1/18. 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 = termination (Clic here for more details about this article) |
2/18. Adams-Stokes seizures due to ventricular tachydysrhythmias in patients with heart block: prevalence and problems of management.One hundred and twelve patients with heart block and chronic tendency to syncope were ECG-monitored during syncope. Ventricular tachycardia and/or fibrillation (VT-VF) was observed as the cause of syncope in 11 patients: in 6 of 20 patients with chronic third degree A-V block, in 3 of 65 with paroxysmal A-V block and in 2 of 27 with S-A block. The R-R interval preceding the escape beat which initiated VT-VF varied between 1.2 and 2.2 seconds. The cerebral attacks were amenable to long-term pacemaker treatment. However, relapses of VT-VF were observed during pacing with a low rate of 55 per minute and during short interruptions in pacing, as produced by intermittent pacemaker failure or threshold determination. In one patient, supplementary treatment with a beta-blocking agent had to be given to suppress exercise-induced attacks of VT-VF after pacemaker implantation.- - - - - - - - - - ranking = 1keywords = termination (Clic here for more details about this article) |
3/18. Spontaneous atrial premature depolarizations during paroxysmal reentrant tachycardia.The spontaneous onset and termination of many episodes of paroxysmal tachycardia, each initiated by an atrial premature depolarization, were studied in one patient. Surface electrocardiograms alone were inadequate to define the mechanisms underlying the frequent irregularity of atrial and ventricular cycle lengths during the tachycardia and the nature of spontaneous termination of the tachycardia. Unipolar atrial electrograms demonstrated that the irregularity during the tachycardia was due to premature atrial depolarizations that reset the reentrant cycle sustaining the tachycardia, and each spontaneous termination was due to an even more premature atrial depolarization interrupting the reentrant pathway. The genesis of the atrial premature depolarizations resetting and terminating the tachycardia, and their relationship to those initiating the tachycardia, are discussed.- - - - - - - - - - ranking = 3keywords = termination (Clic here for more details about this article) |
4/18. Dual-demand pacing for reciprocating atrioventricular tachycardia.By using programmed electrical stimulation of the heart and studying the initiation and termination of reciprocating atrioventricular tachycardia two patients with the wolff-parkinson-white syndrome were shown to respond rapidly and consistently to fixed-rate pacing. A demand pacemaker was implanted in each patient, having been modified so as to switch into the fixed-rate mode whenever the tachycardia began, thereby terminating the arrhythmia. This appears to be a promising form of treatment in patients with otherwise intractable paroxysmal tachycardia who have been shown by careful study to respond in this way.- - - - - - - - - - ranking = 1keywords = termination (Clic here for more details about this article) |
5/18. adenosine in the treatment of maternal paroxysmal supraventricular tachycardia.Paroxysmal supraventricular tachycardia is the most common sustained cardiac arrhythmia in pregnant women. Because nearly 50% of these supraventricular tachyarrhythmias fail to respond to vagal maneuvers, other therapies are used, including electrocardioversion and pharmacologic agents. propranolol, verapamil, and adenosine have food and Drug Administration-approved labeling for acute termination of supraventricular tachycardia. verapamil has been the most commonly used agent in the general population but it has several shortcomings, such as its potential to cause or exacerbate systemic hypotension, congestive heart failure, bradyarrhythmias, and ventricular fibrillation. In addition, verapamil readily crosses the placenta and has been shown to cause fetal bradycardia, heart block, depression of contractility, and hypotension. adenosine has several advantages over verapamil, including rapid onset, brevity of side effects, theoretical safety, and probable lack of placental transfer. adenosine ultimately may prove to be the preferred agent for termination of paroxysmal supraventricular tachycardia in the gravid woman.- - - - - - - - - - ranking = 2keywords = termination (Clic here for more details about this article) |
6/18. Cryoablation of medically refractory nodoventricular tachycardia.Paroxysmal wide QRS tachycardia, based on a nodoventricular accessory connection, is an uncommon arrhythmia. In this report, the endocardial and epicardial mapping and cryoablation of a nodoventricular fiber, documented to participate in medically refractory tachycardia in an 11-year-old boy, are described. Epicardial cryothermia, applied at the earliest site of right ventricular activation, resulted in the abrupt termination of tachycardia. Endocardial cryothermia was subsequently applied in the perinodal region, the presumed site of origin of the nodoventricular fiber. No tachyarrhythmias were inducible postoperatively, and no antiarrhythmic treatment has been required during 18 months of follow-up. Based on precise anatomic localization of the nodoventricular connection, a definitive cure of associated tachyarrhythmias may be possible utilizing cryothermia, without the requirement for extensive intraoperative dissection.- - - - - - - - - - ranking = 1keywords = termination (Clic here for more details about this article) |
7/18. Frequent attacks of supraventricular tachycardia in a patient treated with an automatic scanning pacemaker (PASAR): Holter documentation of 554 episodes.A 68-year-old woman suffering from frequent attacks of supraventricular tachycardia received an implantable, automatic scanning pacemaker for tachycardia termination (PASAR). Electrophysiological study had shown the mechanism to be atrioventricular reentry with retrograde conduction through a concealed bypass tract. During 1 year of follow-up, a total of twenty-one 24-hour Holter recordings documented 554 episodes of tachycardia. In spite of marked fluctuation in tachycardia rate from 135 to 195 bpm and a considerable variation in diurnal pattern of onset of episodes, a clinical improvement resulted. Previous episodes of tachycardia had been isolated and of longer duration. Following implantation, an unexpected observation was made of numerous episodes of supraventricular tachycardia confined to periods lasting up to several hours. This pattern seemed to result from the efficacy of tachycardia termination combined with a continued presence of factors responsible for initiation of tachycardia.- - - - - - - - - - ranking = 2keywords = termination (Clic here for more details about this article) |
8/18. Spontaneous termination of paroxysmal supraventricular tachycardia following disappearance of bundle branch block ipsilateral to a concealed atrioventricular accessory pathway: the role of autonomic tone in tachycardia diagnosis.We present a case of an 18-year-old man with a history of palpitations in whom episodes of paroxysmal supraventricular tachycardia were easily initiated by administered atrial premature beats. In all 15 control episodes of tachycardia, functional left bundle branch block (LBBB) seen at the onset, resolved within 10-20 cycles (mean, 13.1 /- 0.95). The tachycardia ended with the normalized QRS complex in each episode. Eleven episodes ended because of block within the antegrade pathway (ended with a P-wave), and four episodes stopped because of block within the retrograde pathway (ended without a P-wave). During the administration of isoproterenol (1 mg/min IV) all six episodes of tachycardia had LBBB but these did not end when LBBB disappeared spontaneously. When LBBB subsided, the mean tachycardia cycle interval shortened from 328.5 /- 1.4 to 264.2 /- 2.1 ms (p less than 0.001). Each episode of tachycardia was then terminated by carotid sinus massage. The disappearance of LBBB in control conditions presented the retrograde and antegrade limbs of the reentrant circuit with an early impulse that stopped the tachycardia. After isoproterenol administration, the tachycardia did not end following disappearance of LBBB, thus enabling the tachycardia cycle interval to shorten by a mean of 64.3 /- 1.9 ms. This extent of tachycardia acceleration is diagnostic of the participation of a concealed, left free-wall bypass tract.- - - - - - - - - - ranking = 4keywords = termination (Clic here for more details about this article) |
9/18. Successful termination of combined rapid atrial flutter/fibrillation and ventricular tachycardia by intravenous sotalol.Combined rapid atrial flutter/fibrillation and recurrent ventricular tachycardia occurred in an 82 year old man with acute myocardial infarction. Both arrhythmias were promptly terminated by intravenous sotalol, suggesting another use for this unique drug in the absence of hypotension, heart block or cardiac failure.- - - - - - - - - - ranking = 4keywords = termination (Clic here for more details about this article) |
10/18. Termination of paroxysmal supraventricular tachycardia by digital rectal massage.A 71-year-old woman with an episode of paroxysmal supraventricular tachycardia (PSVT) complicated by angina pectoris and hypotension had her arrhythmia abruptly terminated by digital rectal massage (DRM) after other vagotonic maneuvers had failed. DRM termination of PSVT has not been heretofore reported. In treating PSVT by physical vagotonic maneuvers, DRM may be preferable to other techniques because of the decreased likelihood of complications noted with other such maneuvers.- - - - - - - - - - ranking = 1keywords = termination (Clic here for more details about this article) |
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