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Biomedical subjects

M D Lesh

Publications and source records attributed to M D Lesh.

At least 109 records · Page 6Linked to original sources
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

Interventional electrophysiology--state-of-the-art 1993.

The field of clinical electrophysiology has broadened significantly in the last several years, spawning a new discipline known as Interventional or Therapeutic Electrophysiology. In the United States, Electrophysiology has its own training path and accreditation requirements. One of the reasons for the growth of interest in electrophysiology is the exciting introduction of nonpharmacologic methods of arrhythmia therapy, including curative radiofrequency catheter ablation and implanted devices for antitachycardia pacing/defibrillation. The arrhythmia specialist now has at his/her disposal a wide range of options for patients with symptomatic or life-threatening cardiac arrhythmias.

Accreditation↗
PubMed1993

Comparison of the retrograde and transseptal methods for ablation of left free wall accessory pathways.

OBJECTIVES: The purpose of this study was to compare success rates, procedure and fluoroscopy times and complications for the transseptal and retrograde aortic approaches in a consecutive series of patients undergoing catheter ablation of left free wall accessory pathways. BACKGROUND: Radiofrequency catheter ablation of left-sided accessory pathways can be performed either by a retrograde, transaortic approach or by means of a transseptal puncture. METHODS: A total of 106 patients (mean age 33 years, range 4 to 79) underwent attempted catheter ablation of a single left-sided accessory pathway by either the retrograde or the transseptal approach, or both. In the first 65 patients, the retrograde aortic approach was the preferred initial method. In the most recent 51 patients, we first attempted the transseptal approach whenever a physician trained in the technique was available. Ultimately, 102 (96.2%) of 106 patients had successful ablation. RESULTS: Of 89 retrograde procedures, 85% resulted in elimination of accessory pathway conduction. Four retrograde procedures performed after failure of the transseptal approach were successful. Of the 13 patients with a failed retrograde procedure, 11 later underwent ablation using the transseptal approach. Twenty-six (85%) of 33 transseptal procedures were successful. All four patients with unsuccessful initial transseptal attempts were successfully treated with the retrograde method during the same session in the electrophysiology laboratory. Ten of 11 transseptal procedures after unsuccessful retrograde procedures were successful. Crossover from the retrograde to the transseptal approach was performed during a separate session in 9 of these 11. There was no difference in total procedure time (220 +/- 12.8 vs. 205 +/- 12.5 min) (mean +/- SEM) or fluoroscopy time (44.1 +/- 4.4 vs. 44.7 +/- 5.1 min) between the retrograde and transseptal methods. Ablation time was longer for the retrograde method (69.2 +/- 10.5 vs. 43.4 +/- 9.3 min) (p < 0.01). Of patients > or = 65 or < or = 16 years old, technical factors requiring crossover to the other technique or complications occurred in 7 (42%) of 17 patients undergoing the retrograde and 1 (11%) of 9 patients undergoing the transseptal approach (p < 0.01). The overall rate of complications was the same for both (6.7% for retrograde and 6.1% for transseptal). The most serious complication involved dissection of the left coronary artery with myocardial infarction during a retrograde procedure. CONCLUSIONS: The retrograde and transseptal approaches are complementary; if one method fails, the other should be attempted, yielding an overall success rate close to 100%. Because patients undergo heparinization immediately after the arterial system is entered during a retrograde procedure, failure of that approach requires crossover to the transseptal method during a separate session or reversal of heparin; if the transseptal method is tried first, crossover to the retrograde approach can be accomplished easily during the same session. To avoid complications related to access, the transseptal method should be the first used in children, the elderly and those with arterial disease or hypertrophic ventricles.

Adolescent↗
PubMed1993

Radiofrequency catheter ablation of supraventricular arrhythmias in patients with congenital heart disease: results and technical considerations.

OBJECTIVES: The aim of this study was to report the results and techniques of radiofrequency ablation for treatment of supraventricular arrhythmias in patients with congenital structural heart disease. BACKGROUND: The management of patients with congenital and other structural heart disease may be complicated by serious arrhythmias due to Wolff-Parkinson-White syndrome or by atrial arrhythmias after cardiac surgery. Ablation techniques using radiofrequency current are revolutionizing the management of arrhythmias, but reports have included few with structural heart disease. METHODS: Fifteen patients with significant heart disease underwent radiofrequency ablation: 11 with Wolff-Parkinson-White syndrome and 4 with intraatrial reentrant tachycardia after atrial surgery. Seven had Ebstein's anomaly, complex in two, and the rest had other defects. Coexistence of structural defects introduced significant technical difficulties to radiofrequency ablation in patients with the Wolff-Parkinson-White syndrome and was accomplished by adaptation of current techniques. Ablation of intraatrial reentrant tachycardia was performed by finding early atrial activation sites with electrogram fractionation for radio-frequency application. RESULTS: Radiofrequency ablation was initially successful in 14 of 15 patients, with cure in 10 and clinical improvement in 14. Two patients subsequently underwent cardiac surgery without perioperative arrhythmias. CONCLUSIONS: Radiofrequency ablation in patients with congenital heart disease and arrhythmias in both safe and effective and may be the preferred approach to treatment in some patients. In patients who are to undergo surgical correction or palliation, preoperative radiofrequency ablation of the tachycardia substrate is effective and may be preferred to operative accessory pathway division. The ablation of intraatrial reentrant tachycardia shows promise in the management of patients who have undergone extensive atrial surgery, and it may eventually become the preferred approach, particularly when there are contraindications to the use of antiarrhythmic agents.

Adolescent↗
PubMed1993

Curing reentrant atrial arrhythmias. Targeting protected zones of slow conduction by catheter ablation.

Radiofrequency catheter ablation has become the treatment of choice for paroxysmal supraventricular tachycardia involving dual atrioventricular nodes or an accessory pathway. For reentry confined to the atrium where the arrhythmia itself or the ventricular response cannot be controlled with drugs, catheter ablation of the His bundle is a treatment option, but requires implantation of a permanent pacemaker and does not restore normal rhythm. In the atria, important anatomic obstacles, such as the great veins and the ostium of the coronary sinus, interrupt the normal arrangement of myocardial fibers. Under certain circumstances these natural obstacles, or those created during atrial surgery for congenital heart disease, may help to facilitate conditions for reentrant excitation within the atrium. The purpose of this study was to evaluate the safety and efficacy of radiofrequency ablation directed at a protected isthmus of slow conduction in patients with reentrant atrial tachycardia or flutter. Eighteen patients with drug-refractory atrial arrhythmias underwent invasive electrophysiology testing, followed in the same session by ablation using radiofrequency energy delivered between the large distal electrode of a deflectable catheter and a skin patch. In eight patients, intracardiac echocardiographic imaging was performed to compliment fluoroscopy. These 18 patients had a total of 20 atrial tachyarrhythmias: atypical atrial flutter (1 patient), typical atrial flutter (13), intraatrial reentrant tachycardia (5), and sinus node reentry (1). There were 5 women and 13 men with an age range of 8 to 81 years. Structural heart disease was present in 10 of 14 patients with atrial flutter, and 4 patients with intraatrial reentrant tachycardias had surgery for congenital heart disease. Acute success was achieved in 12 of 13 cases (92%) of typical atrial flutter and in 6 of 6 cases of other atrial reentrant tachyarrhythmias, including sinus node reentry and five arrhythmias associated with congenital heart disease surgery. One patient developed a deep venous thrombosis. Radiofrequency catheter ablation, by severing narrow corridors of slow conduction, can safely abolish reentrant atrial arrhythmias in humans. Long-term follow-up evaluation will be required since these patients generally have atrial disease and recurrence of the ablated arrhythmia or the emergence of new arrhythmias is a possibility.

Adolescent↗
PubMed1993

A new statistical appraisal of baseline ECG features for localization of accessory pathways.

In order to develop a better approach to accessory pathway localization, the authors analyzed 18 separate electrocardiographic characteristics in 93 consecutive patients. All patients had successful radiofrequency catheter ablation of a single accessory pathway causing preexcitation, prolonging QRS duration to > 100 ms, with 56 pathways ablated on the right side of the heart and 37 ablated on the left side. Eight individual locations were specified at the time of ablation, five right sided and three left sided. Initially, a simple statistical approach was used, with group mean statistical comparison for both delta-wave frontal axis and QRS horizontal transition lead being compared between adjacent locations by Student's t-test. Overlap between individual values was assessed by calculating the percentage of total pathway numbers in each of the two adjacent locations being compared that lay within an arc of 2 SDs in the direction of the location being compared. The statistical significance of all 18 variables was tested using univariate analysis and oneway analysis of variance for continuous variables and the chi-square test for categorical data. Post hoc tests performed were Scheffe's test for the analysis of variance and Bonferroni's test for the chi-square test. All electrocardiographic characteristics were then reanalyzed in a stepwise linear discriminant analysis using BMDP statistical software. A jack-knifed classification was made to assess the accuracy of classification. The statistical level for a characteristic to enter the model was set at P < .05 and the statistical level for a characteristic to be removed from the model was set at P > .10. Six linear discriminant analyses were performed: (1) right side versus left side, (2) right free wall versus right septum, (3) right anterior free wall versus right posterior free wall, (4) right anterior septum versus, right midseptum versus right posterior septum, (5) left anterior pathway versus left posterior pathways, and (6) left posteroseptal versus left posterior free walls.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1992

Electrocardiographic and electrophysiologic characteristics of anterior, midseptal and right anterior free wall accessory pathways.

OBJECTIVES: The objective of this study was to define the electrocardiographic (ECG) and electrophysiologic characteristics of midseptal, anteroseptal and right anterior free wall accessory pathways. METHODS: The fully pre-excited 12-lead surface ECGs and ECGs during orthodromic atrioventricular (AV) reentrant tachycardia were compared for 13 patients with an anteroseptal, 7 with a midseptal and 7 with a right free wall accessory pathway. Routine electrophysiologic studies were performed in all and stimulation of the right ventricular summit during tachycardia was accomplished in 10 patients. RESULTS: Differences in the surface ECGs were not sufficiently sensitive to distinguish among accessory pathway locations. Premature ventricular complexes induced from the right ventricular septal summit during ventricular activation either advanced the succeeding atrial depolarization or terminated the tachycardia in three of six patients with a septal pathway and in none of the four with a right anterior pathway. The change in ventriculoatrial (VA) interval with the development of right bundle branch block during orthodromic AV tachycardia proved most helpful in distinguishing these pathways. Patients with a right anterior free wall pathway showed a change in VA interval > or = 40 ms, whereas those with an anteroseptal pathway showed changes of 20 to 30 ms and those with a midseptal pathway showed no change. CONCLUSIONS: Anteroseptal, midseptal and right anterior free wall pathways may be distinguished by using programmed stimulation of the summit of the right ventricular septum and especially with changes in the VA interval with development of right bundle branch block during orthodromic AV reentrant tachycardia.

Adolescent↗
PubMed1992

Curative percutaneous catheter ablation using radiofrequency energy for accessory pathways in all locations: results in 100 consecutive patients.

Patients with accessory pathway-mediated supraventricular tachycardia have typically been treated with drugs or surgery. Although catheter ablation using high voltage direct current shocks has been used to treat patients with drug-refractory supraventricular tachycardia, there are associated disadvantages, including damage due to barotrauma as well as the need for general anesthesia. Recently, transcatheter radiofrequency energy has evolved as an alternative to direct current shock or surgery to ablate accessory pathways. Percutaneous catheter ablation of 109 accessory pathways with use of radiofrequency energy was attempted in 100 consecutive patients. Patient age ranged from 3 to 67 years. The patients had been treated for recurrent tachycardia with a mean of 2.7 +/- 0.2 antiarrhythmic agents that either proved ineffective or caused unacceptable side effects. In seven patients previous attempts at accessory pathway ablation with use of direct current shock had been unsuccessful. Forty-five (41%) of the pathways were left free wall, 43 (40%) were septal and 21 (19%) were right free wall. Eighty-nine (89%) of the 100 patients had successful radiofrequency ablation at the time of hospital discharge. In all but 12 patients the ablation was accomplished in a single session. Complications attributable to the procedure, but not to the ablation itself, occurred in four patients (4%). No patient developed atrioventricular block or other cardiac arrhythmias. Over a mean follow-up period of 10 months, nine patients had some return of accessory pathway conduction; a repeat ablation procedure was successful in all five patients in whom it was attempted. It is concluded that a catheter ablation procedure using radiofrequency energy can be performed on accessory pathways in all locations. The procedure is effective and safer, less costly and more convenient than cardiac surgery and can be considered as an alternative to lifelong medical therapy in any patient with symptomatic accessory pathway-mediated tachycardia.

Adolescent↗
PubMed1992

Importance of recording the right bundle branch deflection in the diagnosis of His-Purkinje reentrant tachycardia.

Eight of 120 consecutive patients with inducible sustained ventricular tachycardia who were studied at our institution from September 1, 1988 to January 1, 1991, were found to have reentry within the His-Purkinje System as the mechanism of their tachycardias. Two of the eight patients (25%) required the recording of the right bundle branch potential to elucidate the tachycardia circuits. The electrophysiological findings of these two patients are described. In both instances, the diagnosis of supraventricular tachycardia with aberrancy was excluded. In patient 1, a His-bundle electrogram preceded each QRS complex during tachycardia and the His-to-His interval variation preceded changes in QRS intervals. However, recordings from the right bundle branch allowed for exclusion of bundle branch reentry and evidence was found for reentry restricted to the left fascicles. In patient 2, despite instances of dissociation of the His-bundle deflection from the tachycardia, a right bundle branch potential preceded each QRS and spontaneous changes in the interval between successive activation of the right bundle branch preceded changes in ventricular activation. Catheter ablation of the right bundle branch eliminated the tachycardia. It is concluded that the recording of a right bundle branch potential should be included in electrophysiology study of patients in whom there is suspicion of reentry within the His-Purkinje System. Clinically, recognizing these forms of tachycardias can be important because they can be effectively treated with catheter ablation.

Adult↗
PubMed1992

Coronary air embolism complicating transseptal radiofrequency ablation of left free-wall accessory pathways.

Radiofrequency catheter ablation is an important new technique for curing patients with accessory pathway-mediated tachycardia. Ablation of left free-wall accessory pathways may be accomplished either by a retrograde, transarterial approach or via a transseptal approach using a long vascular sheath. We describe air embolization into the coronary artery as a complication of the transseptal approach, which was temporally associated with catheter exchange. While there were no permanent adverse sequelae, this report emphasizes the need for scrupulous attention to the possible insinuation of air during procedures involving long vascular sheaths across the atrial septum. To prevent air embolism, we recommend slow removal of the ablation catheter along with continuous flushing with heparinized saline during exchanges.

Coronary Angiography↗
PubMed1992

Electrophysiological findings and long-term follow-up of patients with the permanent form of junctional reciprocating tachycardia treated by catheter ablation.

BACKGROUND: The permanent form of junctional reciprocating tachycardia (PJRT) commonly presents as recurrent drug-refractory, narrow-complex tachycardia. We studied the efficacy and safety of catheter ablation in treating these patients. METHODS AND RESULTS: Six patients with the diagnosis of PJRT were treated at our institution with direct-current catheter ablation. The study cohort comprised three men and three women with a mean age of 33.8 +/- 4.5 years. The mean time from onset of symptoms to ablation was 129 +/- 44.7 months. All failed multiple drug therapy (mean number of drugs failed was 5.3 +/- 0.5). The left ventricular ejection fractions were calculated by echocardiography and were greater than 60% in all except two patients, whose ejection fractions were 25% and 32%. Symptom duration was significantly longer in those with depressed ejection fraction compared with normal patients (258 versus 64.5 months, p less than 0.01). Electrophysiological findings revealed evidence of an atrioventricular reciprocating tachycardia involving retrograde decremental conduction over an accessory pathway localized to the posteroseptal area. Five patients received two direct-current shocks (250 +/- 16.7 J per shock) via paired electrodes from a catheter positioned just outside the coronary sinus os to a patch placed between the scapulae or on the anterior chest wall. One patient received a single direct-current shock of 300 J. The only complication was the development of complete atrioventricular block in one patient. This patient had previously undergone permanent pacemaker insertion for the sick sinus syndrome. The mean hospital stay after ablation was 2.2 days. Mean peak creatinine phosphokinase after ablation was 352 +/- 58.1 units/l and the MB fraction was 12 +/- 2%. Follow-up echocardiograms or gated nuclear studies showed improvement of ejection fraction in the two patients who presented with depressed ejection fractions. After a mean follow-up of 35.8 +/- 10.3 months, all patients remained free of tachycardia without antiarrhythmic drugs. CONCLUSIONS: We conclude that catheter ablation by using direct current energy appears to be an effective treatment in patients with PJRT.

Adult↗
PubMed1991

Ablation of the atrioventricular junction with radiofrequency energy using a new electrode catheter.

Percutaneous catheter ablation using radiofrequency energy can be used to interrupt atrioventricular (AV) conduction in patients with supraventricular tachycardia refractory to drugs. Results of radiofrequency ablation of the AV junction using a custom-designed catheter with a large, 3-mm-long distal electrode, 2-mm interelectrode spacing, and a shaft with increased torsional rigidity were compared with those using a standard quadripolar electrode catheter (Bard EP). An electrocoagulator (Microvasive Bicap 4005) supplied unmodulated radiofrequency current at 550 kHz, which was applied between the distal electrode of the ablation catheter and a large skin electrode. With use of the modified catheter, 12 of 13 patients (92%) had persistent complete AV block induced with 7 +/- 5 applications of 18 +/- 6 W of radiofrequency power. In contrast, complete AV block was produced in only 9 of 18 (50%) historical control patients treated with the standard catheter, despite a similar number of applications (7 +/- 5) and power output (16 +/- 4 W). A rise in impedance, due to desiccation of tissue and coagulum formation, occurred earlier (28 +/- 18 vs 52 +/- 24 seconds, p less than 0.001) and more frequently (54 vs 40% of applications, p = 0.047) in patients treated with the standard catheter than in patients treated with the modified catheter. The use of a catheter designed to increase the surface area of electrode-tissue contact allows more radiofrequency energy to be delivered before a rise in impedance occurs and appears to increase the effectiveness of radiofrequency ablation of the AV junction.

Atrioventricular Node↗
PubMed1991

Patients with supraventricular tachycardia presenting with aborted sudden death: incidence, mechanism and long-term follow-up.

A total of 13 (4.5%) of 290 patients with aborted sudden death had either documented (7; 54%) or strong presumptive evidence of supraventricular tachycardia that deteriorated into ventricular fibrillation. Six (46%) of the 13 had an accessory conduction pathway and either atrial fibrillation (5 patients) or paroxysmal atrioventricular (AV) reentrant tachycardia (1 patient) that deteriorated into ventricular fibrillation. Three patients with AV node reentrant tachycardia and four with atrial fibrillation and enhanced AV node conduction presented with supraventricular arrhythmias that deteriorated into ventricular fibrillation. Patients were treated with medical, surgical or catheter ablative procedures designed to prevent recurrences of supraventricular arrhythmias. Four patients received an implanted automatic defibrillator, but none had an appropriate device discharge. Over a follow-up period of 41.6 +/- 33.6 months, 12 patients are alive without symptomatic arrhythmias. One patient died because of severe chronic lung disease and heart failure. Supraventricular tachycardia was the cause of aborted sudden death in approximately 5% of patients referred for evaluation of sudden cardiac death. Treatment directed at prevention of supraventricular tachycardia was associated with an excellent prognosis. Current treatment techniques appear to obviate the need for automatic defibrillator therapy in these patients.

Adult↗
PubMed1991

Radiofrequency catheter ablation for treatment of bundle branch reentrant ventricular tachycardia: results and long-term follow-up.

Seven of 120 consecutive patients with inducible sustained ventricular tachycardia (from September 1, 1988 to January 1, 1991) had bundle branch reentrant tachycardia and underwent percutaneous radiofrequency ablation of the right bundle branch. The seven patients had been unsuccessfully treated with a mean of 3 +/- 1 drugs. Four patients presented with syncope and three with aborted sudden death. The baseline electrocardiogram revealed a left bundle branch block pattern in three patients and an intraventricular conduction defect in four. The baseline HV interval was prolonged in each case (79 +/- 2 ms). With use of programmed ventricular extrastimuli, sustained bundle branch reentrant tachycardia was inducible in all patients at a mean cycle length of 283 +/- 17 ms (range 230 to 350). Bundle branch reentrant tachycardia characteristics included atrioventricular dissociation, a His deflection that preceded each QRS complex and spontaneous His to His variation that preceded changes in ventricular tachycardia cycle length. A quadripolar catheter was positioned across the tricuspid valve with the distal electrode tip of the catheter near the right bundle branch. One to three applications of continuous unmodulated radiofrequency current at 300 kHz between the distal electrode and a large posterior skin patch resulted in complete right bundle branch block in all patients, after which none had inducible bundle branch reentrant tachycardia on restudy. On restudy, three of the seven patients had ventricular tachycardia of myocardial origin (not bundle branch reentry). One patient required no therapy; drug or defibrillator therapy was used in the others.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗