Sustained ventricular tachyarrhythmias within 2 months of acute myocardial infarction: results of medical and surgical therapy in patients resuscitated from the initial episode

Surgical therapy of ventricular arrhythmias

Since the advent of implantable cardioverters/defibrillators (ICD) and percutaneous ablation, surgery for the treatment of ventricular arrhythmia has decreased tremendously. Nevertheless, surgical treatment of ventricular arrhythmias is still required, especially for cases where ICD discharge occurs very frequently or in patients with other indications for surgery. The choice of surgical therapy may range from radiofrequency- or cryoablation of a single focus (identified either intra- operatively or percutaneously) to more extensive surgical procedures such as surgical ventricular reconstruction with endocardial resection or even resection of the right ventricle and the creation of a cavo-pulmonary circulation for malignant arrhythmias and right ventricular failure in patients with arrhythmogenic right ventricular dysplasia. However, the choice of surgical procedure should be made based on the pathomechanism of the arrhythmia. This is important because any incision in the left or right ventricle or percutaneous ablation may also be the cause for ventricular arrhythmia. In this short review we will describe the most common underlying substrates for ventricular arrhythmia, indications for surgery, the techniques used for treatment and the results achieved. We will conclude that for most cases of patients with ventricular arrhythmia undergoing surgery, ischemia and the presence of a scar after myocardial infarction is the underlying cause and revascularization plus surgical ventricular reconstruction with endocardial resection may be the best treatment option.

Arrhythmic complications of acute coronary syndromes

Cardiac arrhythmias routinely manifest during or following an acute coronary syndrome (ACS). Although the incidence of arrhythmia is directly related to the type of ACS the patient is experiencing, the clinician needs to be cautious with all patients in these categories. As an example, nearly 90% of patients who experience acute myocardial infarction (AMI) develop some cardiac rhythm abnormality and 25% have a cardiac conduction disturbance within 24 hours of infarct onset. In this patient population, the incidence of serious arrhythmias, such as ventricular fibrillation (4.5%) ,is greatest in the first hour of an AMI and declines rapidly thereafter. This article addresses the identification and treatment of arrhythmias and conduction disturbances that complicate the course of patients who have ACS, particularly AMI and thrombolysis. Emphasis is placed on mechanisms and therapeutic strategies.

Incidence and short-term prognosis of late sustained ventricular tachycardia after myocardial infarction: results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-3) Data Base

BACKGROUND

There is little epidemiologic information from large multicenter databases on sustained monomorphic ventricular tachycardia occurring after the initial 48 hours of myocardial infarction.

METHODS

We reassessed its incidence and short-term prognosis in 16,842 patients with a definite myocardial infarction enrolled in the Gruppo Italiano per lo Studio della Soprovvivenza nell'Infarto Miocardico (GISSI-3) trial.

RESULTS

The incidence rate of late sustained ventricular tachycardia by 6 weeks was around 1%. Older age, a history of hypertension, diabetes, and myocardial infarction, nonadministration of lytic therapy, Killip class > I, > or = 6 leads with ST-segment elevation, higher heart rate, and bundle branch block on admission were significantly more frequent among patients with than without late sustained ventricular tachycardia. Patients with ventricular tachycardia had a more complicated course in-hospital and posthospital to 6 weeks than the reference group did. The arrhythmia was associated with a significant excess of pump failure, atrial flutter-fibrillation, asystole, atrioventricular block, ventricular fibrillation within the first 48 hours of myocardial infarction, and recurrent ischemic events. Larger left ventricular end-systolic volumes and lower ejection fractions were more frequent among ventricular tachycardia patients than in the reference group by 6 weeks. Death rates by 6 weeks were 35% for patients with ventricular tachycardia and 5% for those without the arrhythmia. Irrespective of the stratification of patients by site and type of infarct and presence/absence of bundle branch block, the occurrence of the arrhythmia was associated with reduced 6-week survival.

CONCLUSION

In a proportional hazard regression model late sustained ventricular tachycardia was retained as a strong, independent predictor of 6-week mortality after myocardial infarction (hazard ratio 6.13, 95% confidence interval 4.56-8.25).

[Endocardial ablation of substrate of postinfarction ventricular tachycardia during sinus rhythm]

OBJECTIVE

Radiofrequency ablation of ventricular tachycardia requires good tachycardia tolerance during mapping and entrainment, and this limits its application. We present our initial experience with ventricular tachycardia ablation during sinus rhythm in 7 patients with previous inferior myocardial infarction.

METHODS

Seven men, 56-70 years old (mean +/- SD, 65 +/- 4.5) were included in the study. Ventricular tachycardia was unstable in 6 and in 1 it was induced non-sustained. The scar was localized by recording low-voltage, fragmented electrograms (< 2 mV). Ventricular tachycardia "exit" was localized by pace-mapping in sinus rhythm. Radiofrequency lines were made radially, point by point, from normal to scarred tissue. One of the lines crossed the exit area. The objective was to achieve non-inducibility.

RESULTS

Sustained clinical ventricular tachycardia was induced in 6 and non-sustained in 1. Two-four lines were performed per patient with 11-28 (21 +/- 5.4) radio frequency applications. The procedure duration was of 130-280 min (230 +/- 61) and being 49-75 min (63 +/- 7.9) for fluoroscopy. There were no complications. Clinical ventricular tachycardia became non-inducible in 6, although in 4 a rapid (cycle < or = 250 ms), non-clinical ventricular tachycardia remained inducible. Defibrillators were implanted in the patient remaining inducible for clinical ventricular tachycardia and another with > 60 tachycardia episodes the previous week. During 3-22 months (13.8 +/- 5.9) of follow-up, 1 patient died of heart failure at 20 months and another received 3 defibrillator shocks for VT at 13 months. There were no other episodes of ventricular tachycardia, syncope or sudden death.

CONCLUSIONS

This preliminary experience suggests that radiofrequency ablation of post-infarction ventricular tachycardia substrate is possible during sinus rhythm, suggesting that radiofrequency ablation may be applicable in a large proportion of patients with post-infarction sustained ventricular tachycardia.

Role of orthotopic heart transplantation in the management of patients with recurrent ventricular tachyarrhythmias following myocardial infarction

OBJECTIVE

To report the outcome of an intention to treat by heart transplantation strategy in two groups of patients after infarction, one with both left ventricular failure (LVF) and ventricular tachyarrhythmias (VTA) (group A) and the other with progressive LVF following antiarrhythmic surgery for VTA (group B).

PATIENTS AND METHODS

Group A comprised 17 consecutive patients for whom transplantation was considered the best primary non-pharmacological treatment; group B comprised five consecutive patients assessed and planned for transplantation after antiarrhythmic surgery.

RESULTS

In group A, eight patients underwent transplantation and all survived the first 30 day period. At median follow up of 55 months (range 11 to 109) seven of this subgroup were still alive. Five patients died of recurrent VTA before transplantation, despite circulatory support. In the face of uncontrollable VTA, four of these underwent "high risk" antiarrhythmic surgery while awaiting transplantation: three died of LVF within 30 days and one was saved by heart transplantation two days after arrhythmia surgery. Mortality for the transplantation strategy in group A patients was 47% by intention to treat analysis. Quality of life in the eight actually transplanted, however, was good and only one died during median follow up of 56 months. The five patients in group B were accepted for transplantation for progressive LVF at a median of 21 months (range 12 to 28) after antiarrhythmic surgery. One died of LVF before transplantation, 22 months after initial surgery; another died of high output LVF three days after transplantation. Thus mortality of the intended strategy was 40%. The three transplanted patients are alive and well at 8-86 months.

CONCLUSIONS

Although the short and medium term outcome in category A or B patients who undergo transplantation is good, the overall success of the transplantation strategy in category A patients is limited by lack of donors in the short time frame in which they are required.

Perioperative and long-term results with mapping-guided subendocardial resection and left ventricular endoaneurysmorrhaphy

BACKGROUND

Surgical ablation of the arrhythmogenic focus in patients with life-threatening ventricular tachyarrhythmias can be curative. However, the surgical techniques have been plagued by a high perioperative mortality rate (averaging approximately 12%). Reconstruction of the left ventricle may reduce mortality.

METHODS AND RESULTS

Reconstruction of the left ventricle with a pericardial patch, or endoaneurysmorrhaphy, was performed with mapping-guided subendocardial resection for recurrent ventricular tachycardia in 25 patients over a 5-year period. Postoperatively, electrophysiological studies were conducted to assess the results of surgery, which were further evaluated during long-term follow-up with survival analyses. The study included 25 patients, 60 +/- 9 years of age, with coronary artery disease, discrete left ventricle aneurysms, and malignant ventricular tacharrhythmias. Left ventricular ejection fraction was 24 +/- 6% preoperatively. Left ventricular endocardial mapping, endocardial resection, and endoaneurysmorrhaphy were performed in all patients. There was no operative or postoperative (30-day) mortality. Postoperative ventricular tachycardia was induced in 2 of the 25 patients (8%); left ventricular function increased to 32 +/- 9% (range, 19% to 52%). At a mean follow-up of 37 +/- 16 months (range, 6 to 65 months), there had been 6 deaths, including 1 sudden cardiac death, 2 congestive heart failure deaths, and 3 noncardiac deaths. Analysis of multiple variables failed to identify predictors of postoperative inducibility, sudden cardiac death, cardiac death, or total mortality.

CONCLUSIONS

Endoaneurysmorrhaphy with a pericardial patch combined with mapping-guided subendocardial resection frequently cures recurrent ventricular tachycardia with low operative mortality and improvement of ventricular function. Long-term follow-up demonstrates low sudden cardiac death rates.

What is the risk of sudden cardiac death in patients presenting with hemodynamically stable sustained ventricular tachycardia after myocardial infarction?

OBJECTIVES

This study sought to determine the long-term risk of sudden cardiac death in patients with hemodynamically stable sustained ventricular tachycardia complicating coronary artery disease.

BACKGROUND

The prognosis and risk of sudden cardiac death in patients with a history of myocardial infarction and ventricular tachyarrhythmias have not been clearly defined. Prior studies are limited by a short follow-up period and by inclusion of patients with heterogeneous cardiac diseases and presenting arrhythmias.

METHODS

A retrospective cohort analysis was performed on data from 124 patients, followed up for a mean of 36 +/- 30 months, who received electrophysiologically guided therapy for hemodynamically stable ventricular tachycardia after remote myocardial infarction.

RESULTS

Seventy-eight patients were treated pharmacologically (medical group), and 46 patients underwent map-guided subendocardial resection (surgical group). Nine patients (7.3%) died suddenly, 5 (4.0%) died of noncardiac causes, 9 (7.3%) died of a perioperative complication, and 20 (23.4%) died of other cardiac causes. At 1, 2 and 3 years, sudden death occurred at cumulative rates of 2 +/- 1%, 3 +/- 2% and 7 +/- 3%, whereas total mortality was 20 +/- 4%, 28 +/- 4% and 32 +/- 5% (mean +/- SD). Sudden cardiac death (p = 0.047) and total mortality (p = 0.036) were higher in patients with multivessel disease and were similar for both treatment groups.

CONCLUSIONS

Although the overall mortality in postinfarction patients presenting with hemodynamically stable ventricular tachycardia treated with electrophysiologically guided antiarrhythmic therapy is high, the risk of sudden death in these patients appears to be low (average 2.4%/year).

Characteristics of patients with nonfatal cardiac arrest 3 to 180 days after acute myocardial infarction

Patients who survive a tachyarrhythmic cardiac arrest in the first 6 months after acute myocardial infarction (AMI) are at risk for recurrent arrests, but the magnitude, timing and characteristics of this phenomenon are unknown. This study characterizes the nature of recurrent tachyarrhythmic cardiac arrests in the absence of reversible factors or new myocardial necrosis in patients between 3 and 180 days after AMI. We retrospectively assessed 28 patients (mean age 61 +/- 12 years) who survived an initial cardiac arrest a median of 10 days after AMI. Mean left ventricular ejection fraction was 36 +/- 9%. Fourteen patients (50%) had at least 1 recurrence of cardiac arrest, and 10 had > 2 arrests. Almost all (92%) recurrent cardiac arrests occurred within 5 days of the preceding arrest, and the high-risk periods were similar after the first, second or third cardiac arrest. Very fast ventricular tachycardia (mean cycle length 212 +/- 30 ms) was the documented responsible arrhythmia in 44 of 51 cardiac arrests. The morphology was either polymorphic, monomorphic or sinusoidal. No clinical or laboratory values could be found that predicted whether a patient would have a recurrent arrest. Nineteen patients (68%) survived to leave the hospital and have been followed for up to 96 months. For these, actuarial 5-year overall survival was 76% and actuarial 5-year arrhythmia-free probability was 80%. Thus, patients who survive a cardiac arrest in the first 6 months after AMI are at high risk of recurrent cardiac arrest for a further 5 days, and the arrests are due to characteristically fast ventricular tachycardias.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk stratification and prognosis of patients treated with amiodarone for malignant ventricular tachyarrhythmias after myocardial infarction

Seventy-seven consecutive patients (mean age 62 years) with episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) after acute myocardial infarction (AMI) were evaluated to assess the long-term efficacy of first-line amiodarone treatment and to identify clinical and laboratory factors associated with a high risk of death or arrhythmia recurrence. The presenting arrhythmia was VT in 41 cases (53%) and VF in 36 (47%). VT or VF occurred between the 4th and 90th day after AMI in 45 cases (58%) and later (more than 90 days) in the remaining 32 (42%). The mean number of arrhythmic episodes was 4.2. Forty patients (52%) were in New York Heart Association (NYHA) class I or II, and 37 (48%) were in class III or IV. Mean left ventricular ejection fraction was 32%; ventricular aneurysm was present in 41 subjects. Most patients had multivessel coronary artery disease. Amiodarone was administered as a first-choice drug in all patients, in combination with other antiarrhythmic drugs in 14. By ventricular stimulation after loading doses of amiodarone, sustained VT was inducible in 46 (62%) and noninducible in 28 (38%). During a mean follow-up of 28 months the incidence of cardiac mortality at 1, 3, and 5 years was 21%, 37%, and 47%; of sudden death was 7%, 19%, and 23%; of nonfatal VT recurrence was 13%, 13%, and 24%, respectively. The overall incidence of amiodarone side effects was 35%.2+ was a weak predictor only by univariate analysis (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Survivors of acute myocardial infarction: who is at risk for sudden cardiac death?

Coronary artery disease is the leading cause of death in the United States. Approximately half of the deaths attributable to coronary artery disease are sudden cardiac deaths. A logical approach to prevention of sudden death is to identify those who are at risk and then to initiate effective therapy. Left ventricular dysfunction, frequent ventricular ectopic activity, nonsustained ventricular tachycardia, and late potentials have been identified as markers for increased risk of sudden cardiac death. The sensitivity and specificity of these risk factors vary, and the positive predictive power is less than satisfactory. The value of invasive electrophysiologic testing for risk stratification in the general postinfarction patient population remains unclear. In addition to these diagnostic difficulties, prevention of sudden death also has been limited by imperfect efficacy and potential lethal effects of the currently available antiarrhythmic agents. Automatic implantable defibrillators are effective for aborting sudden death; however, the potential for more general use of automatic defibrillators in asymptomatic but high-risk postinfarction patients has not been evaluated.

Clinical and electrophysiologic determinants, treatment and survival of patients with sustained malignant ventricular tachyarrhythmias occurring late after myocardial infarction

To assess the clinical and electrophysiologic determinants, treatment and survival of patients with sustained malignant ventricular tachyarrhythmias late after myocardial infarction, a total of 108 patients (mean age 61 +/- 10 years) were studied. Thirty-two patients (Group I) had sustained ventricular tachyarrhythmias 8 to 60 days (mean 13 +/- 9) after acute myocardial infarction. The remaining 76 patients (Group II), who served as a control group, had no sustained ventricular tachyarrhythmias less than or equal to 60 days after infarction. The most significant independent determinants of sustained ventricular tachyarrhythmias late after infarction were the presence of late potentials (chi square = 16.07, p = 0.0001), defined as an abnormal signal-averaged QRS complex in association with an abnormal root-mean-square voltage in the terminal 40 ms of the QRS complex, and an abnormal ejection fraction of less than 40% (chi square = 10.09, p = 0.001). Sustained ventricular tachycardia was induced in 27 (96%) of 28 Group I patients. Among the 32 patients in Group I, antitachycardia therapy included antiarrhythmic drug therapy as the sole preventive measure in 14 (44%); map-guided surgery or coronary artery bypass surgery, or both, in 14 (44%) and the automatic cardioverter-defibrillator in 4 (12%). The arrhythmias were rendered noninducible in 83% of patients after map-guided surgery and in 41% after drug therapy. During a follow-up period of 20 +/- 14 months, five Group I patients (15%) had an arrhythmic event and four (9.3%) had a cardiac-related death. All five patients who had an arrhythmic event were receiving antiarrhythmic drug therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgery for control of recurrent life-threatening ventricular tachyarrhythmias within 2 months of myocardial infarction

Twenty-seven patients (mean age 57 +/- 7 years) underwent surgery for control of recurrent drug-refractory ventricular tachyarrhythmias (uniform ventricular tachycardia alone in 9 patients, ventricular tachycardia and ventricular fibrillation in 15 and ventricular fibrillation alone in 3) within 2 months of acute myocardial infarction. The mean number of major arrhythmic episodes per patient was 15 (range 2 to 200) and of drug failures 4 +/- 2. Left ventricular function was severely impaired in the majority (ejection fraction 29%; range 14% to 47%) and 18 patients (66%) had a left ventricular aneurysm. Endocardial resection guided by a combination of endocardial activation mapping during tachycardia and fragmentation mapping during sinus rhythm was performed in all patients. All electrically abnormal left ventricular endocardium was excised. Eight patients (29.6%) died within 30 days of surgery. Death was not related to age, time of surgery after infarction, ventricular function, bypass time or type of arrhythmia. Patients requiring emergency surgery had a higher early postoperative mortality rate than did those undergoing planned surgery (43% versus 15%). During a follow-up period of 32 +/- 20 months, there have been no arrhythmic deaths and only three patients (16%) have required antiarrhythmic drug therapy. When required in the early weeks after infarction, surgery for ventricular arrhythmias offers a high cure rate at a risk related to the patient's preoperative arrhythmia frequency, which in turn relates to the risk of arrhythmic death.

Surgical therapy for drug-refractory ventricular tachycardia: results with mapping-guided subendocardial resection

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively. At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. Previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 +/- 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence. Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.

Stability of electrophysiological parameters after acute amiodarone loading: implications for patient management

The appropriate timing of electrophysiological study in patients treated with amiodarone is uncertain. Twenty patients with coronary artery disease in whom sustained ventricular tachycardia was still inducible after 9 +/- 1 days of amiodarone loading (1,200-1,400 mg/day) underwent repeat electrophysiological testing after an additional month of maintenance therapy (400 mg/day). Compared with baseline, both short- and long-term amiodarone therapy caused significant changes in QTc, right ventricular effective refractory period, and ventricular tachycardia cycle length. However, there was no significant change in electrophysiological parameters between the end of the acute amiodarone loading period and 1 month of additional therapy. Sustained ventricular tachycardia remained inducible in 19 of 20 patients after 1 month of maintenance therapy. Amiodarone and desethylamiodarone plasma concentrations remained stable after amiodarone loading, but did not correlate with the magnitude of electrophysiological changes from baseline. These data suggest that electrophysiological testing after 9 days of high dose amiodarone therapy may accurately reflect long-term electrophysiological effects.

Treatment of life-threatening ventricular arrhythmias with nonguided surgery supported by electrophysiologic testing and drug therapy

Forty-six patients who had coronary artery disease, left ventricular aneurysm and life-threatening ventricular tachyarrhythmia underwent surgical treatment to eliminate or facilitate control of the arrhythmia. Surgery was performed without the assistance of intraoperative mapping techniques. Forty-three patients underwent preoperative or postoperative electrophysiologic testing, or both, and antiarrhythmic therapy was added, when indicated, postoperatively. The patients had a mean age of 63 years, a mean preoperative left ventricular ejection fraction of 27 +/- 9% and a mean preoperative left ventricular end-diastolic pressure of 23 +/- 9 mm Hg. Twenty-one patients (46%) underwent surgical treatment within 2 months of their last myocardial infarction. The overall operative mortality rate was 6.5% (three patients). Eighteen of the 43 operative survivors were discharged from the hospital on no antiarrhythmic therapy, whereas 25 received additional antiarrhythmic treatment. During a mean follow-up period of 36 months (range 2 to 88), there were 13 deaths; eight patients died suddenly, three died of congestive heart failure, one of myocardial reinfarction and one from a noncardiac cause. The overall cumulative cardiac mortality rate at 1, 2 and 3 years was 16, 22 and 35%, respectively, whereas the sudden cardiac death rate was 5, 12 and 20%, respectively. This experience suggests that high risk patients who undergo nonguided surgery for life-threatening ventricular arrhythmia and left ventricular aneurysm have a relatively low surgical mortality and a better long-term survival than previously reported. However, if utilized, such an approach must be systematically supported by perioperative electrophysiologic testing to determine the need for supplemental antiarrhythmic therapy.

Prognosis following sustained ventricular tachycardia occurring early after myocardial infarction

Eighty-seven patients with sustained ventricular tachycardia (VT) between 3 and 90 days after acute myocardial infarction (AMI) were evaluated to define factors associated with a high risk of arrhythmia recurrence or death. Most patients had poor left ventricular function (mean ejection fraction 29 +/- 12%), multivessel coronary artery disease (71%) and inducible sustained VT with programmed stimulation (87%). During a mean follow-up of 26 months, 36 patients (41%) died and 21 patients had arrhythmia recurrence (with 19 sudden deaths). Factors independently associated with mortality included: (1) treatment before 1981 (p less than 0.01); (2) anterior AMI (p less than 0.05); (3) short time from AMI to first episode of VT (p less than 0.06); and (4) multivessel coronary artery disease (p less than 0.07). Factors independently associated with arrhythmia recurrence were: (1) medical treatment (as opposed to surgical) (p less than 0.01); (2) greater than or equal to 3 episodes of spontaneous VT (p = 0.01); (3) multivessel coronary disease (p less than 0.05); and (4) anterior AMI (p less than 0.07). Medically and surgically treated patients did not differ significantly in overall survival (49 vs 61%, respectively), although short-term (6 month) surgical survival improved from 31% during the first half of the study to 96% in the latter half (p less than 0.01). For patients with sustained VT early after AMI the risk of death and arrhythmia recurrence can be assessed based on clinical and angiographic characteristics; in addition, surgical treatment is associated with a lower incidence of arrhythmia recurrence than medical treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of efficacy of amiodarone and characteristics of recurrence of arrhythmia in patients with sustained ventricular tachycardia and coronary artery disease

The value of serial electropharmacologic testing during long-term oral amiodarone therapy for prediction of long-term drug efficacy as well as characteristics of arrhythmia recurrence is controversial. One-hundred four consecutive patients with coronary artery disease and sustained ventricular tachyarrhythmias (VT) underwent initial electrophysiologic (EP) evaluation in the drug-free state and again after an amiodarone loading period of 25 +/- 14 days (mean +/- SD). Twenty-six patients (25%) had no inducible ventricular tachyarrhythmia during therapy with amiodarone (VT control group), whereas arrhythmia inducibility persisted in the remaining 78 patients (VT noncontrol group). During 17.4 +/- 13.7 months of follow-up, two patients in the VT control group either had VT recurrence or died suddenly compared with 21 VT recurrences and eight sudden cardiac deaths in the VT noncontrol group (actuarial event rates at 36 months of 0.11 and 0.56, respectively, p = .0065). The cycle lengths of recurrent VT in these 21 patients in the VT noncontrol group were compared with those observed at final EP testing. A significant linear correlation was demonstrated (r = .76, p = .0001). Subgroup analysis of patients in the VT noncontrol group showed no EP predictors of outcome, including cycle length of induced VT. However, patients dying suddenly during the follow-up period had a higher prevalence of new or worsening congestive heart failure (75%) compared with patients with VT recurrence (19%) or those with no arrhythmic event (29%) (p less than .02).2off

Prognosis of ventricular arrhythmias in relation to sudden cardiac death: therapeutic implications

The hypothesis that ventricular arrhythmias represent an independent predictor of sudden cardiac death was examined by analyzing the published data. The frequency and complexity of ventricular arrhythmias increase progressively both with age and severity of heart disease, but no age- or disease-related norms have been established for clinical guidance. Simple and complex arrhythmias, including short runs of ventricular tachycardia, do not increase risk of sudden cardiac death in subjects without heart disease or with heart disease and normal myocardial function. Progression of nonsustained into sustained ventricular tachycardia in such individuals is rare. Simple and complex ventricular arrhythmias are not strong independent predictors of sudden death in survivors of myocardial infarction. In these, the overall incidence of sudden cardiac death averages 3.5 to 5% during the first year, but is about 15 to 20% per year in patients with severely impaired ventricular function. The results of this survey suggest that in patients with well preserved ventricular function, prophylactic use of antiarrhythmic drugs is not indicated, and that treatment of asymptomatic or mildly symptomatic ventricular arrhythmias is not likely to reduce the incidence of sudden cardiac death.

Relation between amiodarone and desethylamiodarone plasma concentrations and electrophysiologic effects, efficacy and toxicity

Because the value of monitoring amiodarone plasma concentrations remains undefined, this study was performed to evaluate its role during the management of patients receiving amiodarone. The early electrophysiologic effects of amiodarone were assessed in 40 consecutive patients with coronary artery disease and sustained ventricular tachycardia or fibrillation who underwent electrophysiologic studies and measurement of amiodarone plasma concentration before and 29 +/- 15 (mean +/- SD) days after initiation of therapy. Amiodarone and desethylamiodarone plasma levels did not correlate with changes in either sinus cycle length, QTc interval, ventricular effective refractory period, AH and HV intervals or ventricular tachycardia cycle length. Amiodarone and desethylamiodarone plasma concentrations and the effects of the drug on conduction intervals or right ventricular effective refractory periods were not related to suppression of arrhythmia induction by ventricular stimulation after 1 month of therapy. The relation between amiodarone plasma concentrations and both toxicity and efficacy during long-term therapy were prospectively assessed in a larger series of 114 consecutive patients with either symptomatic supraventricular or ventricular arrhythmias who were followed up on long-term amiodarone therapy for 26 +/- 15 months. Sixty-three patients (55%) had one or more adverse effects attributed to amiodarone. By life-table analysis, 40, 69 and 80% of patients had experienced an adverse reaction after 1, 2 and 3 years of therapy, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of ischemia by quantitative thallium-201 scintigraphy in patients with ventricular tachycardia or fibrillation inducible by programmed stimulation

The prevalence of exercise-induced ischemia was determined by thallium-201 (TI-201) scintigraphic criteria in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) inducible by programmed electrical stimulation. Thirty-eight patients (age 57 +/- 19 years), of whom 87% had angiographic coronary artery disease, underwent quantitative TI-201 exercise scintigraphy within 14 days of invasive electrophysiologic testing. The mean rest ejection fraction was 38 +/- 9%. Eighty percent of patients had 1 or more regions with akinetic or dyskinetic wall motion. Thallium-201 scan segments were scored as normal or containing redistribution defects or mild or severe persistent defects. Only 4 patients (10%) had only redistribution defects and 9 (24%) had both redistribution defects and persistent defects; 32 of 38 patients (84%) had 1 or more persistent defects, of which 26 had at least 1 severe, persistent defect (more than 50% reduction in TI-201 activity). Patients with and without exercise-induced VT had a similar prevalence of redistribution. Redistribution defect prevalence was similar in patients with polymorphic VT (3 of 13) and monomorphic VT (10 of 25) during programmed electrical stimulation (difference not significant). Thus, patients with VT or VF induced by programmed ventricular stimulation have extensive TI-201 scintigraphic abnormalities on exercise scintigrams, predominantly those suggesting scar, with associated severe regional wall motion abnormalities at rest. The scintigraphic prevalence of exercise-induced ischemia is low and TI-201 redistribution and exercise ST depression are observed with equal frequency in patients with and those without VT induced during exercise.

Surgical management of sustained ventricular arrhythmias presenting within eight weeks of acute myocardial infarction

When it occurs after a recent (less than eight weeks) myocardial infarction, sustained ventricular tachycardia (VT) or fibrillation (VF) has resulted in a high one-year mortality despite antiarrhythmic drug therapy. We have operated on 29 patients with this syndrome either on an emergency basis because they had medically refractory VT or VF (19 patients) or electively if they had persistent congestive heart failure or angina and VT or VF (10 patients). Ages ranged from 36 to 82 years (mean, 60 years), and the mean left ventricular ejection fraction was 31 +/- 13%. Each patient had failed a trial of one or more (average, four) antiarrhythmic drugs and because of VT, required electrical cardioversion on an average of five occasions. Intraoperative mapping was complicated by multiple VT morphologies (9 patients), the rapid degeneration of VT to VF (5 patients), and the inability to induce VT reliably (5 patients). Subendocardial excision was performed at the site of the earliest electrical activity, or if no single site could be identified, a wide subendocardial excision of all visible scar was performed. There were 4 perioperative deaths (14%). All operative survivors underwent postoperative electrophysiological studies. Twenty of them required no further antiarrhythmic therapy, but 5 patients required drug therapy because of either spontaneous (2 patients) or electrically induced (3 patients) VT. During follow-up (average, 16 months) of these 25 patients, there have been 3 late deaths, 2 of them sudden. Two of the 3 late deaths were those of patients taking antiarrhythmic drugs. Our results demonstrate the effectiveness of early operative intervention when sustained ventricular arrhythmias complicate recovery after myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Resection of scarred papillary muscles improves outcome after surgery for ventricular tachycardia

Papillary muscle scarring is encountered frequently during operations for sustained ventricular tachycardia (VT). Indications for excision of the papillary muscle scar and mitral valve replacement (MVR) are controversial. The findings in 46 consecutive patients undergoing operative electrophysiologic map-directed endocardial resections for VT were reviewed. There was papillary muscle scarring in 15 patients (average age: 59 years; sex: 11 male, 4 female; average ejection fraction: 31 +/- 14%). Eleven patients had a VT with the site of origin on a scarred papillary muscle; four had another VT site of origin. Six patients underwent papillary muscle scar resection (5 with MVR); six underwent papillary muscle cryotherapy (-60 C X 2 min); and three had neither papillary muscle resection nor MVR. All six patients with papillary muscle resection +/- MVR are alive and free of arrhythmia after 14.3 +/- 7.6 months of follow-up. Five of six patients treated by papillary muscle cryotherapy alone manifested spontaneous (4 patients) or inducible (1 patient) VT during early postoperative evaluation. Two of the three patients with untreated papillary muscle scarring developed late complications requiring reoperation. One patient developed mitral regurgitation requiring MVR 5 months later. The other developed a previously undocumented VT 2 years after operation. Significant papillary muscle scarring visualized at the time of operation for arrhythmia is an indication for resection of the scar and the papillary muscle, even if this necessitates MVR. In this series, attempts to preserve the papillary muscle, by incomplete resection of the scar or by cryotherapy, resulted in a high failure rate owing to recurrent VT or mitral regurgitation.

Surgical ablation of ventricular tachycardia: improved results with a map-directed regional approach

To determine whether a regional approach to surgery for ventricular tachycardia would improve on the results of previously reported methods of endocardial resection, an analysis was performed of our surgical experience over a 5 year period. Of 46 consecutive patients operated on for recurrent sustained ventricular tachycardia or ventricular fibrillation, 39 patients with ischemic heart disease underwent subendocardial resection and/or cryoablation. The mean age of the patients was 61 +/- 8 (SD) years, the mean left ventricular ejection fraction was 32 +/- 11%, and the mean number of ineffective antiarrhythmic drugs was 3.8 +/- 1.2 per patient. In 35 of 39 patients in whom mapping data were obtainable, 56 (86%) tachycardias had earliest sites of activation in the left ventricle and nine (14%) had earliest sites in the right ventricle. Ten patients had 14 tachycardias (21%) mapped to areas outside visible dense scar. Of these 35 patients, 10 underwent localized subendocardial resection and 25 underwent a regional procedure in which all areas activated before the surface QRS during ventricular tachycardia were excised and/or cryoablated. In the operative survivors of electrophysiologically guided surgery, three of eight (38%) patients with the localized and one of 24 (4%) patients who underwent the regional procedure had recurrence of ventricular tachycardia during a follow-up period of 1 to 59 (mean 22 +/- 17) months (p = .04). The favorable outcome of regional surgery was not influenced by the presence of multiple morphologies in 54%, disparate sites of origin in 29%, or inferior wall foci in 46% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)