Introduction: Successful RF ablation of VT late after MI can involve multiple applications and long lines of RF lesions. The impact on left ventricular function is potentially important, but not well defined. Quantitative echocardiography was used to determine the effect of radiofrequency (RF) ablation on left ventricular function in patients with ventricular tachycardia (VT) after myocardial infarction (MI).
Methods and results: In 62 patients (55 men; age 67 +/- 1.1 yr.) who underwent RF ablation for VT late after MI, left ventricular ejection fraction (LVEF) was quantified from digitized echocardiograms performed </=1 week before and <72 hours after ablation. Patients received a mean of 25.6 +/- 2.2 (range of 3-98) RF lesions. The LVEF pre- and post-ablation did not differ for the group (pre-LVEF 29.8 +/- 11.9% vs. post-LVEF 29.5 +/- 11.2%, p = 0.626), or for the 30 patients who received >25 RF lesions (Pre-LVEF 28.5 +/- 11.1% vs. Post-LVEF 28.1 +/- 10.8%, p = 0.74) or for the 7 patients who received >40 RF lesions (Pre-LVEF 29.9 +/- 12.7% vs. Post-LVEF 29.2 +/- 6.2%, p = 0.84). Although LVEF did not change for the group, LVEF increased >5% in 12/62 (19.4%) pts and decreased >/=5% in 14/62 (22.5%) pts. Patients with a decrease in EF did not differ from the remaining patients with respect to age, gender, number of RF lesions, or use of a cooled RF catheter, but did have a better initial EF (38.8 +/- 12.2% versus 27.2 +/- 10.6%, p = 0.001).
Conclusion: Multiple RF ablation lesions confined to infarct regions do not measurably affect LV function, but a cautious approach, confining ablation lesions to areas of scar, as was attempted in this study, seems prudent.