Remote surveillance is important for patients with atrial fibrillation (AF). Atrial signal recognition with conventional monitoring devices is difficult; remote AF detection is predominantly accomplished by R-R interval analysis. Twelve lead ECG (12L) displays atrial activity and remains the gold standard for AF diagnosis. CardioBip is a portable wireless patient-activated event monitor providing signal reconstruction of a 12L waveform (12CB) using 5 leads and patient-specific transformation matrices. We hypothesized that atrial signal analysis with 12CB can detect atrial activity and improve AF detection.
Methods: 18 patients with AF undergoing DC cardioversion (CV) were studied. Separate 12-lead P and QRS patient-specific transformation matrices were created at baseline AF. Multiple wireless 12CB transmissions were performed 3-7 days before and up to 2 weeks after CV. Rhythm was confirmed with 12-lead ECGs (12L). In SR the number of leads with visible P waves (atrial signal > 0.05 mV), and P wave polarity were analyzed. In AF, the number of leads with AF signal were compared (fibrillatory [f] waves >0.025 mV).
Results: Fourteen of 18 patients successfully cardioverted to SR and 4 failed; thus, 14 SR and 22 AF transmissions were analyzed. SR P wave was visible on 141/168 leads on 12L and 137/168 on 12CB (126 true pos [TP] and 11 false pos [FP] relative to 12L; p=0.26). In 126 leads with P waves in both 12L and 12CB, the methods agreed on P wave polarity in 125. In AF, F waves were visible in 178/264 leads on 12L and 189/264 leads on 12CB (144 TP, 45 FP; p=0.27). All 5 AF relapses were successfully detected by 12CB based on atrial activity.
Conclusion: 12CB is not inferior to 12L in detecting atrial signal in SR and AF, and shows excellent potential for remote wireless monitoring of AF patients.