Purpose: The acute effect of radiofrequency (RF) ablation includes local necrosis and oedema. We investigated the spatiotemporal change of atrial electrograms in the area surrounding the site of single standardized pulse of RF energy.Methods: The study enrolled 12 patients (45–67 years, 10 males) with paroxysmal atrial fibrillation (AF) undergoing ablation procedure with irrigated-tip ablation catheter and 3D navigation. The high-density mapping/remapping (129 ± 63 points) within the circular area with radius of ~10 mm, centered at the pre-specified posterior left pulmonary vein antrum ablation site was performed at baseline, immediately after single RF energy delivery (25 W, 30 s, 20 ml/min) and after 30 min waiting period. Bipolar voltages of atrial electrograms (A-EGM-biV) were averaged within the central and 12 adjacent left atrium segments and their relative change was studied.Results: After the ablation, overall A-EGM-biV within the mapping zone (3.51 ± 1.89 mV at baseline) reduced to 2.83 ± 1.77 mV (immediately) and to 2.68 ± 1.58 mV (after 30 min waiting period). In per-segment pair-wise comparison, we observed highly significant change in A-EGM-biV that extended up to the distance of 8.8 mm from the lesion core. The maximum early A-EGM-biV attenuation by 39–49% (P < 0.001) was registered in segments adjacent to pulmonary vein ostia. The subsequent (delayed) A-EGM-biV reduction by 17–24% (P < 0.05) was observed in opposite direction from the lesion center.Conclusions: Significant alteration of atrial electrograms was detectable rather distant from the central lesion. Spatiotemporal development of ablation lesion was eccentric/asymmetric. While acute A-EGM-biV reduction can be attributed predominantly to direct thermal injury, delayed effects are probably due to oedema progression.

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Atrial fibrillation ablation 573head was performed in less than one-half of patients (43%) with abnormal findings in 57% which was most commonly diffuse air emboli and ischaemia (81%). Trans-thoracic echocardiography was performed in 28% with the most common abnormality being pericardial effusion (33%). Trans-oesophageal echocardiography was also infrequently performed (14%) with the most common abnormality being thrombus/mass in the left atrium (46%). In 10 patients who underwent oesophagram, nine demonstrated contrast extravasation. Of the 10 electrocardiograms performed/documented, most demonstrated S-T segment elevation (8/10). Inflammatory markers were generally elevated when reported, including white blood cell count (73%; 27/37), c-reactive protein (100%; 13/13) and troponin (83%; 5/6). Blood culture consistently grew bacteraemia (26/26) with 42% (11/26) growing multiple organisms. Conclusion(s):CT chest is the most commonly performed non-invasive imaging modality in suspected AOF with high diagnostic yield. Clinicians should be aware that serial testing and follow-up may be necessary where initial CT chest findings are normal. CT head findings are unique to AOF but can be normal despite neurological symptoms. Oesophagram may be useful where diagnosis remains uncertain following CT chest. Blood culture with growth of multiple organisms may raise suspicion of AOF compared with infective endocarditis, especially following AF ablation. Although pulmonary vein isolation is an effective treatment for atrial fibrillation (AF), there is no consensus on the definition of success or follow up strategies. Current data are limited to intermittent Holter monitor with reliance on patients symptoms. Objective: We sought to determine the outcomes on surgical AF ablation and post ablation AF surveillance with an implantable cardiac monitor (ICM). Method: One hundred and nineteen patients with persistent AF who either failed previous catheter ablation or multiple drug therapies underwent minimal invasive surgical modified Maze procedure. An ICM (Medtronic Reveal XT) was implanted subcutaneously post ablation to assess AF recurrence. AF recurrence was defined as >1 AF episodes with a duration of >60 seconds. The device-stored data was downloaded weekly over the internet and all transmitted electrograms were adjudicated. Patients are followed every 6 months in clinic for 30 months. Results: A total of 12680 AF events were analyzed over a follow-up period of 30 months. Of these AF episodes, 56% were asymptomatic. Furthermore, only 45% of patients-activated episodes were truly AF. AF recurrences was highest in the first 3 months and substantially decreased 6 months post ablation. AF recurrences are common after 12 months (Fig. 1). Fifty-two patients underwent repeat AF ablation during the follow up period. The overall freedom from AF recurrence at the end of follow-up was 56%. Thirty days telemetry recordings were used in 35 patients to compare stored device electrograms, the sensitivity and specificity to detect AF was 95% a...