No abstract available.
Tachycardia, Supraventricular* ; Tachycardia, Ventricular*

BACKGROUND AND OBJECTIVES: Identifying the critical isthmus of slow conduction is crucial for successful treatment of scar-related ventricular tachycardia. Current 3D mapping is not designed for tracking the critical isthmus and may lead to a risk of extensive ablation. We edited the algorithm to track the delayed potential in order to visualize the isthmus and compared the edited map with a conventional map. SUBJECTS AND METHODS: We marked every point that showed delayed potential with blue color. After substrate mapping, we edited to reset the annotation from true ventricular potential to delayed potential and then changed the window of interest from the conventional zone (early, 50-60%; late, 40-50% from peak of QRS) to the edited zone (early, 80-90%; late, 10-20%) for every blue point. Finally, we compared the propagation maps before and after editing. RESULTS: We analyzed five scar-related ventricular tachycardia cases. In the propagation maps, the resetting map showed the critical isthmus and entrance and exit sites of tachycardia that showed figure 8 reentry. However, conventional maps only showed the earliest ventricular activation sites and searched for focal tachycardia. All of the tachycardia cases were terminated by ablating the area around the isthmus. CONCLUSION: Identifying the channel and direction of the critical isthmus by a new editing method to track delayed potential is essential in scar-related tachycardia.
Tachycardia ; Tachycardia, Ventricular*

No abstract available.
Aneurysm, False* ; Tachycardia, Ventricular*

No abstract available.
Papillary Muscles* ; Tachycardia, Ventricular*

Humans ; Tachycardia, Ventricular ; genetics

No abstract available.
Aneurysm* ; Cardiomyopathy, Hypertrophic* ; Tachycardia, Ventricular*

No abstract available.
Child* ; Electrocardiography* ; Humans ; Tachycardia, Ventricular*

Reentrant tachycardias can often be terminated by discrete pacing stimuli that penetrate the reentrant circuit. Antitachycardia pacemaker PASAR 4172 (Programmable Automatic Scanning Arrhythmia Reversion, Model 4172, Telectronics) is designed to detect tachycardia automatically and subsequently to deliver programmed one or two extrastimuli to revert to sinus rhythm. We experienced two patients, one paroxysmal supraventricular tachycardia and one paroxysmal ventricular tachycardia, who had had frequent and often prolonged episodes of tachycardia that responded poorly to pharmacologic antiarrhythmic therapy. Each patient underwent a detailed preimplantation clinical electrophysiological study in order to determine the number of stimuli required for termination of tachycardia, the most satisfactory site for electrode placement, and the tachycardia termination zone. During the follow-up period of 7 to 11 months after implantation of PASAR 4172, no patient complained of an episode of sustained tachycardia although they experienced symptoms of an impending attack. We conclude that antitachycardia pacemaker PASAR 4172 is a safe, effective, and well tolerated method for the therapy of drug resistant paroxysmal supraventricular tachycardia and paroxysmal ventricular tachycardia.
Arrhythmias, Cardiac ; Electrodes ; Follow-Up Studies ; Humans ; Tachycardia ; Tachycardia, Paroxysmal* ; Tachycardia, Supraventricular ; Tachycardia, Ventricular

Objectives: The purpose of this study was to examine the relation between exercise intensity and immune function. Methods: Ten healthy young males underwent a constant work rate exercise of three levels, 90%, 80% and 70% ventilatory threshold (VT) work rate, for 20 min on a bicycle ergometer. These work rates were calculated for each individual based on his VT work rate obtained by the incremental exercise tests. Blood samples were collected before and after the exercise, and immune function indices were measured. Results: Compared with the obtained Vo2 at VT (VTVo2) in the incremental test, the Vo2 with the exercise of 70% VT work rate was at a similar level and the one with the exercise of 90% or 80% VT work rate had a significantly greater value. The numbers of leukocytes and neutrophils significantly increased in the 90% and 70% VT work rate groups. In 80% VT work rate group, the CD4/CD8 ratio was significantly depressed. The CD16+CD57− (%), natural killer cell populations, had a tendency to increase at 80% VT work rate, and also the CD16+CD57 + (%) had a similar tendency at 90% or 80% VT work rate. Conclusions: This study shows that moderate exercise reaching or exceeding the VT level acutely affects T cell and NK cell subsets.
Work ; Tachycardia, Ventricular ; Exercise ; Leukocytes ; immune function

BACKGROUND AND OBJECTIVES: In radiofrequency catheter ablation (RFCA), it is an essential point to understand the characteristics of local electrograms at arrhythmic focus. However controversy exists as whether the unipolar or bipolar electrogram is superior in detecting arrhythmic focus. SUBJECTS AND METHODS: We evaluated the characteristics of unipolar and bipolar electrograms at ventricular tachycardia (VT) origin. Electroanatomical mapping and RFCA were performed in 6 patients with idiopathic VT. 22 sites were enrolled and 6 of them were successful sites. We analyzed the relationship between surface and local electrograms in accordance with success or failure. We also analyzed the morphology of local electrograms. RESULTS: At successful sites of RFCA, point of unipolar onset (22.86+/-10.82 msec vs 5.47+/-26.31 msec, p<0.05) and maximal negative slope (16.57+/-17.46 msec vs -4.00+/-22.77 msec, p<0.05) were recorded earlier than unsuccessful sites. R wave amplitude (0.11+/-0.19 mm vs 0.64+/-0.57 mm, p<0.05) and R/S ratio (0.02+/-0.30 vs 0.18+/-0.26, p<0.05) of unipolar electrograms were smaller at successful sites. R wave duration was shorter at successful sites (6.29+/-8.49 msec vs 11.33+/-6.26 msec) but there was no statistical significance. QRS duration of bipolar electrograms was longer at successful sites (66.14+/-17.93 msec vs 49.07+/-13.11 msec, p<0.05). CONCLUSION: In electranatomical mapping for VT, point of unipolar onset and maximal negative slope could predict local activation time more precisely Unipolar electrograms showed shorter R wave duration and smaller R/S ratio at successful sites of RFCA. We can estimate the focus of VT by using these chracteristics of unipolar and bipolar electrogram.
Catheter Ablation ; Electrophysiology ; Humans ; Tachycardia, Ventricular*