NOGAMI A et al.(5) View the monitor during imaging During imaging, the heart rate must be continuously monitored using a pulse oximeter or an ECG monitor. (6) Prepare for unexpected situations It should be ensured that the room is equipped with an electrical defibrillator to be used in an emergency, if necessary. A hospital manual for handling unexpected situations should be established. In addition, it should be kept in mind that the threshold and lead resistance need to be re-measured after imaging and the mode needs to be returned to the original setting.Recommendations are shown in Table 6.
Electrophysiology StudiesThe clinical significance of induced arrhythmia depends on the underlying heart disease, type of arrhythmia, and induction protocol. Electrophysiology studies are considered less useful in patients with frequent premature ventricular contraction (PVCs) without structural heart disease.
Multiple left atrial focal activations with fibrillatory conduction and right atrial focal or reentrant activations are the mechanism in permanent atrial fibrillation associated with mitral valve disease. Intraoperative mapping would facilitate the indication for simplified procedures confined to the left atrium or the pulmonary veins.
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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