Functional paroxysmal ventricular tachycardia

Can the electrophysiologic study predict treatment outcome in patients with sustained ventricular tachyarrhythmias unrelated to coronary artery disease?

Sustained ventricular tachyarrhythmias unrelated to coronary artery disease are uncommon. Currently there are no clear guidelines to aid selection of the most appropriate treatment strategy. Therefore, factors potentially predictive of arrhythmia recurrence and death and the ability of the electrophysiologic study to predict treatment outcome in patients with spontaneous sustained ventricular tachyarrhythmias unrelated to coronary artery disease were examined in 41 medically treated patients followed for a median of 25 (range 1-76) months. Examined factors were: syncope associated with the spontaneous arrhythmia, the morphology and cycle length of the presenting arrhythmia, underlying ventricular function, cardiac pathology, and the results of drug assessment at electrophysiologic study. Random variability in the ease of arrhythmia induction at electrophysiologic study was measured for the group as a whole and was allowed for in prediction of an effective drug response. The 95% confidence intervals for variability in the ease of repeat arrhythmia induction at the same study were < or = 1 extrastimulus and for variability in the ease of repeat arrhythmia inductions at different studies were < or = 2 extrastimuli. Poisson regression models were used for data analysis. Arrhythmia recurrence was most likely in: (1) patients on treatment not predicted to be anti-arrhythmic at electrophysiologic study; (2) patients whose treatment was not assessable at electrophysiologic study because the arrhythmia was not reliably inducible; (3) patients with impaired ventricular function; and (4) re-entered patients whose arrhythmia had recurred on previously allocated therapy. The risk of arrhythmia recurrence decreased with time from hospital assessment. All five deaths occurred in patients with impaired ventricular function.

CONCLUSIONS

drug efficacy should be tested at electrophysiologic study in patients with reproducibly inducible clinical arrhythmias. Treatment not proven to be anti-arrhythmic at electrophysiologic study is usually ineffective. Patients with ventricular dysfunction are at highest risk of death from arrhythmia recurrence and should be considered for an implantable defibrillator, arrhythmia surgery, or heart transplantation if drug treatment is not predicted to be effective or is not assessable at electrophysiologic study.

New-onset ventricular tachycardia during pregnancy

During evaluation for palpitations, presyncope, or syncope, seven pregnant women had documented ventricular tachycardia. Before pregnancy none had a history of significant cardiac disease or symptomatic arrhythmia. The tachycardia rate ranged from 117 to 250 beats/min and lasted up to 65 seconds. Arrhythmia evaluation in five of the patients suggested catecholamine-sensitive ventricular tachycardia. This diagnosis was supported by either a positive relation to exercise or isoproterenol infusion, suppression of arrhythmia by beta-blockade or sleep, and lack of induction of arrhythmia by programmed electrical stimulation of the heart. The arrhythmias resolved in one patient soon after evaluation and in one other patient after 2 months of controlling therapy. Five other patients continued to receive therapy throughout pregnancy. Delivery was accomplished in all patients without significant maternal or neonatal complications.

Conservative treatment of paroxysmal ventricular tachycardia during pregnancy

Paroxysmal ventricular tachycardia during pregnancy presents a therapeutic dilemma for the treating physician. The clinical course of two otherwise healthy pregnant patients with this arrhythmia in whom treatment was withheld is outlined. The indications and guidelines for treatment in relatively asymptomatic patients is discussed.

Significance of signal-averaged electrocardiography in relation to endomyocardial biopsy and ventricular stimulation studies in patients with ventricular tachycardia without clinically apparent heart disease

Signal-averaged electrocardiography (ECG) was performed in 38 patients (mean age 38 years, range 15 to 70) with ventricular tachycardia who had no clinical evidence of structural heart disease. Spontaneous ventricular tachycardia was nonsustained in 23 patients and sustained in 15. None of the patients had symptoms of heart failure or ischemic heart disease, and at cardiac catheterization none had significant coronary artery disease or left ventricular wall motion abnormalities. In addition, all patients underwent left and right ventricular endomyocardial biopsy and ventricular stimulation studies. Signal-averaged ECG was performed and late QRS potentials were defined with use of Simson's method. Late QRS potentials were detected in a minority (18%) of patients including 2 of 23 with nonsustained and 5 of 15 with sustained (p = NS) ventricular tachycardia. Fifteen patients (40%) had abnormal endomyocardial biopsy results and these findings were more common in patients with sustained than in those with nonsustained ventricular tachycardia (9 of 15 versus 6 of 23, p less than 0.05). Late potentials were associated with abnormal endomyocardial biopsy findings (6 of 15 versus 1 of 23, p less than 0.01). An increase in fibrous tissue was the most frequent histopathologic abnormality; this increase was quantified by morphometric methods and compared with biopsy findings in normal control subjects. In the control group the proportion of collagen in relation to myocytes was less than 10%. All patients with both late potentials and abnormal biopsy findings had a greater than 15% ratio of collagen to myocytes in at least one specimen and the biopsies revealed marked interstitial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Unexpected myocardial disease in patients with life threatening arrhythmias

It is not unusual for an individual without recognisable clinical heart disease to have a life threatening arrhythmia. This report describes the results of endomyocardial biopsy in twelve patients who presented with life threatening arrhythmias and normal or near normal cardiac function. The eight men and four women (mean age 35) presented with ventricular tachycardia or fibrillation (nine cases), high grade heart block with inadequate ventricular escape (two cases), and dangerous ventricular extrasystoles (Lown grade 4, one case). In ten of the twelve patients symptoms had been present for less than or equal to 6 months at presentation. No patient had a normal electrocardiogram. Electrophysiological testing confirmed the clinical arrhythmia in all but three patients. Endomyocardial biopsy demonstrated lymphocytic myocarditis in two patients, granulomatous myocarditis in two patients, small vessel vasculitis in one patient, and cardiomyopathic changes in six patients. In one patient the biopsy specimen was normal. Endomyocardial biopsy is a valuable diagnostic tool in patients with unexplained life threatening arrhythmias. In this study half the patients had a treatable form of heart muscle disease.

Determinants of the spontaneous ectopic activity in repetitive monomorphic idiopathic ventricular tachycardia

Twenty-four hour ambulatory electrocardiographic tape recordings of 30 patients (16 men and 14 women, mean age 42 +/- 17 years) with repetitive monomorphic idiopathic ventricular tachycardia were analyzed using a new computerized system designed to study 15 RR cycles and mean heart rate of the 3 minutes preceding any defined event. The mean (+/- SD) number of events analyzed per patient in 24 hours was 610 +/- 483 for single premature ventricular complexes, 622 +/- 490 for couplets, 260 +/- 411 for runs of 3 complexes, 186 +/- 476 for runs of 4, 108 +/- 173 for runs of 5, 82 +/- 129 for runs of 6 to 10 and 83 +/- 116 for runs of more than 10 complexes. The heart rate was faster before runs of ventricular tachycardia than before isolated extrasystoles (p less than 0.01) and a positive linear correlation was observed between the mean preceding heart rate and the type of extrasystolic activity, the length of the runs increasing with increasing preceding heart rate (r = 0.98, p less than 0.001). A long RR interval just before the occurrence of runs was present in 77% of the cases (23 of 30) with or without an oscillatory pattern of RR intervals due to bigeminy or trigeminy, and the length of the runs correlated positively with the duration of this long preceding diastole (r = 0.90, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Solitary beta-blocker therapy for idiopathic life-threatening ventricular tachyarrhythmias

To determine the clinical characteristics of patients with life-threatening ventricular tachyarrhythmias with no identifiable heart disease, we analyzed six patients who presented with either cardiac arrest or syncope associated with documented ventricular tachycardia or fibrillation. Electrocardiographic and echocardiographic examination and cardiac catheterization results were normal in all patients. Electrocardiographic monitoring revealed ventricular tachycardia in all patients. Exercise testing did not provoke sustained ventricular tachycardia in any patient. Programmed extrastimulation did not induce ventricular tachycardia in any patient. Isoproterenol infusion facilitated provocation of sustained ventricular tachycardia in only one patient. All six patients were treated with solitary beta-blocker therapy. Following treatment, there was a significant reduction in the incidence of ventricular tachycardia, couplets and total ventricular ectopic beats. During a follow-up period ranging from 16 to 36 (mean 22) months, all patients remain alive without clinically significant recurrence. Therefore, patients with life-threatening ventricular tachyarrhythmias without identifiable heart disease may respond to solitary beta-blocker therapy.

Ventricular tachycardia in children without heart disease

To assess the natural history of ventricular tachycardia (VT) in children without heart disease, the clinical course of 26 children, aged 1 day to 15 years at initial detection, was reviewed. Symptoms related to the rhythm were present in 8 children at some time during their course of follow-up. Evaluation included echocardiogram (19 patients), Holter monitoring (22 patients), graded treadmill exercise testing (16 patients) and invasive electrophysiology (4 patients). Exercise induced or exacerbated VT in 9 patients, but suppressed rhythm in 7. Ten patients were never treated. Of the remaining 16 treated patients, therapy was discontinued in 10 on the basis of the electrocardiographic or Holter monitor recordings. Six continued to receive therapy without complications. There were no known deaths over a period of 1 month to 34 years (mean 59 months, median 42 months). Although 2 patients have been lost to follow-up, based on our findings and a review of the reported cases of VT in children to date, after undergoing complete noninvasive cardiac evaluation symptomatic patients should be treated and studied with invasive electrophysiology if antiarrhythmic control is inadequate. The rate of VT or age at onset are not predictive of outcome in asymptomatic patients. As a group, these patients do not appear to benefit from therapy, but warrant follow-up since deaths have been reported in untreated asymptomatic patients.

Cardiac histologic findings in patients with life-threatening ventricular arrhythmias of unknown origin

Percutaneous endomyocardial biopsy (right ventricle in 10, left ventricle in 2) was performed in 12 patients, aged 9 to 57 years, with serious ventricular arrhythmias occurring in the setting of normal cardiac anatomy and mechanical function. Light microscopic examination of tissue revealed histologic abnormalities in 11 patients, including myocardial cellular hypertrophy in 7, interstitial fibrosis in 5, endocardial fibrosis in 2, myocardial degenerative changes in 1 and increased interstitial cellularity in 1. One patient had histologic evidence of acute lymphocytic myocarditis. Thus, a majority of patients with serious ventricular arrhythmias and normal cardiac anatomy had histologic abnormalities, bringing into question the concept of primary electrical heart disease or idiopathic ventricular tachycardia.

Prevalence and prognosis of exercise-induced nonsustained ventricular tachycardia in apparently healthy volunteers

Although exercise-induced ventricular tachycardia (VT), whether sustained or nonsustained, is usually associated with significant organic heart disease, its prevalence, associated characteristics and prognostic significance in an asymptomatic, unreferred community-dwelling population are unknown. Therefore, the prevalence of VT associated with maximal treadmill exercise was assessed in 597 male and 325 female volunteers, aged 21 to 96 years (mean +/- standard deviation 54 +/- 16), from the Baltimore Longitudinal Study on Aging who were without apparent heart disease. Ten subjects, 7 men and 3 women, with exercise-induced VT were identified, representing 1.1% of those tested; only 1 was younger than 65 years. All episodes of VT were asymptomatic and nonsustained. In 9 of 10 subjects, VT developed at or near peak exercise. The longest run of VT was 6 beats; multiple runs of VT were present in 4 subjects. Two subjects had exercise-induced ST-segment depression, but subsequent exercise thallium scintigraphic results were negative in each. Compared with a group of age- and sex-matched control subjects, those with asymptomatic, nonsustained VT displayed no difference in exercise duration, maximal heart rate, or the prevalence of coronary risk factors or exercise-induced ischemia as measured by electrocardiography and thallium scintigraphy. Over a mean follow-up period of 2 years, no subject has developed symptoms of heart disease or experienced syncope or sudden death. Thus, exercise-induced VT in apparently healthy subjects occurs almost exclusively in the elderly, is limited to short, asymptomatic runs of 3 to 6 beats usually near peak exercise, and does not portend increased cardiovascular morbidity or mortality rates over a 2-year period of observation.

Clinical characteristics and results of electrophysiologic testing in young adults with ventricular tachycardia or ventricular fibrillation

Thirty-one patients 16 to 40 years of age (mean +/- SD = 30.7 +/- 7 years) had one or more episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Underlying cardiac abnormalities consisted most commonly of cardiomyopathy (nine), long QT syndrome (LQTS) (five), and mitral valve prolapse (five); no identifiable heart disease was found in four patients. Programmed ventricular stimulation induced VT in only one of four patients with the LQTS but induced VT in 64% of 22 patients with other abnormalities. Chronic drug treatment was based either on serial electropharmacologic testing or was empiric when electrophysiologic testing failed to provoke an arrhythmia. Using this approach, we found a 13% incidence of recurrent VT and a 10% mortality over a follow-up period of 18.1 +/- 13.9 months. In young adults with VT or VF, an underlying cardiac abnormality can usually be found. Extensive evaluation should be performed to uncover the underlying cardiac abnormality as this may influence chronic management.

Exercise-induced ventricular tachycardia

Exercise tests were done on all patients referred to us because of ventricular premature beats. Exercise-associated ventricular tachycardia was seen in three of these patients. Once therapy for the arrhythmia was begun in two patients, we performed serial exercise tests, attempting to provoke the arrhythmia again. In the third patients, who was pregnant, we advised against strenuous physical activity and will exercise her post partum to determine whether therapy is warranted. We have shown that exercise testing can be used successfully in unmasking ventricular arrhythmias not detectable on resting evaluation.

Arrhythmogenic right ventricular dysplasia: a cause of ventricular tachycardia in children with apparently normal hearts

Arrhythmogenic right ventricular dysplasia (ARVD), a cardiomyopathy with hypokinetic ares limited to the wall of the right ventricle (RV), has been recently described as a cause of recurrent ventricular tachycardia (VT) in young adults with an otherwise normal heart. We reviewed 26 cases of recurrent VT in children and found 10 patients with no clinically recognizable abnormality aside from the dysrhythmia. Three of these 10 patients had ARVD. These three patients were initially seen at 1, 12, and 14 years of age with premature ventricular contractions (PVCs) and/or VT. Sustained VT occurred spontaneously or during stress testing. The PVCs and the VT were of left bundle branch block contour, suggesting RV site of origin. The diagnosis of ARVD was based on wall motion abnormalities of the RV demonstrated angiographically. We suggest that ARVD could be a significantly common cause of VT in children with an apparently normal heart.

Ventricular tachycardia in children

Thirty-eight patients aged 1 to 20 years (mean 11.2) were evaluated because of recurrent ventricular tachycardia. The follow-up period ranged from 0.5 to 12 years (mean 6). The patients were separated into two groups according to the presence or absence of known structural heart disease. Seventeen of the 21 patients with known heart disease were symptomatic (cardiac arrest in 5, syncope in 5, dizziness in 7) compared with only 6 of the 17 patients without heart disease (syncope in 3 and dizziness in 3) (p less than 0.01). All symptomatic patients had ventricular tachycardia with rates of more than 150 beats/min, whereas all but one of the asymptomatic patients had rates of less than 150 beats/min (p less than 0.01). Graded treadmill exercise testing was performed in 21 of the 38 patients. Exercise increased the degree of ventricular arrhythmia in 8 of the 11 symptomatic patients but decreased or abolished the arrhythmia in 9 of the 10 asymptomatic patients (p less than 0.01). Antiarrhythmic therapy was used in 28 of the 38 patients. Effectiveness of therapy was assessed with both 24 hour Holter monitoring and graded treadmill exercise testing. Therapy effectively abolished ventricular tachycardia and greatly decreased the number of premature ventricular complexes in the symptomatic patients but was less effective in the asymptomatic patients. Thus, this study suggests that the presence of underlying heart disease, the rate of ventricular tachycardia and the results of graded treadmill exercise tests are important in predicting the prognosis of children with ventricular tachycardia.

Idiopathic recurrent sustained ventricular tachycardia in children and adolescents

The electrophysiologic characteristics of recurrent sustained ventricular tachycardia were studied in seven pediatric 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.

Prognosis in primary ventricular tachycardia in the pediatric patient

Five male pediatric patients with primary ventricular tachycardia are described. Although three were initially in congestive heart failure due to the tachycardia and were extremely difficult to manage, all have completely recovered, are not taking medication, and are free of arrhythmia. Three of the patients required long-term management with quinidine, with a therapeutic goal of controlling the heart rather than abolishing the arrhythmia. No growth disturbances were found in those three patients. A review of reported cases revealed 71 infants and children with ventricular tachycardia not associated with heart disease or systemic disorders; only four deaths were reported (5.6%). In the primary form of ventricular tachycardia in children, complete pharmacologic suppression may not be achieved without seriously endangering the normal electrophysiologic functions. Controlling the rate to an asymptomatic level with pharmacologic means is safer for a problem that may be self-limited.

Ventricular tachycardia and ventricular fibrillation in a young population

In this study, we describe the findings in 18 young patients (age range 4 days to 24 years, mean 16.6 years) who had ventricular tachycardia and/or ventricular fibrillation and were followed for 4--70 months (mean 22.4 months). Patients had a variety of problems associated with their arrhythmia, including mitral valve prolapse, cardiomyopathy, myocarditis, prolonged QT syndrome and hypokalemia. Six patients had no clinically recognizable cardiac abnormality. The ventricular tachycardia showed a left bundle branch block contour in 10 of 17 patients, right bundle branch block in four, was multiform in two and had an indeterminate contour in one. Sustained ventricular tachycardia was initiated and terminated reproducibly by atrial and ventricular stimulation in three of seven patients who did not have spontaneous episodes of ventricular tachycardia during the electrophysiologic study. In one other patient, short bursts of ventricular tachycardia were induced. Patients who had ventricular fibrillation, those who died, and those who are still symptomatic with poorly controlled ventricular arrhythmias had significant heart disease. In one patient, a ventricular tachyarrhythmia that had required more than 100 electrical cardioversions spontaneously disappeared after requiring 1 year of antiarrhythmic therapy.

Idiopathic ventricular tachycardia. An intracardiac electrical, hemodynamic and angiographic assessment of six patients

Six patients with idiopathic paroxysmal ventricular tachycardia were investigated by external electrocardiography, intracardiac electrography and pacing, exercise testing, cardiac catheterization and coronary angiography. All had normal hemodynamics and coronary arteries. His bundle electrography proved ventricular origin in five; one had no paroxysmal ventricular tachycardia during His bundle electrography. Treatment with diphenylhydantoin, 4.2 to 8.0 mg/kg/day, and propranolol, 0.8 to 2.7 mg/kg/day, appeared effective, well tolerated therapy in three, and procainamide and propranolol in one requiring medical treatment. Abstinence from tobacco and coffee abolished paroxysmal ventricular tachycardia in one of two who required no medication. The other has no recurrence of paroxysmal ventricular tachycardia since study.

Ventricular tachycardia in 4 patients evaluated by programmed electrical stimulation of heart and treated in 2 patients by surgical division of anterior radiation of left bundle-branch

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Repetitive tachycardia. Effects of exercise tests and amyl nitrite

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