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J H McAnulty

Publications and source records attributed to J H McAnulty.

At least 19 recordsLinked to original sources
PubMed1992

Analysis of local electrogram characteristics correlated with successful radiofrequency catheter ablation of accessory atrioventricular pathways.

UNLABELLED: Due to the limited myocardial lesions produced by radiofrequency current, the ablation of accessory pathways (AP) requires precise localization of such connections. The purpose of this study was to ascertain which characteristic(s) of the local bipolar electrogram, recorded from the ablation and adjacent electrode immediately prior to the application of radiofrequency current, correlated with precision in localization adequate to permit AP ablation. Signal analysis was performed for 326 sets of electrograms preceding the attempted ablation of 107 APs in 100 consecutive patients. For 80 antegrade APs, the following variables were evaluated: (1) the presence or absence of an AP potential; (2) the local atrial-AP interval; (3) the local atrioventricular (AV) interval; and (4) the relationship between the onset of local ventricular depolarization and onset of delta wave of the surface electrocardiogram. For the 27 concealed APs, the following characteristics were evaluated: (1) the presence or absence of an AP potential; and (2) the local VA interval during reciprocating tachycardia or ventricular pacing. RESULTS: Antegrade APs: By statistical analysis, the best correlate of successful ablation of an antegrade AP was a local AV interval less than or equal to 40 msec (positive predictive value = 94%; 95% confidence intervals [CI] = 81%-100%). Local AV intervals less than or equal to 50 msec preceded 88% of successful AP ablations, compared to only 8% of failed radiofrequency current applications. The positive predictive value of the other variables were: presence of an AP potential: 35% (95% CI = 27%-40%); local atrial-AP intervals less than or equal to 40 msec: 54% (95% CI = 43%-66%); and local ventricular depolarization preceding onset of the delta wave 43% (95% CI = 34%-52%). For concealed APs, the positive predictive value of a VA interval less than 60 msec was 71% (95% CI = 48%-88%); the positive predictive value for the presence of an AP potential was 58% (95% CI = 32%-81%). CONCLUSIONS: No single electrogram characteristic had a positive predictive value and a sensitivity greater than 90% for AP localization adequate for radiofrequency current ablation. For antegrade APs, the best correlate of adequate localization was a local AV interval less than or equal to 40 msec; as a corollary, radiofrequency current applications at sites where the local AV was greater than 60 msec, were unlikely to be effective. Objective criteria for the localization of concealed APs were less certain. Electrogram analysis, as a guide to AP localization and ablation, requires careful analysis of multiple variables, with analysis of the local AV interval a salient objective factor.

Adult↗
PubMed1990

Caffeine and ventricular arrhythmias. An electrophysiological approach.

Little information is known regarding caffeine's effect on the substrate supporting sustained ventricular arrhythmias. This prospective study evaluated the effect of coffee (275 mg of caffeine) on this substrate with programmed ventricular stimulation in 22 patients with a history of symptomatic nonsustained ventricular tachycardia, ventricular tachycardia, or ventricular fibrillation. Patients underwent electrophysiological testing before and 1 hour after coffee ingestion. Mean (+/- SEM) plasma caffeine level achieved after coffee consumption was 6.2 +/- 0.5 mg/L. Mean plasma catecholamine and potassium values were not altered significantly 1 hour following caffeine ingestion. The number of extrastimuli required to induce an arrhythmia was unchanged in 10 patients (46%), increased in six (27%), and decreased in six (27%). Rhythm severity was unchanged in 17 patients (77%), more severe in two (9%), and less severe in three (14%). In those patients with clinical ventricular arrhythmias, caffeine did not significantly alter inducibility or severity of arrhythmias, suggesting little effect on the substrate supporting ventricular arrhythmias.

Adult↗
PubMed1990

Analysis of programmed stimulation methods in the evaluation of ventricular arrhythmias in patients 20 years old and younger.

The purpose of this study was to systematically evaluate programmed ventricular stimulation in patients less than 21 years of age undergoing electrophysiologic testing. A standardized protocol was applied in 55 consecutive patients (mean age 14 years) with the following clinical presentations: sustained ventricular tachycardia (VT) (n = 17); ventricular fibrillation (VF) (n = 7); syncope with heart disease (n = 10); nonsustained VT (n = 6); and syncope with an ostensibly normal heart (n = 15). The stimulation protocol consisted of 1 and 2 ventricular extrastimuli during sinus rhythm, followed by 1 to 4 (S2, S3, S4, S5) extrastimuli during pacing at 2 ventricular sites. Of the 17 patients with sustained VT, 12 had induction of the arrhythmia (sensitivity = 71%). Overall, 18 of 55 patients had inducible sustained VT, with this response significantly enhanced by use of S4 or S5 protocols (p = 0.02). Although no syncope patients with an ostensibly normal heart had inducible sustained VT, 7 had polymorphic nonsustained VT in response to ventricular stimulation. The mean number of extra-stimuli preceding the induction of nonsustained or sustained VT or VF did not differ. The induction of VF in 5 cases during this study was preceded in each case by extrastimuli intervals less than or equal to 190 ms. Thus, data indicate that aggressive stimulation protocols appear to be required for induction of sustained VT in most young patients, nonsustained polymorphic VT as a response to aggressive programmed stimulation is of uncertain significance, and that coupling intervals less than or equal to 190 ms may correlate with the induction of VF.

Adolescent↗
PubMed1990

Day-to-day reproducibility of antiarrhythmic drug trials using programmed extrastimulus techniques for ventricular tachyarrhythmias associated with coronary artery disease.

Forty-nine patients with coronary artery disease and documented clinical sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) were studied twice in the drug-free state and twice during treatment with an identical antiarrhythmic medication at therapeutic plasma concentrations using an identical programmed electrical stimulation protocol. Tested drugs included procainamide, quinidine, disopyramide and phenytoin. During their 2 paired tests, 11 patients had nearly identical therapeutic plasma concentrations of antiarrhythmic agents (group I) and 38 patients had therapeutic plasma concentrations, but with more variation in drug levels between otherwise identical paired drug tests (group II). Overall, 71% of patients had inducible sustained VT or VF during drug testing. Induced ventricular arrhythmias were not reproducible in 45% of group I patients, despite restudy at nearly identical therapeutic plasma concentrations of an identical antiarrhythmic agent. Induced arrhythmias were also not reproducible in 16% of group II patients. This variability could not be attributed to the electrophysiologic characteristics of the patients studied. Drug trials directed by programmed stimulation should be cautiously interpreted because time-associated changes can mimic a change attributed to a beneficial or deleterious drug effect.

Anti-Arrhythmia Agents↗
PubMed1990

Spontaneous sustained ventricular tachyarrhythmias during treatment with type IA antiarrhythmic agents.

Twenty-six patients who developed their first clinical episode of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) while taking type IA antiarrhythmic agents for more benign rhythm disturbances were rechallenged with the identical drug during electrophysiologic testing. Patients with these new drug-associated spontaneous ventricular arrhythmias often manifested a preexisting substrate for such arrhythmias: sustained VT or VF was induced in 65% of patients at baseline, and in 58% of patients when tested with their previously taken antiarrhythmic drug. Among those without inducible sustained ventricular arrhythmias in the drug-free state, 78% remained free of inducible sustained arrhythmias when tested with the same drug they had been taking at the time of the clinical arrhythmia. Even patients without a definable electrophysiologic substrate for sustained VT or VF remained at risk for arrhythmia recurrence if treated with alternative antiarrhythmic medications: 40% of such patients who continued to receive an antiarrhythmic agent different from that being administered when their clinical VT or VF occurred had recurrent spontaneous ventricular tachyarrhythmias during follow-up. Thus, patients with drug-associated clinical sustained ventricular tachycardias form a heterogenous group that should be evaluated individually and not empirically managed for a "proarrhythmic effect" simply by antiarrhythmic drug withdrawal or drug substitution.

Anti-Arrhythmia Agents↗
PubMed1990

Bradycardia-mediated tachyarrhythmias in congenital heart disease and responses to chronic pacing at physiologic rates.

The coexistence of bradycardia and a tachyarrhythmia may preclude effective pharmacologic treatment of 1 arrhythmia without paradoxic aggravation of the other. This study evaluated the potential relation between the 2 types of arrhythmias and the effect of conventional modes and rates of pacing for bradycardia on the frequency of the associated tachyarrhythmias. Twenty-one young patients, aged 2 to 19 (mean 11) years with congenital heart disease and a tachyarrhythmia occurring in the setting of chronic bradycardia were studied. The effects of pacing were evaluated by comparison of the number of episodes of clinical tachycardia during the 12-month intervals before and after pacemaker implantation. During these intervals, antiarrhythmic drug therapy was not altered. Patients were analyzed as independent groups, based on the type of tachyarrhythmia: supraventricular (n = 5), atrial flutter (n = 9) and ventricular (n = 7). The modes of chronic pacing were AAI (n = 4), DDD (n = 6) and VVI (n = 11). The prevention of bradycardia by pacing was associated with a significant decrease in the frequency of supraventricular (p = 0.008) and ventricular (p = 0.02) tachyarrhythmias. However, the frequency of atrial flutter was not altered. Prevention of tachycardia was more frequently associated with the AAI and DDD modes of pacing compared to VVI (p = 0.08). Pacing represents an effective therapy for certain tachyarrhythmias associated with chronic bradycardia, although critical modes may be required.

Atrial Flutter↗
PubMed1990

Long-term outcome in patients who survive out of hospital ventricular fibrillation and undergo electrophysiologic studies: evaluation by electrophysiologic subgroups.

The long-term outcome of 241 survivors of out of hospital ventricular fibrillation who underwent programmed electrical stimulation was evaluated. Patients were categorized according to the rhythm induced at baseline drug-free electrophysiologic testing. Ventricular fibrillation was induced in 39 patients (16%) (Group 1), sustained ventricular tachycardia in 66 patients (27%) (Group 2) and nonsustained ventricular tachycardia in 34 patients (14%) (Group 3); 102 patients (42%) (Group 4) did not have an arrhythmia inducible at baseline electrophysiologic testing. Antiarrhythmic drugs were administered over the long term to 92% of patients in Group 2, 91% of patients in Group 1 and 47% of patients in Group 4. At a mean follow-up time of 30 +/- 15 months, recurrent sudden cardiac death or nonfatal ventricular fibrillation occurred in 11 (28%) of 39 patients with inducible ventricular fibrillation (Group 1), 14 (21%) of 66 patients with inducible sustained ventricular tachycardia (Group 2), 4 (12%) of 34 patients with inducible nonsustained ventricular tachycardia (Group 3) and 16 (16%) of 102 patients without inducible arrhythmias (Group 4). Actuarial analysis revealed a 2 year cumulative arrhythmia-free survival rate of 65% for patients in Group 2, 71% for patients in Group 1, 79% for patients in Group 3 and 81% for patients in Group 4 (p = 0.02). Actuarial survival of patients with inducible sustained ventricular tachycardia or ventricular fibrillation suppressed by electrophysiologically guided drug therapy was not significantly different from that in patients whose arrhythmia was not suppressed. Multivariate regression analysis revealed that only the presence of congestive heart failure was an independent predictor of outcome in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1990

Comparison of ventricular arrhythmia induction with use of an indwelling electrode catheter and a newly inserted catheter.

Two methods of serial electrophysiologic testing are in widespread use. Most commonly, the electrode catheter is removed after each study and a new catheter reinserted through the femoral vein for every subsequent test. An alternative method employs an electrode catheter that remains in place during several days of serial testing. Little is known about differences between these two methods with respect to the likelihood of induction of arrhythmia or the frequency of complications. To determine whether inducibility of sustained arrhythmia is altered or if the frequency of complications is unacceptably high with use of an indwelling catheter, a prospective randomized study was conducted in 78 patients. Each patient underwent baseline testing, several days of electropharmacologic testing with an indwelling catheter, a 24 h drug elimination period and placement of a new electrode catheter. Ventricular stimulation studies were then performed in each patient with both the indwelling and new electrode catheters. No differences were found between the indwelling and new catheter tests with respect to induction of arrhythmia, number of extrastimuli required to induce arrhythmia, rate of arrhythmia or requirement for cardioversion. Ventricular pacing thresholds were higher and effective refractory periods were slightly longer when measured with the indwelling catheter. Complications related to the 156 catheter insertions included two that may have been related to the indwelling catheter (one episode of staphylococcal sepsis and one presumed pulmonary embolism) and four that were related to invasive procedures (pneumothorax in all). There were no long-term adverse sequelae of these complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1990

Assessment and follow-up of pediatric survivors of sudden cardiac death.

In the young patient resuscitated from sudden cardiac arrest, the risks of recurrence are uncertain and so are the criteria defining therapeutic efficacy for the presumed cause of the initial event. In this study, we analyzed the outcome of 15 consecutive young patients, who were resuscitated from pulseless ventricular tachycardia or ventricular fibrillation and who were evaluated by comprehensive hemodynamic and electrophysiological testing. Patients were 11.2 +/- 2.7 (mean +/- SD) years old at the time of their event, and each was known to have some form of heart disease before sudden cardiac arrest. Ventricular tachycardia or fibrillation was inducible by programmed electrical stimulation in eight patients. Accessory atrioventricular connections, with antegrade effective refractory periods less than 220 msec, were identified in three patients. Sustained atrial flutter was the only arrhythmia inducible in two patients, and no arrhythmias were inducible in two other patients. Surgical or electrophysiological-guided medical therapy resulted in noninducibility of the ventricular arrhythmias in six patients. Surgical division of the accessory atrioventricular connections was performed in three patients, and arrhythmias were not inducible after operation. The four patients with atrial flutter or without defined arrhythmia were treated with an empiric therapy. During 37 +/- 14 months of follow-up, the nine patients with documented noninducibility of a defined cause of sudden cardiac arrest were free of recurrent events. In contrast, during 18 +/- 10 months of follow-up, two of the six patients with empiric therapy or persistent inducibility of ventricular tachycardia died suddenly, and three others had recurrence of ventricular tachycardia or fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Misdiagnosing ventricular tachycardia in patients with underlying conduction disease and similar sinus and tachycardia morphologies.

Six patients presented with wide-complex tachycardias with QRS morphologies similar to those seen on their electrocardiograms that showed normal sinus rhythms. During normal sinus rhythm, each patient had an underlying intraventricular conduction abnormality or bundle branch block. Despite the similarity of the QRS complexes to those seen during sinus rhythm, the tachycardias subsequently proved to be ventricular in origin in each patient. It is important not to misdiagnose these disorders as supraventricular tachycardia as an erroneous diagnosis may result in inappropriate management.

Aged↗
PubMed1989

Psychophysiological factors in ventricular arrhythmias and sudden cardiac death.

Plasma catecholamine levels were measured preceding programmed electrophysiological studies of patients who had survived a ventricular tachyarrhythmia episode. Psychological assessments of desire for control, locus of control and behavior pattern were obtained. Psychophysiological variables were analysed with respect to the severity of arrhythmias induced by the electrophysiological procedure. Analysis of data from 17 subjects showed desire for control was significantly higher in those with induced sustained arrhythmias than in those in which nonsustained arrhythmias were induced. No relationship was found between behavior pattern and arrhythmia severity or plasma catecholamine levels. There was a significant interaction between desire for control and behavior pattern with respect to epinephrine level. The findings indicate that psychological factors such as desire for control may be associated with potentially lethal arrhythmias and implicated in sudden cardiac death.

Adult↗
PubMed1988

Limited value of programmed electrical stimulation from multiple right ventricular pacing sites in clinically sustained ventricular fibrillation or ventricular tachycardia associated with coronary artery disease.

One-hundred and fifty patients with coronary artery disease and a documented history of sustained ventricular tachyarrhythmias were studied to determine if programmed electrical stimulation (PES) from a second right ventricular (RV) pacing site optimizes the induction of such sustained arrhythmias. The first PES test was performed from 2 RV pacing sites (apex and outflow tract or septum) using the apex first in each patient. All patients underwent a second PES within 6 to 24 hours of the first; both studies used up to 4 ventricular extrastimuli, in the absence of antiarrhythmic treatment. The second PES was performed from a single RV apical site using a pacing catheter retained from the first study. During the first day's study, 74 patients (49%) had sustained ventricular tachycardia induced from the RV apex. Only 11 of the remaining 76 patients (7% of the total group) were inducible exclusively from a second RV pacing location during the first day's testing. Seven of these 11 patients, as well as 15 additional patients who did not have ventricular tachycardia induced from either site on the first day's study, were inducible from the RV apex during the second drug-free study. Among patients with sustained ventricular tachyarrhythmias, limiting PES to a single RV site, with the option of performing a second study in those who are initially noninducible is more effective in inducing sustained ventricular tachyarrhythmias than is PES performed from 2 RV pacing sites.

Adult↗
PubMed1988

Idiopathic dilated cardiomyopathy. Role of programmed electrical stimulation and Holter monitoring in predicting those at risk of sudden death.

The prognostic role of programmed electrical stimulation and Holter monitoring was evaluated in 21 patients with idiopathic dilated cardiomyopathy who had no prior history of ventricular tachyarrhythmias. During a mean follow-up period of 23 months, sudden death or ventricular fibrillation occurred in four (20 percent). One patient died of complications of sepsis, and one underwent cardiac transplantation. Programmed electrical stimulation (PES) resulted in five or more beats of induced ventricular tachycardia in seven patients (33 percent), but was a poor predictor of sudden death (sensitivity = 20 percent). Thirteen patients (62 percent) had complex ventricular ectopy (Lown class 4A or 4B) by ambulatory monitoring. This was a sensitive (80 percent) but not specific (31 percent) marker for sudden death. The predictive value of a negative Holter monitor study was high (80 percent) for identifying those at low risk of sudden death. The results of this prospective study suggest that programmed ventricular stimulation and routine ambulatory monitoring are poor predictors of sudden death in this population.

Adult↗
PubMed1987

Ventricular fibrillation survivors in whom tachyarrhythmia cannot be induced: outcome related to selected therapy.

Eight-five patients were studied to determine the prognosis of the ventricular tachyarrhythmias at the time of electrophysiologic study. Twenty-five patients (29%) were not inducible when we used a stimulation protocol consisting of up to four extrastimuli delivered at two right ventricular sites. Patients with no inducible arrhythmias were younger (53 vs 59 yrs; p = .06) and had higher ejection fractions (.49 vs .34; p less than .04) than the inducible ventricular fibrillation survivors. Sex, cardiac diagnosis, time from event to electrophysiologic study, and antiarrhythmic therapy at the time of event did not discriminate between those with and those without inducible ventricular tachyarrhythmias. Survival free of recurrent sudden death or ventricular tachycardia was .86 +/- .05 and .95 +/- .05 for patients with and without inducible tachyarrhythmias, respectively (p = .22). Nine of 25 (36%) patients with no inducible arrhythmias developed inducible ventricular tachyarrhythmias when testing was repeated with an antiarrhythmic drug. Ventricular fibrillation survivors not inducible at the time of programmed ventricular stimulation (using a stimulation protocol consisting of four extrastimuli delivered at two right ventricular sites) seem to have a good prognosis. Many "noninducible" patients develop inducible tachyarrhythmias when placed on antiarrhythmic therapy. Because it is possible that these drugs are proarrhythmic, empiric antiarrhythmic therapy should be avoided in these patients.

Adult↗
PubMed1986

Measurement of the AH and HV interval and His bundle duration: interobserver and intraobserver variation.

Conduction system intervals measured during intracardiac electrophysiologic testing influence clinical decisions. To evaluate measurement reliability, interobserver and intraobserver variation for AH, HV, and His bundle duration measurements from 50 patients were evaluated. The square of the correlation coefficient (r2) was used as the index for measurement reliability. Three investigators performed the measurements. The r2 for interobserver variation of the AH interval ranged from 0.55 to 0.68 and for intraobserver variability from 0.60 to 0.88. The standard error of measurement based on intraobserver measurements ranged from 10.2 to 18.0 ms. The r2 for interobserver variation of the HV interval ranged from 0.42 to 0.63 and for intraobserver variation from 0.489 to 0.73. The standard error of measurement was 6.2 to 9.9 ms. For the His bundle duration, the r2 for interobserver variation ranged from 0.42 to 0.52 and for intraobserver variation from 0.19 to 0.52. The standard error of measurement was 3.1 to 5.2 ms. Although there is measurement variation for AH and HV intervals, their use in conjunction with the history and the surface electrocardiogram to make clinical decisions is appropriate. His bundle duration cannot be measured reliably using the standard recording technique and should not be used for clinical decision making.

Bundle of His↗
PubMed1986

Prognostic value of programmed electrical stimulation in patients with a recent episode of unstable angina.

Patients with a recent episode of unstable angina have a 10% 1-year risk of sudden cardiac death. To determine prospectively whether electrophysiologic testing might be useful in predicting sudden death, 20 patients admitted to our hospital underwent programmed electrical stimulation as part of their evaluation. None had persistent angina, severe congestive heart failure, or sustained arrhythmias at the time of testing. Because of their long-term benefits, beta-blocking agents were continued whenever possible (18 of 20 patients). Ten of 20 patients (50%) had inducible ventricular tachycardia. In 19.5 months' mean follow-up, three patients (15%) either died suddenly or survived an episode of ventricular fibrillation. Programmed electrical stimulation was an insensitive (33%) and nonspecific (47%) predictor of sudden death in these patients. Programmed ventricular stimulation soon after admission for unstable angina is not a useful prognostic indicator for sudden death. Such patients do have a frequent induction of ventricular arrhythmias which appears to be a nonspecific marker of underlying coronary disease.

Actuarial Analysis↗
PubMed1986

Reproducibility of arrhythmia induction with intracardiac electrophysiologic testing: patients with clinical sustained ventricular tachyarrhythmias.

In order to characterize the day to day reproducibility of arrhythmias provoked during electrophysiologic stimulation, 114 patients with documented sustained clinical ventricular tachyarrhythmias were studied. Two baseline electrophysiologic tests were performed in the drug-free state and within 6 to 24 hours of one another. There was a significant increment (p less than or equal to 0.02) in the induction of sustained ventricular tachyarrhythmias as the number of programmed extrastimuli increased from one (10% induction) to four (64% induction). Provoked arrhythmias were observed to be more frequently nonreproducible (as reflected in a major change in rate or duration, or both, of an induced ventricular arrhythmia between baseline tests) as the number of extrastimuli increased from one (7%) to four (27%). Nonreproducibility with three and four extrastimuli was not significantly greater than when two extrastimuli were utilized. Electrophysiology-directed drug trials should be interpreted in light of this observed variability in induced arrhythmias.

Adolescent↗