International Normalized Ratio of Prothrombin time (INR) is widely used for the appropriate oral anticoagulant therapy with warfarin in patients with atrial fibrillation. The INR values are affected by the International Sensitivity Index (ISI) since the INR is calculated by (patient PT/normal PT) ISI. Although the thromboplastin reagent with an ISI value of nearly 1.0 is recommended, a comprehensive survey of ISI values in Japan has not been achieved. Therefore, we used a questionnaire survey to investigate thromboplastin reagents and their ISI values at the registered institutions of the J-RHYTHM Registry.
The results were obtained from 152 (96.2%) of 158 institutions. The overall average ISI value was 1.20±0.28 (0.82-1.82) . There were significant differences in the average ISI value among ten geographical divisions by ANOVA (p=0.038) , and between South Kanto with a minimum value of 1.09±0.25 and Hokuetsu with a maximum value of 1.47±0.31 using the post hoc test (p=0.012) . The reagent“Thromborel S”with an ISI value around 1.0 was found in 35% of all, whereas two kinds of high-ISI reagents“Thrombochek PT”and“Thromboplastin C Plus”with ISI values of over 1.5 were employed in total up to 23%. In Hokuetsu and Shikoku, the ratio of these high-ISI reagents were more than 50%, where indicated highest average ISI values and lowest average daily warfarin dose at the baseline of the J-RHYTHM Registry.
The present study indicated that the usage of high-ISI reagents might lead to under-doses of warfarin.

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Brugada syndrome is characterized by coved and saddleback-type ST-segment elevation in the right precordial leads (V1-V3) and an increased risk of sudden death due to ventricular arrhythmias. It is important to evaluate diurnal electrocardiogram (ECG) changes since ECG waveform is usually altered by autonomic nerve activities in patients with Brugada syndrome (BS) . In the present study, we assessed the feasibility of automatic detection of Brugada-type ECG in Holter ECG monitoring. We performed Holter ECG with Frank orthogonal leads (X, Y, and Z) in consecutive 39 patients, including 5 patients with BS. Holter ECG monitoring revealed that ECG waveform on the Z lead was more similar to that on the right precordial leads than on the Frank leads. Three BS patients showed both coved and saddleback ST-segment elevation and one BS patient had only saddleback ST-segment elevation, whereas only one patient had saddleback ST-segment elevation among 34 non-BS patients. Brugada-type ECG was frequently observed after dinner as well as during sleeping. In conclusion, automatic detection of Brugada-type ECG on Holter monitoring is useful to evaluate diurnal variations in ECG waveforms in BS patients.

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Narrow QRS tachycardia, exhibiting transient QRS morphology with complete right bundle branch block (CRBBB) and/or 2 : 1 atrioventricular block, was induced by catheter positioning. During the tachycardia, the earliest atrial activation was recorded at the coronary sinus (CS) ostium. The patient developed a suprahisian block with a 2 : 1 atrioventricular block during the tachycardia, which suggested the presence of a lower common pathway. Rapid ventricular pacing resulted in the jump-up phenomenon and changed the earliest retrograde atrial activation site from the bundle of His to the Cs ostium, which induced tachycardia. Tachycardia via an accessory pathway was ruled out because it was associated with a 2 : 1 atrioventricular block. Atrial tachycardia was also ruled out because of the VAV pattern. We made a diagnosis of atypical atrioventricular nodal reentrant tachycardia, and the tachycardia was eliminated after the third ablation procedure. It was speculated that the tachycardia resulted from isologous circuits, because ablation terminated the tachycardia. The induction of tachycardia with CRBBB and 2 : 1 atrioventricular block was rapid because of sympathetic agitation due to strain, indicating a refractory period with right bundle branch and lower common pathway involvement.

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A 55-year-old man who had frequent paroxysmal supraventricular tachycardia underwent radiofrequency catheter ablation. The jump-up phenomenon was noted twice in the antegrade atrioventricular (AV) nodal by atrial premature stimulation. During right ventricular pacing, the earliest retrograde atrial activation was recorded at the left-sided coronary sinus (CS) , and this finding was confirmed by CS angiography. Supraventricular tachycardia was not induced, but two echo beats were induced with a ventricular double response by atrial premature stimulation during isoproterenol infusion. The earliest retrograde atrial activation was concordant with the atrial activation during right ventricular pacing. We ablated the anatomical slow pathway within Koch’s triangle, but the jump-up phenomenon and retrograde AV nodal conduction remained. The earliest retrograde atrial activation was confirmed by a CARTO system, and then we performed catheter ablation guided by CARTO mapping. After two radiofrequency currents were delivered to the roof of the CS, the retrograde AV nodal conduction disappeared. We confirmed that there were no complications by CS angiography after the catheter ablation.

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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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