1/511. Tachyarrhythmias triggered by swallowing and belching. Three cases with supraventricular tachyarrhythmias related to oesophageal transit are reported. A 61 year old man had episodes of atrial tachycardia on each swallow of food but not liquid; this has been reported only rarely. A 55 year old man had atrial fibrillation initiated by drinking ice cold beverages; this has not been described previously although atrial tachycardia triggered by drinking ice cold beverages has been described once. A 68 year old man had supraventricular tachycardia initiated by belching; this has not been described previously. These cases illustrate the diversity of atrial tachyarrhythmias that can be precipitated by oesophageal stimulation and suggest that what is regarded as a very rare phenomenon may be found more commonly when sought. ( info) |
2/511. Supraventricular tachycardia in a human immunodeficiency virus-infected man. Although supraventricular tachycardias and human immunodeficiency virus infections are common diseases by themselves, a combination is not so common. Such a patient was encountered recently and described in this case report. Because misdiagnosis of tachyarrhythmias is not uncommon and may lead to inappropriate therapy-frequently resulting in acute clinical deterioration or even death, a discussion of management of supraventricular tachyarrhythmias in general was included. The recent introduction of adenosine into clinical use provides an effective agent in, and revolutionizes, the management of patients with supraventricular tachyarrhythmias. Its application, both for diagnostic and for therapeutic purposes, was discussed in some details in this report. ( info) |
| We evaluated 39 patients >45 years old with paroxysmal supraventricular tachycardia (SVT), 21 of whom had ST-segment depression during SVT. Treadmill exercise testing, including thallium stress scintigraphy, was performed in all patients and coronary angiography in 21 patients with ST-segment depression. Based on the presence of abnormal findings on exercise electrocardiogram and/or thallium in 7 of 21 patients (33%) with ST-segment depression, with additional corroboration by angiographic data, we conclude that myocardial ischemia and coronary artery disease is one, but not the only, mechanism involved in the genesis of ST-segment depression during paroxysmal SVT. ( info) |
4/511. adenosine-induced atrial pro-arrhythmia in children. adenosine has become the preferred acute treatment for common types of supraventricular tachycardia because of its efficacy and safety. There have been a few reports of serious proarrhythmic events associated with its use, including the induction of atrial fibrillation in adult patients. Three instances of adenosine-induced atrial proarrhythmia (two atrial fibrillation and one atrial flutter) have been observed in children with manifest or concealed wolff-parkinson-white syndrome at the Hospital for Sick Children, Toronto, ontario since 1990, which indicates a previously unreported risk of atrial arrhythmia for children as well. Because adenosine may enhance antegrade bypass tract conduction, its use carries a risk of ventricular acceleration, including progression to ventricular fibrillation. Because of such rare and potentially life-threatening adverse effects, appropriate monitoring and precautions are required during the administration of the drug to children and adults. ( info) |
5/511. Supraventricular tachycardia terminated by external mechanical stimulation: a case of "pothole conversion". Supraventricular tachycardia requires atrial or AV junctional tissue for its initiation and maintenance. Acute management of supraventricular tachycardias include vagal maneuvers, pharmacological treatment, and electrical cardioversion. We describe a case of a supraventricular tachycardias cardioverted by the jolt of the ambulance hitting a pothole. The proposed mechanism of cardioversion is an external mechanical one similar to the precordial thump. ( info) |
6/511. Transplacental flecainide therapy for fetal supraventricular tachycardia in a twin pregnancy. We present the case of a twin pregnancy in which 1 fetus developed hydrops secondary to supraventricular tachycardia at 30 weeks' gestation. Transplacental flecainide administration successfully treated the condition without evidence of maternal or fetal side-effects. The case raises ethical and possibly legal issues that present when 1 fetus in a twin pregnancy develops a condition the management of which could cause complications to the other twin and/or the mother. ( info) |
7/511. Anaphylactoid reaction to adenosine. adenosine (Adenocard) is an endogenous purine nucleoside that has been approved recently for intravenous treatment of paroxysmal supraventricular tachycardia. With a serum half-life of 10 seconds, reported side effects including facial flushing, dyspnea, and chest pressure are common, but very transient. An elderly woman who received adenosine for paroxysmal supraventricular tachycardia had a prolonged anaphylactoid reaction that required pharmacological treatment. This is the first reported case of a prolonged anaphylactoid reaction to adenosine. ( info) |
8/511. Supraventricular tachycardia vs. Marfan's syndrome. Marfan's syndrome is one of several genetic connective tissue disorders that manifest cardiovascular abnormalities. Paroxysmal supraventricular tachycardia is not one of these manifestations. ( info) |
9/511. Neurological morbidity after fetal supraventricular tachyarrhythmia. BACKGROUND: Fetal tachyarrhythmia is a well-documented entity which, in the absence of pharmacological intervention, may lead to congestive heart failure, fetal hydrops and eventually fetal demise. The success rate of the implemented treatment is generally measured by survival and achievement of control of the arrhythmia. We report on the occurrence of associated cerebral damage in three patients with fetal tachycardia. methods: We describe three patients with a history of fetal supraventricular tachyarrhythmia who developed cerebral complications in utero. RESULTS: Two patients had cerebral hypoxic-ischemic lesions and one had hemorrhagic lesions present at birth. They had developed severe congestive heart failure and fetal hydrops secondary to fetal tachyarrhythmia, and there were no other obvious causes for the cerebral pathology. Two of these patients were referred to us antenatally. Therapy was instituted and resulted in control of the tachycardia and resolution of hydrops. The third patient was referred to our clinic shortly after birth because of severe circulatory problems secondary to fetal tachyarrhythmia. CONCLUSION: From these observations, we believe that a fetus with tachyarrhythmia and subsequent hydrops is at increased risk for the development of cerebral complications, due to the circulatory disturbances and sudden changes in heart rate which may lead to fluctuations in cerebral perfusion. This would imply that it is of the utmost importance to aim at immediate and complete control of the heart rate in the treatment of fetal tachyarrhythmia. ( info) |
10/511. Radiofrequency ablation of a concealed nodoventricular Mahaim fiber guided by a discrete potential. INTRODUCTION: We present the case of a 17-year-old woman who underwent an electrophysiological study and radiofrequency (RF) ablation of supraventricular tachycardia refractory to medical treatment. Two right-sided, concealed, nondecremental atrioventricular accessory pathways (AV-APs) involved in orthodromic circus movement tachycardias were identified. After RF ablation of both AV-APs, evidence of bidirectional dual AV nodal conduction was demonstrated and regular narrow complex tachycardia was induced. methods AND RESULTS: During the tachycardia, retrograde slow and fast AV nodal pathway conduction with second-degree ventriculoatrial (VA) block and VA dissociation were observed. During the tachycardia with second-degree VA block, ventricular extrastimuli elicited during His-bundle refractoriness advanced the next His potential or terminated the tachycardia. Mapping the right atrial mid-septal region, a distinct high-frequency activation P potential was recorded in a discrete area, two thirds of the way from the His bundle toward the os of the coronary sinus. Detailed electrophysiologic testing with the recordable P potential demonstrated that the tachycardia utilized a concealed nodoventricular AP arising from the proximal slow AV nodal pathway. CONCLUSION: The tachycardia with slow 1:1 VA conduction could be reset by ventricular extrastimuli elicited during His-bundle refractoriness advancing the subsequent activation P potential and atrial activation. RF ablation guided by recording of the activation P potential resulted in elimination of both the slow AV nodal pathway and the nodoventricular connection with preservation of the normal AV conduction system. ( info) |