Impaired Hyperemic Myocardial Blood Flow Is Associated With Inducibility of Ventricular Arrhythmia in Ischemic Cardiomyopathy

Abstract

O]H 2 O positron-emission tomography was performed to quantify resting MBF, hyperemic MBF, and coronary flow reserve. Left ventricular dimensions, function, and scar burden were assessed with cardiovascular magnetic resonance imaging. An electrophysiological study was performed to test VA inducibility. Positive electrophysiological study patients (n=12) showed reduced hyperemic MBF (1.25±0.30 versus 1.66±0.38 mL•min ; P<0.01) and coronary flow reserve (1.59±0.49 versus 2.12±0.48; P<0.01) compared with electrophysiological study negative patients (n=18). In electrophysiological study positive patients, the number of scar segments >75% transmurality was higher (P<0.05), although scar size and border zone did not differ. Receiver-operating characteristic curve analysis indicated that impaired hyperemic MBF (area under the curve, 0.84; 95% confidence intervals [0.69-0.99 arrhythmias are an important and common cause of death in these classifications of cardiomyopathy, suggesting that quantitative assessment of MBF could be used not merely for risk stratification but specifically to identify patients prone to SCD. 14 The link between the occurrence of VA and impaired myocardial perfusion, however, remains to be elucidated.The aim of this pilot study was to assess whether hyperemic MBF and CFR as assessed with [15 O]H 2 O PET are associated with VA inducibility during an electrophysiological study (EPS) in patients with ischemic cardiomyopathy. Furthermore, the role of alternative risk factors such as LVEF, scar size, transmurality, and border zone as assessed with cardiovascular magnetic resonance (CMR) imaging was evaluated. Methods Study PopulationPatients with ischemic cardiomyopathy and LVEF ≤35%, who were referred for ICD implantation for primary prevention of SCD based on current guidelines, 4 were prospectively included. Exclusion criteria were a cardiac rhythm other than sinus rhythm and a previous history of sustained VA. During the study period, 581 ICD devices were implanted, of which 316 devices were combined with resynchronization therapy or implanted for secondary prevention indication. Of the remaining 265 patients, 109 had nonischemic cardiomyopathy, and another 19 patients did not have sinus rhythm. Of the remaining 137 eligible patients, 107 patients could not be included because of refusal of participation, logistical issues, or other contraindications for PET, CMR, or EPS. A total of 30 patients were included in the described study. None of the patients displayed residual ischemia at noninvasive testing amendable to revascularization before referral for ICD implantation. All patients underwent CMR, PET, and EPS for research purposes after inclusion in this study. The study was approved by the Ethics Committee of the VU University Medical Center, in accordance with the Declaration of Helsinki, and written informed consent was obtained from all patients. CMR Image AcquisitionCMR studies were performed on a clinical 1.5-T MRI scanner (Magnetom Avanto; Siemens, Erlangen, Germany) using a dedicated pha...

Noninvasive myocardial blood flow assessment: Another marker of arrhythmic risk?

“…In patients with ischemic cardiomyopathy, Rijnierse et al found that impaired hyperemic MBF predicted patients who are likely to have inducible VT with programmed electrical stimulation. 17 While both studies are similar in that they showed a relationship between stress MBF and ventricular arrhythmias, the endpoint in the current study was spontaneous ventricular arrhythmia noted on ICD diagnostics, in contrast to inducible arrhythmias in the other study.…”

Non-invasive imaging to identify susceptibility for ventricular arrhythmias in ischaemic left ventricular dysfunction

“…CMR studies and image analyses were performed as described previously 15. In short, a clinical 1.5-T MRI scanner (Magnetom Avanto; Siemens, Erlangen, Germany) was used with a dedicated phased-array body coil.…”

“…In addition, denervated yet viable myocardium may in particular be prone to VA 12 13. Moreover, residual ischaemia even after revascularisation may serve as an important arrhythmic substrate 14 15. Some of these different approaches to evaluate the arrhythmic substrates are, however, intertwined and may actually represent similar pathophysiology.…”

Myocardial Blood Flow in Patients With Transposition of the Great Arteries

“…44 Coronary perfusion abnormalities generate electrical instability of the myocardium and as a predisposing factor for rhythm disturbances this may be an important prognostic factor concerning postoperative morbidity and mortality. These results are hypothesis-generating for a potential role of quantitative PET perfusion imaging in the risk stratification for arrhythmias in patients with morphologic systemic RV.…”

“…These results are hypothesis-generating for a potential role of quantitative PET perfusion imaging in the risk stratification for arrhythmias in patients with morphologic systemic RV. 44 …”