Radiofrequency Catheter Ablation of Drug Refractory Symptomatic Ventricular Ectopy: Short- and Long-Term Results

We performed radiofrequency catheter ablation (RFCA) in 12 consecutive patients (17-77 years) with daily, symptomatic, monomorphic ventricular ectopy (VE) (12,096 +/- 3,326 on 24-hour Holter) resistant to antiarrhythmic drugs. Nine patients had no apparent structural heart disease, 1 patient had a mild dilated cardiomyopathy, 1 patient had a treated mitral stenosis, and 1 patient had arrhythmogenic ventricular dysplasia. VE morphology was LBBB with inferior axis in 9 patients, RBBB with inferior axis in 2 patients, RBBB with superior axis in 1 patient. None of the patients had spontaneous or inducible sustained ventricular tachycardia. The VE focus was targeted with RF energy at the earliest endocardial activation site and based on a matching 12-lead ECG pace map. The VE focus was localized in the right outflow tract in 9 patients and on the left ventricle in 3 patients. RFCA was delivered with a standard 4-mm tip electrode. The ablation was initially successful in 11 patients and unsuccessful in 1 patient. All successfully ablated patients were asymptomatic and discharged without antiarrhythmic drugs. During follow-up (25 +/- 8; 17-38 months), two patients had a recurrence of symptoms, which were controlled by a previously ineffective drug. At the end of follow-up, 1,329 +/- 3198 VE were observed on Holter monitoring (P < 0.001 compared with initial values). No short- and long-term complications were observed. RFCA is a safe and effective method for treating drug-resistant symptomatic monomorphic VE in carefully selected patients. A persistent benefit without complications was obtained over a 2-year follow-up.     

Antiarrhythmic Efficacy of Ethacizine Assessed by Programmed Electrical Stimulation in Patients with Ventricular Tachycardia

The efficacy of ethacizine, a Class Ic drug, was assessed by programmed electrical stimulation (PES), delivering single, double, and triple extrastimuli at paced drives of 100 and 140 beats/min from two right ventricular sites (apex and out flow tract) in 38 patients with recurrent sustained ventricular tachycardia (VT). Underlying disease was coronary artery disease (CAD) in 26 (group I) and other conditions in 12 patients (group II; hypertrophic cardiomyopathy in 7, mitral valve prolapse in 1, and no apparent heart disease in 4). In the baseline study VT was induced in all patients. After a single intravenous dose (0.6-0.7 mg/kg) of ethacizine, VT was still inducible in six patients in group I and seven patients in group II. Ethacizine was administered on a long-term basis to all patients in a dose of 200-400 mg per day. All but one CAD patient remained free of recurrences after a mean follow-up of 16.5 (range 3-22) months, while there were recurrences in six of 12 patients in group II. We conclude that: (1) ethacizine appears to be effective in the treatment of VT in CAD patients; (2) the study demonstrates the clinical utility of PES in the management of VT, although some patients in whom VT remains inducible on ethacizine may have good clinical outcome; and (3) the efficacy of ethacizine in other forms of heart disease remains to be studied.     

Sinus Node Dysfunction and Sudden Cardiac Death Following Treatment with Encainide

Encainide, a class Ic drug, is generally thought of as having little effect on sinus node function. In this article, we present the clinical course and electrophysiological findings of a patient who had cardiac arrest after 1 week of encainide therapy for ventricular extrasystoles. No ventricular tachyarrhythmias were induced during programmed ventricular stimulation (baseline study and while receiving encainide therapy). Prior to encainide therapy, sinus node function was normal, but clinical observations after admission for cardiac arrest and subsequent electrophysiological study revealed that encainide had caused striking impairments in sinus node function. During a 6-month follow-up without antiarrhythmic drug treatment, this patient has had an uneventful course. We concluded that encainide can cause severe and life-threatening sinus node dysfunction.     

Epidemiology of Ventricular Tachycardia/Ventricular Fibrillation and Sudden Cardiac Death

Despite the difficulties correlating pathological data with acute clinical events in the field of sudden cardiac death, information useful to both the clinician and the epidemiologist has developed. Sudden cardiac death may be defined broadly. These definitions have varied, but it is now generally recognized that sudden cardiac death should reflect a time span of less than one hour. The epidemiology of sudden cardiac death incorporates many factors, including age, heredity, gender, and race. Coronary risk factors and the history of prior coronary heart disease constitute additional points of importance. Finally, clinical characteristics of the cardiac arrest patient are variable. Improving outcome in prehospital cardiac arrest victims involves a multifactorial approach involving rescue personnel, resuscitation technology, and the participation of the public.     

Value of Heart Rate Variability Parameters for Prediction of Serious Arrhythmic Events in Patients with Malignant Ventricular Arrhythmias

Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow-up (6–46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event-free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD +EF and L +EF values are powerful predictors of serious arrhythmic events.     

Device Use Patterns and Clinical Outcome of Implantable Cardioverter Defibrillator Patients with Moderate and Severe Impairment of Left Ventricular Function

The beneficial effects of implanted cardioverter defibrillator (ICD) therapy in patients with malignant ventricular tachyarrhythmias and variable degrees of left ventricular (LV) dysfunction are debated. ICD use and patient survival were examined in 128 patients with malignant ventricular arrhythmias and moderate or severe LV dys function. Group I included 64 patients with moderate LV dysfunction (LV ejection fraction of > 30%) and group H, 64 patients with severe LV dysfunction (LV ejection fracfion of ≤ 30%). Follow-up period ranged from 1 to 78 months. The two groups were similar in age, incidence of coronary artery disease and presenting arrhythmia. The mean LV ejection fraction in group I was 44%± 8% and group II was 22%± 5% (P < 0.0001). At 4 years of follow-up, 66% of patients from group I and 62% from group II (P = NS) had ICD activation for presumed ventricular tachyarrhythmia. Survival was calculated using actuarial analysis. Arrhythmic or sudden death mortality at 4 years of follow-up was 4% in group I and 7% in group II (P = NS). Cardiac mortality was for group I, 7% (P < 0.05), 12% (fP < 0,01), 15% (P < 0.01), and 15% (P < 0.01) for follow-up years 1, 2, 3, and 4, respectively. For group II, cardiac mortality was 27%, 36%, 41%, and 41% for follow-up years for 1, 2, 3, and 4, respectively. The majority of cardiac deaths in both groups was observed in the first 2 years of follow-up. However, in both groups, cardiac mortality was comparable in patients who did (users) and did not (nonusers) experience appropriate ICD shocks. Thus, the incidence of long-term ICD use is comparable in patients with moderate and severe LV dysfunction. Cardiac mortality is higher in patients with severe LV dysfunction in the first 4 years of follow-up irrespective of device use. The comparable long-term clinical outcome of ICD users and non users in patients with moderate or severe LV dysfunction can be related to elimination of arrhythmic mortality. Long-term patient survival in ICD recipients with severe LV dysfunction remains substantial even at 4 years of follow-up.     

Comparison of Epicardial and Endocardial Programmed Stimulation in Patients at Risk for Ventricular Arrhythmias After Cardiac Surgery

Programmed ventricular stimulation was performed on 36 patients after recent cardiac surgery using implanted right ventricular epicardial temporary wires and with catheters positioned percutaneously at two right ventricular endocardial sites. Patients were followed for a mean of 18.5 months (range 3 to 36 months). Epicardial wires were nonfunctional in 10 patients (28%) due to excessively high pacing thresholds. Overall, 22 patients (61%) had inducible sustained ventricular tachycardia; epicardial wires were functional in 15 (68%) of these patients. Six patients without inducible ventricular tachycardia with epicardial stimulation were inducible using endocardial stimulation. Of the 24 patients in whom epicardial and endocardial ventricular stimulation could be performed, concordant results were obtained in only 17 (71%), despite similar epicardial and endocardial ventricular effective and functional refractory periods. A total of 14 arrhythmic events occurred during the follow-up period. Of the 22 patients with an inducible sustained ventricular tachycardia, 12 (64%) had subsequent arrhythmic events. Only 2 of the 14 noninducible patients had follow-up arrhythmic events, one of which was caused by medication proarrhythmia. Endocardial ventricular stimulation had a superior sensitivity (83% versus 30%, P < 0.0001) and an improved negative predictive value (86% versus 61%, P < 0.05) compared with epicardial ventricular stimulation. These results indicate that noninducibility using epicardial programmed ventricular stimulation does not reliably portend a low risk for recurrent ventricular tachyarrhythmias. Epicardial programmed stimulation, used alone, may be inadequate for postoperative electrophysiological evaluation of patients at risk for ventricular arrhythmias.     

Computerized Methods of Pace-Mapping for Topical Diagnosis of Ventricular Arrhythmias

BOCKERIA, L.A., ET AL.: Computerized Methods of Pace-Mapping for Topical Diagnosis of Ventricular Arrhythmias. Surgical treatment of ventricular arrhythmias (VAs) is an effective method of solving sudden cardiac death. The important problem of surgical treatment of VAs is the topical diagnosis of the origin of arrhythmia. The precise localization of this area is extremely important for effectiveness of operation. The method of epicardial mapping of the heart during the induced paroxysm of VA is widely used for solving this problem. This problem is difficult when it is impossible to induce tachycardia during the operation. The method of pace-mapping was developed for such cases. This method includes sequential electrical stimulation of ventricles with ECG recording and comparison between intraoperative and preoperative ECG. The goal is the identification of the area of ventricles closed to preoperative ECG with VA. Manual processing of these data is difficult and takes time. The results of such processing have a low precision. That is why we propose using computerized methods. The goal of this investigation is to develop computerized methods of topical ECG diagnosis of VA. We propose a method of computer comparative analysis of ECG morphology for spontaneous and stimulated ECG. The goal is the determination with stimulated ECG the point of ventricles with ECG closest to spontaneous ECG during ventricular tachycardia. Nine patients (15–57 years old) with VA were studied. The main result of this investigation is that computerized pace-mapping method is an effective tool for topical diagnostics of different forms of VAs, which is impossible to induce by electrical programmed stimulation.     

Comparison of Clinical Benefits and Outcome in Patients with Programmable and Nonprogrammable Implantable Cardioverter Defibrillators

Technological advances in implantable cardioverter defibrillators (ICDs) have provided a variety of programmable parameters and antitachycardia therapies whose utility and impact on clinical outcome is presently unknown. ICDs have capabilities for cardioversion defibrillation alone (first generation ICDs), or in conjunction with demand ventricular pacing (second generation ICDs), or with demand pacing and antitachycardia pacing (third generation ICDs). We examined the pattern of antitachycardia therapy use and long-term survival in 110 patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Group I included 62 patients with nonprogrammable first generation ICDs that delivered committed shock therapy after ventricular tachyarrhythmia detection based on electrogram rate and/or morphology was satisfied. Group II included 48 patients with multiprogrammable ICDs (including second and third generation ICDs) that had programmable tachyarrhythmia detection based on rate and tachycardia confirmation prior to delivery of electrical treatment with either programmable shocks and/or, as in the third generation ICDs, antitachycardia pacing. Incidence and patterns of antitachycardia therapy use and long-term survival were compared in the two groups. The incidence of appropriate shocks in patients who completed 1 year of follow-up was significantly greater in group I (30 of 43 patients = 70% vs 11 of 26 patients = 42%; P less than 0.05). In the total follow-up period, a significantly larger proportion of group I patients as compared to group II patients used the shock therapies (46 of 62 patients = 74% vs 25 of 48 patients = 52%; P less than 0.01), with the majority doing so within the first year of implantation (96% and 92%, respectively). Although the frequency of antitachycardia therapy activation was similar, the number of shocks delivered per patient was lower in group II, particularly in the initial 3 months of follow-up (P = 0.06). No clinical variable aided in identifying users from nonusers of antitachycardia therapy. Arrhythmic mortality was virtually eliminated in both groups. Two-year actuarial cardiac survival in the two groups was similar (group I = 78% vs group II = 84%; P greater than 0.2). Survival from cardiac mortality in users and nonusers of antitachycardia therapies was also similar in both groups (P greater than 0.2) and in the total patient group (P greater than 0.2). We conclude that programmable ICDs continue to confer advantages in prevention of sudden death that were observed with nonprogrammable ICDs and can be expected to improve patient tolerance and physician acceptance of device therapy for VT/VF.     

Nonpharmacological Therapy of Ventricular Tachyarrhythmias: Observations in 554 Patients

It has been shown that conventional antiarrhythmic drug treatment is debatable, and there is growing interest in nonpharmacological techniques. We studied the outcome of 554 patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) who underwent nonpharmacological techniques from March 1980 to June 1994 at our institution. Catheter ablation was performed in 51 patients (G1), map guided surgery in 147 (G2), and cardioverter defibrillator implantation (ICD) in 356 (C3). During a mean follow-up of 37 ± 12 (< 1–137) months, incidence of sudden death (G1 4%, G2 6%, C3 3%) and cardiac death (G1 7%, G2 16%, G3 8%) were relatively low, and there was no significant differences between G1-G3. VT/VF recurrences occurred more frequently in G1 (57%) than in G2 (18%) (P < 0.01). ICD discharges occurred in 69% of patients. We conclude that nonpharmacological techniques lead to low sudden death rates; however, there is a high rate of recurrence in G1. Risk stratification is necessary to select the ideal therapy for each individual patient.     

Effects of Coronary Artery Bypass Grafting on Ventricular Arrhythmias: Results with Electrophysiological Testing and Long-Term Follow-Up

Myocardial revascularization was performed in 56 patients with coronary artery disease who presented with ventricular tachycardia (VT) (n = 39) or ventricular fibrillation (n = 17). There were 46 men and 10 women, aged 65 ± 10 years. Three vessel (n = 42) or left main disease (n = 4) was present in 82%. Left ventricular ejection fraction averaged 36%± 11%. Electrophysioiogical studies were performed preoperatively in all patients; 50 (89%) had inducible ventricular arrhythmias. Sustained monomorphic VT was induced in 40 patients (cycle length 284 ± 61 msec). Reproducible symptomatic nonsustained VT was induced in four patients and ventricular fibrillation in six patients, while six patients had no inducible arrhythmia. Preoperatively the patients with inducible VT failed 3.3 ± 1.2 drug trials during electrophysiological studies. In addition to coronary bypass, 22 patients also received an automatic implantable cardioverter defibrillator (ICD), 26 patients received prophylactic ICD patches, and 1 patient had resection of a false aneurysm. There were no perioperative deaths. Postoperative electrophysiological studies were performed in all 56 surgical survivors. Ventricular tachyarrhythmia could not be induced in the six patients who had no inducible VT preoperatively and in 13 of 40 (33%) with preoperatively inducible sustained VT or in 19 of 50 (38%) patients with any previously inducible ventricular arrhythmia, thus a totaJ of 25 patients (45%) had no inducible VT postoperatively. Of the remaining, 11 patients were treated with antiarrhythmic drugs alone, 11 had already received an ICD (combined with drugs in 7), and another 9 received the ICD postoperatively (combined with drugs in 4). At a mean foJJow-up of 28 ± 21 months there were 11 deaths (20%): 2 sudden, 5 nonsudden cardiac, and 4 noncardiac deaths. There were 16 nonfatal VT recurrences (29%): 14 among patients with persistently inducible arrhythmias, and onJy 2 among those with no inducible arrhythmia postoperatively (P = 0.004); 13 occurred in patients with an ICD (P = 0.01). Thus among these patients with malignant ventricular arrhythmias who underwent revascuJarization, 45% had no inducible arrhythmia postoperatively with 33% of those with preoperatively inducible sustained VT apparently rendered noninducible by revascularization, while the majority (70%) remained free of major arrhythmic events during long-term follow-up. We conclude that myocardial revascularization alone can result in no ventricular arrhythmia induction in selected patients with VT inducible prior to surgery. Long-term follow-up of such patients indicates a low sudden death and arrhythmia recurrence rate. Furthermore, in patients with persistently inducible ventricular tachyarrhythmias after coronary revascuJarization, the sudden death rate is low despite a high frequency of nonfatal arrhythmia recurrence when antiarrhythmic medications are guided by programmed stimulation or an ICD is used.     

Management of Nonsustained Ventricular Tachycardia Guided By Electrophysiological Testing

Two hundred eighty patients with spontaneous nonsusfained ventricular tachycardia were treated based on the results of electrophysiological testing. Seventy-nine patients had no evidence of structural heart disease, 134 had coronary artery disease, 43 had idiopathic dilated cardiomyopathy, and 24 patients had miscellaneous types of heart disease. Sustained monomorphic ventricular tachycardia was induced during electrophysiological testing in the drug free state in 52 of 280 patients (19%). Ventricular tachycardia was induced more frequently in patients with coronary artery disease (32%) than in any of the other groups (P < 0.001). The patients with inducible sustained monomorphic ventricular tachycardia underwent a mean of 1.9 ± 1.3 drug trials. Twenty-five patients had the induction of ventricular tachycardia suppressed by pharmacological therapy and were treated with the drug judged to be effective during electropharmacological testing. Twenty-seven patients continued to have inducible sustained monomorphic ventricular tachycardia despite antiarrhythmic therapy and were discharged on the drug that made induced ventricular tachycardia best tolerated. Forty-five of 280 patients (16.1%) died during a mean follow-up period of 19.6 ± 14.4 months, There were 15 sudden cardiac deaths, 21 nonsudden cardiac deaths, 6 noncardiac deaths, and 3 deaths that could not be classified. Sudden cardiac death mortality was lowest in the patients without structural heart disease (0% at 2 years), intermediate in the patients with coronary artery disease and miscellaneous heart disease (4% al 2 years), and highest in the patients with idiopathic dilated cardiomyopathy (13% at 2 years; P < 0.01 for pairwise comparisons). No patient treated with a drug that had suppressed the induction of sustained ventricular tachycardia died suddenly during the follow-up period whereas four of 27 patients who were discharged on “ineffective antiarrhythmic drugs” and 11 of 228 patients without inducible sustained ventricular tachycardia experienced sudden cardiac death during the follow-up period. By multivariate analysis, ejection fraction and inducible ventricular tachycardia during the predischarge eiectrophysiological test were independent predictors of sudden cardiac death. In conclusion, in patients with spontaneous nonsustained ventricular tachycardia: (1) Arrhythmia inducibility varies depending on the underlying heart disease. Ventricular tachycardia is most often inducible in patients with coronary artery disease and least often in patients without structural heart disease; (2) With the exception of patients with idiopathic dilated cardiomyopathy, management of patients with nonsustained ventricular tachycardia guided by electrophysiological testing appears to result in a low incidence of sudden cardiac death although effects on total mortality are less impressive; and (3) Patients with idiopathic dilated cardiomyopathy and patients with other heart diseases who continue to have inducible ventricular tachycardia despite antiarrhythmic drug therapy are at substantial risk of sudden cardiac death.     

The Signal Averaged Electrocardiogram and Programmed Stimulation in Patients with Complex Ventricular Arrhythmias

TURITO, G., ET AL.: The Signal Averaged Electrocardiogram and Programmed Stimulation in Patients with Complex Ventricular Arrhythmias. The signal averaged electrocardiogram (SA-ECG), programmed electrical stimulation (PES), and left ventricular ejection fraction (EF) studies were utilized for risk stratification and management of patients with complex ventricular arrhythmias and nonsustained ventricular tachycardia (VT). The study population included 90 patients (63 with coronary artery disease and 27 with dilated cardiomyopathy). Sustained monomorphic VT was induced in 22 cases (24%), ventricular fibrillation (VF) in 10 (11%), and no sustained VT/VF in 58 (64%). An abnormal SA-ECG was recorded in 23 patients (26%) and was more common in patients with than in those without induced sustained VT (68% vs 12%, p < 0.0001). None of 33 patients with normal SA-ECG and EF ≥ 40% had induced VT. Patients were followed-up for 2.5 ± 0.8 years off antiarrhythmic therapy, unless they had induced sustained VT. The 3-year sudden death rate was 19% in the group with induced sustained VT, 0 in that with induced VF, and 9% in that without induced VT/VF (P = NS). The 3-year total cardiac mortality was higher in patients with than in those without EF < 40% (27% vs 7%, p < 0.05). It is concluded that patients with organic heart disease and spontaneous nonsustained VT may not need PES or antiarrhythmic therapy if SA-ECG is normal and EF is ≥ 40%, since their risk of induced VT and sudden death is low. On the other hand, patients with abnormal SA-ECG and/or EF < 40% may require PES, since their risk for induced VT is high. Antiarrhythmic therapy may also be considered in these patients. (PACE, Vol. 13, December, Part II 1990)     

应激与室性心律失常

室性心律失常与应激密切相关，不仅器质性心脏病个体应激时发生室性心律失常的风险明显增加，健康个体应激时亦对室性心律失常敏感。应激时，心肌的电生理特性明显改变，心肌电不稳定性增加，早期后除极、触发活动易于发生。     

Long-Term Experience with a Preshaped Left Ventricular Pacing Lead

OLLITRAULT, J., et al. : Long-Term Experience with a Preshaped Left Ventricular Pacing Lead. This study describes a long-term experience with a new LV pacing lead. The study population consisted of 62 patients (85% men,   71 ± 10   years old) with advanced dilated cardiomyopathy, in NYHA Class III or IV despite optimal drug therapy, and a QRS duration >150 ms. Patients in sinus rhythm were implanted with a triple chamber pacemaker to maintain atrioventricular synchrony. A dual chamber pacemaker was implanted in patients in atrial fibrillation for biventricular pacing only. A clinical evaluation and interrogation of the resynchronization pacemaker were performed at implant, at 1 week (W1), one (M1), four (M4), and seven (M7) months after implantation. A longer follow-up (2 years) is available for patients implanted at the authors institution. LV measurements were pacing threshold at 0.5-ms pulse duration and pacing impedance. R wave amplitude (mV) was measured at the time of implantation only. The system was successfully implanted in 86% of patients with the latest design of the lead. Mean R wave amplitude at implant was   15 ± 7 mV   and mean pacing impedance was   1054 ± 254 Ω   . Between implant   (n = 38)   and M7   (n = 15)   , pacing threshold rose from   0.73 ± 0.54   to   1.57 ± 0.60 V (P < 0.001)   . In conclusion, the situs lead was successfully implanted in a high percentage of patients. In addition, low pacing threshold and high impedance measured during follow-up are consistent with a low pacing current drain, ensuring a durable pulse generator longevity. (PACE 2003; 26[Pt. II]:185–188)     

Mechanism of Death in Patients with the Automatic Implantable Cardioverter Defibrillator

Fifty patients underwent primary implantation of an automatic implantable cardioverter defibrillator between August 1983 and April 1988 and were entered into a long-term surveillance program. There were a total of 14 deaths (28%) in the entire group occurring at a mean of 8.7 months postimplantation. Eleven deaths were cardiac and three were noncardiac (two pneumonia, one leukemia). The group of deceased patients were similar to the survivors in all respects except for a statistically lower ejection fraction (23% vs 32%) at the time of implantation. In addition, 13/14 (93%) of the deceased patients experienced at least one appropriate AICD discharge at a mean of 4.5 months post implantation. Recorded ECGs at the time of death revealed that most of the sudden deaths were due to electromechanical dissociation and not to AICD-treatable arrhythmias. These data suggest therefore that death in AICD patients is usually cardiac, due primarily to low ejection fraction and occurs in patients who have previously received AICD discharges.