Background: Although ventricular fibrillation waveform characteristics (VFWC) correlate with coronary perfusion pressure and may predict defibrillation outcome, recent animal data indicate that these waveform characteristics are altered in both acute myocardial infarction (AMI) and chronic coronary heart disease (CHD). We wanted to confirm these recent animal data in humans and explore the possibility for such characteristics to identify acute ischemia during cardiac arrest.
Methods: Data from all adult patients admitted to hospital after out-of-hospital VF cardiac arrest in Oslo between May 2003 and July 2007 were prospectively collected. Patients were categorized into one of four pre-defined etiologic groups: patients with AMI (AMI only), patients with AMI and CHD (AMI and CHD), patients with previous CHD without evidence for a new AMI (CHD only), and patients with primary arrhythmia (PA). VFWC were analyzed from prehospital ECG tracings, and the different etiologic groups compared using ANOVA.
Results: One-hundred-and-one patients with ECG recordings usable for VF analysis could confidently be categorized; 16 with AMI only, 34 with AMI and CHD, 41 with CHD only and 10 with PA. The two VFWC median slope (MS) and amplitude spectral area (AMSA) were significantly depressed in patients with AMI only compared to both PA (MS p=0.008, AMSA p=0.035) and CHD only patients (MS p=0.008, AMSA p=0.006).
Conclusions: AMI patients have depressed MS and AMSA compared to patients without AMI during VF cardiac arrest. VFWC might be helpful in identifying patients with AMI during cardiac arrest, but prospective clinical studies are warranted to assess its feasibility and clinical benefit.