Biomedical subjects

Mariko Arai

Publications and source records attributed to Mariko Arai.

4 recordsLinked to original sources

PubMed2004

Brugada syndrome-like ST-segment elevation increase exacerbated by vomiting.

The patient was a 53 year-old male who had 3 syncopal episodes over a 6-month period. In the electrophysiological study, ventricular fibrillation (VF) was repeatedly induced by the ventricular extrastimulus method. Intravenous pilsicainide was administered, and the J-point and ST-segment in the right precordial leads became slightly elevated just following drug administration. Five min later, the patient experienced severe nausea and then vomited twice, at which point the electrocardiogram (ECG) showed increased elevation of the J-point and ST-segment. These ECG changes recovered to normal 30 min later. The cause of his syncope was strongly suspected to be related to the VF associated with Brugada syndrome. An interesting aspect of this case was the particular type of J-point and ST-segment elevation that was induced when the patient experienced nausea and vomiting. It is proposed that this phenomenon originated from the vagal stimulation associated with the nausea and vomiting.

Acetylcholine↗

PubMed2003

Experimental study on the effectiveness and safety of radiofrequency catheter ablation with the cooled ablation system.

Experimental in vitro and in vivo studies were performed to assess the effectiveness and safety of the cooled-tip catheter and the Cooled Ablation System, which enables the creation of deeper and wider burn lesions in the myocardial tissue using radiofrequency current. This system was confirmed to consistently create large burns by cooling the catheter tip with circulating water within the catheter, even under unfavorable conditions. On the other hand, unfavorable effects, as a result of over burning, such as explosive vaporization within the tissue (the 'pop' phenomenon), tissue carbonization, coronary artery injury and lung injury were identified. 'Pop' was difficult to predict, but it is important to know how it can be avoided. No 'Pop' was seen without first observing an impedance decrease, thus it was considered safe to decrease the radiofrequency current if the impedance began to decrease. This system will be very effective for ablation of refractory arrhythmias, such as ventricular tachycardia or atrial flutter, but it is recommended that only experienced electrophysiologists use this system to avoid serious complications.

Animals↗

PubMed2002

Clinical significance of the dispersion of the activation--recovery interval and recovery time as markers for ventricular fibrillation susceptibility in patients with Brugada syndrome.

Brugada syndrome (BS) is associated with sudden cardiac death and the markers for ventricular fibrillation (VF) remain unclear, so the activation-recovery interval (ARI) dispersion and recovery time (RT) dispersion were investigated as possible markers in 20 subjects with BS (BS group) and 22 healthy individuals (H group). The 20 BS subjects were divided into 8 cases with documented VF (BS-VF group), 3 of which had recurrences, and 12 without (BS-N group). The corrected dispersion measurements from the standard 12-lead ECG of the QT interval (QTcd), ARI (ARIcd) and RT (RTcd) were compared among the groups. There were significant differences noted between the BS-VF and BS-N groups for the ARIcd and the RTcd, but not for the QTcd. Further, there were critical differences, 150 ms(1/2), observed for the ARIcd and RTcd, and these were associated with a prolongation of the maximum ARI or RT, shortening of the minimum ARI or RT, and prolongation only of the maximum QT for the QTcd. Susceptibility to VF may be predicted by the ARIcd or RTcd in BS.

Arrhythmias, Cardiac↗

PubMed2002

Electrocardiography subtraction method of detecting low-amplitude, high-frequency components (L-HFCs) within the QRS complex of patients with ventricular tachycardia.

A new method of extracting the low-amplitude and high-frequency components (L-HFCs) was developed and this study investigated its usefulness in 86 subjects: 28 normal subjects (group 1) and 58 patients with a previous myocardial infarction (MI). The patients were classified into 3 groups: group 2 with 38 patients without ventricular tachycardia (VT), group 3 with 13 patients with non-sustained VT, and group 4 with 7 patients with sustained VT. The new electrocardiography (ECG) subtraction method, using a mathematical filtering procedure, was used instead of conventional complex filtering. The continuous L-HFCs within the QRS complex were analyzed using a Z-lead recording. The duration of the continuous L-HFCs was significantly longer in group 4 than in groups 1 (p<0.0001), 2 (p<0.0001) or 3 (p<0.05) with all 3 filters. The ECG subtraction method is a powerful and useful new technique for identifying patients at risk for either sustained or non-sustained VT after MI, and overcomes several of the problems with the conventional signal-averaging method.

Adult↗