Electrophysiological mapping of chronic atrial fibrillation (AF) at high throughput and high resolution is critical for understanding its underlying mechanism and guiding definitive treatment such as cardiac ablation, but current electrophysiological tools are limited by either low spatial resolution or electromechanical uncoupling of the beating heart. To overcome this limitation, we herein introduce a scalable method for fabricating a tissue-like, high-density, fully elastic electrode (elastrode) array capable of achieving real-time, stable, cellular level-resolution electrophysiological mapping in vivo. Testing with acute rabbit and porcine models, the device is proven to have robust and intimate tissue coupling while maintaining its chemical, mechanical, and electrical properties during the cardiac cycle. The elastrode array records epicardial atrial signals with comparable efficacy to currently available endocardial-mapping techniques but with 2 times higher atrial-to-ventricular signal ratio and >100 times higher spatial resolution and can reliably identify electrical local heterogeneity within an area of simultaneously identified rotor-like electrical patterns in a porcine model of chronic AF.

Objectives Surgical ablation of ganglionated plexi (GP) has been proposed to increase the efficacy of the surgical treatment of atrial fibrillation (AF). This experimental canine study examined the electrophysiological attenuation and recovery of atrial vagal effects following GP ablation alone and combined with standard surgical lesion sets used to treat AF. Methods Dogs were divided into 3 groups: Group 1 (N=6) had focal ablation of the 4 major epicardial GP fat pads; Group 2 (N=6) had pulmonary vein isolation with GP ablation; and Group 3 (N=6) had posterior left atrial isolation with GP ablation. All fat pads were ablated. Sinus and atrioventricular (AV) interval changes during bilateral vagosympathetic trunk stimulation were examined before, after, and at four weeks post-ablation. Vagally induced effective refractory period (ERP) changes and mean QRST area changes (index of local innervation) were examined in 5 atrial regions. Results Sinus and AV interval changes and heart rate variability decreased immediately following ablation, but only sinus interval changes were restored significantly after 4 weeks in all groups. Ablation modified vagal effects on ERP or QRST area changed heterogeneously in Groups 1 and 2. In Group 3, regional vagal effects were attenuated extensively post-ablation in both atria. Posterior left atrial isolation with GP ablation incrementally denervated the atria. Chronically, vagal stimulation increased QRST area changes over control values in all groups. Heart rate variability was also assessed. Conclusions GP ablation significantly reduced vagal innervation to the atria. Restoration of vagal effects at 4 weeks suggested early atrial reinnervation.

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Lesions on both the right and left atria can be created successfully on the beating heart with irrigated bipolar radiofrequency. The great majority of lesions with this device were transmural. This device should not be used on valvular tissue.