Fast-Slow Type of Atrioventricular Nodal Reentrant Tachycardia: Horizontal Dissociation of the AV Node During Tachycardia

Two patients with recurrent supraventricular tachycardia are presented. The tachycardia was initiated and terminated by atrial extrastimulation beyond the atrial relative refractory period and the atrial activation sequence during the tachycardia was low to high. The induction of tachycardia was dependent on a critical AH interval. In patient 1 who had ventriculoatrial conduction, the tachycardia was initiated by the premature ventricular stimulation followed by double atrial response. In patient 2 the ventriculoatrial conduction was not observed. In both patients, the unchanged atrial cycle length during the tachycardia with antegrade Wenckebach AH block was observed. When AH block occurred during tachycardia the first AH interval was shorter than the subsequent HA interval. In patient 2 verapamil (5 mg) prolonged the atrial cycle length during tachycardia and rapid intravenous injection of adenosine triphosphate (10 mg) terminated the tachycardia. Oral diltiazem (280 mg/day) suppressed the tachycardia in patient 1. These findings suggest that the mechanism of tachycardia may be fast-slow type of AV nodal reentry in the upper portion of the AV node and this type of arrhythmia has tendency to show incessant form.     

Time- Versus Frequency-Domain Analysis in Predicting Cycle Length of Inducible Ventricular Tachycardia After Myocardial Infarction

To determine whether time- and frequency-domain analyses differ in their ability to predict sustained ventricular tachycardia (VT) induced by programmed ventricular stimulation, 60 consecutive patients with myocardial infarction and 30 healthy control subjects were evaluated. Programmed ventricular stimulation using three extrastimuli and signal-averaged ECG recordings were performed in patients with myocardial infarction. Of the 60 patients, sustained monomorphic VT (SMVT) with cycle length (CL) ± 250 ms (slow SMVT) was inducible in 9, and SMVT with CL < 250 ms (fast SMVT) was inducible in 9. The durations of the filtered QRS (f-QRS) at each high-pass filter (25, 40, and 80 Hz) and the low amplitude signal (LAS) at 25-Hz high-pass filtering were significantly longer in the slow SMVT group than in the fast SMVT, no VT, or normal control group. The root-mean- square voltages at 25-Hz and 8Q-Hz high-pass filters in the slow SMVT group were significantly lower than in the fast SMVT, no VT, or normal control group. There was no significant difference in time- domain variables among fast SMVT, no VT, and normal control groups. The CL of the induced sustained VT was significantly correlated with the durations of f-QRS and LAS, Concerning frequency-domain variables (area ratio and factor of normality), there was no significant difference between slow and fast SMVT groups. Both the slow and fast SMVT groups had a significantly higher area ratio and a significantly lower factor of normality than the group with no VT or the normal control subjects. In conclusion, there were significant correlations between time-domain variables and CL of SMVT, while there was no correlation when using frequency-domain parameters.     

Electrophysiological Findings in Idiopathic Recurrent Ventricular Fibrillation: Special Reference to Mode of Induction, Drug Testing, and Long-Term Outcomes

Electrophysiological studies can be useful in the presence of idiopathic ventricular fibrillation (VF) and may be used when selecting antiarrhythmic drugs. However, the yield, the mode, and the long-term reproducibility of the induction of VF have not yet been fully elucidated. Eight patients with idiopathic VF underwent electrophysiological study. The mean age (± SD) was 45 ± 17 years. Six were males and two were females. Diagnosis was done by exclusion. VF was induced in 6 (75%) of 8 patients using double extra stimuli at coupling intervals of 233 ± 39 and 191 ± 20 ms for the first and second extra stimuli, respectively. Of note, VF was induced by stimulation exclusively at the origin of the premature ventricular beat, which was the first complex of VF in two patients. In another patient, VF was initiated by two premature stimuli and also by a pause produced by rapid pacing. The inducibility of VF was reproduced 9–18 months after the first induction in all of the four patients studied. When the ability of antiarrhythmic drugs to suppress VF inducibility was confirmed, no recurrence was observed during the follow-up period of 40–160 months, but a recurrence of VF was observed in one of two nonresponders. In one patient, amiodarone administration failed in preventing VF induction 9 months after initiation of therapy, and reassessment of long-term drug-efficacy might be indicated in some patients. In conclusion, idiopathic VF was highly inducible (75%) with double extra stimuli. In this study, it was induced from a specific site (2/8) or by a pause (1/8). Induction of VF seemed to be reproduced 9–18 months after the first study. The outcome was considered favorable when the inducibility of VF was suppressed by antiarrhythmic drugs.     

Successful Radiofrequency Current Catheter Ablation of Sustained Ventricular Tachycardia

We performed radiofrequency current catheter ablation in two patients with nonischemic sustained ventricular tachycardia (VT). In one patient, two morphologically distinct VTs were induced by electrical stimulation. One showed right bundle branch block pattern and the other left bundle branch block pattern. The earliest site of activation during each VT was determined at the septum of the right ventricle. However, these two sites were close to the His-bundle elecfrogram recording area. In the other patient, a VT with a left bundle branch block pattern occurred spontaneously after the administration of isoproterenol. The earliest site of activation during VT was determined at the outflow tract of the right ventricle. During tachycardia, radiofrequency current ablation (40 W ± 30 sec) was delivered to the earliest site of activation, A few seconds after fulguration, each VT was terminated and additional radio-frequency currents were given near these sites. After the ablation, VT could not be induced by the electrical stimulations, nor did it recur. No side effects were observed and the atrioventricular conduction remained intact. We feel that nonischemic VTs could possibly be treated by using radiofrequency current catheter ablation.     

Adequacy of Pacing Rate During Exercise in Rate Responsive Ventricular Pacing

Our objective was to determint; the adequate pacing rate during exercise in ventricular pacing by measuring exercise capacity, cardiac output, and sinus node activity. Eighteen patients with complete AV block and an implanted pacemaker underwent cardiopulmonary exercise tests under three randomized pacing rates: fixed rate pacing (VVJ) at 60 beats/min and ventricular rate-responsive pacing (VVIR) programmed to attain a heart rate of about 110 beats/min ar 130 beats/min (VVIR 110 and VVIR 130, respectively) at the end of exercise. Compared with VVI and VVIR 130, VVIR 110 was associated with an increased peak oxygen uptake(VVIR 110:20.3 ± 4.5 vs VVI: 16.9 ± 3.1; P < 0.01; and VVIR 130: 19.0 ± 4.1 mL/min per kg, respectively; P < 0.05) and a higher oxygen uptake at anaerobic threshold (15.3 ± 2.7, 12.7 ± 1.9; P < 0.01, and 14.6 ± 2.6 mL/min per kg; P < 0.05). The atrial rate during exercise expressed as a percentage of the expected maximal heart rate was lower in VVIR 110 than in VVI or VVIR 130 (VVIR 110: 75.9%± 14.6% vs VVI: 90.6%± 12.8%; P < 0.01; VVIR 110 vs VVIR 130: 89.1%± 23.1%; P < 0.05). There was no significant difference in cardiac output at peak exercise between VVIR 110 and VVIR 130. We conclude that a pacing rate for submaximal exercise of 110 beats/min may be preferable to that of 130 beats/min in respect to exercise capacity and sympathetic nerve activity.     

Electrophysiologic Evaluation of Asymptomatic Patients with the Wolff-Parkinson-White Pattern

In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.     

Alpha-delta sleep in a case with non-24 h sleep-wake syndrome: Quantitative electroencephalogram analysis of alpha and delta band waves

Abstract  Four all-night polysomnograms of a 39-year-old male patient with non-24 h sleep-wake syndrome were recorded. We analysed electroencephalograms (EEG) with the power spectrum method and the wave pattern recognition analysis of Fujimori. The EEC of the rest waking condition showed normal patterns. High-voltage diffuse alpha band waves were observed in sleep stages 2, 3 and 4. The integrated area of the alpha band waves in the analysis epochs showed a strong positive correlation to the delta hand components in the power spectrum of the same epoch during sleep (correlation coefficients r = 0.762–0.815). Alpha hand waves during sleep were clearly different from the alpha waves in the rest waking condition, with respect to slower peak frequency and the frontal dominant voltage distribution.     

Radical prostatectomy and adjuvant endocrine therapy for prostate cancer with or without preoperative androgen deprivation: Five-year results

BACKGROUND: The effects of preoperative androgen deprivation on the outcomes of prostate cancer patients who received radical prostatectomy and subsequent adjuvant endocrine therapy have not yet been fully evaluated. METHODS: Patients with stage A(2), B or C prostate cancers were randomized to one of two groups: group I (n = 90), who received androgen deprivation (leuprolide and chlormadinone acetate) for 3 months followed by radical prostatectomy and subsequent adjuvant endocrine therapy (leuprolide alone), and group II (n = 86), who underwent the surgery followed by 3-month androgen deprivation (leuprolide and chlormadinone acetate) and subsequent adjuvant endocrine therapy (leuprolide alone). The effects of preoperative androgen deprivation on survival, clinical relapse (serum prostate specific antigen, PSA, above the normal level, local recurrence, or distant metastases), and PSA relapse (PSA above the detectable level) were evaluated at 5 years or later after treatment. RESULTS: There were no significant differences in overall, cause-specific, clinical relapse-free, or PSA relapse-free survival rates between the two groups. In a subanalysis, no prostate cancer deaths or clinical relapses were noted in 29 patients with organ-confined disease (OCD: negativity of capsular invasion, seminal vesicle invasion, surgical margins or nodal involvement). The odds ratio for OCD depending on group assignment was 2.44 (95% confidence interval, CI 1.04-5.72), for group I, demonstrating a higher probability of having OCD. This ratio was increased to 4.00 (95% CI 1.06-15.16) if the analysis was conducted in a subpopulation with prostate specific antigen levels less than 35.6 ng/mL and with clinical stage B or C cancers. CONCLUSION: Preoperative androgen deprivation has no demonstrable benefit in 5-year outcomes for patients undergoing radical prostatectomy and adjuvant endocrine therapy. However, it did increase the probability of OCD, which was associated with no clinical relapse during the follow-up. A longer observation is needed to clarify the exact extent of the benefits in terms of survival.     

Sufficient prophylactic efficacy with minor adverse effects by intravesical instillation of low-dose bacillus Calmette-Guérin for superficial bladder cancer recurrence

BACKGROUND: Intravesical instillation of bacillus Calmette-Guérin (BCG) is the most efficient strategy for prophylaxis of superficial bladder cancer recurrence. Adverse effects of BCG are major obstacles, but the reduction of BCG dose could minimize these effects. The efficacy and adverse effects of half-dose (40 mg) BCG, Tokyo 172 strain, were prospectively evaluated. METHODS: A total of 93 patients with superficial bladder cancer (pTa or pT1) were sequentially assigned to receive either 40 or 80 mg of BCG after transurethral resection. BCG was administered weekly for 6 weeks postoperatively. Eighty patients observed longer than 12 months after BCG therapy (41, 40 mg group; 39, 80 mg group) were analyzed. RESULTS: BCG therapy course was completed in 71 patients. Tumor recurrence was recognized in 11 of 40 patients in the 40 mg group and in 5 of 31 patients in the 80 mg group. There was no significant difference in tumor recurrence rate between the two groups (P = 0.547). BCG therapy was withdrawn in 1 patient in the 40 mg group and in 8 patients in the 80 mg-group because of BCG-related adverse effects. The morbidity of BCG-related toxicity was significantly higher in the 80 mg group. CONCLUSION: Half-dose of BCG Tokyo 172 strain had a similar efficacy and its toxicity was significantly lower compared to the standard dose. Thus, half-dose of this strain might be suitable, at least for initial BCG therapy, for the prophylaxis of bladder cancer recurrence. Further study would be necessary to clarify the efficacy of low-dose instillation in high-risk patients.