Inducibility of ventricular arrhythmias is related with impaired hyperaemic myocardial blood flow assessed with [15O]H2O PET in patients with ischaemic cardiomyopathy

Abstract

Purpose: Prediction of ventricular arrhythmias (VA) is important to refine selection criteria for implantable cardioverter defibrillator (ICD) therapy in patients with ischaemic cardiomyopathy (ICMP). Cardiac positron emission tomography (PET) allows for absolute quantification of myocardial blood flow (MBF) and is increasingly available in clinical practice. Hyperaemic MBF has been demonstrated to predict cardiac death in ischaemic and non-ischaemic cardiomyopathy. However, data on the relationship with VA are lacking. The aim of this study was to assess whether hyperaemic MBF impairment is related with the inducibility of VA in patients with ICMP. Methods: Patients with ICM who were referred for ICD implantation for primary prevention based on current guidelines were included. They underwent [15O]H2O PET assessment of global MBF under both resting and hyperaemic conditions. After implantation, according to standard procedure, the ICD was used to perform an electrophysiological study (EPS) to test the inducibility of VA. EPS was considered positive in case of sustained VA. Results: Twenty-eight patients were included (24 men, age 67±9 years, LVEF 28±7%). Patients (n=10) with positive EPS had significantly reduced global hyperaemic MBF and coronary flow reserve (CFR) compared with EPS negative patients (1.19±0.28 vs. 1.58±0.35 ml/min/g, p<0.01 and 1.55±0.34 vs. 2.05±0.46, p<0.01, respectively). No significant differences were found in age, sex, LVEF, creatinine, NT-proBNP, NYHA class and resting MBF. ROC-curve analysis demonstrated that hyperaemic MBF (AUC 0.82, 95% CI 0.66-0.99, p<0.01) and CFR (AUC 0.80, 95% CI 0.63-0.97, p=0.01) were predictors for VA inducibility. Univariate analysis revealed that hyperaemic MBF (p=0.02) and CFR (p=0.02) were the only variables significantly associated with a positive EPS. Conclusion: Impaired global hyperaemic MBF and CFR predict inducibility of VA in patients with ICMP. These results suggest that impaired hyperaemic MBF might contribute to electrical instability. Risk stratification for VA might be enhanced by quantitative [15O]H2O PET MBF assessment in ICMP patients.