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

Patients with chronic obstructive pulmonary disease (COPD), especially during acute exacerbations of their disease, show a greater incidence of cardiac arrhythmias than healthy subjects of the same age. The type of arrhythmias found may be supraventricular (premature atrial beats, paroxysmal supraventricular tachycardia, multifocal atrial tachycardia, atrial flutter, atrial fibrillation) or ventricular (premature ventricular beats, sustained ventricular tachycardia, torsades de pointes, ventricular fibrillation) that may lead to sudden cardiac death. The pathogenesis of arrhythmias is complex and many factors may be involved such as hypoxemia, hypercapnia, respiratory acidosis, metabolic and respiratory alchalosis, hypokalemia, concomitant ischemic heart disease, chronic cor pulmonale, left ventricular diastolic dysfunction. Remarkable attention has been drawn to the possible arrhythmogenic effect of drugs such as theophylline, beta-adrenergic stimulants and digitalis which are commonly used in the therapy of COPD. Both of the main classes of bronchodilators (methylxanthynes and beta-adrenergic agonists), even when used together, apparently do not increase the incidence of dangerous cardiac arrhythmias. However, these drugs should be used with caution in the elderly, in patients with preexisting cardiac arrhythmias, with heart disease or with reduced hepatic function. In these cases Holter monitoring, repeated measurements of plasma drugs concentration and prompt hospitalization of high risk patients in Intensive Care Unit may be needed.
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PMID:[Evaluation of hyperkinetic cardiac arrhythmia in chronic obstructive bronchopneumopathy]. 944 64

Azimilide, a novel class III antiarrhythmic agent, blocks both the slowly activating (IKs) and rapidly activating (IKr) components of the delayed rectifier potassium current, which distinguishes it from conventional potassium channel blockers such as sotalol and dofetilide, which block only IKr. Azimilide is being developed to prolong the time to recurrence of atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia in patients with and without structural heart disease. Azimilide is also being studied for its role in prevention of sudden cardiac death in high-risk patients after myocardial infarction (MI). Preclinical and clinical studies indicate that azimilide prolongs cardiac refractory period in a dose-dependent manner, as manifested by increases in action potential duration, QTc interval, and effective refractory period. Azimilide does not affect PR or QRS interval and minimally affects hemodynamic properties such as blood pressure and heart rate. Its in vivo effects appear to be rate-independent and are maintained under ischemic or hypoxic conditions, properties of potential clinical significance. Azimilide has shown excellent efficacy (>85%) in suppressing supraventricular arrhythmias in a variety of dog models. It also suppressed complex ventricular arrhythmias in infarcted dogs and, in a sudden death cardiac model, decreased mortality. Azimilide pharmacokinetics are very predictable. The drug is completely absorbed, and the extent of absorption is not affected by food. It can be administered once daily. Clinical data suggest that dose adjustments of azimilide are not required for age, gender, hepatic or renal function, or concomitant use of digoxin or warfarin. Azimilide has a good safety profile in open-label safety studies in >800 supraventricular arrhythmia patients, most with structural heart disease. The incidence of serious adverse events, including torsade de pointes, is low. The rate of patient withdrawal from long-term studies is also encouragingly low. Unlike amiodarone, azimilide has shown no evidence of pulmonary or ocular toxicity. Azimilide is expected to provide a unique new therapy for the prevention of supraventricular arrhythmias and sudden cardiac death when Phase III clinical trials are complete and safety and efficacy are confirmed.
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PMID:Azimilide dihydrochloride, a novel antiarrhythmic agent. 953 22

Paroxysmal supraventricular tachycardia (SVT) may have numerous electro-physiologic mechanisms. The most common type of SVT is AV-nodal reentry tachycardia (60%) followed by the bypass tract-mediated SVT (preexcitation. 30%) and a smaller group (10%) comprising paroxysmal atrial flutter or fibrillation and atrial ectopic tachycardia. In persons with otherwise normal hearts symptoms are usually mild and include palpitations or an uneasy feeling in the chest. But some describe precordial pain. Weakness, dizziness, nausea, vomiting, and even syncope. Whenever possible a 12-lead-ECG during an episode of SVT should be obtained. If not possible the use of several Holter-ECG or of an event-recorder may be helpful. Conversion of a SVT can be accomplished by vagal maneuvers or intravenous adenosine (6-18 mg bolus injection). Further diagnostic procedures should prove or rule out a significant structural heart disease. Therapeutic options (expectative, pharmacological prophylaxis, invasive electrophysiologic testing and catheter-mediated modification or ablation) are chosen according to the objective threat (e.g. ventricular fibrillation due to 1:1 conducted atrial fibrillation in a preexcitation syndrome) and the subjective complaints. Definitive healing of the AV-nodal reentry tachycardia and the bypass tract-mediated SVT can be achieved by use of catheter-mediated modification or ablation in 95 to nearly 100%.
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PMID:[Modern therapy of paroxysmal supraventricular tachycardia]. 1009 47

Sixty-three patients with paroxysmal supraventricular tachycardia were studied and 25 patients (39%) showed newly acquired negative T waves after tachycardia termination. Silent coronary artery disease could not be found in about 90% of these patients; moreover, age, sex, organic heart disease, and tachycardia duration and rate did not predict the appearance of negative T waves.
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PMID:Significance of newly acquired negative T waves after interruption of paroxysmal reentrant supraventricular tachycardia with narrow QRS complex. 1095 89

OBJECTIVE: To investigate the correlation between RFCA catheter cumulative energy and autonomic nerve injury. METHODS: Forty-one patients with paroxysmal supraventricular tachycardia were enrolled, Patients were excluded if they had Diabetes, Hypertension, Congestive Heart Failure or other organic heart disease. HRV and biochemical markers were measured before and after the RFCA. RESULTS: Compared with pre-ablation values,there was significantly decrease in post-ablation low frequency (LF) and high frequency (HF). This was noted in both the septal group (AVNRT and septal pathway) and free wall group (free wall accessory pathway).Post-procedure,the sensitivity of cardiac troponin I(cTnI) for myocardial injury detection was 58.3%, AST was 41.7%. This was significantly higher than other markers(CK:4.2%, CK-MB:10.4%, LDH:20.8%). The post-ablation sensitivity of cTnI was 54.2%, 6.3% and 52.1%at 1 hour, 12 hours, and 24 hours respectively. A significant correlation between cumulative energy and delta HF(r=0.688,P=0.01) or delta LF (r=0.462, P<0.05).was noted in free wall group.(delta HF=pre-ablation HF-post-ablation HF/pre-ablation HF x 100%). There was no significant correlation between biochemical markers and either delta HF or delta LF. CONCLUSION: RFCA induced injury on cardiac autonomic nerves related to both cumulative energy and ablation site,but not size of myocardial injury as determined by cTnI measurement. cTnI is an excellent biochemical marker of myocardial injury.
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PMID:[Radiofrequency catheter ablation autonomic nerve injury] 1259 13

Pregnancy can precipitate cardiac arrhythmias not previously present in seemingly well individuals. Risk of arrhythmias is relatively higher during labor and delivery. Potential factors that can promote arrhythmias in pregnancy and during labor and delivery include the direct cardiac electrophysiological effects of hormones, changes in autonomic tone, hemodynamic perturbations, hypokalemia of pregnancy, and underlying heart disease. Paroxysmal supraventricular and ventricular tachycardia may cause hemodynamic compromise with consequences to the fetus. Management of arrhythmias in pregnant women is similar to that in non-pregnant but a special consideration must be given to avoid adverse fetal effects. No drug therapy is usually needed for the management of supraventricular or ventricular premature beats, but potential stimulants, such as smoking, caffeine, and alcohol should be eliminated. In paroxysmal supraventricular tachycardia, vagal stimulation maneuvers should be tried first. Adenosine or a cardioselective beta-blocker could be used if vagal maneuvers are ineffective. Alternatively, verapamil or diltiazem may be given. In pregnant women with atrial fibrillation, the goal of treatment is conversion to sinus rhythm or to control ventricular rate by a cardioselective beta-adrenergic blocker drug or digoxin. Ventricular arrhythmias may occur in the pregnant women with cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse. Termination of ventricular arrhythmias can usually be achieved by intravenous lidocaine or procainamide or by electrical cardioversion. Amiodarone is not safe for the fetus. Beta-blocker therapy must be continued during pregnancy and postpartum period in women with long QT syndrome and torsade de pointes.
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PMID:Cardiac arrhythmias in pregnancy: clinical and therapeutic considerations. 1271 90

Most wide-complex tachycardias encountered in the emergency department (ED) are ventricular in origin, most commonly associated with structural heart disease. Ventricular tachyarrhythmias range in severity from life-threatening rhythms (eg, ventricular fibrillation and hemodynamically compromising ventricular tachycardia [VT]) to idiopathic forms of VT, which have a benign clinical course and a more favorable prognosis. The authors present the case of a 34-year-old woman who presented to the ED, with a wide-complex tachycardia with a right-bundle-branch block (RBBB) morphology and a right inferior axis, which was terminated with adenosine. The patient was previously misdiagnosed as suffering from a paroxysmal supraventricular tachycardia (SVT), which was unresponsive to beta-blocker therapy. Although the tachycardia responded to adenosine, suggestive of an SVT, the patient was referred to the arrhythmia service, where further work-up revealed an uncommon form of an idiopathic VT, originating from the left anterior fascicle. The authors discuss the unique electrocardiographic and electrophysiologic properties and useful diagnostic maneuvers required to properly identify this form of VT.
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PMID:Adenosine-sensitive wide-complex tachycardia: an uncommon variant of idiopathic fascicular ventricular tachycardia--a case report. 1278 32

Clinical tachycardias are a major cause of morbidity with detrimental effects on quality of life, physical activity and health care costs. Catheter ablation delivered by radiofrequency energy (RFA) has gradually expanded as a therapeutic modality for cure or palliation and is being adapted to address the most difficult to treat tachycardias. The purpose of this paper is to inform decision makers about the current evidence base of RFA through a comprehensive literature review. Of the 968 citations identified through the literature search strategy, 111 studies (11%) met the inclusion criteria. Only 10 of these studies (9%) were randomized, controlled trials. RFA of paroxysmal supraventricular tachycardia, atrial flutter and focal atrial tachycardias are all procedures associated with high procedural success rates and sustained clinical improvement within two years of follow-up. Limited evidence also demonstrates that elimination of these tachycardias improves symptoms and quality of life. RFAs of atrial fibrillation and ventricular tachycardia secondary to underlying structural heart disease are currently considered experimental procedures because there remains insufficient published data to draw conclusions about their clinical efficacy and safety profile. For all of the ablation procedures, there is a paucity of high-quality outcome studies comparing ablation with alternative therapeutic approaches and this provides the opportunity for future research.
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PMID:Clinical review of radiofrequency catheter ablation for cardiac arrhythmias. 1457 12

Azimilide is an investigational Class III antiarrhythmic that has been developed for treating both supraventricular and ventricular tachyarrhythmias. Similar to other Class III antiarrhythmics, azimilide prolongs myocardial repolarization in a dose-dependent manner by increasing the action potential duration, QT interval, and effective refractory period. The most frequent reported side effect is headache, with rare serious adverse events of early reversible neutropenia and Torsades de Pointes. In long-term follow up, the patient withdrawal rate has been low. Azimilide has very predictable pharmacokinetics, is predominantly hepatically metabolized, and has no significant drug interactions with digoxin or warfarin. In animal models, azimilide has been shown to be very effective in suppressing both atrial and ventricular tachyarrhythmias, decreasing the defibrillation energy requirement, and preventing post-myocardial infarction ventricular tachycardia and fibrillation. Clinically, in a series of 4 double-blind, randomized, placebo-controlled trials, the Azimilide Supraventricular Arrhythmia Program which included over 1000 patients and approximately 70% with structural heart disease, azimilide showed a significant prolongation in the time to first recurrence of paroxysmal supraventricular tachycardia or atrial fibrillation/flutter. With respect to ventricular tachyarrhythmias, the AzimiLide post-Infarct surVival Evaluation Trial was a large randomized, multinational, prospective, placebo-controlled study in recent survivors of myocardial infarction at high risk for sudden cardiac death. After 1 year of follow-up, this study showed no statistical difference in all-cause mortality between placebo and azimilide. However, azimilide did statistically reduce the incidence of new atrial fibrillation. Further trials are necessary to evaluate the efficacy of azimilide in patients with symptomatic ventricular arrhythmias.
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PMID:Azimilide, a novel oral class III antiarrhythmic for both supraventricular and ventricular arrhythmias. 1572 Feb 25

Several different mechanisms are responsible for paroxysmal supraventricular tachycardia in children. Different forms of tachycardia occur at different age. Atrio-ventricular reentry tachycardia results from the presence of congenital atrio-ventricular bypass tracts and is frequently encountered at all ages. Infants may present with ectopic atrial tachycardia or atrial flutter. Atrio-ventricular node reentry tachycardia becomes more frequent in adolescence. Atrial scarring resulting from open heart surgery predisposes to complex intra-atrial reentry. Certain forms of congenital and acquired heart disease are associated with specific types of arrhythmia. Many children with paroxysmal supraventricular tachycardia do not require any therapy. The decision to proceed with treatment should be based on the frequency and severity of symptoms and on the effect of arrhythmia on the quality of life. Infants require medical treatment because of the difficulty to recognize symptoms of tachycardia and a risk of heart failure. Patients with Wolff-Parkinson-White syndrome as well as those with significant heart disease are at risk of sudden death. Syncope in children with paroxysmal tachycardia may indicate a severe fall in cardiac output from extremely rapid heart rate. Patients with potentially life-threatening arrhythmia should not participate in competitive physical activities. Treatment options have undergone significant evolution over the past decade. Indications for the use of specific antiarrhythmic medications have been refined. Contemporary catheter ablation procedures employ different forms of energy allowing for safe and effective procedures. Catheter ablation is the treatment of choice for symptomatic paroxysmal tachycardia in school children and in some infants who failed medical treatment. Surgery is the preferred treatment in few selected cases. The goal of this review is to present the state of the art approach to the diagnosis and management of paroxysmal supraventricular tachycardia in infants, children and adolescents.
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PMID:Supraventricular tachycardia in children. 1607 47


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