Cardiac sarcoidosis with a rare initial manifestation: sustained monomorphic ventricular tachycardia

Sarcoidosis is a multisystem disease of unknown cause. Life-threatening complications or sudden death can occur when the disease involves the heart. Because cardiac sarcoidosis has diverse clinical presentations, its diagnosis can be a major challenge for clinicians. It is very rare for the initial manifestation of cardiac sarcoidosis to be sustained ventricular tachycardia, especially in a patient with no prior symptoms or history of the disease. Herein, we discuss the case of a 41-year-old black man who presented with nausea, vomiting, and palpitations on the day after he had consumed alcoholic beverages heavily. Electrocardiographic examination revealed sustained monomorphic ventricular tachycardia. An automatic implantable cardioverter-defibrillator corrected the patient's abnormal heart rhythm, and therapy with steroids and β-blockers resolved his symptoms. We describe the process that led to the diagnosis of cardiac sarcoidosis in this patient.     

Sustained ventricular tachycardia in patients with idiopathic dilated cardiomyopathy: electrophysiologic testing and lack of response to antiarrhythmic drug therapy

Eleven consecutive patients with idiopathic dilated cardiomyopathy and spontaneous, sustained ventricular tachycardia (VT) of uniform morphology underwent programmed ventricular stimulation and serial antiarrhythmic drug testing. The mean ejection fraction was 30 +/- 6.4%. Sustained VT was induced by programmed electrical stimulation in all 11 patients. A mean of 3.7 +/- 2.4 antiarrhythmic drugs were evaluated by programmed stimulation, including at least one experimental agent in eight patients. In nine of 11 patients VT remained inducible on all drug therapy. During a mean follow-up period of 21 +/- 14 months there were four sudden deaths and two patients with recurrences of VT. In all six patients with sudden death or recurrence of VT, the arrhythmia remained inducible on drug therapy. Three patients who died suddenly had a hemodynamically stable, induced tachycardia on antiarrhythmic therapy. Of eight patients treated with amiodarone, only two were successfully treated. We conclude that in patients with sustained VT and idiopathic dilated cardiomyopathy, VT can be induced by programmed electrical stimulation. VT will usually remain inducible on antiarrhythmic therapy, and sudden death can occur despite slowing and improved tolerance of the induced arrhythmia. Amiodarone may have limited efficacy, and more aggressive therapy, such as surgery or implantation of an automatic internal defibrillator, should be considered in this patient population.     

Usefulness of programmed ventricular stimulation in predicting future arrhythmic events in patients with cardiac sarcoidosis

The utility of programmed ventricular stimulation to predict future arrhythmic events in patients with cardiac sarcoidosis is unknown. Similarly, the long-term benefit of implantable cardioverter-defibrillators (ICDs) in cardiac sarcoidosis has not been established. Thirty-two consecutive patients with cardiac sarcoidosis underwent programmed ventricular stimulation. Patients with spontaneous or inducible sustained ventricular arrhythmias (n = 12) underwent ICD insertion. All study patients were followed for the combined arrhythmic event end point of appropriate ICD therapies or sudden death. Mean length of follow-up to sustained ventricular arrhythmia or sudden death was 32 +/- 30 months. Five of 6 patients (83%) with spontaneous sustained ventricular arrhythmias and 4 of 6 patients (67%) without spontaneous but with inducible sustained ventricular arrhythmias received appropriate ICD therapy. Two of 20 patients (10%) with neither spontaneous nor inducible sustained ventricular arrhythmias experienced sustained ventricular arrhythmias or sudden death. Programmed ventricular stimulation predicted subsequent arrhythmic events in the entire population (relative hazard 4.47, 95% confidence interval [CI] 1.30 to 15.39) and in patients who presented without spontaneous sustained ventricular arrhythmias (relative hazard 6.97, 95% CI 1.27 to 38.27). No patient with an ICD died of a primary arrhythmic event. In patients with spontaneous or inducible sustained ventricular arrhythmias, mean survival from first appropriate ICD therapy to death or cardiac transplant was 60 +/- 46 months, with only 2 patients dying or reaching transplant at study end. In conclusion, programmed ventricular stimulation identifies patients with cardiac sarcoidosis at high risk for future arrhythmic events. ICDs effectively terminate life-threatening arrhythmias in high-risk patients, with significant survival after first appropriate therapy.     

Surgical possibilities in the treatment of ventricular tachycardia

Medical therapy for recurrent sustained ventricular tachycardia is often disappointing. We report on the direct i.e. electrophysiologically guided surgical approach to 44 patients with sustained ventricular tachycardia. 43 patients had previous myocardial infarction, one patient had arrhythmogenic right ventricular dysplasia. During preoperative electrophysiologic study, sustained ventricular tachycardia was induced in 41 patients, three patients had an incessant sustained ventricular tachycardia. 30 patients underwent endocardial catheter mapping. In 28 of 30 cases, the earliest endocardial activation during ventricular tachycardia was detected. Intraoperative mapping was performed in 42 patients, in two cases surgical approach was guided by the result of endocardial catheter mapping. In 34 patients endocardial mapping revealed the earliest site of ventricular tachycardia, in eight patients the arrhythmogenic area was identified by mapping during sinus rhythm. An encircling endocardial ventriculotomy was performed in 14 patients, whereas 29 patients underwent a circumscribed endocardial resection. A cryosurgical technique was performed in the patient with arrhythmogenic right ventricular dysplasia. The hospital mortality rate was 16% (seven of 42 patients), in one patient the cause of death was ventricular fibrillation. The late mortality rate is 14% (five of 37 patients), one patient had sudden cardiac death. Two patients had a recurrence of ventricular tachycardia postoperatively. In one of these an antitachycardia pacemaker was implanted, the other was successfully reoperated with endocardial resection. Postoperatively, a sustained ventricular tachycardia was inducible by programmed stimulation in three patients. Complex ventricular ectopic activity was found in ten patients, all of these were administered antiarrhythmic drugs. With respect to the poor prognosis of medically refractory ventricular tachycardia, we conclude that the electrophysiologically guided surgical approach has become an acceptable therapeutical alternative.     

Short- and long-term experience with flecainide acetate in the management of refractory life-threatening ventricular arrhythmias

Thirty-eight patients with organic heart disease and history of sudden cardiac arrest or recurrent sustained ventricular tachycardia were treated with flecainide. Coronary artery disease was present in 33 patients. Previous antiarrhythmic therapy consisted of two to eight drugs (mean four). Fourteen patients were resuscitated from sudden cardiac death and 24 patients had chronic recurrent sustained ventricular tachycardia. Twenty-eight patients had electrophysiologic testing before and during flecainide treatment. Sustained ventricular tachycardia became noninducible in 5 patients, nonsustained in 5 patients and slowed in 13 patients (cycle length increased from 278 +/- 64 to 395 +/- 91 ms; p = 0.002). Three of the 14 patients with sudden cardiac death and 15 of the 24 patients with recurrent sustained ventricular tachycardia remained on long-term flecainide treatment. The mean left ventricular ejection fraction in 16 of these 18 patients was 37%. Nonlimiting side effects occurred in seven patients (18%). Proarrhythmic effects were seen in four patients (10%). At a mean follow-up time of 11 +/- 3 months, 15 patients (39%) had had no recurrence, including 5 who had inducible sustained ventricular tachycardia and 5 who did not on retesting during treatment. In the 18 patients who received long-term therapy, 3 late deaths occurred, 1 of which was of arrhythmic origin. These data suggest that flecainide is effective in about 40% of patients with severe refractory ventricular arrhythmias. Its value as a single drug in the treatment of sudden cardiac death remains to be defined.     

Role of electrophysiologic testing in managing patients who have ventricular tachycardia unrelated to coronary artery disease

This study examined the usefulness of programmed electrical stimulation in managing 83 patients who had ventricular tachycardia not due to coronary artery disease. Among 39 patients with a history of sustained ventricular tachycardia, programmed stimulation induced ventricular tachycardia in 14 of 14 patients with mitral valve prolapse or primary electrical disease (arrhythmias without evidence of structural heart disease) and in 13 of 25 with cardiomyopathy (total 27 of 39, 69 percent). Programmed stimulation induced nonsustained ventricular tachycardia in 15 (34 percent) of 44 patients with a history of nonsustained tachycardia (5 of 13 with mitral valve prolapse, 6 of 19 with primary electrical disease and 4 of 12 with cardiomyopathy). Seventy-three of the 83 patients were treated with antiarrhythmic drugs and then followed up for 14.4 ± 11.4 months (mean ± standard deviation). Drug therapy was determined with serial electrophysiologic testing in 31 patients. Twenty-four of these 31 patients had a history of sustained ventricular tachycardia, and drugs prevented induction of ventricular tachycardia in 9 (none of whom manifested symptomatic events) but did not prevent it in 15 (6 of whom had symptomatic events). Among seven patients with a history of nonsustained ventricular tachycardia, drugs prevented induction of ventricular tachycardia in five (none of whom had symptomatic events) and did not prevent it in two (none of whom had symptomatic events). Forty-two patients were treated using the results of noninvasive testing. Drugs suppressed spontaneous ventricular tachycardia in 15 of 15 patients with a history of sustained tachycardia (7 of whom had symptomatic events including one sudden death), and in 26 of 27 with a history of nonsustained tachycardia (6 of whom had symptomatic events including one sudden death).Thus, in patients with ventricular tachycardia unrelated to coronary artery disease: (1) programmed electrical stimulation induced ventricular tachycardia less often than in patients whose tachycardia was due to coronary artery disease; (2) programmed stimulation induced ventricular tachycardia less often in patients with a history of nonsustained versus sustained tachycardia; and (3) suppression of inducible ventricular tachycardia appeared to predict effective drug therapy but drug therapy predicted with noninvasive testing appeared to be unreliable.     

Prognostic significance of programmed ventricular stimulation in patients surviving complicated acute myocardial infarction: a prospective study.

In survivors of complicated myocardial infarction, the inducibility of sustained ventricular tachycardia may help identify a subset that is at increased risk for subsequent sudden cardiac death or spontaneous sustained ventricular tachycardia. We performed prehospital discharge programmed ventricular stimulation in 86 survivors of acute myocardial infarction complicated by heart failure, angina pectoris, or nonsustained ventricular tachycardia. These patients also underwent cardiac catheterization with coronary angiography and 24-hour ambulatory ECG recording. Programmed ventricular stimulation induced sustained ventricular tachycardia in 19 patients (22%) and ventricular fibrillation in six (7%) and did not induce these arrhythmias in 61 patients (71%). During an average follow-up of 18 +/- 13 months, 11 patients had arrhythmic events (seven sudden death and four nonfatal spontaneous sustained ventricular tachycardia) and 10 patients had nonsudden cardiac death. The total cardiac mortality rate was 20%. Arrhythmic events occurred in 32% of the 19 patients with inducible sustained ventricular tachycardia compared with 7% of the remaining 67 patients (p less than 0.003). By multivariate analysis the occurrence of arrhythmic events was independently predicted by both inducible sustained ventricular tachycardia and Killip class III or IV heart failure. The risk of arrhythmic events was 4.4% in the absence of both variables versus 38.4% (p less than 0.001) when both variables were present. The total cardiac mortality rate was best predicted by low left ventricular ejection fraction (less than 30%). Thus programmed ventricular stimulation is useful in risk stratification of survivors of complicated acute myocardial infarction. The prognostic utility appears to be particularly high in patients with infarction complicated by Killip class III or IV heart failure.     

Idiopathic recurrent sustained ventricular tachycardia in children and adolescents

The electrophysiologic characteristics of recurrent sustained ventricular tachycardia were studied in seven pediatrie patients. The mechanisms of the ventricular tachycardia were evaluated using programmed electrical stimulation. Ventricular tachycardia could be reproducibly initiated in two patients and terminated in one patient in the basal state. It could be initiated in one additional patient and terminated in two additional patients after administration of a type IB drug. In four patients, ventricular tachycardia could not be initiated or terminated by programmed electrical stimulation. The site of origin of the ventricular tachycardia determined by catheter endocardial mapping was the right ventricular outflow tract in four patients, the interventricular septum in two patients and the inferior left ventricle in one patient. The ventricular tachycardia more frequently had an automatic than a reentrant mechanism, and originated more often in the right than in the left ventricle; it was not frequently associated with structural heart disease in this group of patients.     

Long-term arrhythmic outcome in survivors of ventricular fibrillation with absence of inducible ventricular tachycardia

While programmed electrical stimulation of the heart is useful in directing therapy in cardiac arrest survivors who exhibit inducible ventricular tachycardia (VT), controversy exists as to the risk of recurrent ventricular fibrillation (VF) and need for antiarrhythmic therapy in patients without inducible VT during drug-free control programmed stimulation studies. In this study, the clinical features and arrhythmic outcome of 43 survivors of VF without inducible VT at control programmed stimulation were examined. In 38 patients, factors that may have played a potentiating role in the genesis of VF included ischemia in 15, proarrhythmia in 18, rapid rate response to atrial fibrillation in 3 and acute alcoholism in 2. Three patients required antiarrhythmic drugs for supraventricular tachyarrhythmia and 40 patients were discharged without antiarrhythmic therapy. At 32 +/- 21 months (range 1 to 82), 37 (92%) have remained free of arrhythmic recurrence while 3 have had sustained subsequent major arrhythmic events (syncope 1 patient, VF 1, sudden cardiac death 1). Thus, survivors of VF without inducible VT at drug-free control programmed stimulation are characterized by (1) potentiating factors--often identifiable and correctable--that may be important to the genesis of VF; (2) generally low risk of arrhythmic recurrence; and (3) effective long-term management often achieved without the use of additional antiarrhythmic drugs or antitachycardia/defibrillation devices.     

Programmed stimulation in the evaluation of life-threatening or potentially life-threatening ventricular arrhythmias

Conclusion In conclusion, programmed stimulation is an excellent and appropriate method to guide thrapy for life-threatening and potentially life-threatening arrhythmias that occur infrequently and with unpredictable timing.The sensitivity and specificity of programmed stimulation is excellent in patients whose clinical presentation is by sustained uniform ventricular tachycardia and cardiac arrest. In contrast, such parameters are substantially less in patients with nonsustained ventricular tachycardia and in those who present wit syncope. The predictive accuracy of therapy guided by programmed electrical stimulation in cohorts with cardiac artest and sustained uniform ventricular tachycardia cohorts is reasonably well established and appears to be very good. Although no large randomized controlled comparative study of noninvasive versus PES-guided therapy has yet been completed, preliminary evidence suggests that there is a decreased incidence of arrhythmia recurrence and sudden cardiac death when therapy is guided by PES. In the minority of patients with syncope in whom sustained uniform ventricular tachycardia is induced during PES, therapy may be effectively guided by this modality. PES appears to be of benefit in managing patients with coronary artery disease who present with nonsustained ventricular tachycardia and depressed ejection fraction thereby defining a high risk subset for a subsequent arrhythmic event. However, we have not found electrophysiologic testing postmyocardial infarction to be prognostically useful.Dr. Josephson is the Robinette Foundation Professor of Medicine (Cardiovascular Diseases)Supported in part by grants from the American Heart Association, Southeastern Pennsylvania Chapter, Philadelphia, PA; and National Heart, Lung, and Blood Institute, Bethesda, MD (HL28093, HL07346, HL24278).     

The automatic implantable cardioverter-defibrillator in young patients

An international survey identified 40 patients less than 20 years old who underwent surgical implantation of an automatic implantable cardioverter-defibrillator (AICD). There was a history of aborted sudden cardiac death or sustained ventricular tachycardia in 92.5% of these patients. Twenty-two patients (55%) had structural heart disease; dilated and hypertrophic cardiomyopathy were the most common diagnoses. Eighteen patients (45%) had primary electrical abnormalities including seven with the congenital long QT syndrome. There were no perioperative deaths associated with device implantation. Concomitant drug therapy was administered to 75% of the patients. Defibrillator discharge occurred in 70% of the patients, with 17 patients (42.5%) receiving at least one appropriate shock. There were two sudden and two nonsudden deaths at 28.2 months' median follow-up. Sudden death-free survival rates by life table analysis at 12 and 33 months were 0.94 and 0.88, respectively. Total survival rates at 12 and 33 months were 0.94 and 0.82, respectively. The AICD represents an effective treatment approach for young patients with life-threatening ventricular tachyarrhythmias.     

Bedside programmed ventricular stimulation for sudden death risk stratification

BACKGROUND: Patients with myocardial infarction and left ventricular dysfunction are at risk for sudden death. This research was conducted to determine the applicability and safety of a bedside programmed stimulation protocol to determine the risk for sudden death in these patients. METHODS: Four hundred and twelve patients with acute myocardial infarction were studied. Left ventricular ejection fraction was evaluated by means of an echocardiogram. Ventricular arrhythmia, late potentials and heart rate variability were determined by means of Holter recordings. Fifty patients (60 +/- 14-year-old; 85% male) presented a left ventricular ejection fraction lower than 0.40 (0.36 +/- 0.10) associated with late potentials, low heart rate variability or ventricular arrhythmia greater than Lown I. After a central venous access was placed under fluoroscopy guidance and ECG monitoring, a quadripolar catheter was advanced to the right ventricular apex to perform programmed ventricular stimulation with up to three extrastimuli. The patients were followed-up to determine in-hospital morbidity and/or mortality. RESULTS: No patient suffered complications. Ventricular tachycardia or ventricular fibrillation was induced in six patients. All of them received amiodarone and in five an automatic cardioverter-defibrillator was implanted. After a 22 +/- 6 month follow-up, five patients had received appropriate discharges from the implanted device and none had suffered from arrhythmic sudden death. CONCLUSION: Bedside programmed stimulation is a safe and useful means for sudden death risk stratification in post myocardial infarction patients. It moreover presents the advantage of being cheaper than conventionally used procedures.     

Ventricular tachyarrhythmia associated with cardiac sarcoidosis: its mechanisms and outcome

BACKGROUND: Cardiac sarcoidosis is increasingly recognized and is associated with poor prognosis. Ventricular tachycardia (VT) associated with cardiac sarcoidosis is the most likely cause of sudden death in most patients, but the mechanism has not been well established. HYPOTHESIS: This study investigated the mechanisms and outcome of VT associated with cardiac sarcoidosis. METHODS: The study included eight consecutive patients (five men, three women, aged 54 +/- 19 years) who had sustained monomorphic VT associated with cardiac sarcoidosis in our hospital. RESULTS: The average ejection fraction was 43 +/- 11%. Twenty-two VTs were observed in these patients, and mean heart rate during VT was 192 +/- 29 beats/min (range 144-259). The phenomenon of transient entrainment was documented in 10 of 22 (45%) VTs by ventricular pacing (eight in the active phase). Another five (23%) VTs could not be entrained, but could be initiated by programmed stimulation and terminated by rapid pacing, reproducibly. In 3 of the 22 (14%) VTs, cardioversion was required urgently because of the fast rate, while the remaining 4 (18%) could be induced during electrophysiologic study. CONCLUSIONS: In this study, there was a high possibility that the mechanism of 15 (68%) VTs was reentry. Reentrant substrate is formed not only in association with the healing of cardiac granulomas in the inactive phase of cardiac sarcoidosis but also in the active phase. Ventricular tachycardia with cardiac sarcoidosis, even if this mechanism is reentry, has different inducibility between the active and inactive phases in an electrophysiologic study. This makes the therapy for cardiac sarcoidosis (e.g., corticosteroids, antiarrhythmic agents, and catheter ablation) difficult. The implantable cardioverter-defibrillator is an effective treatment for ventricular tachyarrythmia with cardiac sarcoidosis.     

Programmed stimulation in patients with malignant ventricular arrhythmias. I: Diagnostic value

Sudden cardiac death is a leading cause of death in industrially developed countries and accounts for approximately 90 000 deaths yearly in the FRG. While the majority of victims have severe coronary heart disease, sudden cardiac death is infrequently caused by acute myocardial infarction (20%) but is predominantly related to malignant ventricular arrhythmias (i.e., ventricular fibrillation or sustained ventricular tachycardia). Patients with a history of such malignant ventricular arrhythmias are at high risk for sudden death. Spontaneous occurrence of sustained ventricular tachycardia and of ventricular fibrillation is critically related to two factors: 1. trigger-arrhythmias consisting usually of complex ventricular extrasystoles (Lown classification IV to V); 2. increased vulnerability of the myocardium representing the target organ for trigger-arrhythmias. While trigger-arrhythmias can be easily recorded by noninvasive techniques including Holter monitoring or exercise and stress ECG, ventricular vulnerability is more difficult to determine and often requires ventricular stimulation with intracardiac electrocatheters. In patients with documented spontaneous malignant ventricular arrhythmias, two aspects of programmed stimulation must be considered: 1. diagnostic, and more importantly, 2. therapeutic purposes of this method. Diagnostic purposes include determination of the mode of initiation and unequivocal ventricular localization of the tachycardia excluding other arrhythmias with broad QRS complex. In patients with spontaneous sustained ventricular tachycardia, programmed stimulation can reproducibly initiate the clinical arrhythmia in 85% (sensitivity and specificity of the method approximately 90%). In patients with cardiac arrest due to ventricular fibrillation, programmed stimulation is less reliable (50%). However, the main purpose of programmed stimulation in patients with documented clinical malignant arrhythmias is not diagnostic or prognostic evaluation but is serial electrophysiological studies for individual optimization of antiarrhythmic therapy.     

Electrophysiologic drug testing in patients with malignant ventricular arrhythmias: Importance of stimulation at more than one ventricular site

Sixty-four patients with symptomatic ventricular tachycardia or ventricular fibrillation underwent right ventricular apical programmed stimulation and had no inducible ventricular tachycardia during drug testing. Thirty patients (Group I) did not undergo left ventricular stimulation. Left ventricular stimulation in 38 drug trials induced no ventricular tachycardia in 50% (Group HA), nonsustained ventricular tachycardia in 26% (Group IIB), and sustained ventricular tachycardia In 24% (Group IIC).Patients in Groups I, IIA, and IIB received chronic antiarrhythmic drug therapy based on the results of electrophysiologic drug testing. Patients in Group IIC underwent further drug testing until sustained ventricular tachycardia was no longer inducible and were then entered into Group IIA or IIB; 4 patients in whom the induction of sustained ventricular tachycardia could not be suppressed by any drug regimen tested were excluded from long-term follow-up. The duration of follow-up (mean ± standard deviation) was 15.8 ± 11.5 months in Group I, 13.6 ± 3.7 months in Group IIA, and 12.1 ± 4.9 months in Group IIB. Recurrence rates of symptomatic ventricular tachycardia or sudden death were 27% in Group I, 0% in Group IIA, and 20% in Group IIB (p < 0.02 for Group IIA versus Group I and p > 0.05 versus Group IIB).If only right ventricular apical stimulation is performed during electrophysiologic drug testing in patients with malignant ventricular arrhythmias, approximately 50% of drug trials may be Incorrectly judged as suppressing the induction of ventricular tachycardia. Drug therapy that suppresses ventricular tachycardia induction with both right and left ventricular programmed stimulation results in a significantly better clinical response than therapy based on the results of only right ventricular apical stimulation.     

Risk stratification and long-term therapy with amiodarone in patients with idiopathic dilated cardiomyopathy]

Patients with cardiomyopathy are known to suffer from a high prevalence of tachyarrhythmic complications and sudden cardiac death. In a prospective study, 30 patients (25 men, 5 women, mean age: 52 +/- 12 years) with dilated cardiomyopathy underwent 48-h-Holter monitoring and programmed electrical stimulation and, independent from the results of the diagnostic work-up, were then randomized either to amiodarone or to a conventional or no antiarrhythmic therapy. At baseline, frequent ventricular arrhythmias (> 30 ventricular premature beats/h) were observed in 15/30 patients (50%), 13 patients (43%) had repetitive ventricular arrhythmias, additionally. Four patients suffered spontaneous sustained tachyarrhythmias. During programmed electrical stimulation, sustained monomorphic ventricular tachycardia was induced in 3/3 patients with and in 1/25 patients (4%) without a history of sustained tachycardia. Sustained monomorphic ventricular tachycardia was induced with one to two extrastimuli; three extrastimuli only increased the incidence of inducible ventricular fibrillation (8 patients, 28%). During a mean follow-up of 28 +/- 6 months 10/30 patients (33%) died for cardiac reasons (sudden cardiac death: 4/10 patients). Cardiac death was most likely in patients with a left-ventricular ejection fraction < 35% (5/18 patients, 28% versus 1/12 patients with ejection fraction > 35%, 8%) and further increased in the presence of reduced exercise tolerance and frequent and repetitive ventricular arrhythmias (4/7 patients, 57%). In the amiodarone group 4/15 patients died (27%, sudden cardiac death: one patient), while in patients not treated by amiodarone 8/15 patients died (54%; sudden cardiac death: three patients). Amiodarone therapy was well tolerated in all but one patient.     

Prognosis in Patients with Left Ventricular Dysfunction and Ventricular Tachycardia Following Programmed Ventricular Stimulation

We performed programmed ventricular stimulation on 69 patients with left ventricular ejection dysfunction (ejection fraction < 50%) and clinically recognized ventricular tachycardia including 28 patients with sustained ventricular tachycardia and 41 patients with nonsustained ventricular tachycardia. An inducible arrhythmia (> 6 beats ventricular tachycardia) was found in 74% of patients. Patients with clinically sustained arrhythmias were frequently inducible (89%) with a high incidence of inducible monomorphic ventricular tachycardia (82%). Patients with clinically nonsustained ventricular tachycardia had a lower rate of inducibility (63%) including a high incidence of inducible polymorphic ventricular tachycardia (27%). Inducible patients with left ventricular dysfunction and ventricular tachycardia had a low incidence of electrophysiologically demonstrated effective drug therapy (16%). However, if an effective drug was found, the prognosis was good. Empirical drug therapy was associated with a poor prognosis in inducible and noninducible patients. Finally, an unfavorable prognosis was associated with a clinically sustained arrhythmia, a lower ejection fraction, and the presence of a left ventricular aneurysm. An inducible arrhythmia did not predict an unfavorable course. Indeed, patients with noninducible ventricular tachycardia in this group of patients were still at risk for sudden cardiac death.     

Prognostic significance of ventricular late potentials in the postmyocardial infarction period

Ventricular late potentials in patients after myocardial infarction can be assumed to herald an increased risk of future sudden cardiac death or symptomatic sustained ventricular tachycardia. This holds particularly true for patients studied early after recent myocardial infarction whereas patients assessed later in the subsequent course have a substantially lesser incidence of arrhythmic events, probably due to intercurrent death of those at high risk. Of prognostic importance appears not only the presence but also the duration of late potentials. A meaningful role is also assumed by the extent of left ventricular functional impairment (EF less than 40%). However, in consideration of the complex mechanisms that can lead to sudden cardiac death, no single method predicts with high sensitivity the occurrence of a ventricular tachyarrhythmic event. Sudden cardiac death can be incurred on the basis of chronic electrophysiological abnormalities as a consequence of regional slow conduction in the border zone of a previous myocardial infarction precipitated by trigger factors such as spontaneous ventricular arrhythmias. Sudden cardiac death or symptomatic sustained ventricular tachycardia can also occur due to sudden and transient changes in the electrophysiological properties of the myocardium due to ischemia. Whether the combination of late potentials with clinical parameters such as ventricular arrhythmias detected in the ambulatory ECG and those induced with programmed electrical stimulation will lead to more accurate identification of patients at risk prerequisites further elucidation. Currently available literature indicates that in patients with late potentials, ventricular tachycardias can be induced more frequently by programmed electrical stimulation and that the combination of both phenomena confers a particularly high risk.     

Mode of stimulation versus response: validation of a protocol for induction of ventricular tachycardia

Electrophysiologic studies were prospectively performed in 91 consecutive patients referred for evaluation of sustained ventricular tachycardia or sudden cardiac death. Fifty-two patients had a history of sustained ventricular tachycardia and 39 patients had a history of sudden cardiac death. The identical stimulation protocol was used in all patients. The stepwise protocol involved atrial pacing, burst ventricular pacing, single, double, and triple extrastimuli during ventricular pacing. Stimulation was performed at the right ventricular apex at two and five times diastolic threshold. Using this protocol, ventricular tachycardia was inducible in 48 (92%) of the 52 patients with a history of sustained ventricular tachycardia and in 28 (72%) of 39 patients with a history of sudden cardiac death (p less than 0.02). The use of a third extrastimulus increased the yield of inducible ventricular tachycardia by 37% in patients with a history of sustained ventricular tachycardia and by 25% in patients with a history of sudden cardiac death. Stimulation at five times diastolic threshold and stimulation from the right ventricular outflow tract added a 15% increment in overall yield of inducible ventricular tachycardia in patients with a history of sustained ventricular tachycardia, and a 26% increment in yield in patients with a history of sudden cardiac death. Forty-four (92%) of the 48 inducible patients in the sustained ventricular tachycardia group had inducible monomorphic ventricular tachycardia as compared to 19 (68%) of 28 patients in the sudden cardiac death group (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)     

Predictors of ventricular tachycardia recurrence in 100 patients receiving tiered therapy defibrillators

BACKGROUND AND HYPOTHESIS: Programmed electrical stimulation (PES) is a time-honored diagnostic tool in patients with ventricular tachyarrhythmias. The response to PES can be used to assess efficacy of pharmacologic or electrical therapy, as well as to obtain prognostic information. Reproducible induction of ventricular tachycardia with invasive electrophysiologic testing, or stimulation through defibrillator lead systems, can help optimize antiarrhythmic drug therapy and device programming during clinical follow-up. METHODS: We present our experience with 100 patients who had inducible sustained monomorphic ventricular tachycardia (SMVT) during invasive PES at baseline, and received a third-generation implantable cardioverter-defibrillator (ICD) alone, or in combination with antiarrhythmic drug therapy. Noninvasive programmed stimulation (NIPS) was performed prior to hospital discharge in 61 patients. RESULTS: The inducibility of SMVT was concordant between the invasive study and NIPS in a subgroup of 40 (82%) patients who had invasive PES on the same drug regimen. During a mean follow-up of 16 months, there were 12 nonarrhythmic deaths and recurrence of spontaneous SMVT in 36 (40%) of the surviving patients. Using a Cox proportional hazards model, the following variables were associated with early arrhythmia recurrence: persistent inducibility of SMVT during the NIPS session (relative risk 11, range 2.6-47); induction of SMVT with a cycle length > 280 ms during invasive baseline PES (2.5, 1.2-5) and presence of prior inferior myocardial infarction (2.1, 1-4.2). Timing to initial recurrence of spontaneous tachycardia was unaffected by other clinical variables or concomitant antiarrhythmic drug use. CONCLUSION: Programmed electrical stimulation techniques offer insight into the patterns of spontaneous ventricular tachycardia recurrence and have significant practical utility in the management of patients receiving third-generation ICDs.