Isaac Wiener

Comprehensive clinical electrophysiologic studies in the investigation of documented or suspected tachycardias. Time, staff, problems and costs.

To assess time, staff, problems and costs involved in clinical electrophysiologic studies for documented or suspected tachycardia, 33 consecutive cases were analyzed prospectively. At least seven staff members were used for each study. Insertion of catheters required 24-105 minutes (mean 63 ± 20 minutes). Programmed stimulation required 12-210 minutes (mean 87 ± 38 minutes). Total fluoroscopy times were 6-67 minutes (mean 22 ± 15 minutes). Each study used 360-2100 feet (mean 1260 ± 390 feet) of recording paper. Detailed analysis of tracings took 1-11 hours (mean 5 ± 2.5 hours). Delays occurred during electrophysiologic study in 25 cases (76%), with multiple causes of delay in 14 cases (42%). These were caused by 1) difficulty in obtaining venous access (five patients); 2) difficult initial catheter placement (15 cases); 3) repositioning of catheters during stimulation (17 cases); 4) sustained atrial fibrillation (four cases). Coronary sinus catheterization was achieved from the groin in 21 of 27 cases (78%) in whom a sustained attempt was made. The approximate cost of each study was greater than

Reciprocal Tachycardias Using Accessory Pathways With Long Conduction Times

800. Our data show that clinical electrophysiologic studies in the investigation and management of tachycardia are difficult, time-consuming and expensive.

Determinants of ventricular tachycardia in patients with ventricular aneurysms: results of intraoperative epicardial and endocardial mapping.

Three patients with reentrant tachycardia are described who had an accessory pathway with a very long conduction time that was incorporated in the tachycardia circuit. The accessory pathway was able to conduct in one direction only, in retrograde manner in two patients and in anteriograde manner in the remaining patient. Evidence is presented that reveals that in the first two patients the accessory pathway was septally located, had completely bypassed the normal atrioventricular (A-V) conduction system, had properties of decremental conduction, and had an atrial exit close to the coronary sinus and a ventricular exit relatively far from the atrioventricular A-V ring. In the third patient, who manifested wide QRS complex during tachycardia, the ventricular end of the accessory pathway seemed to be located close to the right ventricular apex. The atrial end of the pathway could not be localized exactly.

Anatomic and electrophysiologic relation between the coronary sinus and mitral annulus: Implications for ablation of left-sided accessory pathways

We performed epicardial and endocardial mapping in 11 patients with ventricular aneurysms; six had chronic, recurrent ventricular tachycardia and five had no ventricular arrhythmias more severe than isolated ventricular premature complexes. Forty to 66 epicardial and 16-40 endocardial points were recorded during stable sinus rhythm in each patient. Local electrograms were evaluated as to timing and presence of fragmentation (duration > 50 msec, amplitude < 1 mV, absence of discrete intrinsicoid deflection). Activation of the epicardial surface of the aneurysm was abnormal in all patients, and extended beyond completion of the QRS in three patients in the arrhythmia group and two in the nonarrhythmia group (NS). Activation of the epicardial border zone was normal in all patients. Electrograms from the endocardial surface of the aneurysm were abnormally fragmented in all patients and the mean duration of activation was not different between patients with and without arrhythmias (85.5 ± 14.1 vs 96.2 13.8 msec, NS). However, in patients with ventricular tachycardia, electrograms from 33-58.3% (mean 45.5 ± 8.8%) of the endocardial border zone showed fragmentation, compared with 0-16.7% (mean 4.9 ± 7.4%) of the endocardial border zone in patients without arrhythmias (p < 0.05). Fragmentation was always along the septal border of the aneurysm. The mean duration of the most prolonged endocardial border zone electrogram was 97.5 ± 17.0 msec in ventricular tachycardia patients and 67.0 ± 27.1 msec in patients without arrhythmia (p < 0.05). Five of six ventricular tachycardia patients had electrical activity in the endocardial border zone extending beyond the end of the QRS, compared with one of five patients without ventricular tachycardia (p < 0.05). We conclude that fragmented electrical activity is present in all patients with ventricular aneurysms, but the extent and severity of fragmentation in the endocardial border zone is greatest in patients with recurrent ventricular tachycardia.

Fragmented endocardial electrical activity in patients with ventricular tachycardia: A guide to surgical therapy

To determine whether precise left-sided accessory pathway localization is possible from the coronary sinus, electrocardiogram (ECG) characteristics from the coronary sinus pair demonstrating earliest activation via the accessory pathway were compared to simultaneous mitral annular ablation catheter ECGs at successful ablation sites in 48 patients. To define the coronary sinus-mitral annular relation, the coronary sinus to mitral annulus distance (D) was measured at sequential distances from the coronary sinus os in 10 cadaver hearts. Mitral annular ECGs demonstrated earliest activation via the accessory pathway more frequently than the earliest coronary sinus pair (p < 0.001), more frequent continuous electrical activity (p < 0.001), and more frequent accessory pathway potentials (p < 0.01). D was >10 mm at 20, 40, and 60 mm, respectively, from the coronary sinus os. Coronary sinus ECGs do not precisely localize left-sided accessory pathways, which may be due in part to an average anatomic separation of more than 10 mm between the coronary sinus and accessory pathways bridging the mitral annulus.

Low-Dose Amiodarone for Atrial Fibrillation: Time for a Prospective Study?

Eight patients with ventricular aneurysms and ventricular tachycardia refractory to drugs were studied. Each patient underwent intraoperative epicardial and endocardial mapping during stable sinus rhythm. After aneurysmectomy, areas of the endocardial border zone which demonstrated fragmented activity were excised. Mapping was then repeated to ensure that major areas of fragmentation did not remain. Mapping was completed in less than 20 minutes in each patient. One patient died of pump failure before hospital discharge and a second patient, who was arrhythmia-free, died of pump failure 12 months postoperatively. Six patients are alive and free of ventricular tachycardia 5 to 25 months (mean 11.5) postoperatively. We conclude that excision of areas of fragmented electrical activity in the endocardial border zone of ventricular aneurysms is a useful approach to surgical therapy for ventricular tachycardia. This approach allows an excision directed to arrhythmogenic areas without the need for tachycardia induction in the operating room.

Initiation and termination of ventricular tachycardia by supraventricular stimuli

Because atrial fibrillation is associated with substantial morbidity, restoration of sinus rhythm is desirable. Long-term maintenance of sinus rhythm often requires chronic antiarrhythmic therapy. Class I antiarrhythmic drugs such as quinidine or propafenone maintain sinus rhythm in approximately 50% of patients at 1 year and have risks for proarrhythmia and noncardiac toxicity. Studies of low-dose amiodarone for atrial fibrillation have reported sinus rhythm maintenance in 53% to 79% of patients during a mean follow-up of 27 months. Amiodarone has a lower incidence of proarrhythmia and heart failure exacerbation compared with class I drugs. Most noncardiac side effects are dose related, and low-dose amiodarone (less than 300 mg/d) is well tolerated. The time has come for a large-scale prospective evaluation of low-dose amiodarone treatment early in the course of atrial fibrillation.

Initiation and termination of ventricular tachycardia by supraventricular stimuli: Incidence and electrophysiologic determinants as observed during programmed stimulation of the heart

In 7 of 43 patients in whom a sustained ventricular tachycardia could be induced during programmed electrical stimulation by a single ventricular premature stimulus, an identical tachycardia could also be initiated by a single atrial premature stimulus. This phenomenon was observed only in those patients in whom the ventricular tachycardia could be induced by a single ventricular extrastimulus having a prematurity index (ratio between the longst ventricular premature stimulus interval resulting in tachycardia and th duration of the basic cycle length of the paced ventricular rhythm) above 54 percent. No single instance of initiation of ventricular tachycardia by atrial premature stimuli was observed in patients with a ventricular prematurity index below 54 percent or requiring more than one consecutive ventricular extrastimulus to have tachycardia initiated. Other features of patients showing initiation of ventricular tachycardia by atrial premature stimuli were a right bundle branch block configuration of the QRS complex during tachycardia in all seven patients and a relatively slow rate during tachycardia. In one patient ventricular tachycardia was terminated by a conducted atrial premature stimulus.

Implantable defibrillators for high-risk patients with heart failure who are awaiting cardiac transplantation

In 7 of 43 patients in whom a sustained ventricular tachycardia could be induced during programmed electrical stimulation by a single ventricular premature stimulus, an identical tachycardia could also be initiated by a single atrial premature stimulus. This phenomenon was observed only in those patients in whom the ventricular tachycardia could be induced by a single ventricular extrastimulus having a prematurity index (ratio between the longst ventricular premature stimulus interval resulting in tachycardia and th duration of the basic cycle length of the paced ventricular rhythm) above 54 percent. No single instance of initiation of ventricular tachycardia by atrial premature stimuli was observed in patients with a ventricular prematurity index below 54 percent or requiring more than one consecutive ventricular extrastimulus to have tachycardia initiated. Other features of patients showing initiation of ventricular tachycardia by atrial premature stimuli were a right bundle branch block configuration of the QRS complex during tachycardia in all seven patients and a relatively slow rate during tachycardia. In one patient ventricular tachycardia was terminated by a conducted atrial premature stimulus.

Spontaneous termination of circus movement tachycardia using an atrioventricular accessory pathway: incidence, site of block and mechanisms

The objective of this study was to assess the operative risk and efficacy of implantable defibrillators for preventing sudden death in patients with heart failure awaiting transplantation. The average waiting time for elective cardiac transplantation is 6 months to 1 year. Sudden cardiac death is the major source of mortality in outpatients in stable condition awaiting cardiac transplantation. The efficacy of implantable defibrillator therapy in this population is not established. We analyzed the operative risk, time to appropriate shock, and sudden death in 15 patients determined to be at high risk of sudden death who were accepted onto the outpatient cardiac transplant waiting list. Nonfatal postoperative complications occurred in two (13%) subjects with epicardial defibrillating lead systems and in none with transvenous lead systems. Defibrillation energies were 16 +/- 2 J versus 24 +/- 2 J with epicardial and transvenous lead systems, respectively. Sudden death free survival until transplantation was 93%. Most of the patients (60%) had an appropriate shock during a mean follow-up of 11 +/- 12 months. The mean time to an appropriate shock was 3 +/- 3 months. Hospital readmission was required in three (20%) subjects to await transplantation on an urgent basis. However, two of these subjects had received appropriate shocks before readmission. In selected patients at high risk for sudden death while on the outpatient cardiac transplant waiting list, the operative risk is low and adequate defibrillation energies can be obtained to allow implantable defibrillator placement. Most subjects will have an appropriate shock as outpatients before transplantation, and sudden death free survival is excellent.(ABSTRACT TRUNCATED AT 250 WORDS)