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)

The effects of intravenous administration of mexiletine on the refractory periods of the atrium and atrioventricular (AV) node were studied using His bundle recordings and the extrastimulus technique with atrial pacing. The drug was administered to 10 children with heart disease in an intravenous bolus dose of 3 mg/Kg, injected over a 5-min period, followed by an infusion of 1 mg/Kg/hr of mexiletine, achieving a mean therapeutic plasma concentration of 0.762 +/- 0.270 microgram/ml. The AH and HV intervals, the resting sinus cycle length, and the functional and effective refractory periods of the atrium and AV node were measured before and 5 min after initiation of the mexiletine infusion. The sinus cycle length was reduced significantly. However, neither the refractory periods nor the AH and HV intervals changed in a significant manner. Except for the heart rate, these results are similar to those reported in adults without conduction disturbances. In adults, mexiletine did not affect the sinus cycle length. However, in children, it consistently increased the heart rate. The lack of side effects in children is in contrast to adults, who usually suffer from gastrointestinal and neurologic symptoms upon receiving comparable doses parenterally.
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PMID:Electrophysiologic effects of mexiletine in children. 717 82

In a series of 250 cases of cerebral vascular accident, the authors have selected 12 patients whose embolus appeared to have originated in the heart, although this could not be confirmed by clinical examination, ECG, Holter system monitoring and echocardiographic studies. Angiocardiography, complemented or not by His bundle exploration and/or coronary arteriography, revealed the presence of a heart disease likely to produce emboli in 11 cases, and in 8 cases, this was prolapsed mitral valve. These 11 cases represent 4.5% of the whole series and 22% of cases with emboli of suspected cardiac origin. Thorough cardiological studies, therefore, seem to be justified in young adults presenting with stroke. The high incidence of prolapsed mitral valve is in keeping with recently published data.
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PMID:[Cerebral emboli due to subclinical heart disease. Value of thorough investigations (author's transl)]. 723 69

Disopyramide has been successfully used to treat a variety of supraventricular and ventricular arrhythmias. The electrophysiologic effects of this drug were studied following diagnostic cardiac catheterization in 14 children aged 7 months to 14 years, suffering from congential heart disease. Surface EKG, intra-atrial, and His bundle electrogram as well as right atrial pacing with the use of extrastimulus technique were obtained before and after a single intravenous dose of disopyramide (2 mg/Kg, max 50 mg). The drug significantly prolonged the HV interval, effective and functional refractory periods of the atrium and the AV node. The most consistent change was the prolongation of the atrial refractory periods. The electrophysiologic effects of this drug on the conduction system have been variable and this variability has been attributed to the degree of vagal tone. The findings in this age group are similar to adults with simultaneous cholinergic blockade. This might be due to the direct depressant effects of disopyramide on the atrial and AV nodal tissue, and point to the potential usefulness of this drug in the pediatric age group.
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PMID:Electrophysiologic effects of disopyramide in children. 742 Jul 32

We present three cases of primary sclerodermic cardiopathy with an electrocardiographic picture of anterior myocardial infarction not preceded by chest pain. On one of the cases a coronary angiography was performed with negative results. The echocardiogram of case no 1 showed a pattern of congestive cardiomyopathy, while case no 2 showed a picture of an infiltrative cardiomyopathy. In case no 2 the electrocardiographic picture changed to that of a right bundle branch block with left posterior fascicular block and with the disappearance of the anterior infarction. The His bundle electrogram showed a prolongation of the HV interval, while hemodynamically no signs were shown of impaired mechanical heart function. The clinical and echocardiographic aspects of the sclerodermic cardiopathy are here discussed with particular reference to the possibility of the prevalent compromise of the conduction system that could explain the not uncommon incidence of sudden death.
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PMID:[The sclerodermic cardiopathy. Infarction-like electrocardiographic picture and clinico-echocardiographic correlation in three observed cases (author's transl)]. 746 49

This report details our experience with documented chronic second-degree atrioventricular (AV) nodal block (proximal to His [H]) in 56 patients. Forty-six men (82%) and 10 women (18%), ages 18-87 years, were studied. Nineteen of the patients (34%) had no organic heart disease (including seven trained athletes) and 37 (66%) had organic heart disease. ECGs in all patients demonstrated episodes of type I second-degree block; five patients also had periods of 2:1 block. Prospective follow-up patients with no organic heart disease (157-2280 days, mean 1395 +/- 636 days) revealed one patient with clear indication for permanent pacing because of bradyarrhythmic symptoms (permanently placed on day 220 of follow-up). Two patients died nonsuddenly. In patients with organic heart disease (prospective follow-up of 60-2950 days, mean 1347 +/- 825 days), pacemakers were implanted in 10 patients, primarily for treatment of congestive heart failure in eight and syncope in two. Sixteen patients died -- three suddenly, seven with congestive heart failure, two of an acute myocardial infarction and four of causes unrelated to cardiac disease. In summary, chronic second-degree AV nodal block has a relatively benign course in patients without organic heart disease. In patients with organic heart disease, prognosis is poor and related to the severity of underlying heart disease.
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PMID:Natural history of chronic second-degree atrioventricular nodal block. 747 63

To confirm the role of HNK-1 in conduction tissue, the ultrastructural localization of monoclonal antibody HNK-1 was analyzed in developing rat hearts at embryonal day 14.5 by immunoelectron microscopic labeling procedures with post-embedding immunogold staining. Tissue sections in different planes containing the sino-atrial (SA) node, atrio-ventricular (AV) node and His bundle were used to demonstrate HNK-1. Immunogold labeling was detected on the cell surfaces and in the extracellular matrices of cells that had features common to conduction tissue cells. Non-specialized contractile myocytes were not labeled by this antibody. Furthermore, immunogold labeling was more prominent in wide intracellular spaces than in narrow intercellular spaces, and rarely observed in cell-cell contact regions. The cell surfaces and extracellular matrices of mesenchymal cells in the endocardial cushion, which contacts the His bundle, were also positive, suggesting the involvement of tract formation to the AV node. These findings may indicate that HNK-1 plays an important role in cell-cell adhesion processes both temporally and spatially in the developing conduction tissue. It was concluded, therefore, that HNK-1 is a suitable marker of the embryonic heart conduction system and might be useful in analyzing anomalous conduction systems, as in congenital heart disease.
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PMID:Immunoelectron microscopic localization of HNK-1 in the embryonic rat heart. 752 92

A 38-year-old man with no significant structural heart disease suffered from one episode of wide QRS tachycardia. The electrocardiogram showed a PR interval of 0.20 second and a QRS duration of 0.10 second. His bundle recording revealed an HV interval of 90-100 ms. The tachycardia was inducible with programmed stimulation and displayed a QRS morphology of complete left bundle branch block. It was characterized by an atrioventricular dissociation, a cycle length of 280 ms, and an H deflection preceding each QRS complex. Pacing from the right ventricular apex at a cycle length of 270 ms entrained the tachycardia, while at a cycle length of 260 ms, the tachycardia was terminated. Four years later, the patient presented with complete atrioventricular block with a wide QRS escape rhythm. An electrophysiologic study conducted while he was in 1:1 atrioventricular conduction showed an HV interval of 100 ms. Second-degree infrahisian block developed at an atrial paced cycle length of 700 ms. There was no induction of tachycardia with programmed stimulation before or after isoproterenol. The patient was treated with an implantation of a permanent pacemaker.
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PMID:Progression to complete atrioventricular block in a patient with bundle branch re-entry tachycardia. 759 28

In recent years, there has been a major shift from the use of antiarrhythmic drugs that act by slowing conduction to those that exert their beneficial actions by lengthening cardiac repolarisation. Such a shift is occurring because sodium channel blockers may increase mortality, especially in patients with structural heart disease, and because drugs such as sotalol and amiodarone are effective, with a potential for decreasing arrhythmic mortality. In this context, the electrophysiological and antiarrhythmic properties of d-sotalol, the dextro-isomer of sotalol, are of major importance. d-Sotalol is essentially devoid of beta-blocking actions and may be considered a pure class III compound. It has been assumed that its clinical efficacy would approximate that of amiodarone and sotalol, but without the complex adverse effect profile of amiodarone and the adverse beta-blocker effects of racemic sotalol. d-Sotalol has pharmacokinetic properties that resemble those of the racemate. It lengthens the QT/QTc interval but does not affect other electrocardiographic (ECG) intervals. It increases the refractory period in the atria, ventricles, bypass tracts and the His-Purkinje system while minimally slowing the heart rate. In preliminary studies, it had a weak suppressant effect on premature ventricular contractions, prevented inducibility of ventricular tachycardia or fibrillation in about 40% of patients, and demonstrated the potential to terminate atrial flutter and fibrillation and maintain stability of sinus rhythm during prophylactic administration. The drug exhibits little or no negative inotropic actions. Thus, it is likely to be better tolerated in patients with congestive heart failure dependent on sympathetic stimulation for compensation. Because it produces less bradycardic effect than the racemate, it is believed that the drug might induce a lower rate of torsade de pointes. The role of d-sotalol in controlling cardiac arrhythmias is being addressed in a number controlled clinical trials. However, one such double-blind, placebo-controlled trial, Survival With Oral d-Sotalol (or SWORD), in survivors of myocardial infarction with depressed ventricular function was recently terminated prematurely because of a strikingly greater all-cause mortality compared with placebo (4.6 versus 2.6%). These preliminary findings, still to be fully analysed and interpreted for clinical significance, nevertheless raise valid concerns regarding the currently popular concept of controlling cardiac arrhythmias by the selective or isolated prolongation of repolarisation ('pure' class III action) as an antiarrhythmic principle.
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PMID:Pharmacodynamic, pharmacokinetic and antiarrhythmic properties of d-sotalol, the dextro-isomer of sotalol. 760 Oct 9

We present two symptomatic patients of five and six months old with unilateral agenesis of main pulmonary branch (right and left) without associated anomalies. The diagnostic was made with magnetic resonance imaging and two-dimensional echocardiographic with Doppler color flow. We think that the magnetic resonance, must be used with priority in this pathology for being a non invasive diagnostic method, that is able to diagnostic the basic cardiopathy and the intracardiac and extracardiac associated anomalies. His association with the Doppler-echocardiography allow to ignore the arteriography upon to get a accurate diagnostic.
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PMID:[Unilateral agenesis of the pulmonary branch. Its diagnosis by color echo-Doppler and nuclear magnetic resonance]. 764 13

Idiopathic left ventricular tachycardia (ILVT) characterized by right bundle branch block, left axis morphology, response to verapamil and inducibility from the atrium in patients without structural heart disease may represent a distinct clinical entity. We report our experience with catheter ablation of this uncommon arrhythmia using radiofrequency energy (RF) and/or direct current (DC) shocks. Six men and 2 women, aged 16-50 years (mean +/- SD, 32 +/- 13), had recurrent VT for 16 +/- 16 years with a mean frequency of 4 +/- 3 episodes/year. Three patients had syncope during VT. None had identifiable structural heart disease. Catheter ablation was guided by earliest endocardial activation, presence of a high frequency presystolic potential and/or pacemapping of the left ventricle. The left ventricle was accessed via a retrograde aortic approach in 6 patients, a transeptal approach in 1 patient, and a combined approach in the remaining patient. All patients had inducible right bundle branch block morphology, left axis VT with a mean cycle length (CL) of 361 +/- 61 ms. A presystolic potential preceding ventricular activation and the His potential during VT was identified in 4 patients. All ablation sites were identified in a relatively uniform location, in the inferoapical left ventricle. Noninducibility of VT was obtained with RF in 3 patients and with DC in 5 patients. In 1 patient, DC delivery after unsuccessful RF prevented further inducibility. Similarly, RF was successful in 1 patient in whom an initial DC attempt was ineffective. Mean total procedure time was 282 +/- 51 minutes and mean total fluoroscopy time was 40 +/- 15 minutes. There were no complications. One patient treated with DC shock had recurrence of VT during treadmill test the day after ablation and refused repeat ablation. During a mean follow-up of 17 +/- 13 months, no VT recurrences or other cardiovascular events occurred. In conclusion, catheter ablation in the inferoapical left ventricle is an effective treatment for this type of ILVT. RF energy can be safely complemented by low energy DC shocks when the former is ineffective.
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PMID:Catheter ablation of idiopathic left ventricular tachycardia. 765 79


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