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

Catheter ablation techniques have evolved as an alternative to map-guided surgery and proven effective in a variety of supraventricular tachyarrhythmias. Direct current catheter ablation has been shown to be effective in about 50 to 70% of cases. Approximately, 60% of patients with structural heart disease and monomorphic ventricular tachycardia were successfully treated using direct current ablation techniques. This overall success rate and possible risks associated with the use of direct current have stimulated the search for other energy sources appropriate for catheter ablation. Presently, only a few preliminary reports on the clinical efficacy of radiofrequency energy for the treatment of ventricular tachyarrhythmias in man exist. 23 patients with identifiable heart disease at a mean age of 52 +/- 17 years underwent radiofrequency catheter ablation. 16 patients had coronary artery disease, one patient dilative cardiomyopathy and six patients had arrhythmogenic right ventricular disease. All patients presented with chronic current sustained ventricular tachycardia. After detailed endocardial catheter mapping radiofrequency energy was applied at the site of earliest ventricular activation during ventricular tachycardia which could be entrained during fixed rate ventricular pacing at the site of origin of ventricular tachycardia. At all ablation sites a long latency between the stimulus and QRS complex was noted. Of 23 patients 18 were treated with radiofrequency alone whereas in five patients a second ablation procedure using direct current was performed. Following the ablation procedures, 14 patients (61%) remained free of ventricular tachycardia. One patient died due to congestive heart failure 21 months following ablation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Catheter ablation of ventricular tachycardia using radiofrequency current. 163 36

A 30-year-old woman presented with life-threatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445-0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochrome c oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.
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PMID:Ultrastructural abnormalities of mitochondria and deficiency of myocardial cytochrome c oxidase in a patient with ventricular tachycardia. 164 45

Exercise testing is an important noninvasive method for the exposure of arrhythmias. It provides complementary information to that obtained from ambulatory monitoring or electrophysiologic testing. By producing a number of important physiologic changes, especially activation of the sympathetic nervous system and an increase in circulating catecholamines, exercise testing provides a more complete assessment. On continuous monitoring, exercise-induced ventricular premature beats may be found in up to 34% of healthy subjects, in 60 to 70% of those with heart disease and in all patients who have experienced sustained ventricular tachycardia. Couplets or nonsustained ventricular tachycardia can be found during exercise in 0 to 6% of healthy subjects, in 15 to 31% of patients with heart disease and in 75% of those with sustained ventricular tachycardia. Even in patients with heart disease, there is only a small risk of inducing sustained ventricular tachycardia or ventricular fibrillation during exercise. The prognostic relevance of exercise-induced ventricular arrhythmias in patients with coronary artery disease or cardiomyopathy has not been clearly established. There appears to be an increased risk, however, in patients with ventricular premature beats as well as ST-segment depression or in patients with repetitive forms of ventricular arrhythmias during exercise which cannot be medically controlled. In healthy subjects, exercise-induced ventricular premature beats are of no prognostic relevance. In particular, for patients in whom arrhythmias are induced by exercise, exercise testing should be used to assess the effectiveness of antiarrhythmic drug treatment. Importantly, serious cardiac toxicity, often not observed at rest or during routine activities, may become apparent during exercise testing. It should be a standard part of arrhythmia assessment and management.
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PMID:Evaluation of cardiac arrhythmias by exercise testing. 169 Jan 68

The shape of a premature ventricular complex (PVC) might reflect the presence or absence of myocardial disease. To test this, 100 patients with a PVC on a 12-lead electrocardiogram at cardiac catheterization or nuclear angiography were classified according to PVC morphology. Group 1 (n = 50) had PVC QRS complexes with either smooth and uninterrupted contour or with narrow (less than 40 msec) notching. Group 2 (n = 50) demonstrated PVC with broad (greater than or equal to 40 msec) notching or shelves. Clinical, electrocardiographic and angiographic variables were assessed to define group differences. All patients had one or more etiological forms of heart disease none of which distinguished either group. Groups 1 and 2 differed with respect to a history of congestive heart failure (12% vs. 66%, p = 0.0004), dilated cardiomyopathy (2% vs. 38%, p = 0.0005), and the presence of mitral regurgitation (13% vs. 58%, p = 0.001), respectively. In group 1, 45 of 50 (90%) patients with a PVC had no notching. Patients in group 2 had greater PVC QRS duration as compared with patients in group 1 (181 +/- 6 vs. 134 +/- 3 msec, p = 0.0001). End-diastolic volume index (EDVI) (78 +/- 3 vs. 139 +/- 11 ml/m2, p = 0.0000) and ejection fraction (EF) (0.59 +/- 0.02 vs. 0.34 +/- 0.03, p = 0.0000) significantly discriminated between group 1 and 2, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Premature ventricular complex morphology. A marker for left ventricular structure and function. 169 Jun 14

Refsum's disease is a polyneuropathy due to a hereditary error in the metabolism of a fatty acid, phytanic acid, usually leading to cardiac failure only at an advanced stage of the disease. The authors report the case of two brothers with Refsum's disease revealed by a heart failure before the clinical stage of the peripheral neuropathy. In the younger brother, the affection started at the age of 22 years by an acute pulmonary oedema which revealed a dilated, hypokinetic myocardiopathy, associated with retinitis pigmentosa, ptosis, anosmia and biological myolysis. The normal plasma concentration of phytanic acid measured several times led to the conclusion of Kearns-Sayre syndrome even if certain aspects were atypical (moderate conduction disorders, no characteristic aspect in the muscle biopsy). Five years later, the older brother, aged 28, presents a dyspnea on effort which leads to the discovery of a hypokinetic, hypertrophic myocardiopathy, slightly dilated, associated with cardiac conduction disorders, retinitis pigmentosa, anosmia and biological myolysis. The plasma concentration of phytanic acid being very high. Refsum's disease was diagnosed and the diagnosis of younger brother was corrected. From the study of these two cases, the characteristics of the cardiac disorders can be specified: the cardiopathy can reveal the disease and correspond to a dilated or hypertrophic myocardiopathy. The diagnosis of the disease can be difficult because the plasma phytanic acid may remain at normal level, thus requiring the assay of the activity of phytanate oxydase. The existence of ophthalmologic signs (retinitis pigmentosa or progressive ophthalmoplegia externa) associated with a myocardiopathy must systematically lead to a search for Refsum's disease, this diagnosis having fundamental therapeutic implications (died, even plasmapheresis).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Refsum's disease. Apropos of 2 cases disclosed by myocardiopathy]. 169 53

Tachycardia in children is generally considered harmful and frequently is transformed into so-called arrhythmogenic cardiomyopathy. The goal of this report was the investigation of the result of surgical treatment and how it was dependent on the type of tachycardia, the presence of combined, or concomitant heart pathology. We have operated on 146 patients at an age of 8 months to 16 years (mean 9.6 +/- 2.7 yrs) from 1982 until April 1, 1990. Surface mapping was performed in patients with WPW syndrome. All patients underwent electrophysiological study. The duration of the disease was 8.4 +/- 1.9 years. 89% of patients suffered from syncopal episodes. The heart rate during tachycardia exceeded 200 beats/min in 95% of children. In 98% of patients palpitation lasted more than 3 hours. Seven types of tachycardia were seen in operated children. All patients were divided into three groups depending on the absence or presence of CHD or several types of arrhythmia. Sixty-seven patients (45.8%) with so-called noncomplicated tachycardias (without additional heart disease) were included in group I. Forty-seven patients (32.2%) with tachycardia and CHD were in group II and 52 patients (21.9%) with multiple tachycardias that had life-threatening prognosis were in group III. The total efficacy of surgical treatment in group I was 97%. The worst results were in group II patients. The total positive results in this group was 81%. In group III patients with life-threatening arrhythmias, total efficacy was 93.8%.
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PMID:The results of surgery for tachyarrhythmias in children. 170 80

Atrial flutter is associated with a macro-reentrant loop including an area of slow conduction cryoablation of which prevents atrial flutter to occur. Three patients underwent such intervention. Atrial fibrillation is associated with multiple reentrant circuits (leading circle of Allessie) that requires a critical surface area to perpetuate. We have designed an operation, the corridor operation, which isolate the sinus node and the AV node within a small segment of atrial tissue, to restore the chronotropic function of the sinus node. Nine patients underwent the corridor operation at our institution. There were eight men and one woman. Five had incessant atrial fibrillation and four paroxysmal. One patient had associated mitral valve stenosis and one cardiomyopathy. There were no perioperative complications. Six patients had normal sinus node function postoperatively including all the four patients with documented normal sinus node function preoperatively. Three patients required implantation of an AAI pacemaker. Two patients had recurrence of atrial fibrillation within the corridor. Our experience suggests that the corridor operation should be restricted to patients with documented good sinus node function and without structural heart disease. Our experience with five patients with paroxysmal sinus node tachycardia has been disappointing. Only one patient had long-term success although better series have been published.
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PMID:Surgery for atrial tachycardia. 170 81

The aim of this study was to investigate the efficacy and the side effects of a long-term treatment with amiodarone. We analyzed the data of 41 patients in whom amiodarone therapy had been initiated between 1974 and 1984. Twenty-one patients had dilative cardiomyopathy, 14 patients had chronic myocardial infarction, four patients suffered from WPW syndrome with intermittent atrial fibrillation, one patient had aortic valve surgery, whereas in one patient there was no clinical evidence of a heart disease. All patients had salvos of ventricular extrasystoles, ventricular tachycardia or documented intermittent ventricular fibrillation. There have been seven drop-outs up to the present time. In each patient, the lowest antiarrhythmically effective dose was applied, which was generally higher in patients with low ejection fraction. Effective treatment of the ventricular tachycardia was achieved in 55-92% of patients and did not depend on the duration of treatment. In 10 patients in whom amiodarone therapy had to be stopped for various reasons. Sudden cardiac death was slightly more frequent than in the 24 patients treated with amiodarone, though the difference was not significant. In cases with a history of syncope the prognosis was poor, even with amiodarone therapy. Due to side effects, a dosage reduction or discontinuation of amiodarone treatment became necessary in 14 patients. Amiodarone proved to be an effective drug also for the long-term treatment of ventricular tachycardia, and possibly for the prevention of sudden cardiac death. With the exception of blue skin color, there was no accumulation of side effects, even during long-term treatment of several years.
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PMID:[Long-term treatment with amiodarone]. 171 39

Although antiarrhythmic drugs remain the first and most frequently used approach to therapy for arrhythmias, there is growing concern about their safety. It has long been recognized that this class of drug is associated with frequent side effects, especially in patients with extensive underlying heart disease. However, the recent report from the Cardiac Arrhythmia Suppression Trial (CAST) has pointed out that serious toxicity may occur even in patients with less serious heart disease. There are two major reasons for antiarrhythmic therapy. First is for relief of symptoms documented to be the result of arrhythmia. Although there are few studies showing that the antiarrhythmic drugs are effective for this indication, clinical experience does confirm that this is the case. The second indication is to prevent sudden cardiac death. Although antiarrhythmic drugs are of benefit for preventing recurrent arrhythmias in those patients who have already experienced a sustained ventricular tachyarrhythmia, there are, as yet, no data that they are effective for preventing such arrhythmias in patients thought to be at high risk; for example, postinfarction patients or those with a cardiomyopathy and who have nonsustained ventricular tachycardia. Unfortunately, therapy with antiarrhythmic drugs is associated with substantial risks. Although the majority of the side effects are not serious but only "nuisance" complaints, there are more serious toxic reactions that are often idiosyncratic. Organ toxicity may occur with some of these drugs. However, the most serious problems are cardiac side effects including conduction abnormalities, worsening of congestive heart failure, and aggravation of arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Safety and toxicity of antiarrhythmic drug therapy: benefit versus risk. 172 22

Determining safe and effective antiarrhythmic therapy in paediatric patients requires definition of the mechanism of the arrhythmia, determination of associated risk factors for treatment (such as the presence of congenital cardiac defects, myocarditis or cardiomyopathy), and monitoring for potential drug side effects related to the treatment. A number of modalities for non-invasive evaluation of arrhythmias is available, including ECG, 24-hour ambulatory Holter monitoring, and transtelephonic ECG transmission. Arrhythmias requiring medical treatment in children with normal cardiac anatomy and function include supraventricular tachycardia (SVT), ventricular tachycardia (VT) and primary atrial tachycardias. SVT is treated acutely with vagal manoeuvres or drugs which slow AV conduction [adenosine (adenine riboside), edrophonium, phenylephrine or verapamil]. When medical conversion is not achieved, transoesophageal overdrive pacing or direct current (DC) cardioversion may be required. Long term drug therapy for SVT includes first-line treatment with digoxin, verapamil or propranolol. Ventricular tachycardia is managed acutely with DC cardioversion and intravenous lidocaine (lignocaine). Chronic drug regimens include mexiletine, propranolol or amiodarone. In children with structural congenital heart disease or myocardial dysfunction, hazards of drug therapy for arrhythmias include depression of cardiac function, proarrhythmia (drug-induced worsening of arrhythmias), and conduction abnormalities. Care must be taken to choose medication regimens which are likely to be effective with minimum risk of potentiating abnormal haemodynamics or conduction.
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PMID:Cardiac arrhythmias in childhood. Diagnostic considerations and treatment. 172 43


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