Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine the factors relating to prognosis, the records of 15 neonates with persistent prolongation of the QT interval on the electrocardiogram after the fourth day of life were reviewed. Patients were admitted for symptoms (syncope, cardiac failure, or seizures), abnormal auscultation with an irregular heart rate or bradycardia, or because of a family history of a long QT syndrome. All infants had a long QTc, ranging from 0.46 to more than 0.70 second. Eight patients who had a QTc over 0.60 second developed severe ventricular arrhythmias (torsades de pointes, ventricular tachycardia) or second-degree AV block. Twelve of 15 were treated with beta-blocking agents, combined with ventricular pacing in five cases. Four infants died in the first month of life; they all had a very long QT interval and had experienced ventricular arrhythmias and AV block. Six children are still being treated with beta-blocking agents for the long QT syndrome and are doing well. In five infants, electrocardiographic abnormalities were transient and the QT interval returned to normal within 1 year. Therefore (1) prolongation of the QT interval in neonates may be transient or may represent an early form of the long QT syndrome and (2) the length of the QT interval may provide data on prognosis: those with a QTc less than 0.50 second returned to normal; those with a QTc greater than 0.60 second were associated with severe arrhythmias and four of eight infants died.
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PMID:Prolonged QT interval in neonates: benign, transient, or prolonged risk of sudden death. 135 80

A 21-year-old woman was brought to the emergency department after being found unconscious in a hotel lobby. On presentation, she was awake but confused. The initial evaluation revealed no evidence of trauma, metabolic abnormality, drug ingestion, or intracranial process. The only abnormality noted was electrocardiographic, and included a long QT interval as well as occasional atrial and junctional beats within a normal sinus rhythm. While in the department the patient developed tonic-clonic activity and was concurrently noted to have developed ventricular tachycardia. A precordial thump was given with the simultaneous cessation of the arrythmia and the seizure. After definitive electrophysiologic study, the diagnosis of long QT syndrome was made. Treatment consisting of beta blockade and pacemaker insertion prevented further arrythmia or seizure activity. Long QT syndrome should be considered a possible etiology in any patient presenting with new onset seizures, especially in the young.
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PMID:Long QT syndrome presenting as a seizure. 135 75

Seven out of 829 pediatric cardiac patients (0.84%) were found to have sinus node dysfunction (SND) over the past seven years. Of the seven patients, three had structurally normal hearts. One of these three patients had long QT syndrome. In four patients, structural heart disease was noted. In three of these four patients the sinus node dysfunction was attributed to cardiac surgery. The age of onset of SND ranged from four months to eight years. Presenting symptoms and signs included syncope, near-syncope, seizure and congestive heart failure. Two patients were asymptomatic. Five patients had episodic sinus pause. Sinus or junctional bradycardia was noted in four patients. Three had tachy-bradycardia. High grade atrioventricular block was noted in one patient. Treadmill exercise test revealed a nonsustained ventricular tachycardia in two patients. All seven patients were found to have prolonged maximal corrected sinus node recovery time. Prolonged intra-atrial conduction time was found in three, prolonged AV nodal conduction time in one, and prolonged His-Purkinje conduction time in one patient during the electrophysiologic study. All seven patients showed abnormal results in intrinsic heart rate study. Anti-arrhythmic drugs were prescribed. During the follow-up study, no patient died, but two patients received a pacemaker implantation. Because of the extent of their conduction system diseases, it is recommended that patients with SND should be thoroughly investigated.
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PMID:Sinus node dysfunction in children. 151 8

A permanent pacemaker was inserted in eight patients with the long QT syndrome. All had recurrent syncope or seizures, six had documented torsade de pointes and four had aborted sudden death. Among the eight patients, permanent pacing was instituted in three who were unsuccessfully treated with both a beta-adrenergic blocking agent and left cardiothoracic sympathectomy, and in two who proved refractory or intolerant to beta-blockers. Another three patients had pacemaker implantation and long-term beta-blocker therapy because of spontaneous atrioventricular (AV) block in one, aborted sudden death in one and patient preference in one. After pacing (70 to 85 beats/min), there was no significant change in the mean corrected QT interval, but the mean QT interval decreased significantly (534.4 +/- 51.4 to 425.6 +/- 18.9 ms, p less than 0.0001). Over a mean follow-up period of 35.1 +/- 18.9 months, all patients are alive and currently free of syncope. One patient without a history of stress-induced syncope had two syncopal episodes (believed to be due to hyperventilation) while under severe emotional stress, but has been symptom free for the past 5 years. One patient with an atrial demand (AAI) pacemaker developed dizziness due to documented episodes of AV block, but remains asymptomatic after conversion to atrial rate-responsive dual chamber (DDD) pacing. Either atrial or ventricular pacing combined with beta-blocker therapy appears to be effective treatment for a subset of patients with the long QT syndrome, by either preventing episodes of torsade de pointes or alleviating symptoms due to bradycardia from beta-blocker therapy.
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PMID:Permanent cardiac pacing in patients with the long QT syndrome. 362 66

The congenital long QT syndrome is an unusual disorder characterized by Q-T interval prolongation on electrocardiogram that predisposes the heart to ventricular tachycardia and fibrillation. We describe herein four patients with the congenital long QT syndrome who initially presented with generalized seizures. Three of these children were initially misdiagnosed as having a primary seizure disorder. The causal relationship of complex ventricular arrhythmias to seizure activity was documented in each child. This experience emphasizes the importance of obtaining an electrocardiogram in all children with a seizure disorder of unknown origin.
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PMID:The congenital long QT syndrome. An unusual cause of childhood seizures. 371 3

We studied a family with the long QT syndrome. The initial case was in a patient who presented with seizures, ventricular fibrillation, and syncope. After a trial of conventional modalities of treatment including left stellate ganglionectomy, primidone (Mysoline) therapy was initiated. This drug has been successful in suppressing ventricular arrhythmias and shortening the QT interval over a 2-year follow-up period. Two additional family members with QT prolongation have been treated with primidone. During an 8-month follow-up, electrocardiographic and Holter recordings showed shortening of the QT interval.
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PMID:Primidone in the treatment of the long QT syndrome: QT shortening and ventricular arrhythmia suppression. 739 15

In the long QT syndrome (LQT), individuals suffer from syncope, seizures and sudden death due to cardiac arrhythmias, specifically torsade de pointes and ventricular fibrillation. Many of these individuals also have prolongation of the QT interval on electrocardiograms, suggesting abnormal cardiac repolarization. To improve our understanding of the mechanisms underlying LQT and to facilitate presymptomatic diagnosis, we have begun to study families with autosomal dominant LQT. In 1991, we reported tight linkage between the LQT phenotype and the Harvey ras-1 gene (HRAS) in several families of Northern European descent. This discovery localized an LQT gene to chromosome 11p15.5 and made presymptomatic diagnosis in some families possible. In initial experiments, no recombination between HRAS and LQT was observed, making this protoncogene a candidate for LQT. This hypothesis was supported by physiologic data; other investigators had shown that ras proteins modulate cardiac potassium channels and an abnormality of potassium homeostasis could explain LQT. We eliminated HRAS as a candidate, however, by sequencing the coding region in 10 unrelated patients and finding no mutations. This indicated that the LQT locus was nearby, but not HRAS. Autosomal dominant LQT was previously thought to be genetically homogeneous and the first seven LQT families we studied were linked to 11p15.5. In 1992, however, several groups, including my laboratory, identified locus heterogeneity for LQT. Recently we identified a second LQT locus, LQT2, on chromosome 7q35-36. Because several families were unlinked, at least one more LQT locus exists. This degree of heterogeneity presents opportunities. It seems likely, for example, that proteins encoded by distinct LQT genes interact to modulate cardiac repolarization.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular genetics of long QT syndrome. 767 24

Infants and young children cannot describe symptoms of cardiogenic syncope accurately. If the attention in such cases is focused on the seizure activity that may follow, the patient will be treated inappropriately with anticonvulsants. We report such a presentation in 4 infants and young children (ages 6 to 48 months) with idiopathic long QT syndrome. All patients presented with recurrent seizures. All patients had a corrected QT interval (QTc) > or = 0.44 s and none had deafness. The diagnosis was suspected by careful history-taking which revealed episodes of loss of consciousness before convulsions in all patients. All patients were treated successfully with propranolol and remained free of symptoms during the follow-up period of 1-2 years. Screening the other family members revealed a prolonged QTc in 9 out of 16, and a history of 3 sudden and unexplained deaths in two families.
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PMID:Idiopathic long QT syndrome: asking the right question. 809 37

Prolongation of the QT interval, either on a congenital or an acquired basis, is associated with an increased likelihood of malignant ventricular arrhythmias with a high rate of morbimortality. Symptoms are variables, and patients may develop seizures, syncope and sudden death. Herein we report a young woman 17 years old with long QT syndrome, seizures and recurrent attacks of syncope; her initial diagnosis was primary epilepsy. An electrocardiogram performed 3 years after the initials symptoms was able to make the diagnosis long QT syndrome. The specific treatment controlled the malignant ventricular arrhythmias and the symptomatic status of this patient.
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PMID:[The long QT syndrome: epilepsy as the form of presentation]. 851 75

Long QT syndrome (LQT) is an inherited cardiac disorder that causes syncope, seizures and sudden death from ventricular tachyarrhythmias. We used single-strand conformation polymorphism (SSCP) and DNA sequence analyses to identify mutations in the cardiac sodium channel gene, SCN5A, in affected members of four LQT families. These mutations include two identical intragenic deletions and two missense mutations. These data suggest that SCN5A mutations cause LQT. The location and character of these mutations suggest that this form of LQT results from a delay in cardiac sodium channel fast inactivation or altered voltage-dependence of inactivation.
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PMID:Cardiac sodium channel mutations in patients with long QT syndrome, an inherited cardiac arrhythmia. 854 46


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