Impact of Chronic Total Coronary Occlusion on Recurrence of Ventricular Arrhythmias in Ischemic Secondary Prevention Implantable Cardioverter-Defibrillator Recipients (VACTO Secondary Study): Insights From Coronary Angiogram and Electrogram Analysis.

OBJECTIVES: This study sought to evaluate the incidence and clinical effect of coronary chronic total occlusions (CTOs) in patients with ischemic cardiomyopathy receiving an implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac death (SCD). BACKGROUND: CTOs are common in patients with ischemic cardiomyopathy, which is the major cause of SCD. However, the impact of CTO in SCD survivors receiving an ICD is unknown. METHODS: A total of 425 patients who had survived an episode of ventricular arrhythmias and underwent ICD implantation for secondary prevention in 8 centers were included. Coronary angiogram, CTO angiographic characteristics, and ventricular arrhythmia pattern were centrally analyzed. Primary and secondary endpoints were appropriate ICD therapies and mortality during a median follow-up of 4.1 years, according to the presence of CTO in the baseline angiogram. RESULTS: Appropriate ICD therapies were higher in patients with CTO (51.7% vs. 36.3%; p = 0.001 at 4 years). Left ventricular ejection fraction (LVEF) (p = 0.015) and CTO (p = 0.001) were independent predictors of appropriate ICD therapy. Ventricular arrhythmia onset was associated to a shorter coupling interval and lower prematurity index in CTO patients. Defibrillator therapies were independently associated with worse LVEF (p = 0.046) and renal dysfunction (p = 0.023) among patients with CTO, and a tendency was observed in patients with better collateral flow (p = 0.093). Patients with poorer renal function (p = 0.029), LVEF (p = 0.041), and CTO (p = 0.033) experienced higher mortality rate. CONCLUSIONS: Among ICD recipients for secondary prevention of SCD, coronary CTO conferred a higher risk of VA recurrence and mortality in long-term follow-up. Angiographic and VA patterns could provide insights into the mechanisms of SCD and may have implications for the use of interventions designed to limit ICD shocks in this high-risk population.

Impact of a chronic total occlusion in an infarct-related artery on the long-term outcome of ventricular tachycardia ablation.

INTRODUCTION: In patients with a prior myocardial infarction (MI), angiographic predictors of ventricular tachycardia (VT) recurrence after ablation are lacking. Recently, a proarrhythmic effect of a chronic total occlusion (CTO) in a coronary artery has been suggested. METHODS AND RESULTS: A total of 191 patients with prior MI were referred to our Hospital between 2010 and June 2013 for a first ablation of VT. Of these, 84 patients (44%) with stable coronary artery disease that underwent a coronary angiography during the index hospitalization were included in this study. A CTO in an infarct-related artery (IRA-CTO) was present in 47 patients (56%). Patients with and without IRA-CTO did not differ in terms of comorbidities, severity of heart failure, presentation of VT or acute outcome of ablation, that was completely successful in 93% of cases. At electroanatomic mapping, IRA-CTO was associated with greater scar and especially with greater area of border zone (34 cm(2) vs. 19 cm(2) , P = 0.001). Median follow-up was 19 months (IQR 18). At follow-up, patients with IRA-CTO had a significantly higher rate of VT recurrence (47% vs. 16%, P = 0.003). At multivariate analysis, IRA-CTO resulted to be an independent predictor of VT recurrence after ablation (HR 4.05, P = 0.004). CONCLUSIONS: IRA-CTO is an independent predictor of VT recurrence after ablation and identifies a subgroup of patients with high recurrence rate despite a successful procedure. IRA-CTO is associated with greater scars and border zone area; however, this association does not completely justify its proarrhythmic effect.

Hyperbaric oxygenation applied immediately after coronary occlusion reduces myocardial necrosis and acute mortality in rats.

1. Because in ischaemia there is a critical lack of O2, it has been reasoned that increasing O2 delivery to the ischaemic myocardium could serve as adjunctive therapy for acute myocardial infarction (MI). Accordingly, in the present study, the effect of early hyperbaric oxygenation (HBO) on mortality and MI size after coronary occlusion was examined in rats. 2. After coronary occlusion, male Wistar rats were randomly assigned to receive either HBO for 1 h in a hyperbaric chamber (100% O(2) at 253 kPa; n = 106) or ambient O2 as the control (n = 111). The extent of myocardial necrosis was assessed (triphenyltetrazolium) immediately after treatment in the HBO (n = 50) and control (n = 47) groups. The remaining rats were evaluated 24 h after occlusion to enable calculation of MI size and mortality. 3. Immediately after therapy, the size of the MI was significantly greater in the control group compared with that in the HBO group (40 +/- 3 vs 27 +/- 2% of the left ventricle (LV), respectively; P < 0.001). The 24 h mortality of control rats was higher than that of HBO rats (34 vs 16%, respectively; P = 0.02). Control rats that survived 24 h had a larger MI than did HBO rats that survived 24 h (40 +/- 4 vs 29 +/- 3% of the LV, respectively; P = 0.005). Furthermore, large necrotic areas (> 40% of the LV) were more frequent in control than HBO rats (55 vs 27% of infarcted hearts, respectively; P = 0.01). There was less pulmonary congestion observed in HBO rats compared with control rats. 4. In conclusion, early therapy with HBO during the onset of an acute ischaemic event decreases the necrotic area and reduces acute mortality. These data support further investigation of HBO as an adjuvant therapy for acute MI.