Exercise testing after chronic total coronary occlusion revascularization in patients with STEMI and a concurrent CTO: A subanalysis of the EXPLORE‐trial

Abstract

Objectives To assess the effect of chronic total occlusion percutaneous coronary intervention (CTO PCI) on ventricular ectopy (VE) and symptomatology during exercise testing. Background During exercise, the hypoxic myocardium in the CTO‐territory can act as a substrate for VE and could lead to anginal complaints. Methods In the EXPLORE‐trial, 302 ST‐segment elevation myocardial infarction (STEMI)‐patients were randomized to CTO PCI or no‐CTO PCI. For this sub‐study, we analyzed all available exercise electrocardiograms (X‐ECGs) at 4 months follow‐up on symptoms and electrocardiographic parameters. Results A total of 155 X‐ECGs were available, 80 in the CTO PCI group (51.6%) and 75 in the no‐CTO PCI group (48.4%). There were no differences regarding exercised time, achieved endurance, ST‐deviation nor maximum heart‐rate. The percentage of patients experiencing chest‐pain during exercise was lower in the CTO PCI group (0% vs. 8.5%, p = .03). Also, there was a trend towards a higher maximum systolic blood pressure (SBP, 185 mmHg vs. 175, p = .09). No difference in VE was found between randomization groups, but patients with successful CTO PCI had a higher frequency of VE, compared to failed and no‐CTO PCI (26% vs. 8%, p = .02). This did not result in higher frequencies of sustained ventricular arrhythmias or mortality. Conclusion In conclusion, in STEMI‐patients, CTO PCI is associated with a small reduction of chest‐pain during exercise and tended to be associated with an increase of maximum SBP. The observation that successful CTO PCI was associated with more VE during exercise, compared with failed/no‐CTO PCI needs further exploration.

Predictors and outcomes of procedural failure of percutaneous coronary intervention of a chronic total occlusion—A subanalysis of the EXPLORE trial

“…26 Interestingly, a previous study has demonstrated higher rates of ventricular ectopy during exercise in patient who underwent SPCI compared to FPCI. 27 Thus, although previous research indicates an association between arrhythmogenesis and CTOs, the extent to which FPCI affects arrhythmogenesis remains hard to define.…”