1/179. Severe cardiac dysrhythmia in patients using bromocriptine postpartum.Used worldwide since 1980 for the prevention of breast engorgement in the puerperium, in 1994 bromocriptine mesylate was withdrawn from the American market as an agent suitable for ablactation. The relevant recommendation of the food and Drug Administration rested on case reports that described severe vasospastic reactions among users of the drug. Some patients so affected suffered stroke, intracranial bleeding, cerebral edema, convulsions, myocardial infarction, and puerperal psychosis. More recently, it has been suggested that the side effects of the drug may also include circulatory collapse secondary to cardiac dysrhythmia. This report describes two additional cases in this category. The antepartum clinical evaluation of these women suggested that they were predisposed to arrhythmias.- - - - - - - - - - ranking = 1keywords = rhythm (Clic here for more details about this article) |
2/179. Preoperative hypoglycaemia, propranolol and the Jervell and Lange-Nielsen syndrome.The Jervell and Lange-Nielsen syndrome is an autosomal recessive trait characterized by deafness and electrocardiographic changes. These changes include prolongation of the QT interval and T-wave inversion. Treatment may include the use of beta-blockers to prevent the development of malignant ventricular arrhythmias and sudden death. We report a patient with this syndrome, who was receiving propranolol orally and who became hypoglycaemic during the preoperative fasting period prior to cochlear implantation.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
3/179. The exercise test in andersen syndrome.BACKGROUND: andersen syndrome is a rare form of periodic paralysis (PP) associated with dysmorphic features and potentially fatal cardiac dysrhythmias. To date, no electrodiagnostic abnormalities have been reported that can be used to confirm the presence of PP in this condition. OBJECTIVES: To determine if the exercise test could be used to confirm the diagnosis of PP in andersen syndrome. To evaluate the exercise test as a means to assess neuromuscular status during treatment. methods: We performed the exercise test on 2 patients with andersen syndrome. In 1 patient, we used a modified version of the test to document responsiveness to treatment with tocainide. RESULTS: Studies in both patients demonstrated a progressive decline in the compound muscle action potential amplitude after exercise that was characteristic of the phenomenon seen in other forms of PP. In 1 patient, improvement in interattack strength and a reduction in the number of attacks of weakness correlated with improvement in the test results. CONCLUSIONS: Our cases demonstrate that the exercise test can confirm the diagnosis of PP in andersen syndrome. A modified version of exercise testing may also be considered as an objective method for documenting treatment responses in PP.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
4/179. Prominent bifid T waves observed in the QT prolongation caused by complete atrioventricular blockade in a hypokalemic diabetic patient.A 63-year-old diabetic man was admitted with general fatigue. Electrocardiogram (ECG) on admission showed complete atrioventricular (AV) blockade associated with prominent bifid T waves. The second component of the bifid T waves was distinguished from U waves by the beat-to-beat varying bifidity and the nadir between the two components located at > or = 1 mm above the isoelectric line. Range of absolute QT interval was 535 to 650 ms. hypokalemia (3.6 mEq/L) was noted at admission. Partial restoration of the potassium level (3.9 mEq/L) prior to temporary ventricular demand pacing obscured the bifid T waves and attenuated the QT prolongation and dispersion to some extent (absolute QT interval ranging 520 to 620 ms). It was concluded that marked bradycardia caused by complete AV blockade (ie, a junctional escaped rhythm at a rate of 42 beats/min), hypokalemia, and underlying diabetes mellitus contributed in concert to the QT prolongation and dispersion leading to the prominent bifid T waves.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
5/179. Splicing mutations in KCNQ1: a mutation hot spot at codon 344 that produces in frame transcripts.BACKGROUND: Long-QT syndrome is a monogenic disorder that produces cardiac arrhythmias and can lead to sudden death. At least 5 loci and 4 known genes exist in which mutations have been shown to be responsible for the disease. The potassium channel gene KCNQ1, previously named KVLQT1, on chromosome 11p15.5 is one of these. methods AND RESULTS: We initially analyzed one family using microsatellite markers and found linkage to KCNQ1. mutation detection showed a G to C change in the last base of exon 6 (1032 G-->C) that does not alter the coded alanine. Restriction digest analysis in the family showed that only affected individuals carried the mutation. A previous report suggested that a G to A substitution at the same position may act as a splice mutation in KCNQ1, but no data was given to support this hypothesis nor was the transcription product identified. We have shown by reverse-transcription polymerase chain reaction that 2 smaller bands were produced for the KCNQ1 gene transcripts in addition to the normal-sized transcripts when lymphocytes of affected individuals were analyzed. Sequencing these transcripts showed a loss of exon 7 in one and exons 6 and 7 in the other, but an in-frame transcript was left in each instance. We examined other families in whom long-QT syndrome was diagnosed and found another unreported splice-site mutation, 922-1 G-->C, in the acceptor site of intron 5, and 2 of the previously reported 1032 G-->A mutations. All these showed a loss of exons 6 and 7 in the mutant transcripts, validating the proposal that a consensus sequence is affected in the exonic mutations and that the integrity of the base at position 1032 is essential for correct processing of the transcript. CONCLUSIONS: The 6 cases already reported in the literature with the 1032 G-->A transition, the novel 1032 G-->C transversion, and a recent G-->T transversion at the same base show that codon 344 is the second most frequently mutated after codon 341, suggesting at least two hotspots for mutations in KCNQ1.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
6/179. Homozygous premature truncation of the HERG protein : the human HERG knockout.Background-In long-QT syndrome (LQTS), heterozygosity for a mutation in 1 of the K( ) channel genes leads to prolongation of the cardiac action potential, because the aberrant protein exhibits "loss of function." HERG, which is involved in LQT2, is the gene encoding the rapid component of the delayed rectifier, I(Kr). methods and Results-In a consanguineous family, a stillbirth was followed by the premature birth of a child in distress due to ventricular arrhythmia in the presence of QT prolongation. LQTS was diagnosed, beta-blocker therapy was begun, and a pacemaker was implanted. She developed well and remained symptom-free for 1.5 years. In the index patient, we identified a duplication of bp 558 to 600 in exon 4 of HERG on both alleles. This will result in a frameshift and a premature stop codon before the S1 domain of the HERG protein. Because it is present on both alleles, no functional I(Kr) is anticipated. The same mutation was found heterozygously in both parents and homozygously in the stillborn brother. Conclusions-It is concluded that absence of I(Kr) gives rise to a severe cardiac phenotype, with no indication of malfunction of any other organ.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
7/179. Congenital long-QT syndrome: a case report illustrating diagnostic pitfalls.This article reviews the clinical course of a 10-year-old child with a lifelong history of seizures and congenital deafness who presented after an episode of sudden cardiac arrest secondary to long-QT syndrome-induced torsade de pointes. Jervell-Lange-Nielsen syndrome is a rare cardioauditory syndrome in which affected subjects are susceptible to recurrent syncope and sudden death from ventricular dysrhythmias, usually before the second decade of life. Careful evaluation of suspected subjects is important because of the variability of the QTc interval. Recent research has identified specific gene sequences that encode ion channels responsible for both prolonged QTc interval and deafness. Treatment of symptomatic cardiac disease with beta-blockers in combination with pacemakers and automated internal cardioverter defibrillators can markedly improve quality of life and suppress ventricular dysrhythmias even in the most severely affected subjects. The recent identification of gene sequences identifying some congenital long-QT syndromes may improve screening methods for affected patients and lead to potential therapeutic intervention.- - - - - - - - - - ranking = 0.33333333333333keywords = rhythm (Clic here for more details about this article) |
8/179. fetus with long qt syndrome manifested by tachyarrhythmia: a case report.We encountered a fetus who exhibited transient (at most 30 s), repeated episodes of tachyarrhythmia (240 bpm). This female neonate was born at 36 weeks of gestation and showed a markedly prolonged QT interval and transient, repeated episodes of polymorphic ventricular tachycardia. Congenital long qt syndrome was diagnosed. Retrospective analysis of the videotape showing fetal cardiac movement revealed that atrio-ventricular dissociation was present prenatally and thus, the fetal tachyarrhythmia was due to ventricular tachycardia. To our knowledge, there are few reports of a fetus with the long qt syndrome who exhibited ventricular tachycardia in utero. In the presence of unexplained fetal tachyarrhythmia, long QT syndrome should be considered as a possible underlying cause disorder. The presence of atrio-ventricular dissociation may be useful in prenatal diagnosis of long qt syndrome.- - - - - - - - - - ranking = 1.1666666666667keywords = rhythm (Clic here for more details about this article) |
9/179. haloperidol-induced torsade de pointes.OBJECTIVE: To report a case of torsade de pointes related to the administration of high-dose intravenous haloperidol for the treatment of severe agitation. CASE SUMMARY: Reports in the literature of intravenous haloperidol-induced torsade de pointes are rare. We describe the case of a 41-year-old white woman with no predisposing factors who developed torsade de pointes 55 minutes after a dose of intravenous haloperidol 80 mg (total dosage 915 mg over 7 d). The results of the electrocardiogram were consistent with torsade de pointes and showed a prolonged QTc interval of 610 milliseconds. Intravenous magnesium sulfate 2 g/100 mL NaCl 0.9% was administered, which controlled the arrhythmia. The patient received one additional 80-mg haloperidol dose six hours after the arrhythmia-triggering dose, without reoccurrence of torsade de pointes. haloperidol was then discontinued, and the patient had no further arrhythmias. CONCLUSIONS: Our case report and others from the literature suggest that intravenous haloperidol administration may prolong QT intervals in some patients, precipitating the potentially life-threatening arrhythmia torsade de pointes. Clinicians should be aware of haloperidol's potential to induce torsade de pointes, since it is used regularly for agitation and delirium in the critical care arena.- - - - - - - - - - ranking = 0.66670238156421keywords = rhythm, hour (Clic here for more details about this article) |
10/179. Cardio-auditory syndrome of Jervell and Lange-Nielsen.An 8-year-old deaf-mute girl experienced syncopal attacks. Past medical history revealed cardiac arrhythmia which had developed following an abdominal surgery for a twisted ovarian cyst. Electrocardiogram showed a Q-Tc interval of 40/100 second. The diagnosis was Jervell and Lange-Nielsen syndrome. Etiology, physiopathology, clinical picture, and management of the disease are discussed.- - - - - - - - - - ranking = 0.16666666666667keywords = rhythm (Clic here for more details about this article) |
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