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Background: To know the underlying mechanisms of J waves, the response to atrial pacing was studied in patients with idiopathic ventricular fibrillation (IVF) and patients with non-IVF.Methods and Results: In 8 patients with IVF, the J-wave amplitude was measured before, during, and after atrial pacing. All patients had episodes of ventricular fibrillation without structural heart disease. The responses of J waves were compared with those of the 17 non-IVF control subjects who revealed J waves but no history of cardiac arrest and underwent electrophysiological study. The IVF patients were younger than the non-IVF patients (28±10 versus 52±14 years, respectively; P=0.002) and had larger J waves with more extensive distribution. J waves decreased from 0.35±0.26 to 0.22±0.23 mV (P=0.025) when the RR intervals were shortened from 782±88 to 573±162 ms (P=0.001). A decrease (≥0.05 mV) in the J-wave amplitude was observed in 6 of the 8 patients. In addition, 1 patient showed a distinct reduction of J waves in the unipolar epicardial leads. In contrast, J waves were augmented in the 17 non-IVF subjects from 0.27±0.09 to 0.38±0.10 mV (P<0.001): augmented in 9 and unchanged in the 8 subjects. The different response patterns of J waves to rapid pacing suggest different mechanisms: early repolarization in IVF patients and conduction delay in non-IVF patients.Conclusions: The response to atrial pacing was different between the IVF and non-IVF patients, which suggests the presence of different mechanisms for the genesis of J waves. [ABSTRACT FROM AUTHOR]

The patient was a 33-year-old male. Twenty years ago, he underwent radiofrequency catheter ablation for idiopathic sustained monomorphic ventricular tachycardia (VT) with an RBBB and superior axis pattern. The VT was inducible by programmed stimulation and entrained by rapid pacing. At this presentation, he developed palpitation and VT with the same morphology at the peak exercise on a treadmill with appearance of typical ECG pattern for Brugada syndrome (BrS). Pilsicainide induced the typical ECG pattern and premature ventricular beats (PVBs) of the same morphology as VT. The relationship between BrS and VT of left ventricular origin was discussed. [ABSTRACT FROM AUTHOR]

Background: Anticoagulation therapy is essential in atrial fibrillation (AF), and in Japan, less intense control is popular. Purpose: To assess the efficacy and safety with a special reference to low intensity warfarin therapy. Subjects and methods: In 488 out of 508 patients with non-valvular AF, prothrombin time-international normalized ratio (PT-INR) was kept at 1.6-2.59, and they were followed for 49.5 months: 2098 personyears. The mean age was 73.7 ± 9.9 years and 62% were male. The patients were divided by age: ≥70 years and <70 years, and by the intensity of warfarin therapy: PT-INR at 1.6-1.99 and at 2.0-2.59, respectively. The clinical data and event rates, ischemic stroke and major bleeding, were compared among the subgroups. Results: Heart failure, previous stroke, and higher CHADS2 score were more often reported in patients ≥ 70 years while males were involved more often as younger patients. A total of 166 of 339 patients ≥ 70 years and 69 of 149 patients <70 years belonged to the low intensity group. Ischemic stroke and major bleeding occurred in 1.47%/year and 1.27%/year, respectively but there was no difference between the two age groups and between the two intensities of warfarin therapy. Time in therapeutic range was a predictor for ischemic stroke. A fall of PT-INR to <1.6 was found in 41.9% with ischemic stroke and a rise >2.61 in 40.0% with major bleeding at the time of the events. Blunt trauma and concomitant use of antiplatelets were risks for intracranial hemorrhage in the patients ≥ 70 years. Conclusions: The event rates were similar between the low- (1.6-1.99) and high- (2.0-2.59) intensity warfarin therapy groups in aged patients: <70 years and ≥ 70 years. Time in therapeutic range and a transient fall or rise in PT-INR were risks for clinical events. Blunt head trauma and concomitant use of antiplatelets were risks for intracranial hemorrhage. [ABSTRACT FROM AUTHOR]

Thrombotic microangiopathy (TMA) is one of the lethal complications after hematopoietic stem cell transplantation (SCT). The levels of fragmented red cells (FRCs), thrombomodulin (TM), and factor VIII–related antigen in the blood are the most important markers for estimating TMA. However, the FRC level has been measured by using microscopy and the naked eye; therefore, an improvement in technology to objectively count FRC is necessary. We established a novel technique to sensitively measure FRC as glycophorin A dull–positive small particles using a flow cytometer and estimated its reliability in patients treated with SCT. The blood level of FRC was compared with other clinical data in 257 blood samples in 16 clinical courses after SCT of 15 patients. Sorted glycophorin A dull–positive small particles morphologically showed FRC. Measured FRC percentage had a weak correlation with serum levels of lactate dehydrogenase (LDH) and total bilirubin but not with TM level, whereas TM showed a weak correlation with the levels of aspartate aminotransferase and LDH. In a patient with fulminant TMA, decrement of the FRC level led to improvement in liver parameters after treatment, presumably due to the rapid clearance of FRC, and increased simultaneously with the levels of LDH and bilirubin by the TMA recurrence. Levels of FRC percentage and TM were independent parameters of TMA. This novel technique may be used as a standard methodology in diagnosing TMA. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]