1/159. ST segment elevation in the right precordial leads induced with class IC antiarrhythmic drugs: insight into the mechanism of brugada syndrome.We evaluated two patients without previous episodes of syncope who showed characteristic ECG changes similar to brugada syndrome following administration of Class IC drugs, flecainide and pilsicainide, but not following Class IA drugs. Patient 1 had frequent episodes of paroxysmal atrial fibrillation resistant to Class IA drugs. After treatment with flecainide, the ECG showed a marked ST elevation in leads V2 and V3, and the coved-type configuration of ST segment in lead V2. A signal-averaged ECG showed late potentials that became more prominent after flecainide. Pilsicainide, a Class IC drug, induced the same ST segment elevation as flecainide, but procainamide did not. Patient 2 also had frequent episodes of paroxysmal atrial fibrillation. Pilsicainide changed atrial fibrillation to atrial flutter with 2:1 ventricular response, and the ECG showed right bundle branch block and a marked coved-type ST elevation in leads V1 and V2. After termination of atrial flutter, ST segment elevation in leads V1 and V2 continued. In this patient, procainamide and quinidine did not induce this type of ECG change. In conclusion, strong Na channel blocking drugs induce ST segment elevation similar to brugada syndrome even in patients without any history of syncope or ventricular fibrillation.- - - - - - - - - - ranking = 1keywords = rhythm (Clic here for more details about this article) |
2/159. Left ventricular ischemia due to coronary stenosis as an unexpected treatable cause of paroxysmal atrial fibrillation.We present a patient with exercise-induced paroxysmal atrial fibrillation who was eventually scheduled for a Cox-maze operation due to persistence of his complaints of fatigue, impaired exercise tolerance, and predominantly exercise-related irregular palpitations despite treatment with several antiarrhythmic drugs. A preoperative exercise stress test without antiarrhythmic or negative chronotropic drugs, however, showed clear evidence of myocardial ischemia. After coronary angioplasty of a significant stenosis in the left anterior descending artery, there was no recurrence of atrial fibrillation during a follow-up of 7 months.- - - - - - - - - - ranking = 0.5keywords = rhythm (Clic here for more details about this article) |
3/159. caffeine intoxication: a case of paroxysmal atrial tachycardia.Caffeinism is a syndrome resulting from the excessive ingestion of caffeine and characterized primarily by cardiovascular and central nervous system manifestations. A variety of tachyarrhythmias and extrasystoles are believed to reflect the toxic, cardiotonic effects of caffeine. A case of paroxysmal atrial tachycardia (PAT) related to caffeine abuse is PAT. The importance of considering this and other less frequent conditions as potential causes for this arrhythmia is stressed.- - - - - - - - - - ranking = 0.5keywords = rhythm (Clic here for more details about this article) |
4/159. Arrhythmias in the coronary-care unit. IV. Physiologic bases of paroxysmal tachycardia-dependent bundle branch block.Paroxysmal BBB may be either tachycardia-dependent which is referred to as "phase 3 block" or bradycardia-dependent, referred to as "phase 4 block." tachycardia-dependent BBB is related to prolonged recovery. bradycardia-dependent BBB is related to hypopolarization and SDD. These fundamental electrophysiological properties aid in understanding of transient BBB occurring during an acute MI.- - - - - - - - - - ranking = 1keywords = rhythm (Clic here for more details about this article) |
5/159. Wide QRS complex tachycardia: ECG differential diagnosis.Wide QRS complex tachycardias (WCT) present significant diagnostic and therapeutic challenges to the emergency physician. WCT may represent a supraventricular tachycardia with aberrant ventricular conduction; alternatively, such a rhythm presentation may be caused by ventricular tachycardia. Other clinical syndromes may also demonstrate WCT, such as tricyclic antidepressant toxicity and hyperkalemia. Patient age and history may assist in rhythm diagnosis, especially when coupled with electrocardiographic (ECG) evidence. Numerous ECG features have been suggested as potential clues to origin of the WCT, including ventricular rate, frontal axis, QRS complex width, and QRS morphology, as well as the presence of other characteristics such as atrioventricular dissociation and fusion/capture beats. Differentiation between ventricular tachycardia and supraventricular tachycardia with aberrant conduction frequently is difficult despite this clinical and electrocardiographic information, particularly in the early stages of evaluation with an unstable patient. When the rhythm diagnosis is in question, resuscitative therapy should be directed toward ventricular tachycardia.- - - - - - - - - - ranking = 0.75keywords = rhythm (Clic here for more details about this article) |
6/159. Arrhythmias in the coronary-care unit. VI. Physiologic bases for the use of antiarrhythmic drugs.classification of antiarrhythmic drugs based on their electrophysiologic and hemodynamic properties coupled with an understanding of the transmembrane action potential of the cardiac cell (see the first of this series of six vignettes) help in the appropriate choice of therapy in a given clinical setting.- - - - - - - - - - ranking = 2.25keywords = rhythm (Clic here for more details about this article) |
7/159. Concomitant reentrant tachycardias from concealed accessory atrioventricular bypass tract and atrioventricular nodal reentry in a patient with williams syndrome.williams syndrome is characterized by a constellation of features including mental retardation and supravalvular aortic stenosis. Other cardiovascular abnormalities including arrhythmias contributing to sudden death have been described in these patients. In this report we describe a case of a 49-year-old female with williams syndrome who presented with severe symptomatic supraventricular tachycardia. cardiac electrophysiology study identified a left posteroseptal concealed accessory bypass tract responsible for atrioventricular reentrant tachycardia and a concomitant typical atrioventricular nodal tachycardia. Such unusual association of combination of two different types of supraventricular tachycardia and williams syndrome has not been previously reported. Radiofrequency ablation was successfully performed to cure these arrhythmias.- - - - - - - - - - ranking = 0.5keywords = rhythm (Clic here for more details about this article) |
8/159. Paroxysmal supraventricular tachycardia caused by 1:2 atrioventricular conduction in the presence of dual atrioventricular nodal pathways.One-to-two atrioventricular conduction, ie, the double response to a single sinus or atrial impulse, resulting in two QRS complexes for one P wave, is a rare manifestation of dual atrioventricular (AV) nodal pathways. This report describes the case of a 61-year-old woman with continuous episodes of supraventricular tachycardia caused by independent conduction to the ventricles of sinus impulses over both the fast and the slow AV nodal pathway, giving rise to a ventricular rate that was twice the sinus rate. A wide spectrum of electrocardiographic manifestations of 1:2 AV conduction was observed on the surface electrocardiogram. The diagnosis was suggested by several elements including evidence of dual AV nodal pathways during sinus rhythm and cycle length alternans during tachycardia. The patient underwent successful slow pathway ablation with complete disappearance of symptoms and electrocardiographic manifestations of 1:2 AV conduction.- - - - - - - - - - ranking = 0.25keywords = rhythm (Clic here for more details about this article) |
9/159. Case 2: a patient with an intermittent racing heartbeat.Most clinicians currently rely on patient history and specific electrocardiographic criteria to establish the diagnosis of arrhythmias. However, as illustrated by this case, the physical examination-especially auscultation of the first heart sound-can also provide useful diagnostic clues.- - - - - - - - - - ranking = 0.25keywords = rhythm (Clic here for more details about this article) |
10/159. Transient QT prolongation with torsades de pointes tachycardia after ablation of permanent junctional reciprocating tachycardia.INTRODUCTION: catheter ablation with radiofrequency energy is a curative therapy in patients with permanent junctional reciprocating tachycardia (PJRT). methods AND RESULTS: For the first time, we report a case of transient QT prolongation with torsades de pointes tachycardia 18 hours after successful radiofrequency energy ablation of PJRT in a 25-year-old woman with tachycardia-induced cardiomyopathy. Of note, the torsades de pointes occurred in the absence of bradycardia, electrolyte disturbances, or QT-prolonging drugs. This patient initially was thought to have a hereditary long qt syndrome that was unmasked by PJRT ablation. Therefore, the patient received an implantable defibrillator in addition to beta-blocker therapy, which was discontinued 6 months later. Surprisingly, the QT interval completely normalized within 1 week after PJRT ablation, and the patient remained free of arrhythmias during a follow-up period of 4.5 years. CONCLUSION: patients with incessant tachyarrhythmias should undergo ECG monitoring for at least 24 hours following successful radiofrequency catheter ablation because transient QT prolongation with torsades de pointes may occur even in the absence of bradycardia, QT-prolonging drugs, or electrolyte disturbances.- - - - - - - - - - ranking = 0.5keywords = rhythm (Clic here for more details about this article) |
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