Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In up to 10% of patients who present with ventricular tachycardia (VT), obvious structural heart disease is not identified. In such patients, causes of ventricular arrhythmia include right ventricular outflow tract (RVOT) VT, extrasystoles, idiopathic left ventricular tachycardia (ILVT), idiopathic propranolol-sensitive VT (IPVT), catecholaminergic polymorphic VT (CPVT), Brugada syndrome, and long QT syndrome (LQTS). RVOT VT, ILVT, and IPVT are referred to as idiopathic VT and generally do not have a familial basis. RVOT VT and ILVT are monomorphic, whereas IPVT may be monomorphic or polymorphic. The idiopathic VTs are classified by the ventricle of origin, the response to pharmacologic agents, catecholamine dependence, and the specific morphologic features of the arrhythmia. CPVT, Brugada syndrome, and LQTS are inherited ion channelopathies. CPVT may present as bidirectional VT, polymorphic VT, or catecholaminergic ventricular fibrillation. Syncope and sudden death in Brugada syndrome are usually due to polymorphic VT. The characteristic arrhythmia of LQTS is torsades de pointes. Overall, patients with idiopathic VT have a better prognosis than do patients with ventricular arrhythmias and structural heart disease. Initial treatment approach is pharmacologic and radiofrequency ablation is curative in most patients. However, radiofrequency ablation is not useful in the management of inherited ion channelopathies. Prognosis for patients with VT secondary to ion channelopathies is variable. High-risk patients (recurrent syncope and sudden cardiac death survivors) with inherited ion channelopathies benefit from implantable cardioverter-defibrillator placement. This paper reviews the mechanism, clinical presentation, and management of VT in the absence of structural heart disease.
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PMID:Ventricular tachycardia in the absence of structural heart disease. 1694 51

The clinical precipitants of ventricular fibrillation (VF) remain poorly understood. Clinical factors such as hypoxemia, acidosis or electrolyte imbalance, drug-related toxicity, autonomic nervous system disorders as well as viral myocarditis have been proposed to be associated with sudden cardiac death particularly in patients with structural heart disease. However, In the Brugada syndrome, concurrent febrile illness has been reported to unmask the electrocardiographic features of the Brugada syndrome and be associated with an increased propensity for VF. More recently, a febrile illnesses of infectious etiology was associated to polymorphic ventricular tachycardia or VF in patients with normal hearts and without known repolarization abnormality. In this review we detail this phenomenon and its putative mechanisms.
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PMID:May fever trigger ventricular fibrillation? 1694 53

The frequency of Brugada sign was found to differ among ethnic groups. Yet, there is no data regarding the prevalence of Brugada syndrome and sign in our country. The aim of this study was to determine the frequency of a Brugada-type electrocardiogram (ECG) pattern in southern Turkey. A total of 1,238 subjects (males, 671, females, 567) were included in the study. The previously archived ECGs of 807 subjects without any evidence of structural heart disease were chosen randomly and evaluated. In addition, prospective analysis of the ECGs of 431 subjects (males, 293, females, 138) randomly chosen from healthy university students were also included. The mean age was 38.9 +/- 17.6 years. Six subjects (0.48%) had a Brugada-type ECG pattern. One (0.08%) of them had the coved-type and 5 (0.40%) had the saddleback-type. All subjects were asymptomatic. A Brugada-type ECG pattern was obtained in 1 (0.17%) female and in 5 (0.74%) males (OR: 4.2 CI: 0.5-36.4, P = 0.2). The Brugada-type ECG pattern frequency was 0.12% in subjects >or= 25 years old and 1.16% in subjects between 17-24 years old (OR: 9.4 CI: 1.1-81.2, P = 0.02). Young males between 17-24 years had the highest (1.70%) frequency. The results indicate that the frequency of the Brugada-type ECG pattern was 0.48% in the general population, being more prevalent in young males in our region. These results are similar to the findings of studies performed in other countries.
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PMID:Frequency of Brugada-type ECG pattern (Brugada sign) in Southern Turkey. 1696 Apr 9

Fetal dysrhythmias are usually transient. Abnormal fetal rates and rhythms during labor are "functional." Fetal dysrhythmias may be associated with congenital heart disease and fetal hydrops. Bradycardia is usually related to fetal distress; supraventricular tachycardia, atrial flutter, and atrial fibrillation may be associated with severe congestive heart failure. Ventricular fibrillation is rare in the fetus and infant and is usually associated with myocardial necrosis with perimembranous septal defect; the nonbranching atrioventricular (AV) bundle may have an aberrant position and result in cardiac arrhythmia. Wolff-Parkinson-White syndrome with conduction abnormalities and left ventricular hypertrophy (LVH) is due to an accessory pathway that bypasses the AV sulcus and results in faster conduction. Carnitine deficiency may be primary or secondary and may result in cardiac arrhythmia. Histiocytoid cardiomyopathy is characterized by cardiomegaly, incessant ventricular tachycardia, and frequently sudden death. Arrhythmogenic right ventricular dysplasia (ARVD) results in ventricular tachycardia and left bundle branch block. Noncompaction of the left ventricle predisposes to potentially fatal arrhythmias. Long Q-T syndromes (LQTS) are a heterogeneous group of disorders with many genetic mutations. Brugada syndrome is an autosomal dominant trait with right bundle branch block and ST elevation. Barth syndrome is an X-linked disorder with dilated cardiomyopathy, cyclic neutropenia and skeletal myopathy. Hypertrophic cardiomyopathy in infancy may be related to metabolic diseases, particularly glycogen storage diseases; the familial form predisposes to sudden death. Arrhythmias following cardiac surgery may occur after closure of a ventricular septal defect (VSD) or damage to the conduction system.
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PMID:Pathogenesis of cardiac conduction disorders in children genetic and histopathologic aspects. 1696 59

A 24-year-old man without structural heart disease was admitted following recurrent syncopes. His baseline ECG revealed a right bundle-branch block (RBBB) pattern. Spontaneous monomorphic and polymorphic ventricular tachycardias (VT) were observed during monitoring. The provocation test by propafenone brought out recurrent spontaneous polymorphic VT and provocation by ajmaline caused an ST elevation in V2. Programmed ventricular stimulation test during the electrophysiologic study revealed both monomorphic and polymorphic VT. The patient received an internal cardioverter/defibrillator with the diagnosis of Brugada syndrome.
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PMID:Monomorphic and propafenone-induced polymorphic ventricular tachycardia in Brugada syndrome: a case report. 1697 61

Brugada syndrome (BS) is an inherited cardiac disorder characterized by typical electrocardiographic patterns of ST segment elevation in the precordial leads, right bundle branch block, fast polymorphic ventricular tachycardia in patients without any structural heart disease, and a high risk of sudden cardiac death. The incidence of BS is high in male vs. female (i.e., 8-10/1: male/female). The disorder is caused by mutations in the SCN5A gene encoding Nav1.5, the cardiac sodium channel, which is the only gene in which mutations were found to cause the disease. Mutations in SCN5A associated with the BS phenotype usually result in a loss of channel function by a reduction in Na+ currents. We review the clinical aspects, risk stratification, and therapeutic management of this important syndrome.
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PMID:Clinical aspects and physiopathology of Brugada syndrome: review of current concepts. 1711 Oct 25

Brugada syndrome (BS) is an inherited cardiac disorder associated with a high risk of sudden cardiac death and is caused by mutations in the SCN5A gene encoding the cardiac sodium channel alpha-subunit (Na(v)1.5). The aim of this study was to identify the genetic cause of familial BS and characterize the electrophysiological properties of a novel SCN5A mutation (W1191X). Four families and one patient with BS were screened for SCN5A mutations by PCR and direct sequencing. Wild-type (WT) and mutant Na(v)1.5 channels were expressed in tsA201 cells, and the sodium currents (I(Na)) were analyzed using the whole-cell patch-clamp technique. A novel mutation, W1191X, was identified in a family with BS. Expression of the WT or the mutant channel (Na(v)1.5/W1191X) co-transfected with the beta(1)-subunit in tsA201 cells resulted in a loss of function of Na(v)1.5 channels. While voltage-clamp recordings of the WT channel showed a distinct acceleration of Na(v)1.5 activation and fast inactivation kinetics, the Na(v)1.5/W1191X mutant failed to generate any currents. Co-expression of the WT channel and the mutant channel resulted in a 50% reduction in I(Na). No effect on activation and inactivation were observed with this heterozygous expression. The W1191X mutation is associated with BS and resulted in the loss of function of the cardiac sodium channel.
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PMID:A novel mutation in the SCN5A gene is associated with Brugada syndrome. 1714 Dec 78

Brugada syndrome is a clinical entity characterized by coved type ST-segment elevation in the right precordial electrocardiographic leads (V(1-3)) and an episode of ventricular fibrillation in the absence of structural heart disease. Although a number of clinical and experimental reports have elucidated the electrocardiographic, electrophysiologic, cellular, and molecular aspects, several problems remain unsolved. Recently developed high-resolution optical mapping techniques in arterially-perfused wedge preparations enable recording of transmembrane action potentials from 256 sites simultaneously at the epicardial surface, thus providing further advances in the understanding of the cellular mechanism of the specific ST-segment elevation and subsequent ventricular arrhythmias. In this review article, new findings relating to several unresolved problems such as gender difference (male predominance) and ethnic difference (higher incidence in Asian population) are also presented.
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PMID:Mechanism and new findings in Brugada syndrome. 1758 37

We report the case of a 38-year-old Asian man with a pericardial hemangioma on the left main coronary artery. The patient presented initially at our hospital after cardiopulmonary resuscitation following an episode of ventricular fibrillation (VF). Because of spontaneous coved-type ST segment elevation on the higher intercostal space V1 to V2 in a 12-lead electrocardiogram, documented VF in the absence of structural heart disease, and a family history of sudden death, he was diagnosed with Brugada syndrome. Transesophageal echocardiography showed a smooth-surfaced mass with well-demarcated borders, directly above the left main coronary artery. Computed tomography confirmed the presence of the mass, which showed no enhancement at early phase, but did demonstrate homogenous enhancement at delay phase by contrast material. There were no findings from either the nuclear medicine or the tumor marker investigations which indicated that the mass located just above the main coronary arteries was malignant. Therefore, taken together, these findings suggested that the tumor might be a pericardial hemangioma. The relationship between the location of the hemangioma just above the left main coronary artery and the occurrence of VF was not clear, i.e. whether the presence of the hemangioma caused the stimulation of the left main coronary artery and as a result, led to the spasm of the left main coronary artery and the occurrence of VF. Furthermore, as the tumor did not extend into any of the adjacent structures, such as the coronary arteries or the right ventricular outflow tract, surgical resection was not performed; instead, the patient received a dual chamber implantable cardioverter-defibrillator.
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PMID:Hemangioma located just above the left main coronary artery, in a subject who had cardiac arrest due to ventricular fibrillation, led to a diagnosis of Brugada syndrome. 1766 96

The paper presents a case of a 20-year-old student with a history of cardiac arrest due to ventricular fibrillation. The episode of cardiac arrest occurred when the patient did not complain of any health problems, and there was no visible structural heart disease. Consequently, permanent anoxaemic brain damage was observed. Based on ECG examination, the Brugada syndrome was diagnosed as the cause of cardiac arrest. The ajmaline challenge test was performed in the members of the patient's family.
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PMID:[Cardiac arrest with subsequent permanent anoxaemic brain damage in a patient with the Brugada syndrome]. 1785 20


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