evaluate the clinical significance of VAT following coronary stenting by assessing the changes in the VAT during the 6 months following coronary stenting in patients with ischemic heart disease. SUBJECTS AND METHODS: The VAT was measured in 92 patients who had underdone coronary stenting due to of significant coronary artery stenosis on coronary angiography. The electrocardiography was recorded with a high paper speed at pre-stenting, immediate after and at 1 and 6 months after coronary stenting. RESULTS: The VAT was significantly decreased during the 6 month follow-up following coronary stenting (pre-stenting ; 45.9 +/-5.9 msec, immediate after stenting ; 38.5+/-2.7 msec, after 1 month ; 38.8+/-2.8 msec and after 6 months ; 38.8+/-2.5 msec, p<0.05). The VAT dispersion was significantly decreased during the 6 month follow-up following coronary stenting in the patients with one vessel disease (p<0.05), but not with two vessels disease. CONCLUSION: Coronary stenting significantly decreased the VAT during the 6 month follow-up. We would conclude that coronary stenting relieves depolarization abnormalities caused by myocardial ischemia, and improves the intraventricular conduction velocity. However, further studies are needed to assess the usefulness of VAT in evaluating myocardial ischemia.