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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In recent years calcium channel blockers have emerged as a new class of antiarrhythmic agents for the control of certain supraventricular and ventricular arrhythmias. Electrophysiologically, they are heterogeneous but their main action is mediated through a depressant effect on the slow calcium channel in cardiac muscle. In isolated muscle, their actions are modulated by their reflex actions and by their interaction with the autonomic nervous system due to the nonocompetitive adrenergic blocking actions that some of the compounds exhibit. The major agents exerting antiarrhythmic actions are verapamil, diltiazem, gallopamil, tiapamil, and bepridil; the dihydropyridines are devoid of significant electrophysiologic actions in vivo. Calcium antagonists prolong intranodal conduction time, lengthen the effective and functional refractory periods in the AV node, but exert little or no effect on atrial, ventricular, His-Purkinje, or bypass tract conduction or refractoriness (except in the case of bepridil, which has additional electrophysiologic properties). These effects form the basis of the clinical antiarrhythmic effects of this class of agents. The most striking action is the predictable and prompt termination of reentrant supraventricular tachycardia by intravenous verapamil and diltiazem and the slowing of the ventricular response in atrial flutter and fibrillation. These agents may also be of value in the chronic control of ventricular response in atrial flutter and fibrillation; their role in multifocal atrial tachycardia and other ectopic tachycardias is less well defined. Calcium antagonists reverse ischemic ventricular arrhythmias due to coronary artery spasm but exert little or no action in the usual forms of sustained ventricular tachyarrhythmias associated with severe structural heart disease. They are poor suppressants of premature ventricular contractions. Recent data have established their role in exercise-induced tachycardia occurring in the context of ischemic heart disease; they are also of value in ventricular tachycardia occurring in young subjects developing tachycardia with a right bundle branch block with left axis deviation morphology, an arrhythmia thought to be due to triggered automaticity. The role of calcium antagonists in reducing the incidence of sudden death in the survivors of acute myocardial infarction remains uncertain.
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PMID:Control of cardiac arrhythmias by calcium antagonism. 328 60

A 29-year-old woman with idiopathic sustained ventricular tachycardia (VT) of about 70 days' duration who was in congestive heart failure is described. VT showing QRS morphologic pattern of right bundle branch block and left axis deviation during an episode of tachycardia is suggested to make a unique clinical entity; (1) it occurred in young and asymptomatic adults without demonstrable organic heart disease; (2) the VT was inducted and terminated with atrial or ventricular stimulation; and (3) it responded to verapamil.
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PMID:A case of idiopathic sustained ventricular tachycardia of about 70 days' duration. 361 12

A retrospective study of the medical records of our hospital from 1965 to 1985 was carried out to characterize for the first time chronic Chagas' heart disease in the elderly (more than 70 years old). A total of 25 patients (mean age = 76) were suitable for the study. Congestive heart failure, sudden cardiac death, thromboembolism and atypical chest pain were found in 68, 16, 8 and 8% of cases, respectively. Ventricular premature contractions (60%), right bundle branch block (32%), left anterior hemiblock (28%), atrial fibrillation (28%) and right bundle branch block associated with left anterior hemiblock (20%) were the ECG changes most frequently found. A morphological study was performed on 8 (32%) patients. All of them showed cardiac abnormalities, with apical aneurism being detected in 100% of cases. At autopsy, pulmonary embolism was observed in 3(37%) of these patients who presented with congestive heart failure, ventricular premature contractions and/or intraventricular conduction defect and/or atrial fibrillation. Thus, the characteristics of chronic Chagas' heart disease in the elderly are similar to those found in middle-aged patients. We suggest that these patients are important for the study of the pathogenesis of chronic Chagas' heart disease because they may have less aggressive pathophysiologic mechanisms than middle-aged patients.
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PMID:Chronic Chagas' heart disease in the elderly: a clinicopathologic study. 365 79

In order to evaluate the etiology of so-called idiopathic ventricular tachycardia, endomyocardial biopsies were performed in four patients with electrocardiographically documented recurrent and sustained ventricular tachycardia. During the episodes of ventricular tachycardia, standard ECG showed a QRS pattern of right bundle branch block with left axis deviation in two patients and left bundle branch block in two patients. The episodes were associated with palpitation, dyspnea and hypotension in all cases. No organic heart disease was detected by physical examination, chest X-ray films, echocardiograms, left ventriculograms or coronary cineangiograms. His bundle electrograms showed blocks at various sites in the atrioventricular conduction system. The biopsy specimens revealed nonspecific myocardial degeneration in the right and left ventricles. These findings suggest mild but wide-spread myocardial damage in both the working myocardium and the conduction system. The clinical course of these patients appeared benign according to follow-up data of one to nine years' duration. None developed overt clinical signs of dilated, hypertrophic or restrictive cardiomyopathy.
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PMID:Histological findings of the right and left ventricular myocardium and clinical follow up in idiopathic ventricular tachycardia. 376 28

A systematic investigation was performed in patients with familial amyloidotic polyneuropathy, Portuguese type (AFp) to assess the pattern and incidence of cardiac involvement. Of 327 patients investigated, ECG abnormalities were present in 285 (87.2%). Low voltage and QS pattern in V1, V2, V3 were found in 51.3% and 35.7% patients respectively. Conduction disturbances were present in 211 (64.5%). Sinus node disease, 1st degree and Wenckebach interventricular blocks were frequent. Complete atrioventricular block was observed in only 2 patients (0.6%). Left anterior hemi-block was present in 30.8%, left bundle branch block in 3.9%, left posterior hemi-block in 2.4% and right bundle branch block in 2.1%. Holter monitoring showed a much higher incidence of conduction disturbances, most of these occurring at night. The mean values of septum and posterior wall thickness and mass evaluated by echocardiography in 72 patients were normal. The systolic and diastolic global and regional functions, determined in 12 patients, analysing the echo by a digitization computer technique, were normal. In 7% a trivial pericardial effusion was observed. In 16 patients with ECG changes and normal echocardiograms the technetium 99m pyrophosphate scanning was negative. We conclude that the ECG is the most precise, sensitive and clinically useful method for detecting cardiac amyloidosis in patients with AFp. In spite of the rarity of congestive and restrictive patterns, the incidence and severity of conduction disturbances does not allow us to consider heart disease in AFp as a benign entity.
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PMID:The heart in Portuguese amyloidosis. 377 1

A cohort of 1,960 white men aged 40 to 56 years without initial apparent heart disease and with 11 years of annual rest electrocardiograms and 20 year mortality data was followed in the Chicago Western Electric Company Study. Incomplete right bundle branch block was found in 134 men (6.8%) at entry. During follow-up, 222 men developed such block, an incidence rate of 13.6%. Left axis deviation of -30 degrees or less was more frequent in men with than in those without incomplete block at entry (8.2 versus 2.4%). Men with left axis deviation also had a higher incidence of incomplete right bundle branch block. Similarly, men developing incomplete block had a significantly greater risk of developing left axis deviation. The associations between incomplete block and left axis deviation were unrelated to age and body weight. Men with incomplete block had a significantly greater likelihood of developing complete right bundle branch block. The 11 year incidence rate of complete block was 5.1% for men with baseline incomplete block and 0.7% for those without. Complete block developed in 2 of 220 incident cases of incomplete block but in none of the 440 control men matched by age and duration of follow-up. Although incomplete right bundle branch block was not related to an increased risk of death in 20 years from coronary heart disease and cardiovascular diseases, the study data suggest that such block is frequently a manifestation of primary abnormality of the cardiac conduction system in middle-aged men.
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PMID:Characteristics and prognosis of incomplete right bundle branch block: an epidemiologic study. 395 Feb 28

We performed a prospective, randomized crossover study to evaluate the comparative efficacy of transvenous cardioversion and rapid ventricular pacing for termination of induced ventricular tachycardia in patients with spontaneous ventricular tachycardia and organic heart disease. Sixty-two episodes of ventricular tachycardia were induced in 15 patients, mean age 60 +/- 10 years, during electrophysiologic studies. All patients underwent a preselected electrical therapy protocol in a randomized crossover sequence. Transvenous cardioversion was performed by an incremental protocol of three sequential shocks (0.5, 1.1, and 2.7 J). Six asynchronous sequential bursts of rapid ventricular pacing (10 and 15 paced stimuli at 90%, 75%, and 65% of ventricular tachycardia cycle length) were used. Mean cycle length of ventricular tachycardia for the study population was 391 +/- 85 msec. The morphology of the tachycardia was left bundle branch block in 27, right bundle branch block in 32, and indeterminate in three. Characteristics of ventricular tachycardia terminated by the two techniques were comparable. Rate of success for termination of tachycardia with the two methods was also comparable (transvenous cardioversion 83%, rapid ventricular pacing 80%; p greater than .1) and these responses were concordant in 78%. The modes of termination of ventricular tachycardia were similar. The incidence of acceleration of ventricular tachycardia per episode with these preselected protocols was also comparable (transvenous cardioversion 11%, rapid ventricular pacing 6%; p greater than .2). Transient supraventricular tachyarrhythmias were more frequent after transvenous cardioversion (23%) than after rapid ventricular pacing (3%). Significant patient discomfort occurred only after transvenous cardioversion (incidence of 57%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparative efficacy of transvenous cardioversion and pacing in patients with sustained ventricular tachycardia: a prospective, randomized, crossover study. 400 26

Recently a unique clinical entity has been suggested in subjects without apparent heart disease presenting with recurrent ventricular tachycardia (VT) characterized by RBBB + LAH electrocardiographic pattern, relatively slow rate, induction by atrial stimulation, and interruption by verapamil. According to these characteristics, three cases (2 M and 1 F, aged 18, 33 and 66 years) are presented in this study. They have had palpitations from one to twenty years, but not syncopal episodes. During VT the cycle length ranged from 300 to 480 msec. VT was terminated both by verapamil and by ajmaline. VT was inducible in 3/3 cases by incremental atrial pacing when cycle length of pacing became similar to that of spontaneous VT; in 2/3 cases VT was induced by programmed right atrial stimulation and in 2/3 cases by programmed ventricular stimulation. Serial electrophysiological studies for pharmacological and therapeutic evaluation applied to 1/3 cases showed: amiodarone given orally (200 mg/die) for two months prevented the induction of VT while verapamil, propranolol, mexiletine, and propafenone tested intravenously were ineffective. In the remaining two patients amiodarone, tested only intravenously, was not effective to prevent the induction of VT but lengthened its cycle length. All patients received amiodarone orally (200 mg/die) and were followed for 2,7 and 8 years respectively. Two of them had no more episodes of VT and one, while asymptomatic, continued to present with. The electrophysiological mechanism of this form of VT cannot be identified with certainty, but many data suggest a reentry in the posterior fascicle of left bundle branch as the most probable mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Idiopathic ventricular tachycardia responsive to verapamil. Presentation of 3 cases and review of the literature]. 400 54

In order to investigate the anatomic substrate of 'idiopathic' ventricular tachycardia (VT) 10 patients with chronic recurrent VT and no apparent sign of heart disease underwent an echocardiographic, haemodynamic and histologic study (5 males, 5 females: mean age = 40 +/- 11 years). In the patients with a left bundle branch block morphology of VT (7 cases), four showed findings compatible with an arrhythmogenic right ventricular dysplasia or a right ventricular cardiomyopathy. In the other three all examinations were normal with the exception of endomyocardial biopsy, which showed slight non specific changes in two. Of the remaining 3 cases (characterized by a right bundle branch block morphology of VT or by the presence of polymorphic VT) one had histologic evidence of myocarditis while another developed dilated cardiomyopathy. Macroscopic and/or microscopic ventricular abnormalities are frequently found in patients with VT which appears idiopathic. In these cases myocardial disease is frequently progressive, despite optimal control of VT.
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PMID:Morphological findings in apparently idiopathic ventricular tachycardia. An echocardiographic haemodynamic and histologic study. 402 88

A retrospective study of the medical records filed at the University Hospital from 1965 to 1983 and of 18456 autopsies carried out in the Department of Pathology of this Institution from 1953 to 1983, referring to patients aged less than 18 years was performed in an attempt to fully characterize chronic Chagas' heart disease in children and adolescents. Only 19 of these patients fulfilled the criteria for inclusion in the present study (12 cases with only clinical information and 7 cases with clinical and pathological information). We noted that the clinical manifestations of chronic Chagas' heart disease are congestive heart failure, thromboembolism and sudden death. Radiologic, electrocardiographic and anatomo-pathological findings demonstrated serious myocardial involvement. This set of alterations is also detected in adults with chronic Chagas' heart disease. Among adolescents, however, the disease exhibits relevant peculiarities such as rapid evolution to death within a short period of time (128 days), diagnostic difficulty related to the presence of significant mitral regurgitation (61% erroneous initial diagnosis), and low frequency of right bundle branch block (11% of cases). These findings suggest that among children and adolescents, chronic Chagas' heart disease may be of a peculiar type and therefore may be useful to clarify the pathogenetic mechanism of the disease.
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PMID:Chronic Chagas' heart disease in children and adolescents: a clinicopathologic study. 407 2


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