Regularly irregular atrial rhythm after superior vena cava isolation: Another manifestation of sinoatrial node injury?

The present case described an unusual clinical manifestation of the sinoatrial node (or sinoatrial junction) injury during superior vena cava isolation.

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.

Cilostazol protects the heart against ischaemia reperfusion injury in a rabbit model of myocardial infarction: focus on adenosine, nitric oxide and mitochondrial ATP-sensitive potassium channels.

1. The present study examined whether or not cilostazol reduces the myocardial infarct size, and investigated its mechanism in a rabbit model of myocardial infarction. 2. Japanese white rabbits underwent 30 min of coronary occlusion, followed by 48 h of reperfusion. Cilostazol (1 and 5 mg/kg) or vehicle was given intravenously 5 min before ischaemia. 8-p-sulfophenyl theophylline (8SPT; an adenosine receptor blocker, 7.5 mg/kg), Nω-nitro-L-arginine methylester (l-NAME; an NOS inhibitor, 10 mg/kg) or 5-hydroxydecanoic acid sodium salt (5-HD; a mitochondrial ATP-sensitive potassium (KATP) channel blocker, 5 mg/kg) was given intravenously 5 min before cilostazol injection. Infarct size was determined as a percentage of the risk area. 3. The myocardial interstitial levels of adenosine and nitrogen oxide (NOx) during ischaemia and reperfusion, and the intensity of myocardial dihydroethidium staining were determined. 4. Infarct size was significantly reduced in the cilostazol 1 mg/kg (38.4% (2.9%)) and cilostazol 5 mg/kg (30.7% (4.7%)) groups compared with that in the control group (46.5% (4.2%)). The infarct size-reducing effect of cilostazol was completely abolished by 8SPT (46.6% (3.5%)), L-NAME (49.0% (5.5%)), or 5HD (48.5% (5.1%)). 8SPT, L-NAME or 5HD alone did not affect the infarct size. Cilostazol treatment significantly increased myocardial levels of adenosine and NOx during ischaemia, and attenuated the intensity of dihydroethidium staining during reperfusion. 5. These findings show that cilostazol reduces the myocardial infarct size by increasing adenosine and NOx levels, attenuating superoxide production and opening the mitochondrial KATP channels. Cilostazol might provide a new strategy for the treatment of coronary heart disease.

Treatment with Lindera strychnifolia reduces blood pressure by decreasing sympathetic nerve activity in spontaneously hypertensive rats.

Lindera strychnifolia (Tendai-Uyaku), a medicinal plant, has long been used for the treatment of cardiac, renal and rheumatic diseases in Japan. We investigated the effect of Lindera strychnifolia on systolic blood pressure, cardiac function, and plasma noradrenaline levels in rats. Spontaneously hypertensive rats (SHR) were given free access to water or extract solution of Lindera strychnifolia, which was extracted with a ratio of 10 g Lindera strychnifolia roots/20 ml water. Systolic blood pressure was measured by using a tail-cuf sphygmomanometer twice a week from 10 to 30 weeks of age, and compared to the age-matched Wistar Kyoto rats (WKY) as a control group. At 30 weeks of age, heart function was measured by echocardiography and blood samples were taken for detection of plasma noradrenaline levels, and rats were then sacrificed. Systolic blood pressure gradually increased from 10 to 30 weeks of age in the SHR group, while it did not change in the WKY group. In the Lindera-treated SHR group, the increase in systolic blood pressure was significantly attenuated from 21 to 30 weeks of age. Echocardiography showed a significant increase in ejection fraction in the Lindera-treated SHR group (60.4 +/- 7.8%) as compared to the SHR group (39.7 +/- 23.4%). Plasma noradrenaline levels were significantly decreased in Lindera-treated SHR group compared to the SHR group. These results suggest that Lindera strychnifolia has an anti-hypertensive effect and improves cardiac function in spontaneous hypertensive rats. These effects may be related to the decrease in plasma noradrenaline levels by Lindera strychnifolia.