Biomedical subjects

Shigeru Oki

Publications and source records attributed to Shigeru Oki.

3 recordsLinked to original sources

PubMed2005

Support adapter for radiofrequency ablation probe: experimental study.

BACKGROUND: The purpose of the present study was to experimentally evaluate a new support adapter, which was created in order to insure a more complete contact between the ablation probe and a beating heart. METHODS: Support sleeve adapters for the Cobra Cooled probe were fashioned using a semi-rigid plastic. Forty epicardial radiofrequency ablation (RFA) lesions were created on both atria under the condition of a beating heart in six pigs weighing 26-30 kg. A Cobra Cooled surgical probe was used with continuous internal irrigation of a saline solution (500 mL/h). The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30 and 60 s. RESULTS: A support adapter ensured a more complete epicardial contact between the probe and a beating heart. An RFA probe supported by the adapter delivered greater power to the tissue. The histopathological transmural coagulation was obtained in 82% and 72% in RFA lesions with and without the adaptor, respectively. CONCLUSION: A new adapter was effective in the epicardial RFA under the condition of a beating heart.

Animals↗

PubMed2005

Epicardial radiofrequency ablation on a beating heart: an experimental study.

PURPOSE: The effect of epicardial radiofrequency ablation (RFA) during normal heart beating was experimentally studied in order to establish safe and effective procedures for RFA. METHODS: Seven pigs weighing approximately 30 to 50 kg were used in this study. Fifty-one epicardial RFA lesions were created on both atria using a Cobra Cooled probe with continuous internal irrigation of a saline solution. The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30, 60 and 120 seconds. RESULTS: There was significant positive correlation between the right and left atria in wall thickness. Transmural coagulation was obtained in 69% of the total specimens, which decreased according to the increase of wall thickness especially over 3 mm. Transmural coagulation was seen in 64% of the specimens after RFA of less than 30 seconds, and 86% after ablation of >or=60 seconds. Occurence of 90% or deeper coagulation was higher in the right atrium than in the left one (97% vs. 78%). Right atrial rupture occurred in a region of 1 mm in thickness after ablation of 60 seconds. CONCLUSION: Further technical improvements associated with new instruments are indispensable to complete epicardial RFA procedures on a beating heart.

Animals↗

PubMed2004

What influences the results in critical patients after cardiovascular surgery?

The predictive factors of surgical outcome were evaluated in compromised patients following cardiovascular surgery. Of 608 patients undergoing cardiovascular surgery between 1991 and 1999, 55 stayed in the intensive care unit for 2 weeks or longer. The mean age of these 55 patients was 56 years. There were 35 survivors and 20 nonsurvivors. Postoperative respiratory failure and gastrointestinal complications were significantly more frequent in those who died. The survival rate was significantly higher in patients who had enteral feeding compared to those who did not (88% versus 43%). Serum cholinesterase and total cholesterol concentrations were higher in the survivors. It was concluded that postoperative respiratory and gastrointestinal conditions influenced the surgical outcome, and serum cholinesterase and total cholesterol concentrations were valuable predictors of survival.

Adolescent↗