Electrophysiological effects and clinical efficacy of propafenone in children with recurrent paroxysmal supraventricular tachycardia

Twenty-four patients aged 10.1 +/- 4.5 (mean +/- SD) years with recurrent paroxysmal supraventricular tachycardia underwent an electrophysiological study. Eleven patients had an overt and seven had a concealed accessory connection; six patients had no accessory connection. An orthodromic reciprocating tachycardia was inducible in 17 of 18 patients with an accessory connection, and an atrioventricular nodal reentrant tachycardia was inducible in four of six patients without accessory connection. After administration of propafenone, the sinus cycle length decreased. Intra-arterial, intranodal, and His-ventricle intervals and QRS duration increased. The atrial and ventricular effective refractory periods and anterograde and retrograde effective refractory periods of the atrioventricular node increased. The cycle length at which nodal second-degree block occurred increased. Of 18 patients with accessory connection, propafenone prolonged retrograde conduction in all, blocked anterograde conduction in five, and prolonged it in six. The drug terminated the orthodromic reciprocating tachycardia in all 17 patients and the atrioventricular nodal reentrant tachycardia in three of four patients. In three of four patients with atrioventricular nodal reentrant tachycardia and in 15 of 17 patients with orthodromic reciprocating tachycardia, the tachycardia was no longer inducible or nonsustained after propafenone. A follow-up of 26 +/- 10 months revealed that the drug when orally administered to all patients prevented recurrences of tachycardia in 15 of 18 patients with and in four of six patients without accessory connection. The results of short-term drug testing with propafenone predict the response to long-term oral therapy with this drug.     

Radiofrequency catheter ablation of both atrial ventricular nodal reentrant and atrial ventricular reentrant tachycardia in a single session

Radiofrequency catheter ablation is a new therapeutic approach to treat patients with symptomatic drug-resistant paroxysmal supraventricular tachycardia. Ablation of two accessory atrioventricular pathways in a single session has been frequently described previously. However, ablation in a single session of both the fast pathway, involved in atrial ventricular nodal reentrant tachycardia, and a concealed atrioventricular accessory pathway involved in a circus movement tachycardia has rarely been reported. A 57-year-old man with a grade III aortic incompetence had the infrequent association of atrial ventricular nodal reentrant tachycardia and orthodromic circus movement tachycardia due to a concealed accessory pathway. He presented with drug-resistant reentrant supraventricular tachycardia and, in a single session, underwent a successful radiofrequency catheter ablation of the fast atrial ventricular nodal pathway and a concealed posteroseptal accessory pathway. During a 10-month follow-up he was free of palpitations without any antiarrhythmic therapy and underwent elective aortic valve replacement.     

Supraventricular tachyarrhythmias: Drug therapy versus catheter ablation

Until recently, the only options available for treatment of supraventricular arrhythmias involved the use of drug therapy or cardiac surgery. However, over the past several years with the introduction of radiofrequency energy sources as well as steerable catheters, the clinician has a variety of additional nonpharmacologic options. This article reviews the use of pharmacologic therapy versus catheter ablation for the treatment of reentrant supraventricular arrhythmias, involving the atrioventricular junction and/or accessory atrioventricular connection, as well as arrhythmias emanating from the atria such as atrial fibrillation, atrial flutter, and atrial tachycardia.     

Patients with supraventricular tachycardia presenting with aborted sudden death: incidence, mechanism and long-term follow-up

A total of 13 (4.5%) of 290 patients with aborted sudden death had either documented (7; 54%) or strong presumptive evidence of supraventricular tachycardia that deteriorated into ventricular fibrillation. Six (46%) of the 13 had an accessory conduction pathway and either atrial fibrillation (5 patients) or paroxysmal atrioventricular (AV) reentrant tachycardia (1 patient) that deteriorated into ventricular fibrillation. Three patients with AV node reentrant tachycardia and four with atrial fibrillation and enhanced AV node conduction presented with supraventricular arrhythmias that deteriorated into ventricular fibrillation. Patients were treated with medical, surgical or catheter ablative procedures designed to prevent recurrences of supraventricular arrhythmias. Four patients received an implanted automatic defibrillator, but none had an appropriate device discharge. Over a follow-up period of 41.6 +/- 33.6 months, 12 patients are alive without symptomatic arrhythmias. One patient died because of severe chronic lung disease and heart failure. Supraventricular tachycardia was the cause of aborted sudden death in approximately 5% of patients referred for evaluation of sudden cardiac death. Treatment directed at prevention of supraventricular tachycardia was associated with an excellent prognosis. Current treatment techniques appear to obviate the need for automatic defibrillator therapy in these patients.     

Double-blind study of intravenous propafenone for paroxysmal supraventricular reentrant tachycardia

Propafenone was administered during electrophysiologic testing to determine its efficacy and safety for terminating and preventing reinduction of paroxysmal supraventricular reentrant tachycardia. Four men and 10 women (mean age 50 years, range 28 to 69) were studied. Five patients had Wolff-Parkinson-White syndrome with orthodromic atrioventricular (AV) reentrant tachycardia, three had a concealed accessory pathway with AV reentrant tachycardia and six had tachycardia due to reentry within the AV node. In the five patients with Wolff-Parkinson-White syndrome, propafenone terminated reentrant tachycardia in three (the tachycardia was reinducible in one) and had no effect in two. In the three patients with a concealed accessory pathway, propafenone terminated reentrant tachycardia in all three and prevented reinduction of the tachycardia in two. In the six patients with tachycardia due to reentry within the AV node, propafenone terminated and prevented reinduction of reentrant tachycardia. Propafenone had no effect on blood pressure, heart rate, PA interval, AV node refractoriness or rate of reentrant tachycardia. Propafenone significantly (p less than 0.05) prolonged the AH, HV, QRS and ventriculoatrial intervals and decreased the AV node Wenckebach rate. Of the nine patients receiving long-term oral propafenone therapy, eight had a reduction of at least 90% in reentrant tachycardia during a mean follow-up period of 14.5 months (range 11 to 22); all eight patients had had noninducible reentrant tachycardia after intravenous propafenone. One patient had increased frequency of reentrant tachycardia; this patient had had inducible reentrant tachycardia after intravenous propafenone. In conclusion, intravenously administered propafenone terminated reentrant tachycardia in 85% of patients and prevented reinduction in 71%, with no adverse hemodynamic effects.     

腺苷终止房室结和房室旁道折返性心动过速的心内电生理评价

探讨腺苷对阵发性室上性心动过速 (PSVT)的终止效果 ,观察PSVT终止后出现的心律失常。 2 5例患者 ,其中房室结折返性心动过速 (AVNRT) 11例、房室折返性心动过速 (AVRT) 14例 ,于心内电生理检查时 ,由前臂静脉注射(简称静注 )腺苷 6～ 12mg ,观察其终止心动过速的疗效和作用部位。结果 :11例AVNRT患者静注腺苷后 ,10例恢复窦性心律 ,其中 9例终止AVNRT于慢径前传 ,1例于快径逆传 ;14例AVRT患者静注腺苷后 ,14例均恢复窦性心律 ,终止AVRT 12例于房室结前传 ,2例于旁道逆传。心动过速终止后最常出现的心律失常是房性早搏和一过性Ⅰ和Ⅱ度房室阻滞 ;此外 ,室性早搏也很常见 ,部分患者可出现短阵室性心动过速 ,1例患者出现预激综合征伴心房颤动。结论 :腺苷终止PSVT有较高的成功率 ,但有潜在的促心律失常作用。     

Efficacy of propafenone in Wolff-Parkinson-White syndrome: electrophysiologic findings and long-term follow-up

The efficacy and safety of intravenous propafenone was studied in 10 patients with Wolff-Parkinson-White syndrome and in 2 patients with a concealed accessory pathway. During electrophysiologic study, the effect of propafenone on the effective refractory period of the accessory pathway was determined, as well as its effect during orthodromic atrioventricular (AV) reentrant tachycardia and atrial fibrillation. Propafenone caused significant increases in the accessory pathway refractory period, both in the anterograde direction (290 +/- 19 versus 474 +/- 50 ms, p less than 0.05) and in the retrograde direction (238 +/- 15 versus 408 +/- 44 ms, p less than 0.05). Complete anterograde accessory pathway conduction block occurred in four patients. Sustained AV reentrant tachycardia was inducible in 11 patients before administration of propafenone. Drug infusion during AV reentrant tachycardia promptly terminated arrhythmia in 10 of these 11 patients and caused slowing of AV reentrant tachycardia in the remaining patient. Before propafenone, sustained atrial fibrillation was inducible in six patients and nonsustained atrial fibrillation in four patients. After propafenone, no patient had inducible sustained atrial fibrillation. Furthermore, propafenone caused a marked decrease in peak ventricular rate during atrial fibrillation. Eight patients have been treated with oral propafenone and followed up for 12 +/- 2 months. All have remained virtually free of recurrent arrhythmia and none has developed significant side effects. Propafenone is a very promising agent for emergency intravenous therapy as well as long-term oral therapy in patients with Wolff-Parkinson-White syndrome.     

Intravenous propafenone for termination of reentrant supraventricular tachycardia. A placebo-controlled, randomized, double-blind, crossover study

To assess the antiarrhythmic efficacy of intravenous propafenone, 20 patients with inducible sustained supraventricular tachycardia received propafenone, 2 mg/kg body weight, or placebo in a double-blind, randomized, crossover study. Three patients had intra-atrial reentrant tachycardia, 3 had atrioventricular nodal reentrant tachycardia, and 14 had atrioventricular reciprocating tachycardia associated with the Wolff-Parkinson-White syndrome. Termination of supraventricular tachycardia occurred in 15 of the 20 patients receiving propafenone but 0 of the 11 patients receiving placebo (p less than 0.01). Propafenone prolonged refractoriness and slowed conduction of the atrium, the atrioventricular node, and accessory atrioventricular bypass tracts, and these effects provided antiarrhythmic action to halt tachycardia. No adverse effects were observed in any patient. We conclude that intravenous propafenone is safe and effective in the acute treatment of various forms of reentrant supraventricular tachycardia.     

希氏束旁起搏鉴别间隔部隐匿性AVRT与AVNRT的临床价值

目的：探讨希氏束旁起搏鉴别间隔部隐匿性房室旁道与慢一快型房室结折返性心动过速（AVNRT）的临床价值。方法：采用希氏束逆传不应期心室早搏刺激法将61例患者分别诊断为37例慢一快AVNRT和24例间隔部房室折返性心动过速（AVRT）；再对61例患者采用希氏束旁起搏方法进一步检测。结果：采用希氏束旁起搏法检测37例AVNRT患者中有6例未检测成功，其余31例均为逆传房室结图形；24例AVRT患者中4例未检测成功，15例呈逆传旁道／旁道图形，5例呈非逆传旁道／旁道图形。如以逆传旁道／旁道图形为标准，鉴别间隔快旁路引起的AVRT与慢一快型房室结折返性心动过速，敏感性75％，特异性可达1009／6。结论：希氏束旁刺激法对鉴别诊断AVRT与AVNRT有较高的特异性。     

An approach to therapy of supraventricular tachyarrhythmias: An algorithm versus individualized therapy

Approaches to the treatment of supraventricular arrhythmias, including atrial fibrillation, atrial flutter, atrial tachycardia, atrioventricular (AV) reentrant tachycardia, and AV nodal reentrant tachycardia, continue to evolve. Within the past two decades, many new and effective treatments have become available. These include several new antiarrhythmic agents, ablative therapies, pacing and surgical modalities, and cardioversion/defibrillation techniques. This paper provides an algorithm for the treatment of these supraventricular arrhythmias which includes therapy for the acute episode as well as the prevention of subsequent episodes of the tachyarrhythmia.     

Administration of adenosine for termination of atrioventricular nodal reentry tachycardia: induction of atrial fibrillation with rapid conduction over an accessory pathway and unmasking of concomitant Wolff-Parkinson-White syndrome

The antiarrhythmic properties of adenosine, its ultra-short half-life and the absence of frequent serious side effects make it a front-line agent in arrhythmia management, especially in the treatment of atrioventricular nodal reentrant tachycardia. Due to a shortening of atrial refractoriness, adenosine can facilitate the induction of atrial fibrillation. Life threatening tachycardias may result from a potential rapid conduction of atrial fibrillation over an accessory pathway especially if the latter one has a short antegrade refractory period. We report a case of a 59 year old female patient in which intravenous administration of adenosine during typical atrioventricular nodal reentrant tachycardia was followed by atrial fibrillation with rapid conduction over a hitherto unknown accessory pathway. After intravenous administration of adenosine the tachycardia was terminated successfully within 38 s. After a short period of asystole, spontaneous atrial fibrillation developed unmasking an antegrade preexcitation with subsequent rapid ventricular response (210 b/min). The three-lead ECG showed a narrow QRS complex tachycardia. Because of spontaneous conversion to sinus rhythm and the absence of hemodynamic compromise there was no need for external cardioversion. During electrophysiological study an antidromic atrioventricular reentrant tachycardia was recorded over a left posteroseptal accessory pathway including antegrade conduction properties only. Because of its ultrashort half-life, serious side effects after adenosine administration are rare. The possibility of life threatening proarrhythmias after intravenous adenosine administration should be taken into consideration if the etiology of a paroxysmal supraventricular tachycardia is not clear and a concomitant Wolff-Parkinson-White syndrome cannot be excluded. As with application of all intravenous antiarrhythmic agents, the administration of adenosine should only be performed if continuous ECG monitoring and cardioversion facilities are available and possible.     

Slowing of the Ventricular Rate During Atrial Fibrillation by Ablation of the Slow Pathway of AV Nodal Reentrant Tachycardia

Influence of Slow Pathway Ablation on Atrial Fibrillation. Introduction : The mechanisms whereby radiofrequency catheter modification of AV nodal conduction slows the ventricular response are not well defined. Whether a successful modification procedure can be achieved by ablating posterior inputs to the AV node or by partial ablation of the compact AV node is unclear. We hypothesized that ablation of the well-defined slow pathway in patients with AV nodal reentrant tachycardia would slow the ventricular response during atrial fibrillation.
Methods and Results : In 34 patients with dual AV physiology and inducible AV nodal reentrant tachycardia, atrial fibrillation was induced at baseline and immediately after successful slow pathway ablation and at 1-week follow-up. The minimal, maximal, and mean RR intervals during atrial fibrillation increased from 353 ± 76,500 ± 121, and 405 ± 91 msec to 429 ± 84 (P < 0.01), 673 ± 161 (P < 0.01), and 535 ± 98 msec (P < 0.01), respectively. These effects remained stable during follow-up at 1 week. The AV block cycle length increased from 343 ± 68 msec to 375 ± 60 msec (P < 0.05) immediately and to 400 ± 56 msec (P < 0.01) at 1-week follow-up. The effective refractory period of the AV node prolonged from 282 ± 83 msec to 312 ± 89 msec and to 318 ± 81 msec after 1 week (P < 0.05), respectively.
Conclusion : This study shows a decrease in ventricular response to pacing-induced atrial fibrillation after ablation of the slow pathway in patients with AV nodal reentrant tachycardia. Since the AV nodal conduction properties could be defined, this study supports the hypothesis that the main mechanism of AV nodal modification in chronic atrial fibrillation is caused by ablation of posterior inputs to the AV node.     

心室融合波伴心房激动提前对间隔旁路逆传的房室折返性心动过速的诊断作用

目的 观察心室融合波伴心房激动提前对间隔旁路逆传的顺向型房室折返性心动过速(OAVRT)的诊断作用。方法 按心内电生理检查标准和射频消融结果，将47例符合人选条件的患者分为两组：房室结折返性心动过速(AVNRT)组和间隔旁路逆传的0AVRT组，分别为24例和23例。心动过速时行心室期前程序刺激(RS2刺激)和心室快速刺激，测量体表心电图上心室融合波之后的心房激动时间是否提前。结果 RS2刺激和心室快速刺激均能形成多个心室融合波。AVNRT组无l例伴有心房激动提前(特异性100％)，而OAVRT组在心室刺激成分明显的心室融合波时，心房激动均被提前(敏感性100％)。两组间的差异十分显著(P＜0．001)。结论 心室融合波伴心房激动时间提前是诊断间隔旁路逆传OAVRT的可靠指标，具有敏感性和特异性高的特点，而且也可用于未能记录到希氏束电图的患者。     

Unmasking of left free wall ventricular preexcitation by His bundle ablation.

His bundle ablation was performed in a 48 year old man with drug refractory orthodromic atrioventricular reentrant tachycardia and paroxysmal atrial fibrillation. Reentry was caused by a left free wall concealed accessory pathway. Interruption of the His bundle by low energy direct current shock (25 J) was quickly followed by anterograde conduction via the accessory pathway, with various forms of advanced block. The combined effect of unfavourable anterograde conduction (prolonged anterograde effective refractory period and decremental conduction), the left lateral location of the accessory pathway and intra-atrial conduction delay on one side, and normal conduction via the atrioventricular node and His bundle with retrograde concealed conduction into the accessory pathway on the other side resulted in masking of the anterograde conduction capability of the anomalous pathway. This observation does not seem to invalidate the choice of His bundle ablation in similar cases.     

Electrophysiologic effects and clinical efficacy of flecainide in children with recurrent paroxysmal supraventricular tachycardia

The electrophysiologic effects of intravenous flecainide were evaluated in 16 patients aged 9 +/- 4 years: 15 with recurrent paroxysmal supraventricular tachycardia (SVT) and 1 with overt accessory pathway and history of syncope. Eleven patients had an accessory pathway; it was concealed in 2, overt in 9 and in 10 of these patients an orthodromic atrioventricular reentrant tachycardia was induced. Five patients without accessory pathway had an atrioventricular nodal reentrant tachycardia. After intravenous flecainide (1.5 mg/kg) the effective refractory period of the atrium and ventricle increased significantly; the anterograde and retrograde effective refractory periods of the atrioventricular node did not. Flecainide blocked retrograde conduction in the accessory pathway in 4 patients (effective refractory period 245 +/- 41 ms) and anterograde conduction in 8 of 9 patients (effective refractory period 284 +/- 57 ms). The mean cycle length of orthodromic reciprocating tachycardia and atrioventricular nodal reentrant tachycardia increased significantly. After flecainide tachycardia was noninducible in 6 patients with orthodromic reciprocating tachycardia and in 1 with atrioventricular nodal reentrant tachycardia. It was inducible but nonsustained (less than or equal to 30 seconds) in 1 patient with orthodromic reciprocating tachycardia and in 3 with atrioventricular nodal reentrant tachycardia. Fifteen patients continued oral flecainide treatment for 19 +/- 11 months.(ABSTRACT TRUNCATED AT 250 WORDS)     

Typical atrioventricular nodal reentrant tachycardia in a patient with fasciculoventricular pathway

We report a 34-year-old female patient with preexcitation electrocardiogram and recurrent paroxysmal palpitations. Standard 12-lead electrocardiogram showed minimal preexcitation with normal PR interval and normal frontal QRS axis. The electrophysiologic study showed normal AH intervals, short HV intervals, and no change in the degree of preexcitation by rapid atrial pacing. These findings were compatible with the fasciculoventricular pathway. Typical atrioventricular nodal reentrant tachycardia with narrow QRS complex and normal HV interval was induced reproducibly by programmed electrical stimulation. Slow pathway was ablated successfully with radiofrequency catheter ablation, and then the patient remained asymptomatic during a follow-up of 12 months. Although the fasciculoventricular pathway is rare and supraventricular tachycardia in a patient with fasciculoventricular pathway may mimic Wolff-Parkinson-White syndrome, possibility of typical atrioventricular nodal reentrant tachycardia with fasciculoventricular pathway should be considered as a mechanism of supraventricular tachycardia in a patient showing preexcitation electrocardiogram.     

Criteria for a pathogenetic approach to antiarrhythmic therapy in paroxysmal supraventricular reciprocal tachycardia

An electrophysiological study using programmed transesophageal atrial pacing was performed in 106 patients with abnormalities in the myocardial conduction system, of whom 102 suffered from paroxysmal supraventricular reciprocal tachycardia and/or paroxysmal atrial fibrillation. The electrophysiological properties of the myocardial conduction system were demonstrated to be labile. The factors determining the frequency and length of palpitations were outlined. The conditions for an onset of supraventricular reciprocal tachycardiac paroxysm and for existence of a reentrant chain were found to be minimal in the effective refractory period of the accessory pathway, which was less or equal to the effective refractory period of the atrioventricular junction. An approach to antiarrhythmic therapy was proposed, which was based on modifying the ratio of the effective refractory periods of normal and abnormal excitation pathways.     

Sympathetic predominance of cardiac autonomic regulation in patients with left free wall accessory pathway and orthodromic atrioventricular reentrant tachycardia

AIMS: The aim of this study was to compare cardiac autonomic regulationin patients with a history of paroxysmal supraventricular tachyarrhythmias,such as atrioventricular nodal reentrant tachycardia and atrioventricularreentrant tachycardia, and healthy controls. METHODS AND RESULTS: Seventeen patients with paroxysmal atrioventricular nodal reentranttachycardia (atrioventricular nodal reentrant tachycardia group),14 patients with overt preexcitation and paroxysmal atrioventricularreentrant tachycardia caused by a left free wall accessory pathway(atrioventricular reentrant tachycardia group) and 14 healthycontrol subjects, were studied. The patients and the controlswere age and gender matched. Cardiac autonomic regulation wasassessed by means of frequency domain analysis of heart ratevariability at rest, during head-up tilt, active standing, treadmillexercise and after exercise. The high frequency component (0·15–0·5 Hz)of heart rate variability tended to be lower and the low frequencycomponent (0·04–0·15 Hz) tended to be higheramong the atrioventricular reentrant tachycardia patients thanin atrioventricular nodal reentrant tachycardia patients andcontrols. The difference reached statistical significance atrest (P<0·05) and during standing (P<0·05atrioventricular reentrant tachycardia vs atrioventricular nodalreentrant tachycardia and P<0·01 atrioventricularreentrant tachycardia vs controls). Accordingly, the low-to-highfrequency ratio — the marker of cardiac sympathetic regulation— was higher in atrioventricular reentrant tachycardiapatients than in atrioventricular nodal reentrant tachycardiapatients (P<0·05 at rest and during standing) andcontrols (P<0·01 during standing). CONCLUSION: The cardiac autonomic status in atrioventricular reentrant tachycardiapatients was suggestive of a higher sympathetic tone than inatrioventricular nodal reentrant tachycardia patients or healthycontrols. This may be related to inhomogeneous ventricular activationin the presence of antegrade conduction via the accessory atrioventricularpathway.     

食管心房调搏诱发与终止房室折返性心动过速的研究

目的探讨经食管心房调搏诱发与终止房室折返性心动过速的价值。方法选择255例有心动过速发作史,并且既往心电图证实有阵发性室上性心动过速(PSVT)的患者行食管心房调搏检查。结果在被检的255例患者中诱发房室折返性心动过速229例,占89.8%(其中顺向型217例,占94.8%,逆向型12例,占5.2%)。诱发成功的最佳刺激方法为程序期前刺激法(S1S2、S1S2S3),诱发率为88.2%。诱发的必备条件是旁路有效不应期长于房室结有效不应期。在诱发房室折返性心动过速的229例中215例经电刺激成功终止,转复为窦性心律,成功率为93.9%,其中64例采用短阵快速刺激一次性成功终止,转复成功率达100%。结论食管心房调搏能有效地诱发与终止房室折返性心动过速,诱发顺向型房室折返性心动过速的关键因素是旁路不应期大于房室结有效不应期,终止发作的最有效的刺激方法为短阵快速刺激。本法可作为急诊终止阵发性室上性心动过速的首选方法。     

Electrophysiological effects of intravenous propafenone for treating atrial-ventricular nodal dual pathways reentrant tachycardia]

The acute electrophysiological effects of intravenous propafenone were studied through programmed electrical stimulation in 9 patients with atrio-ventricular nodal dual pathways reentrant tachycardia (AVNDP-RT). The results showed that propafenone prolonged significantly the effective refractory period of atrial ventricular nodal fast pathway (AVN-FP) in retrograde conduction and might further terminate the paroxysmal supraventricular tachycardia (PSVT). It is an effective drug for treating AVNDP-RT. Neither blood pressure dropping nor other side effects were observed.