Irrigated Microwave Catheter Ablation Can Create Deep Ventricular Lesions Through Epicardial Fat With Relative Sparing of Adjacent Coronary Arteries.

BACKGROUND: Radiofrequency ablation depth can be inadequate to reach intramural or epicardial substrate, and energy delivery in the pericardium is limited by penetration through epicardial fat and coronary anatomy. We hypothesized that open irrigated microwave catheter ablation can create deep myocardial lesions endocardially and epicardially though fat while acutely sparing nearby the coronary arteries. METHODS: In-house designed and constructed irrigated microwave catheters were tested in in vitro phantom models and in 15 sheep. Endocardial ablations were performed at 140 to 180 W for 4 minutes; epicardial ablations via subxiphoid access were performed at 90 to 100 W for 4 minutes at sites near coronary arteries. RESULTS: Epicardial ablations at 90 to 100 W produced mean lesion depth of 10±4 mm, width 18±10 mm, and length 29±8 mm through median epicardial fat thickness of 1.2 mm. Endocardial ablations at 180 W reached depths of 10.7±3.3 mm, width of 16.6±5 mm, and length of 20±5 mm. Acute coronary occlusion or spasm was not observed at a median separation distance of 2.7 mm (IQR, 1.2-3.4 mm). Saline electrodes recorded unipolar and bipolar electrograms; microwave ablation caused reductions in voltage and changes in electrogram morphology with loss of pace-capture. In vitro models demonstrated the heat sink effect of coronary flow, as well as preferential microwave coupling to myocardium and blood as opposed to lung and epicardial fat phantoms. CONCLUSIONS: Irrigated microwave catheter ablation may be an effective ablation modality for deep ventricular lesion creation with capacity for fat penetration and sparing of nearby coronary arteries because of cooling endoluminal flow. Clinical translation could improve the treatment of ventricular tachycardia arising from mid myocardial or epicardial substrates.

Optic Chiasm Involvement With Concurrent Typical Wernicke Encephalopathy Magnetic Resonance Findings: A Case Report.

The variable clinical presentation of Wernicke encephalopathy often complicates interpretation. Prompt and accurate diagnosis relies on a constellation of typical and atypical magnetic resonance imaging (MRI) findings, which are not always simultaneously present. Our case demonstrates concurrent presentation of all typical Wernicke encephalopathy MRI findings with additional signal abnormalities involving the optic chiasm and optic tract. We suggest that optic pathway involvement may be considered among several atypical MRI manifestations, reinforcing the prompt diagnosis of the potentially life-threatening encephalopathy.

Mechanotransduction channels of the trabecular meshwork.

PURPOSE: To determine whether the trabecular meshwork (TM), like the other organs engaged in filter like activities (such as kidneys), show the expression of known mechanotransduction channels at protein level. METHODS: Human donor eye globes (n = 20), Donor eye derived TM tissue and primary TM cells were utilized for these studies. Commercially available antibodies to channels, immunohisto- and immunocytochemistry, Western blot and mass spectrometric analyses were performed to determine the presence of mechanosensitive channels at protein level. The study was performed adhering to tenets of declaration of Helsinki. RESULTS: We demonstrate here the presence of 11 mechanotransduction channels (Piezo1, Piezo2, TASK1, TREK1, TRPA1, TRPC1, TRPC2, TRPC3, TRPC6, TRPM2, TRPP2) as expressed protein in the TM tissue and at the isolated TM cell level. Presence of at least one known isoform of these channels was demonstrated using Western blot analyses. CONCLUSIONS: We demonstrated the presence of 11 mechanotransduction channels in the TM and in isolated TM cells at protein level. Demonstration of these channels as proteins at tissue and cellular level will pave the way for further experimentation.