Ventricular Tachyarrhythmias In Patients Research Articles

Surgical therapy of ventricular tachyarrhythmias in patients with coronary artery disease.

Surgical therapy of ventricular tachyarrhythmias in patients with coronary artery disease.

Circadian variation of ventricular tachyarrhythmias in patients with and without coronary artery disease

Circadian variation of ventricular tachyarrhythmias in patients with and without coronary artery disease

The Clinical Spectrum of Ventricular Tachyarrhythmias in Patients with Coronary Artery Disease

The Clinical Spectrum of Ventricular Tachyarrhythmias in Patients with Coronary Artery Disease

Radiofrequency ablation--what is left?

The purpose of this paper is to present briefly a review on the current state of the art of radiofrequency catheter ablation and describe areas of future challenge: what is left. We must ensure quality control of our training programmes and procedures as we progress to the next challenge, that of atrial fibrillation and ventricular tachyarrhythmias in patients with structural heart disease.

Circadian pattern of ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators

This study examined the temporal patterns of ventricular tachycardia detections by implantable cardioverter-defibrillators for circadian variability. Previous studies of circadian arrhythmia patterns have been methodologically limited by very brief observational periods. Late-generation implantable cardioverter-defibrillators accurately record the times of arrhythmia detections during unlimited follow-up. Forty-three patients with late-generation implantable cardioverter-defibrillators were followed up for 226 +/- 179 days (mean +/- SD). The times of all recorded episodes of ventricular tachyarrhythmias were retrieved from the data log of each device during follow-up. The weighted distribution of 830 ventricular tachyarrhythmia episodes from the 43 patients fit a single harmonic sine curve model with a peak between 2 and 3 P.M. (95% confidence interval 1:13 to 4:13 P.M., R = 0.75, p < 0.05). The distributions of spontaneously terminating episodes, episodes receiving device therapy, episodes receiving shocks and episodes in the absence of antiarrhythmic therapy also fit the sine curve model (all R = 0.53 and 0.73, all p < 0.05), all with peak frequencies between 2:08 and 3:09 P.M. and 95% confidence intervals for peak frequencies between 11:38 A.M. and 5:07 P.M. Episodes recorded during continuous antiarrhythmic drug therapy did not fit the model (p > 0.05). The distribution of ventricular tachyarrhythmias detected by late-generation implantable cardioverter-defibrillators follows a circadian pattern, with a peak tachycardia frequency between noon and 5 P.M. This pattern was not observed in patients receiving antiarrhythmic drug therapy. Knowledge of circadian periodicity for these events has implications for patient management.

Effectiveness of noninvasive programmed stimulation for initiating ventricular tachyarrhythmias in patients with third-generation implantable cardioverter defibrillators.

Previous generations of implantable cardioverter defibrillators (ICDs) required invasive electrophysiological testing to assess defibrillator function. Newer third-generation ICDs include the capability for performing noninvasive programmed stimulation (NIPS) and may reduce the need for invasive studies to assess tachycardia recognition and antitachycardia therapy algorithms. The effectiveness of ICD-based NIPS for the induction of ventricular arrhythmias has not, however, been formally assessed. Third-generation ICDs were implanted in 79 patients, who underwent a total of 166 postoperative defibrillator tests. NIPS with rapid ventricular pacing was performed in all patients in an attempt to induce ventricular fibrillation. In patients with prior sustained uniform ventricular tachycardia, programmed stimulation with up to three extrastimuli was performed in order to attempt to initiate the clinical ventricular tachcardia. Ventricular fibrillation was induced with NIPS in 146 of 166 studies (88%). Ventricular tachycardia was initiated with NIPS in 104 of 123 studies (85%). The type of defibrillator and the use of endocardial or epicardial rate sensing/pacing leads did not influence the efficacy of NIPS. NIPS with third-generation ICDs is generally effective at inducing ventricular fibrillation and clinically relevant ventricular tachycardias, and reduces the need to perform invasive electrophysiological testing following device implantation. In a minority of patients temporary transvenous pacing catheters must still be used to facilitate arrhythmia induction.

Experience with an implantable tiered therapy device incorporating antitachycardia pacing and cardioverter/defibrillator therapy

The implantable cardioverter-defibrillator provides an alternative therapy for medically refractory ventricular tachyarrhythmias in patients who are not candidates for ventricular operations or in whom these operations have failed. Currently, however, available devices have limitations. In this report we describe our experience with a programmable, tiered therapy device with anti-ventricular tachyarrhythmia pacing and VVI pacing capabilities (Cadence V-100, Ventritex Inc., Sunnyvale, Calif.). This device offers certain advantages compared with conventional implantable cardioverter-defibrillators: (1) tiered, anti-ventricular tachyarrhythmia therapy incorporating programmable, rate-adaptive burst pacing in addition to energy-programmable cardioversion/defibrillation, (2) biphasic cardioversion/defibrillation waveforms, resulting in lower defibrillation thresholds, (3) the ability to abort therapy for nonsustained ventricular tachyarrhythmias, (4) electrogram storage of detected events for later retrieval and analysis, (5) noninvasive, device-generated programmed stimulation for system testing, and (6) backup VVI pacing capability. Forty patients (aged 14 to 79 years) with ventricular tachyarrhythmias refractory to medical therapy received this device. The mean left ventricular ejection fraction was 33% +/- 16%. Preoperative electrophysiologic testing revealed inducible monomorphic ventricular tachyarrhythmia responsive to rapid ventricular pacing in 36 patients (90%). An extrapericardial two-patch configuration was used with either epicardial screw-in or bipolar endocardial sensing/pacing wires. No operative mortality and no device-related infection occurred. During a follow-up period of 16 +/- 7 months (range 3 to 30 months), 38 patients remained active with the implanted device; one patient died of congestive heart failure 4 months after implantation, and the system was explanted in one patient who underwent cardiac transplantation. In 33 patients a total of 1815 ventricular tachyarrhythmias were detected that resulted in therapy. Rate-adaptive burst pacing was used as the initial therapy in 1470 episodes and was successful in 1352 instances (92%). Pacing-induced ventricular tachyarrhythmia acceleration occurred in 4% of episodes. The remaining ventricular tachyarrhythmia episodes were treated with cardioversion. In 18 patients (45%) cardioversion therapy was aborted after spontaneous termination of ventricular tachyarrhythmia.(ABSTRACT TRUNCATED AT 400 WORDS)

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ БЕТА-АДРЕНОБЛОКАТОРОВ ПРИ ИДИОПАТИЧЕСКОЙ ЖЕЛУДОЧКОВОЙ ТАХИКАРДИИ У БЕРЕМЕННЫХ

The aim of the research: to assess neurovegetative status according to the variability of the heart rhythm in pregnant women with idiopathic ventricular extrasystole and to estimate the efficiency of beta-adrenoblockers in this category of patients. Materials and methods. To study the variability of the heart rhythm daily ECG recording was made in 38 pregnant women with ventricular arrhythmias. Control groups consisted of somatically healthy pregnant and non-pregnant women. Patients with sympathicotonia detected during Holter ECG monitoring were given metoprolol in a dose of 25 mg per day. The efficiency of the treatment was assessed by Holter ECG monitoring one week after the start of therapy. Results. It was found that the decrease of the main time and spectral indices of cardiac rhythm variability is characteristic for pregnant women with idiopathic ventricular arrhythmias V gradation by Ryan. In addition in this category of patients against the background of a lower total cardiac rhythm variability there was a significantly greater contribution of central neurohumoral influences (VLF%) and on the contrary - a smaller contribution of peripheral vagal influences (HF%). In control Holter ECG monitoring after a week use of metoprolol ventricular tachycardia was not recorded. Conclusion. In pregnant women with ventricular extrasystole V gradation by Ryan overexertion of adaptive processes in the form of a predominant influence on the regulation of the rhythm of the heart of higher vegetative centers and moderate sympathicotonia were detected. A small doses beta-adrenoblockers therapy showed high efficiency in the treatment of ventricular tachyarrhythmias in patients with autonomic dysfunction.

Incidence of QT interval prolongation during pentamidine therapy of Pneumocystis carinii pneumonia

Pentamidine isethionate, a first-line drug for the therapy of Pneumocystis carinii pneumonia, has been linked with QT interval prolongation and ventricular tachyarrhythmias in patients with the acquired immunodeficiency syndrome, 1–6 but strategies for preventing, detecting and treating pentamidine-associated QT prolongation require a better understanding of its rate of occurrence and its complications. To estimate the incidence of QT prolongation during pentamidine therapy and the incidence of serious cardiac arrhythmias among patients with QT prolongation, and to identify patients at risk for QT prolongation, we reviewed all patients treated with intravenous pentamidine at our institution over a 6-month period.

Diagnostic value of ventricular stimulation in patients with idiopathic dilated cardiomyopathy

To assess the response to programmed ventricular stimulation and the clinical outcome, we performed a prospective study in 103 patients with idiopathic dilated cardiomyopathy. The protocol used up to three extrastimuli delivered at two right ventricular sites during sinus rhythm and ventricular pacing at 100 and 150 beats/min and was repeated during infusion of 1 to 4 μg/min of isoproterenol. Sustained monomorphic ventricular tachycardia (VT) was induced in 8 of 11 patients with spontaneous sustained VT, in none of 35 patients without significant ventricular arrhythmias during Holter monitoring, and in 9 of 56 patients with salvos of ventricular premature beats. Isoproterenol infusion facilitated the induction of two episodes of sustained VT in patients with spontaneous sustained VT; however, in all but one of the remaining patients, induction of ventricular tachyarrhythmias was not impaired. During the follow-up period there were eight sudden deaths among patients who initially had syncope, inducible sustained VT, or both and three episodes of sustained VT in patients who initlally had nonsustained VT but inducible sustained VT. Isoproterenol infusion can be used to safely facilitate induction of ventricular tachyarrhythmias in patients with dilated cardiomyopathy. The induction of sustained VT was associated with a poor prognosis.

Cardiac electrophysiology: Promises and contributions

Patient J.D. is a 53 year old man who was recovering uneventfully in a coronary care unit 5 days after having an acute inferior myocardial infarction. Fifteen seconds after being told that his mother died, J.D. developed ventricular fibrillation (Fig. 1). In this presentation, I discuss concepts that relate to the onset of ventricular tachyarrhythmia in patients like J.D. I do this by reviewing some of the clinically relevant contributions made by cardiac electrophysiology and the promises that the future offers in understanding and treating patients with cardiac arrhythmias. Selected aspects of four areas will be discussed: pathogenesis, treatment, prognosis and future directions.

Predictors of inducible sustained ventricular tachyarrhythmias in patients with coronary artery disease

To determine predictors of inducible sustained ventricular tachycardia or fibrillation by programmed electrical stimulation in patients with coronary artery disease and ventricular tachyarrhythmias, 14 clinical and angiographic variables were analyzed in 60 consecutive patients. All patients had angiographically documented coronary artery disease and symptomatic ventricular arrhythmias (sustained ventricular tachycardia in 21, ventricular fibrillation in 21 and nonsustained ventricular tachycardia in 18). Baseline programmed electrical stimulation while the patient was not taking antiarrhythmic drugs was performed with use of single, double and triple extrastimuli and burst pacing from two right ventricular sites. The variables analyzed were presenting arrhythmia; presence, frequency and complexity of ventricular ectopic activity on baseline 24 h electrocardiographic (Holter) monitoring; ≥70% narrowing in either the left anterior descending, proximal left anterior descending, right coronary or circumflex coronary artery (independently assessed); single, double or triple vessel coronary disease; anterior, apical or inferior wall motion abnormalities; segmental dyskinesia and ejection fraction.Thirty-seven patients (62%) had inducible sustained ventricular tachycardia (rate >100 beats/min, duration >30 s or requiring cardioversion) and two patients (3%) had ventricular fibrillation induced. Eleven patients (18%) had nonsustained ventricular tachycardia (duration ≥3 beats, <30 s) induced and 10 patients (17%) had no inducible arrhythmia (duration <3 beats). Multivariate stepwise logistic regression analysis identified three independent variables predictive of inducible sustained ventricular arrhythmias: sustained ventricular tachycardia as the presenting arrhythmia (p = 0.0004), proximal left anterior descending artery lesion (p = 0.002) and anterior wall motion abnormality (p = 0.005). A multivariate predictor function incorporating these variables revealed a predictive accuracy of 88% for inducible sustained ventricular arrhythmia.Specific angiographic and clinical variables are, therefore, useful in identifying patients with coronary artery disease and symptomatic ventricular arrhythmia likely to have inducible sustained ventricular tachycardia by programmed electrical stimulation.

Sensitivity of an automatic external defibrillator for ventricular tachyarrhythmias in patients undergoing electrophysiologic studies

An automatic advisory external defibrillator (AED) was activated during all arrhythmias occurring at the time of 77 electrophysiologic studies in 45 patients. Sustained ventricular tachycardia (VT) occurred during 55 studies in 31 patients and nonsustained VT was induced during 10 studies in 9 patients. Ventricular fibrillation was induced 5 times in 5 patients and atrial arrhythmias with a rapid ventricular response occurred during 7 studies in 4 patients. The AED detection algorithm advised “shock” during 36 of 55 (65%) episodes of sustained VT and all 5 episodes of ventricular fibrillation. The device correctly advised “shock” for all 6 episodes of nonsustained VT that spontaneously terminated after analysis was complete. Thus, the sensitivity of the device for all ventricular arrhythmias analyzed was 47 of 66 (71%). The device recommended “shock” for all 31 episodes of rapid VT and 1 of 2 episodes of atrial fibrillation associated with systemic hypotension (32 of 33, 97%). The 19 episodes of VT for which “no shock” was advised were comparatively slow and were hemodynamically well tolerated. The device recommended “no shock” during all 21 episodes of normal sinus rhythm and all 20 episodes of rapid atrial pacing (cycle length 400 ms) analyzed. “No shock” was advised during 4 episodes of sustained narrow QRS complex supraventricular tachycardia and 4 brief episodes of nonsustained VT that terminated before analysis was complete. Thus, in this study the specificity of the AED for wide complex tachycardias was 100%.

Proarrhythmic effects of antiarrhythmic drugs during programmed ventricular stimulation in patients without ventricular tachycardia

The proarrhythmic effects of class IA antiarrhythmic drugs were prospectively evaluated during programmed ventricular stimulation in 24 consecutive patients with frequent ventricular premature beats whose baseline study, performed while no antiarrhythmic drugs were being taken, showed no inducible sustained ventricular arrhythmias. No patient had nonsustained (greater than 5 beats) or sustained ventricular tachycardia by history or baseline 24 hour ambulatory electrocardiographic monitoring. Sequential stimulation studies using up to three extra-stimuli were performed after administration of procainamide, quinidine and disopyramide on different days. Proarrhythmic response was defined as induction of one or more of the following: sustained monomorphic ventricular tachycardia; sustained polymorphic ventricular tachycardia; ventricular fibrillation; reproducibly inducible nonsustained monomorphic ventricular tachycardia. During 55 antiarrhythmic drug trials (24 of procainamide, 21 of quinidine, 10 of disopyramide) in the 24 patients, 6 patients had a proarrhythmic response: sustained monomorphic ventricular tachycardia in 3, ventricular fibrillation in 2, nonsustained monomorphic ventricular tachycardia in 1. Thus, 11% of drug trials resulted in a proarrhythmic response and 25% of patients had a proarrhythmic response to one of the drugs tested. A proarrhythmic response to one drug did not predict a similar response to another drug of the same class. The 6 patients with a proarrhythmic response did not differ significantly from the other 18 patients with regard to underlying heart disease, electrocardiographic or baseline 24 hour ambulatory electrocardiographic characteristics; however, they did have a higher incidence of digoxin usage (p less than 0.02), a shorter baseline right ventricular effective refractory period (p less than 0.01) and a smaller increment in effective refractory period during antiarrhythmic drug testing (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Susceptibility to atrial fibrillation and ventricular tachyarrhythmia in the Wolff-Parkinson-White syndrome: Role of the accessory pathway

Clinical and electrophysiologic characteristics associated with spontaneous and inducible atrial fibrillation and ventricular tachyarrhythmia were assessed in 20 consecutive patients with Wolff-Parkinson-White (WPW) syndrome undergoing surgical division (n = 12) or transcatheter electrical ablation (n = 8) of accessory pathways. Patients with spontaneous atrial fibrillation were characterized by the trend (not significant) of a shorter antegrade accessory pathway effective refractory period (256 ± 26 vs 303 ± 109 msec). However, patients with and without spontaneous atrial fibrillation did not differ with respect to prevalence of structural heart disease (3 of 11 vs 2 of 9), intra-atrial conduction time (34 ± 10 vs 32 ± 10 msec), or interatrial conduction time (86 ± 21 vs 88 ± 17 msec). Thus, atrial and accessory pathway electrophysiologic properties (per se) were not clear determinants of susceptibility to atrial fibrillation. Among the 20 patients, 10 to 35 beats of nonsustained ventricular tachycardia (seven patients) or ventricular fibrillation (three patients) were induced at electrophysiologic study with one to three programmed extrastimull. Clinically, a ventricular arrhythmia (ventricular fibrillation during atrial fibrillation) had occurred in only one of these patients. The discordance of these observations was significant ( p < 0.01). Patients with and without inducible ventricular arrhythmias were not distinguished by clinical factors or by electrophysiologic properties of the accessory pathway or ventricles. Accessory pathway conduction was completely or partially eliminated by ablation procedures in 14 of 20 patients. During a mean follow-up of 27 months, atrial fibrillation recurred in two patients with failed ablation procedures and in one patient with left atrial enlargement (despite accessory pathway division) ( p = 0.019 vs pre-ablation). Ventricular arrhythmias remained inducible in two patients in whom accessory pathway ablation failed ( p = 0.01 vs initial study). However, spontaneous ventricular tachyarrhythmias did not occur during follow-up. We conclude that susceptibility to spontaneous or inducible atrial fibrillation and ventricular tachyarrhythmia in patients with WPW syndrome and no organic heart disease depends primarlly on the existence of a functional accessory pathway. These susceptibllities are eliminated by interruption of accessory pathway conduction. Ventricular tachyarrhythmias remain infrequent spontaneous events in the WPW syndrome. Their more frequent induction at electrophysiologic study is not predictive of clinical occurrence.

Utility of ambulatory electrocardiographic monitoring for predicting recurrence of sustained ventricular tachyarrhythmias in patients receiving amiodarone

The prognostic implications of changes in ventricular ectopic activity on serial 24 hour ambulatory electrocardiographic (Holter) recordings were prospectively evaluated in 107 patients with a history of sustained ventricular tachyarrhythmias treated with amiodarone for at least 30 days. Twenty-seven patients (25%) had insufficient ventricular ectopic activity (less than 10 ventricular premature complexes/h and no repetitive forms) on baseline Holter recordings for serial statistical analysis. In 53 (66%) of the remaining 80 patients, serial 24 hour Holter monitor recordings showed efficacy of treatment, defined as a 75% decrease in ventricular premature complexes, a 95% decrease in ventricular couplets and absence of ventricular tachycardia. During a mean follow-up period of 14.2 +/- 9.9 months, 34 (32%) of the 107 patients had recurrence of a sustained ventricular tachyarrhythmia. Holter recording correctly predicted nine recurrences and correctly identified 37 patients who did not experience a recurrence. Holter efficacy failed to predict recurrence of a sustained ventricular tachyarrhythmia in 16 patients, and 18 patients remained free of recurrence despite failure to achieve Holter efficacy. The positive predictive value of Holter monitoring efficacy was 33% and the negative predictive value was 70%; however, these differences were not statistically significant by chi-square analysis. Similar results were obtained using Holter recordings performed relatively early in therapy (6 weeks and 4 months). Of the 27 patients without significant ventricular ectopic activity on the baseline Holter recording, 9 had an arrhythmia recurrence despite continued infrequent ventricular premature complexes and no repetitive forms on subsequent recordings. The recurrence rate in this group (33%) was similar to the overall recurrence rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Is the renin-angiotensin system really unnecessary in patients with severe chronic heart failure: The price we pay for interfering with evolution

Inhibition of the angiotensin-converting enzyme has become an established approach in the management of patients with severe chronic heart failure (1,2). Both captopril and enalapril produce shortand long-term hemodynamic and clinical improvement in these patients (3), and both drugs have been shown to be more effective than placebo in randomized double-blind clinical trials (4-9). The most recently published trial documenting the efficacy of enalapril in ambulatory patients with heart failure by Creager et al. (9) appears in this issue of the Journal. Other studies (I) suggest that the benefits of long-term treatment with captopril are greater than can be achieved with other vasodilator drugs, particularly hydralazine and prazosin. Furthermore, converting enzyme inhibition may reduce the frequency of ventricular tachyarrhythmias in patients with severe left ventricular dysfunction, perhaps by reducing circulating levels of catecholamines or preserving total body stores of potassium (6). By these favorable hemodynamic and antiarrhythmic actions, long-term therapy with captopril and enalapril may prolong survival in selected patients (10,11). This accumulated evidence creates a compelling case for a direct deleterious effect of the renin-angiotensin system in severe

The Sock Electrode Array: A Tool for Determining Global Epicardial Activation during Unstable Arrhythmias

The conventional technique for mapping the sequence of epicardial activation uses a hand-held electrode moved over the heart to record from a number of epicardial sites one at a time, and requires 5-15 minutes to record from 50 or more sites distributed over the entire ventricular epicardium. This method is inadequate for arrhythmias that are transient or vary from beat to beat. To overcome these limitations the "sock electrode array," a contour-fitting sock containing 26 or 52 electrodes, has been developed. The nylon mesh sock is pulled over the heart and permits simultaneous recording of potentials from electrodes distributed over the entire ventricular epicardium. The electrograms are recorded and converted to digital form for computer generation of isochronous maps. Most of the epicardial activation sequence derived from the sock electrode were compared to those obtained by the hand-held electrode in six normal dogs during sinus rhythm and ventricular pacing. The sequence of local activation times acquired by both methods showed similar areas of early and late activation and comparable isochronous maps. The hand-held electrode technique required 10-15 minutes for data acquisition and another 15-30 minutes for analysis. The sock electrode array allowed electrograms from 26 epicardial electrodes to be recorded simultaneously during one cardiac cycle and computer generated isochronous maps could be displayed within 10 minutes. This method allows rapid recording and analysis of epicardial electrical phenomena and should meet the time constraints imposed during the intraoperative study of ventricular tachyarrhythmias in patients.

Electrophysiologic properties of perhexiline

Perhexiline maleate (Pexid), a promising clinical antiarrhythmic and antianginal drug, was evaluated for its electrophysiologic effects on the entire conduction system of the intact canine heart throughout a wide range of therapeutic and potentially toxic doses. Intracardiac conduction times were measured by bipolar intramyocardial and transvenous endocardial electrodes before and following the intravenous administration of each dose of perhexiline maleate, 3 mg/kg every 30 min for a total of 4 doses in 7 open-chest anesthetized dogs. Eight animals served as controls in which similar operative technique and electrophysiologic variables were recorded after infusion of the maleate diluent. In addition, the effects of perhexiline on atrial and ventricular thresholds to electrical stimulation were recorded, as well as the QRS and QT intervals, sinus rate, and rhythm disorders. It was observed that perhexiline did not significantly (p greater than .05) alter sinus rate, QT interval, QRS duration, PR interval, intra-atrial conduction time, atrioventricular nodal conduction time, and His-Purkinje conduction velocity. The drug did not affect the cardiac threshold to electrical stimulation of less than 0.1 ma. No ectopic atrial or ventricular activity emerged during the accumulated influence of the agent. From this study, it is concluded that perhexiline does not exert deleterious actions on the conduction system of the intact canine heart. In view of the negligible toxic effects and its efficacy in treating ventricular tachyarrhythmias in patients, the drug deserves further clinical evaluation.