Purpose Pulmonary vein isolation (PVI) for atrial fibrillation has been shown to result in inexcitability of a large fraction of pulmonary veins (PVs), but the mechanism is unknown. We investigated the mechanism of PV inexcitability by assessing the effects of PVI on the electrophysiology of PV sleeves. Methods Patients undergoing first‐time radiofrequency PVI were studied. Capture threshold, effective refractory period (ERP), and excitability were measured in PVs and the left atrial appendage (LAA) before and after ablation. Adenosine was used to assess both transient reconnection and transient venous re‐excitability. Results We assessed 248 veins among 67 patients. Mean PV ERP (249.7 ± 54.0 ms) and capture threshold (1.4 ± 1.6 mA) increased to 300.5 ± 67.1 and 5.7 ± 5.6 mA, respectively (P < .0001 for both) in the 26.9% PVs that remained excitable, but no change was noted in either measure in the LAA. In 16.3% of the 73.1% inexcitable veins, transient PV re‐excitability (as opposed to reconnection) was seen with adenosine administration. Conclusions Antral PVI causes inexcitability in a majority of the PVs, which can transiently be restored in some with adenosine. Among PVs that remain excitable, ERP and capture threshold increase significantly. These data imply resting membrane potential depolarization of the of PV myocardial sleeves. As PV inexcitability hampers the assessment of entrance and exit block, demonstrating transient PV re‐excitability during adenosine administration helps ensure true isolation.
Background: Lambl’s excrescences (LEx) are thin, filiform structures that arise on the lines of closure of heart valves. Although rare, we have come across various case reports in the literature describing thromboembolic events associated with LEx. We report the case of a 63-year-old female who presented with TIA-like symptoms and was found to have a LEx on the aortic side of native aortic valve. We conducted a comprehensive literature review with emphasis on different therapeutic strategies utilized to provide insight for future encounters.Case presentation: A 63-year-old female with a past medical history significant for hypertension and hyperlipidemia presented to the emergency room with symptoms of dysarthria and unsteady gait. While in the hospital, the patient returned to her baseline gait and speech without intervention. Work-up for including computed tomography of the head, magnetic resonance imaging, and carotid doppler, as well as prolonged telemetry monitoring was negative. A transthoracic echocardiogram showed a 0.81 cm linear echodensity attached to the aortic side of the aortic valve, highly suggestive of LEx that was later confirmed on transesophageal echocardiogram. Patient was placed on clopidogrel alone for antiplatelet therapy due to an aspirin allergy and she was subsequently discharged home.Discussion: No standard management for LEx currently exists. We aim to add to the evidence of effective management and explore the literature of patients who have experienced TIA/CVA symptoms secondary to LEx.
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