Impact of recanalization of chronic total occlusion on left ventricular electrical remodeling

Abstract

BackgroundSuccessful percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is associated with reduction of cardiac mortality, as well as reducing fatal ventricular arrhythmias. The aim of this study was to evaluate the effect of recanalization of CTO on endocardial left ventricular voltages by paired electrophysiological studies.MethodsSixteen consecutive patients who underwent PCI for de novo CTO lesions were included. High‐density mapping was performed during sinus rhythm before and 8 months after PCI. According to the amplitude of bipolar electrograms, the left ventricular endocardium was classified into a preserved normal voltage (>1.5 mV), border zone (0.5–1.5 mV), and dense scar areas (<0.5 mV).ResultsThe border zone area had a significant positive correlation with CTO length, as well as a significant negative correlation observed in the preserved voltage region. In the successful PCI patient, the median dense scar area did not change significantly (reported as [median difference: 95% confidence interval]) between baseline and after PCI (0.1 cm2: –2.8 to 2.9). However, the area of the border zone decreased (–10.5 cm2: –16.8 to –4.1) and the preserved voltage area increased significantly (19.2 cm2: 7.7–30.6). In addition, successful PCI was related to slight, but significant, increase in the amplitude of unipolar and bipolar voltage (1.55 mV: 0.88–3.33, 0.23 mV: 0.08–0.36).ConclusionsRecanalization of CTO may promote reverse electrical remodeling in the border zone of the left ventricle, without affecting the dense scar tissue.

Revascularization of coronary chronic total occlusions in an infarct‐related artery and recurrence of ventricular arrhythmias among patients with secondary prevention implantable cardioverter defibrillator

“…Thus, it is legitimate to expect that the chronic ischemia associated with IRACTO might have an effect on scar remodeling and that, in turn, the recovery of normal coronary flow may impact this remodeling and the electrical properties of the scar. Emerging evidence would support this hypothesis: two independent research groups have performed electro‐anatomical mapping before and after percutaneous revascularization of an IRACTO in small series of patients and they have both observed a reduction in scar area after IRACTO revascularization 17,18 . Interestingly, a significant change in the electrical properties of the scar was already observed immediately after IRACTO revascularization and it further increased after 6 months 17 .…”

“…Given the observational nature of the study and the lack of wide band protocols to avoid ICD artifacts at cardiac magnetic resonance, non‐invasive evaluation of the scar before and after IRACTO revascularization was not performed, so the present study do not provide direct information about the possible process of scar remodeling after IRACTO revascularization. However, other reports suggest the existence of such remodeling 17,18 …”

“…3 Recently, patients with a first MI treated with primary percutaneous coronary intervention were examined with serial cardiac magnetic resonance scans up to 4 years after the MI: a progressive reduction in the scar size, together with an increase in scar heterogenicity, were observed, confirming that scar remodeling persists during years. 15 17,18 Interestingly, a significant change in the electrical properties of the scar was already observed immediately after IRACTO revascularization and it further increased after 6 months. 17 Of note, the positive effect of IRACTO revascularization was mainly concentrated in the border zone which usually harbors the critical VT isthmus.…”

Vulnerability for ventricular arrhythmias in patients with chronic coronary total occlusion

“…After CTO revascularization there is immediate decrease in scar border zone area. Furthermore, there is improvement of markers of heterogeneity of repolarization as reflected by QT dispersion [41,42]. It is known that heterogenous ventricular repolarization is associated with an increased risk for ischemia-related VA after myocardial infarction [43].…”

“…Interestingly, recent 3D electro-anatomically mapping studies demonstrated reduction of the area of the scar border zone after successful CTO PCI [42,62]. Yamashita et al performed high-density endocardial mapping during sinus rhythm before and 8 months after CTO PCI in 16 patients [42]. Thirteen patients had a successful CTO PCI and no restenosis; 3 patients had a failed CTO PCI or in-stent occlusion during follow-up.…”