Drug-induced supraventricular tachycardia: a case report of fluoxetine

We report the occurrence of supraventricular tachycardia and hypotension in a 54-year-old woman after maintenance therapy with fluoxetine. Although cases of tachycardia and palpitations have been reported, supraventricular tachycardia and hypotension have not been directly attributed to fluoxetine.     

Long-term supraventricular tachycardia in a patient with triiodothyronine toxicosis

There was presented a case of a therapy-resistant paroxysmal supraventricular tachycardia 130-140/min lasting about 100 days in a 21 years old barmaid drinking 5-6 glasses of natural coffee a day within last 3 years. Supraventricular tachycardia did not impair her working abilities; she was treated with propranolol within last 3 weeks before the admission to hospital. After 4 day therapy with 800 mg of quinidine, 10% potassium chloride and 75 mg of hydroxyzine performed electrocardioversion restored the sinus rhythm 90/min, but unfortunately supraventricular tachycardia returned 4 hours later. Thyroid hormones examination revealed isolated increase of serum T3 level to 3.0 ng/ml (normal value range 0.8-1, 6 ng/ml). Ultrasound examination showed mild parenchymatous goitre. Authors diagnosed a rare type of thyrotoxicosis-triiodothyronine toxicosis+, which was only manifested by long-lasting supraventricular tachycardia without clinical state impairment. Thiamazole-40 mg/day (60 mg from the 28th day of therapy), propranolol-160 mg/day as well as sedatives, 10% KCl and vitamins C and B6 were started to be given. After 72 days of treatment, when serum T3 level lowered to 2.35 ng/ml sinus rhythm 88/min returned, which was proved by 24 hour ECG Holter monitoring. The woman put on weight 10.5 kg during hospitalization and discharged from hospital to out-patient follow-up in good condition. Other authors emphasized that T3-Thyrotoxicosis did not clinically stray from the toxic multinodular or Graves-Basedow's goitre. Three year coffee overdosage deceived physicians at the start of therapy, because its abuse is a known factor inducing supraventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)     

The mechanisms of exercise provocation of supraventricular tachycardia

Treadmill exercise tests, electrophysiologic studies, and isoproterenol infusions were performed in 14 patients with exercise provocable supraventricular tachycardia to delineate the mechanisms of exercise provocation of paroxysmal supraventricular tachycardia. Treadmill exercise tests reproducibly provoked supraventricular tachycardia in all patients. Supraventricular tachycardia similar to that provoked by exercise occurred spontaneously during isoproterenol infusions in 9 of 11 patients tested. The specific supraventricular tachycardia diagnoses of all patients were atrial reentrant tachycardia (two patients), automatic atrial tachycardia (three), atrial flutter-fibrillation (one), atypical junctional tachycardia (two), and orthodromic atrioventricular (AV) reentrant tachycardia (six) as defined by electrophysiologic studies. Various mechanisms of exercise or isoproterenol induction of supraventricular tachycardia were identified. A critical heart rate and/or appropriate sympathetic state was found to provoke all instances of reentrant or automatic atrial tachycardia and atypical junctional tachycardia. A properly timed atrial premature beat provoked five of six cases of AV reentrant tachycardia and the only case of atrial flutter-fibrillation. The remaining case of AV reentrant tachycardia was induced by a ventricular premature beat. In conclusion, the mechanisms of exercise provocation of reentrant or automatic supraventricular tachycardia are multiple and include a critical sinus rate, increased sympathetic tone, and properly timed atrial or ventricular premature beats.     

Paroxysmal supraventricular tachycardia as a major clinical presentation of the primary coronary sinus lymphoma: A case report

Rationale:Primary cardiac lymphoma is a rare tumor, especially a tumor located in coronary sinus (CS). The most common symptom of cardiac tumors is dyspnea, accounting for 64%, followed by chest pain, accounting for 26%. However, the cases with paroxysmal supraventricular tachycardia (SVT) as a major clinical presentation are extremely rare.Patient concerns:We report a 55-year-old female patient with primary CS lymphoma and paroxysmal SVT.Diagnoses:After the surgical resection, pathology revealed the evidence of diffuse large B-cell lymphoma.Interventions:The patient underwent chemotherapy after CS tumor resection.Outcomes:The patient was disease-free during the 6-month follow-up.Lessons:CS enlargement may be the cause of SVT. Echocardiography should focus on the CS section to arrive at the right diagnosis.     

Encainide for resistant supraventricular tachycardia in children: Follow-up report

Forty-one children (26 weeks gestational age to 20 years) with drug-resistant supraventricular tachycardia were treated with oral encainide, and 29 were followed for 3 to 34 months (mean 15). Diagnoses obtained by electrocardiographic criteria (23 patients) or electrophysiologic testing (18 patients) included permanent junctional reciprocating tachycardia in 15 children, paroxysmal atrioventricular reciprocating tachycardias (AVRT) in 13, atrial ectopic tachycardia in 4, atrial flutter in 1, chaotic atrial tachycardia in 5 and junctional ectopic tachycardia in 3. Encainide was completely effective in 54% (22 of 41 study patients) and partially effective in an additional 24% (10 of 41 patients), when combined with propranolol or verapamil. Within 1 month, 13 (32%) discontinued encainide for inefficacy or intolerance. Encainide was most effective in the treatment of permanent junctional reciprocating tachycardia (60% effective) and AVRT (69% effective). It controlled only 40% of primary atrial tachycardias. Encainide was well tolerated on a long-term basis in patients not experiencing symptoms during initiation. In study infants younger than age 6 months, encainide was associated with excessive QRS aberrancy during initiation in 4 of 13 (31%), compared with 3 of 28 (11%) in older children. Ventricular proarrhythmia occurred in 2 children and 1 died suddenly. Mean effective encainide dose was 3.5 mg/kg/day or 86 mg/m₂/day. In 4 children who had nonextensive metabolism of encainide, the drug was ineffective. Encainide is effective in the treatment of some resistant forms of permanent junctional reciprocating tachycardia and AVRT in otherwise healthy children. Children younger than age 6 months and those with either previous proarrhythmic events or severe cardiac dysfunction appear to have a high incidence of adverse effects.     

Refractory paroxysmal supraventricular tachycardia incited by multiple mechanisms

A patient with refractory paroxysmal supraventricular tachycardia post acute myocardial infarction is presented. His bundle recordings and atrial stimulation studies suggest atrioventricular nodal reentry precipitated by three different mechanisms. Therapy required permanent coronary vein pacing and drugs.     

Triple antegrade nodal pathway in a patient with supraventricular paroxysmal tachycardia

A 69-year-old patient is described in whom programmed atrial extrastimulus testing revealed dual discontinuity of atrioventricular nodal conduction suggesting a triple antegrade nodal pathway. In this patient, programmed right ventricular pacing initiated two types of tachycardia due to intranodal reciprocating rhythms. In both cases, antegrade conduction occurred via the slow nodal pathway, and retrograde conduction by the fast and intermediate pathways, respectively. During ventricular extrastimulus testing, a single echo beat was elicited via a third circuit: the intermediate nodal pathway in a retrograde direction, and the fast pathway in an antegrade direction.     

Successful transcatheter cryoablation in infants with drug-resistant supraventricular tachycardia: a case series

Purpose  

Drug-resistant supraventricular tachycardia can cause hemodynamic instability, especially in infants. There are no case-series reports of transcatheter cryoablation treatment for infants with drug-resistant supraventricular tachycardia. Our purpose is to report our experience with transcatheter cryoablation in three infants with drug-resistant supraventricular tachycardia.     

Radiofrequency catheter ablation for paroxysmal supraventricular tachycardia: a report of 135 procedures

Background: Paroxysmal Supraventricular Tachycardia (PSVT) is a common condition which until recently has been treated with anti-arrhythmic drugs or surgery. Radiofrequency (RF) catheter ablation is a new mode of treatment which provides a cure of this condition. Aims: To present our early experience of RF catheter ablation for PSVT. Methods: One hundred and thirty-five procedures were performed in 117 patients. The diagnostic study and therapeutic catheter ablation were performed as a combined electrophysiological procedure in 74 patients (63%). In 58 patients (50%), PSVT was due to Atrio-ventricular junctional (nodal) re-entrant tachycardia (AVJRT). Twenty-five of the 58 patients underwent a fast pathway ablation while 33 had ablation of their slow pathway. The mean number of radio-frequency pulses delivered was ten for a mean duration of 25 seconds. Radiofrequency ablation of accessory pathways was attempted in 58 patients; pathways were left-sided in 29 patients, postero-septal in 21, midseptal in five, Mahaim connection in two, antero-septal in one and right free wall in one patient. One patient with incessant automatic atrial tachycardia also underwent a successful RF ablation. Results: Using RF ablation cure of PSVT was achieved in 90% of patients. Cure of AVJRT was achieved in 95% (55/58) of patients using either fast or slow pathway ablation. Only one patient required permanent pacemaker implantation for Mobitz type I AV block following fast pathway ablation. The overall success rate for ablation of accessory pathways was 85%. There is an operator learning curve for this procedure suggested by the fact that the success rate for accessory pathway ablation at first attempt was 63% in the first 29 patients and 93% in the remaining 29. There was no significant morbidity or mortality during or after the procedure. In a mean follow-up of nine months in the patients with successful ablation only two patients with AVJRT had a recurrence of documented PSVT. Both these patients had successful repeat RF ablation. Catheter ablation using radiofrequency energy is an effective and safe therapeutic option for patients with symptomatic PSVT. (Aust NZ J Med 1993; 23: 317–324.)     

Fetal supraventricular tachycardia diagnosed and treated at twenty-four weeks of gestation and after birth: a case report.

Supraventricular tachycardia is the most common clinically significant fetal tachycardia. The diagnosis is usually made at routine sonographic workup during the second-third trimester of pregnancy. Treatment goals are cardioversion to sinus rhythm and reversal of cardiac dysfunction. We describe a case of fetal supraventricular tachycardia diagnosed at 24 weeks of gestation. The first-line treatment was oral maternal digoxin and sotalol. This therapy was not sufficient for complete control of the tachycardia. Hence, second-line treatment with digoxin and flecainide was started and successfully achieved conversion to sinus rhythm. No adverse maternal side effects were noted during the 14 weeks of therapy. A normal male infant was delivered at elective cesarean section performed for obstetric indications at 38 weeks of gestation. A persistent junctional reciprocating tachycardia with a ventriculo-atrial/atrioventricular ratio > 1 was diagnosed following delivery at transesophageal electrophysiological study. At the age of 8 months the child is on therapy with sotalol (4 mg/kg/day) and flecainide (3 mg/kg/day) and is in good clinical conditions.