Recently, ICH-E14 guidelines were published by the Ministry of Health, Labor and Welfare. As a result, an accurate and reliable QT interval measurement method is required in a clinical trial. We investigated the reliability of the computer assisted procedure using the tangent line method in QT interval measurement from the results of a training program for three laboratory technicians. In 12-lead electrocardiogram from 20 healthy volunteers, QT interval was measured twice by three trainee technicians for two beats of each lead (480 measurements). Averaged QT intervals measured by two expert technicians were used as a reference. Inter-observer difference (between each trainee data and the reference data) and intra-observer difference (between the first and the second measurements) were evaluated. The inter-observer differences for the three trainee technicians were 0.8+6.2 msec,0.1+5.7 msec, and 2.1+6.5 msec, and correlation coefficient of their measurement for two times was 0.94-0.97. The present semi-automated QT-interval measurement system, which depends on simple tangent line setting work, showed sufficient reliability and reproducibility in a short technician training program.

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A 57-year-old man had been diagnosed with long-standing atrial fibrillation and dilated cardiomyopathy. We tried PV isolation to improve his LV function. Left PV consisted of a huge common trunk. After left PV isolation was completed, regular tachycardia appeared in the left PV common trunk. We performed 3D mapping. Regular PV tachycardia (PVT) was circling around the scar area in PV. PVT was proved to be macro-reentrant tachycardia by an entrainment study.

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A 79-year-old female presented to our hospital with a history of experiencing palpitations occasionally from the age of around 20, which suddenly worsened when she became 78-years-old. She developed dyspnea and was hospitalized with acute heart failure. Monitoring during hospitalization revealed incessant wide-QRS tachycardia, and echocardiography revealed low ejection fraction, which suggested tachycardia-induced cardiomyopathy. A cardiac electrophysiologic study was performed, and a left accessory pathway was diagnosed to be present, because impulses along the accessory pathway arrived earliest at the left-sided wall in both the anterograde and retrograde conductions. Wide-QRS tachycardia was easily induced by extra stimulation from the high right atrium and right ventricle. The tachycardia was diagnosed as antidromic AVRT (atrioventricular reciprocating tachycardia), in which impulses are conducted in the anterograde direction through the accessory pathway and in the retrograde direction through the slow pathway, because : 1) the QRS waveform was similar to that seen during normal sinus rhythm ; 2) the site of earliest activation in the ventricular wall was CS1-2 ; and 3) Retrograde conduction was long and the earliest site of atrial activation was the coronary sinus ostium. Furthermore, orthodromic AVRT, in which the conduction is anterograde over the atrioventricular node and antidromic over the accessory pathway, was also induced by premature ventricular contractions, which developed accidentally. Ablation was performed, and after the accessory pathway had been blocked. Improvement in cardiac function was observed after correcting the WPW syndrome.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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