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T J Cohen

Publications and source records attributed to T J Cohen.

At least 37 records · Page 2Linked to original sources
PubMed1996

Development of an interactive computer-guided method for radiofrequency catheter ablation of ventricular tachycardia.

The purpose of this study was to develop a simple computer-guided approach to localizing ventricular tachycardias during ventricular mapping. Six patients with sustained monomorphic ventricular tachycardia were connected to a 32-lead computer body surface mapping system. Isoarea maps of induced ventricular tachycardia were recorded. Then a pacing probe was placed in either the right or left ventricle, and maps were generated from a variety of sites. Differences between ventricular tachycardia and pace map maxima X, Y coordinates were utilized to guide catheter manipulation and localization. In 6 of 6 patients (100%) this method appeared to provide a systematic approach to ventricular tachycardia localization. Computer-generated correlations as well as the X, Y coordinates of the QRS isoarea maxima were used to determine proximity to the ventricular tachycardia foci and direct catheter manipulation. In the next three patients this method was applied prospectively to help guide catheter manipulation during ventricular tachycardia (two right ventricular outflow tract tachycardias, and one left ventricular tachycardia). After a mean of 4.0 +/- 1.7 radiofrequency applications, ventricular tachycardia was no longer inducible, and at 7 +/- 0 months follow-up there have been no arrhythmia recurrences. We conclude that online computerized body surface mapping can assist in localizing ventricular tachycardia. Differences in maxima during pace maps and in-situ ventricular tachycardias can help with catheter manipulation as well as with more precise identification of focal tachycardias. This technique appears to hold the promise of a simple computer-guided method that may facilitate radiofrequency catheter ablation.

Adult↗
PubMed1995

Implantable cardioverter-defibrillator patch shunting effect manifestations on the body surface map.

The purpose of this study was to demonstrate the known shunting effect of implantable cardioverter-defibrillator patches using the body surface map. Using a 32-lead body surface mapping computer system (Corazonix Predictor, Oklahoma City, OK) we recorded body surface potential maps both prior to and 7 days after implantable cardioverter-defibrillator patch placement in a patient during right ventricular pacing at 60 beats/minute. This study demonstrated a marked shunting effect from the patches to the body surface during electrical depolarization as well as repolarization. In addition, patch orientation and configuration were evaluated by this method. Specifically, the waveforms were affected by the presence of insulator patches. This may be an important explanation, which may prevent appropriate transthoracic defibrillation using standard configurations. Further research is necessary to elucidate the true effect of the depolarization and repolarization waveform and defibrillator patches.

Aged↗
PubMed1995

Efficacy of pindolol for treatment of vasovagal syncope.

The purpose of this study was to evaluate the efficacy, safety, and tolerance of pindolol as initial therapy for vasovagal syncope. Head-up tilt table testing (HUT) was performed on 192 patients for syncope or near-syncope of unknown cause. Forty-four (23%) patients had a positive HUT for vasovagal syncope, and 28 (64%) received oral pindolol as initial therapy. Three patients were lost to follow-up; of the remaining 25 patients (mean age 60 +/- 22 years), 15 were women, 14 had syncope, and 11 had near-syncope. At 14 +/- 6 months' follow-up, 16 (64%) patients were without recurrence or side effects from pindolol. Of the 9 patients who stopped taking pindolol, 3 were switched to another regimen for recurrent symptoms, 2 stopped because of side effects, and 4 did not comply with the regimen. In conclusion, pindolol appears to be safe and effective as initial treatment for vasovagal syncope.

Adolescent↗
PubMed1995

Clinical experience with transvenous implantable cardioverter-defibrillators for treatment of malignant ventricular arrhythmias.

The need for thoracotomy has previously limited the use of the implantable cardioverter-defibrillator. Prior investigators have shown the efficacy and reduced risk of the transvenous implantable cardioverter-defibrillator. In this study, we report our experience with the transvenous implantable cardioverter-defibrillator as a first-line system. Thirty-four patients with mean age 63.2 +/- 10.3 years and mean ejection fraction 32.6 +/- 11.4% underwent implantation of a transvenous cardioverter-defibrillator using an Endotak lead with or without a subcutaneous patch. Twenty-one patients received a biphasic device and the remainder a monophasic device. Thirty-three of 34 patients (97%) were successfully implanted. The mean defibrillation threshold was than < or = 15.3 +/- 3.6J. Overall, 25 of 34 (74%) patients were implanted with a single endocardial lead alone. In the group receiving a biphasic device 19 of 21 (90%) were successfully implanted with a single endocardial lead alone whereas in the group receiving a monophasic device only 6 of 12 (50%) were successfully implanted with single endocardial lead alone (p < 0.05). There were no serious complications. One postoperative death was a result of end-staged congestive heart failure. We conclude that the transvenous implantable cardioverter-defibrillator is safe and efficacious and that incorporation of biphasic waveform may lead to higher rates of implantation of single transvenous lead alone without the need for subcutaneous patch.

Adult↗
PubMed1995

Radiofrequency catheter ablation as primary therapy for supraventricular tachycardia.

BACKGROUND: Initial management of patients with supraventricular tachycardias has traditionally been with medications. More recently, radiofrequency catheter ablation offers curative therapy thus obviating the need for medications with potential side effects. The purpose of this study was to evaluate radiofrequency catheter ablation as an initial strategy to cure supraventricular tachycardias. METHODS: Radiofrequency catheter ablation was attempted as the initial therapy in 49 patients with supraventricular tachycardia, 25 with atrioventricular nodal reentrant tachycardia, 20 with atrioventricular reentrant tachycardia, two with both atrioventricular nodal reentrant tachycardia and atrioventricular reentrant tachycardia, and two with atrial tachycardia. RESULTS: Supraventricular tachycardia was rendered non-inducible in 48 of 49 (98%) patients undergoing radiofrequency catheter ablation. Thirteen of 14 patients returning for follow-up electrophysiologic study at 4.9 +/- 2.2 months had no evidence of recurrence. Three patients experienced documented recurrences of supraventricular tachycardia. One of these three patient's supraventricular tachycardia was rendered non-inducible after a final ablation session, and has had no recurrence after 24 months. The other two patients await repeat ablation. Two patients required treatment for atrial fibrillation which was documented prior to ablation. There were no complications or mortality from the procedure. CONCLUSIONS: Radiofrequency catheter ablation should be considered as first line therapy for symptomatic supraventricular tachycardia.

Adolescent↗
PubMed1994

Pseudorecurrence of paroxysmal supraventricular tachycardia after radiofrequency catheter ablation.

Over an 11-month period (November 1992 to October 1993), 32 radiofrequency catheter ablations were performed for recurrent symptomatic supraventricular tachycardia in 17 patients with atrioventricular (AV) nodal reentry, 13 with AV reentry with an accessory pathway), and 2 with both AV and AV nodal reentry. Each patient underwent both diagnostic and therapeutic electrophysiologic study with radiofrequency catheter ablation in a single session. Twelve of the 32 patients had recurrent symptoms after catheter ablation. A repeat study was performed in 9 of the 12 patients. At 7.7 +/- 0.8 months (range 4 to 11) of follow-up only one patient had had a true symptomatic recurrence. Additional sessions of ablation cured this patient. We conclude that pseudorecurrence of paroxysmal supraventricular tachycardia is a common phenomenon in patients after radiofrequency catheter ablation. Follow-up electrophysiologic study demonstrates and helps differentiate pseudo from true paroxysmal supraventricular tachycardia recurrence.

Adult↗
PubMed1994

Radiofrequency catheter ablation as a primary therapy for treatment of ventricular tachycardia in a patient after repair of tetralogy of Fallot.

A 20-year-old man with previous surgical repair of tetralogy of Fallot was admitted with hemodynamically significant ventricular tachycardia that was terminated with cardioversion. He was found at electrophysiological study to have easily inducible ventricular tachycardia that was mapped to the right ventricular outflow tract. Radiofrequency catheter ablation of the ventricular tachycardia focus rendered the patient's arrhythmia noninducible. This case represents a successful radiofrequency catheter ablation of a ventricular tachycardia focus associated with tetralogy of Fallot repair.

Adult↗
PubMed1993

A comparison of active compression-decompression cardiopulmonary resuscitation with standard cardiopulmonary resuscitation for cardiac arrests occurring in the hospital.

BACKGROUND: Recent studies have demonstrated improved cardiopulmonary circulation during cardiac arrest with the use of a hand-held suction device (Ambu CardioPump) to perform active compression-decompression cardiopulmonary resuscitation (CPR). The purpose of this study was to compare active compression-decompression with standard CPR during cardiac arrests in hospitalized patients. METHODS: All patients over the age of 18 years who had a witnessed cardiac arrest while hospitalized at our center were enrolled in this trial; they were randomly assigned according to their medical-record numbers to receive either active compression-decompression or standard CPR. The study end points were the rates of initial resuscitation, survival at 24 hours, hospital discharge, and neurologic outcome. Compressions were performed according to the recommendations of the American Heart Association (80 to 100 compressions per minute; depth of compression, 3.8 to 5.1 cm [1.5 to 2 in.]; and 50 percent of the cycle spent in compression). RESULTS: Sixty-two patients (45 men and 17 women) with a mean age (+/- SE) of 68 +/- 2 years were entered into the trial. Sixty-two percent of the patients who underwent active compression-decompression were initially resuscitated, as compared with 30 percent of the patients who received standard CPR (P < 0.03); 45 percent of the patients who underwent active compression-decompression survived for at least 24 hours, as compared with 9 percent of patients who underwent standard CPR (P < 0.004). Two of the 62 study patients survived to hospital discharge; both were randomly assigned to receive active compression-decompression. Neurologic outcome, as measured by the Glasgow coma score, was better with active compression-decompression (8.0 +/- 1.3) than with standard CPR (3.5 +/- 0.3; P < 0.02). CONCLUSIONS: In this preliminary study, we found that, as compared with standard CPR, active compression-decompression CPR improved the rate of initial resuscitation, survival at 24 hours, and neurologic outcome after in-hospital cardiac arrest. Larger trials will be required to assess the potential benefit in terms of long-term survival.

Aged↗
PubMed1993

Ventricular septal summit stimulation in atrioventricular nodal reentrant tachycardia.

In all, 18 consecutive patients with atrioventricular nodal reentry tachycardia (AVNRT) underwent right ventricular (RV) stimulation during AVNRT from either the RV apex or summit. Stimulation from the RV apex advanced the tachycardia with the same atrial sequence in 6 of 18 patients (33%), but never conclusively excluded the presence of a low atrial tachycardia. RV summit stimulation resulted in direct stimulation of the low septal right atrium in 6 patients. RV summit stimulation advanced the tachycardia in 4 patients, delayed it in 2 and terminated it in 3 without an atrial electrogram. The latter 2 findings exclude the presence of a low atrial tachycardia. Thus, in patients with AVNRT, application of extrastimuli closer to the putative reentrant site enables greater efficacy in tachycardia resetting and in excluding a low septal atrial tachycardia.

Cardiac Pacing, Artificial↗
PubMed1993

Active compression-decompression resuscitation: analysis of transmitral flow and left ventricular volume by transesophageal echocardiography in humans. Cardiopulmonary Resuscitation Working Group.

OBJECTIVES: This study was designed to test the hypothesis that active compression-decompression cardiopulmonary resuscitation increases transmitral flow and end-decompression left ventricular volume over levels achieved with standard manual cardiopulmonary resuscitation. BACKGROUND: Recently, cardiopulmonary resuscitation incorporating active compression and decompression of the chest has been demonstrated to improve hemodynamic status in a canine model and in humans after cardiac arrest. METHODS: The active compression-decompression device was applied midsternum in five consecutive patients and results compared sequentially (in random order) with those of standard manual cardiopulmonary resuscitation. Both techniques were performed at 80 compressions/min with a 1.5- to 2-in. (3.8 to 5.1 cm) compression depth and a 50% duty cycle. Transesophageal echocardiographic data obtained in each patient included the velocity-time integral of transmitral pulsed Doppler recordings and two-dimensional images of the left ventricle in the long-axis view. Planimetric volume measurements of the left ventricle were obtained at both end-compression and end-decompression. RESULTS: No difference was observed in end-compression volume between the two techniques (p = 0.81). Increased end-decompression volume (active compression-decompression technique 81.3 +/- 12.5 vs. standard technique 69.4 +/- 10.8, p < 0.05), stroke volume (active compression-decompression technique 32.6 +/- 6.8 vs. standard technique 17.6 +/- 5.2, p < 0.05) and velocity-time integral of transmitral flow (active compression-decompression technique 15.8 +/- 4.3 vs. standard technique 7.8 +/- 2.3, p < 0.05) were found in the active compression-decompression group. The transmitral velocity-time integral was highly correlated with left ventricular stroke volume (r = 0.90). CONCLUSIONS: Improved transmitral flow, end-decompression left ventricular volume and stroke volume are seen with active compression-decompression resuscitation, suggesting a biphasic cardiothoracic cycle of flow. Active decompression of the chest appears to be a beneficial adjunct to standard cardiopulmonary resuscitation.

Aged↗