Impact of the pulmonary vein orifice area assessed using intracardiac echocardiography on the outcome of radiofrequency catheter ablation for atrial fibrillation.

PURPOSE: The purposes of this study were to investigate pulmonary vein cross-sectional orifice area (PV-CSOA) using intracardiac echocardiography (ICE) and to determine its association with atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA). METHODS: We studied 77 patients undergoing initial RFCA for AF (55 paroxysmal and 22 persistent AF patients, mean age 61 ± 12 years, 59 men). The PV-CSOA was measured in each patient and expressed as an index divided by the body surface area-left superior (LSPV-CSOA), left inferior (LIPV-CSOA), right superior (RSPV-CSOA), and right inferior (RIPV-CSOA). RESULTS: After a mean follow-up of 21 ± 14 months, 61 patients maintained sinus rhythm (non-recurrence group) and AF recurred in 16 patients (recurrence group). The LSPV-CSOA index was significantly greater in the recurrence group compared with the non-recurrence group (146 ± 41 vs. 126 ± 30 mm2/m2, p = 0.04). A Cox regression multivariate analysis revealed that the LSPV-CSOA was the independent predictor of AF recurrence (HR 1.02, 95% CI 1.01-1.04, p = 0.01). The LSPV-CSOA cutoff value of 154 mm2/m2 predicts AF recurrence with 50% positive predictive value and 89% negative predictive value. CONCLUSIONS: The present study suggests that ICE can be used as an alternative imaging tools for assessing the PV-CSOA during RFCA and that the LSPV-CSOA index was a useful independent predictor of AF recurrence after RFCA.

Hyperglycemia and subsequent torsades de pointes with marked QT prolongation during refeeding.

OBJECTIVE: A fatal cardiac complication can occasionally present in malnourished patients during refeeding; this is known as refeeding syndrome. However, to our knowledge, hyperglycemia preceding torsades de pointes with QT prolongation during refeeding has not been reported. In the present study, we present a case in which hyperglycemia preceded torsades de pointes with QT prolongation during refeeding. The aim of this study was to determine the possible mechanism underlying QT prolongation during refeeding and indicate how to prevent it. METHODS: A 32-y-old severely malnourished woman (body mass index 14.57 kg/m2) was admitted to the intensive care unit of our institution after resuscitation from cardiopulmonary arrest due to ventricular fibrillation. She was diagnosed with anorexia nervosa. Although no obvious electrolyte abnormalities were observed, her blood glucose level was 11 mg/dL. A 12-lead electrocardiogram at admission showed sinus rhythm with normal QT interval (QTc 0.448). RESULTS: Forty mL of 50% glucose (containing 20 g of glucose) was intravenously injected, followed by a drip infusion of glucose to maintain blood glucose level within normal range. After 9 h, the patient's blood glucose level increased to 569 mg/dL. However, after 38 h, an episode of marked QT prolongation (QTc 0.931) followed by torsades de pointes developed. CONCLUSIONS: Hyperglycemia during refeeding can present with QT prolongation; consequently, monitoring blood glucose levels may be useful in avoiding hyperglycemia, which can result in QT prolongation. Furthermore, additional monitoring of QT intervals using a 12-lead electrocardiogram should allow the early detection of QT prolongation when glucose solution is administered to a malnourished patient with (severe) hypoglycemia.