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。     

Ventriculoatrial intervals: diagnostic use in paroxysmal supraventricular tachycardia.

Reciprocating tachycardias due to reentry either within the atrioventricular (AV) node or using an accessory AV pathway are a common cause of paroxysmal supraventricular tachycardia in humans. Unfortunately, although of potential therapeutic value, differentiation of these forms of reciprocating tachycardia may be difficult and require detailed electrophysiologic study. To develop diagnostic criteria that permit exclusion of participation of an accessory AV pathway in reciprocating tachycardia without extensive laboratory testing, results of electrophysiologic studies were examined in 50 patients with Wolff-Parkinson-White syndrome, 15 patients with accessory AV pathways that conducted only in the ventriculoatrial direction, and 15 patients with reentry within the AV node. The interval between onset of ventricular activation and both earliest recorded atrial activity (V-Amin) and high lateral right atrial electrogram (V-HRA) was measured during tachycardia. A V-Amin of 61 ms or less or V-HRA of 95 ms or less did not occur in patients with accessory AV pathways, but occurred frequently (12 of 15 and seven or eight, respectively) in patients with reentry within the AV node. Therefore, in patients with paroxysmal reciprocating tachycardias, V-A interval measurements provide a screening test capable of excluding participation of an accessory AV pathway.     

Usefulness of the pre-excitation index to determine the mechanism of supraventricular paroxysmal tachycardia and the location of the anomalous pathway

To evaluate the preexcitation index in determinate the mechanism of paroxysmal supraventricular tachycardia and localize accessory pathway, fifty nine patients with clinical and electrocardiographic supraventricular tachycardia were analyzed. There were thirty eight patients (64.4%) with orthodromic AV reentry using an accessory pathway for retrograde conduction and 21 patients (35.6%) with typical AV nodal reentrant tachycardia. Preexcitation of the atrium during tachycardia by premature ventricular complex at a time when anterograde His bundle activation was present in 30 o 38 (79%) patients with AV reentry while only 8 of 21 (38%) patients with AV nodal reentry demonstrated preexcitation during tachycardia. There was no significant difference between left and right accessory pathways and in mean tachycardia cycle length between the two groups. However, atrioventricular reentry demonstrated atrial preexcitation during tachycardia more frequently than AV nodal reentry. In conclusion, our findings show that the preexcitation index is a useful method for determinate the mechanism of supraventricular tachycardia and to localize accessory pathways.     

Electrophysiological mechanisms of the effect of allapinin in patients with paroxysmal supraventricular tachycardia

An intracardiac electrophysiological study was undertaken to examine 15 patients with paroxysmal supraventricular tachycardias. Allapinin intravenously given in a dose of 0.4 mg/kg, was tested for effects. The agent was demonstrated to cause a substantial inhibition of rapid retrograde pathway function in atrioventricular nodal tachycardia and abnormal antero- and retrograde pathway function. This is the major aspect of the drug's action that prevents the development of episodes of paroxysmal supraventricular tachycardias. The agent fails to virtually affect the function of the atrioventricular node in the anterograde direction in the two types of the tachycardia. Thus, allapinin has the mechanism of action that is typical of quinidine-like drugs used in supraventricular tachycardias.     

The anti-arrhythmia effect and hemodynamic effects of Bonnecor in intravenous administration

For testing the efficiency of Bonnecor in intravenous administration (0.3 mg/kg) 36 patients were examined electrophysiologically (31 with paroxysmal supraventricular tachycardias, 5 with ventricular tachycardias). In other 6 patients haemodynamic investigations were performed by means of right-heart catheterization and thermodilution. The supraventricular tachycardias induced by programmed electrostimulation could be interrupted by administration of Bonnecor in 45% of the cases. After the administration of Bonnecor the inducibility of supraventricular tachycardias was suppressed in 11 of the 31 patients. In 2 of the 5 patients with ventricular tachycardia an evocation of ventricular tachycardias was no more possible after an intravenous application of Bonnecor; a medicamentous termination of the ventricular tachycardias had been tried only in one case. Clinically relevant negatively inotropic effects could not be proved. Apart from insignificant malaises in few cases, no side-effects occurred.     

Supraventricular tachycardia in patients without overt preexcitation

In this article, the authors discuss the features and differential diagnosis of supraventricular tachycardia with a regular ventricular rate that occurs in patients without overt preexcitation during sinus rhythm. In the authors' experience, the two most common mechanisms of these tachycardias are reentry within the atrioventricular node (AV nodal reentry) and atrioventricular reentry using a concealed accessory pathway for retrograde conduction and the AV node/His-Purkinje system for antegrade conduction (AV reentry). Sinus nodal reentry, intra-atrial reentry, automatic atrial tachycardia, and nonparoxysmal junctional tachycardia account for the remaining episodes of regular supraventricular tachycardia. Therapy for AV and AV nodal reentry is also discussed.     

Treatment of supraventricular arrhythmias with encainide

Encainide has been used to treat 230 patients with supraventricular arrhythmias, including patients with reentry supraventricular tachycardia of the atrioventricular reentry (Wolff-Parkinson-White syndrome) and the atrioventricular nodal reentry types associated with atrial fibrillation, paroxysmal supraventricular tachycardia or both, as well as incessant supraventricular tachycardia. The available data are summarized in this review. The short- and long-term response to encainide for preventing recurrence or lessening symptoms was excellent in most cases. There was little arrhythmia aggravation, and side effects, which were mostly central nervous system and visual in nature, did not cause discontinuation of the drug. Anterograde accessory pathway block was clearly an important effect. Whether retrograde block or refractoriness in the accessory pathway is the most important mechanism remains to be resolved. Pediatric patients with tachycardia-related cardiomyopathy responded well to encainide. Oral encainide's absence of effect on blood pressure or myocardial contractility is an added benefit.     

Atrioventricular nodal reentry in the Wolff-Parkinson-White syndrome

Although supraventricular tachycardia in the Wolff-Parkinson-White (WPW) syndrome is generally due to atrioventricular reentry, the presence of the accessory pathway does not preclude other mechanisms of tachycardia. We observed AV nodal reentry in three of 95 consecutive patients (3.1%) referred for assessment of arrhythmias associated with WPW syndrome. The unique observation of spontaneous transition from atrioventricular reentry to AV nodal reentry at a similar cycle length was observed in one patient and is the subject of this report.     

Use of Propafenone in Patients With Supraventricular Tachycardia

Propafenone prolongs refractoriness and slows conduction of the atrium, atrioventricular node, and accessory atrioventricular pathway. By interfering with conduction in locations necessary to support supraventricular tachycardia, propafenone effectively treats several mechanisms of rhythm disturbance. Early experience shows that propafenone, when administered in the electrophysiology laboratory, effectively terminates or prevents reinduction of paroxysmal supraventricular reentrant tachycardia in 50% to 75% of patients. The most effective dose associated with the fewest side effects has been 2 mg/kg infused over 10 minutes. Long-term success with propafenone has been demonstrated in patients with paroxysmal atrial fibrillation, paroxysmal atrial flutter, atrioventricular node reentrant tachycardia, atrioventricular reentrant tachycardia using a concealed accessory pathway, and tachycardias associated with the Wolff-Parkinson-White syndrome, including paroxysmal atrial fibrillation and atrioventricular reentrant tachycardia. In 67% (range, 27% to 89%) of patients receiving long-term therapy with propafenone, episodes of supraventricular tachycardia have been either eliminated or significantly reduced in frequency and treatment has not had to be stopped because of side effects. The effective daily dose for longterm therapy has been 550 to 750 mg administered in three or four divided doses. Although the number of patients reported in the literature at this time is small, propafenone appears to be an effective agent for treating supraventricular tachycardia due to one of several mechanisms.     

Supraventricular tachycardia dependent upon accessory pathways in the absence of ventricular preexcitation

Paroxysmal supraventricular tachycardia is a common disorder of cardiac rhythm, generally thought to be due to reentry within the atrioventrlcular (A-V) node. The possibility that this disorder may be a manifestation of the Wolff-Parkinson-White syndrome should always be considered, but this etiology is usually rejected if the electrocardiogram in sinus rhythm falls to demonstrate a delta wave (i.e., ventricular preexcitatlon). Several recent reports have demonstrated that an accessory A-V pathway may conduct impulses only in the retrograde or ventriculo-atrial direction. Hence, reentrant tachycardia based on a mechanism identical to that observed in patients with classic Wolff-Parkinson-White syndrome may occur, and the electrocardiogram in sinus rhythm fail to show a delta wave. This report describes 11 patients who presented with paroxysmal supraventricular tachycardia without QRS changes in sinus rhythm that suggested the Wolff-Parkinson-White syndrome. Electrophysiologic studies demonstrated that an accessory pathway participated in the mechanism of the tachycardia. Eight of these 11 patients were successfully treated by surgical interruption of either the accessory pathway or the bundle of His. Accessory pathways are not rare among patients with paroxysmal supraventricular tachycardia; and it follows that this variant of the Wolff-ParkinsonWhite syndrome is more common than would be suspected if the Wolff-Parkinson-White syndrome is considered only when delta waves are observed on the electrocardiogram.     

Antitachycardia pacing therapy in supraventricular tachycardia using the microcomputer-guided Tachylog 651 pacemaker

Microprocessor-controlled antitachycardia pacemaker expand the automatic detection of the tachycardia and incorporate multiple, different termination modes. We report our results in the long-term therapy of paroxysmal supraventricular tachycardia with the antitachycardia pacemaker "Tachylog 651". The system was implanted in 10 patients with a mean age of 48 years (from 20 to 68 years): Wolff-Parkinson-White syndrome 4 patients, paroxysmal AV nodal reentrant tachycardia 6 cases. The rate of the reentrant tachycardia was 162 +/- 23/min. The system reliably differentiated between paroxysmal supraventricular tachycardia and sinus tachycardia, including 4 patients with a tachycardia rate of less than 150/min. Burst overdrive pacing was effective in 6 patients and the "self-search system" in 3 patients. During follow-up of 9 +/- 4 months 104 +/- 93 successful interventions per patient were observed; change of the termination mode became necessary in 4 patients and of the detection mode in 3 patients. The incorporation of programmable detection and multiple termination modes in the microprocessor-controlled antitachycardia systems allows the effective long-term antitachycardia pacing. The multiprogrammable "Tachylog 651" pacemaker is an advancement in the electrotherapeutic treatment of paroxysmal supraventricular tachycardias, including the automatic treatment of tachycardias with low rates.     

Supraventricular tachycardia: diagnosis and treatment

Specific mechanisms of supraventricular tachycardia include sinoatrial, intra-atrial, atrioventricular (AV) nodal as well as concealed and manifest bypass tract reentry. In dual pathway reentry, at least one of the pathways involves the AV node, usually the slow pathway and the other pathway, perinodal fibers within the atria. Localization of the perinodal fibers is critical for ablative procedures to eliminate AV nodal tachycardias. Other mechanisms of supraventricular tachycardia include chaotic atrial tachycardia and automatic atrial tachycardia with and without AV block. However, drug therapy includes intravenous adenosine 6 mg, as well as the older standbys of digoxin, calcium and beta-blocking agents, and type 1a and 1c antiarrhythmias. In resistance cases, amiodarone is usually effective. However, for incessant supraventricular mechanisms, catheter or surgical ablative techniques are recommended to eliminate long-term drug administration.     

Therapeutic electrical procedures in recurring, drug refractory tachycardias. I. Antitachycardiac implantable pacemaker systems

In 9 Patients with medicamentously therapy-refractory tachycardias (twice paroxysmal AV-node-reentry tachycardia, four times paroxysmal orthrodromic reentry tachycardia in the WPW-syndrome, once paroxysmal atrial reentry tachycardia, twice recurrent ventricular tachycardia) after adequate electrophysiological testings antitachycardiac pacemakers able to activate the patients were implanted. In these cases the implantable tachyblocker TUR-RFP-01 was used in 4 cases for the highly frequent volley atrial stimulation, in 2 cases for the more highly frequent volley ventricular stimulation. In 3 patients the interruption of the tachycardia was performed by ventricular underdrive stimulation by means of putting the magnet on a conventional R-wave-inhibited ventricular pacemaker. In all cases the recurrent tachycardias could reliably be terminated by the patients themselves by activation of the antitachycardiac systems (duration of the follow-up period 3-14 months, on an average 10.7 +/- 3.4 months); only in one case in the further course a change of the stimulation parameters was necessary which were carefully tested at the beginning. On account of the danger of the acceleration of the tachycardia and of the evocation of ventricular fibrillation, respectively, should, however, be performed highly frequent ventricular stimulations for the termination of ventricular tachycardias only in readiness for defibrillation.     

Surface electrocardiographic recognition of dual atrioventricular nodal pathways during sinus rhythm

Atrioventricular nodal reentry is the most common mechanism of paroxysmal supraventricular tachycardia. Electrocardiograms obtained during sinus rhythm rarely serve to identify the mechanism of paroxysmal supraventricular tachycardia. We report two cases of dual atrioventricular nodal reentry in which electrocardiograms recorded during sinus rhythm disclosed two separate PR intervals that suggested dual atrioventricular nodal pathways.     

Variation of P-QRS relation during atrioventricular node reentry tachycardia

ObjectivesThe main objective of this study was to characterize the phenomenon of variation in the P-QRS relation during atrioventricular node reentry tachycardia.BackgroundVariation of P-QRS relation during tachycardia has been observed occasionally in atrioventricular node reentry tachycardia. However, the incidence, the characteristics and the mechanisms of this phenomenon have not been investigated previously.MethodsRetrospective analysis was performed in 311 consecutive patients with slow-fast form and 108 patients with atypical or multiple form of atrioventricular node reentry tachycardia to examine whether variation of P-QRS relation with changes in AH, HA and AH/HA (A = atria; H = His bundle) ratio occurred during tachycardia.ResultsA total of 28 patients, 8 with slow-fast and 20 with atypical or multiple tachycardias, were found to manifest this phenomenon. There were 6 males and 22 females, with an average age of 38 ± 16 years. In 10 patients, this phenomenon occurred transiently following electrical induction of the tachycardia. In 15 patients, changes in AH, HA and AH/HA ratio were associated with the occurrence of Wenckebach or 2:1 block proximal to the His bundle (H) recording site without interruption of the tachycardia. In nine patients, three with nonsustained tachycardia and six after administration of adenosine triphosphate, this phenomenon was observed at the termination of the tachycardia. This phenomenon was usually accompanied by a mild lengthening of the tachycardia cycle length.ConclusionsVariation of P-QRS relation with or without block may occur during atrioventricular node reentry tachycardia, especially in atypical or multiple-form tachycardias. It was postulated that decremental conduction in the distal common pathway, which exists between the distal link of the reentry circuit and the H, is primarily responsible for this phenomenon.     

Atrioventricular block in the atypical form of junctional reciprocating tachycardia: evidence supporting the atrioventricular node as the site of reentry

Serial electrophysiologic studies were performed in 19 patients with the atypical form of supraventricular tachycardia having a long RP and short PR interval. In all 19 patients, supraventricular tachycardia was found to have a 1:1 P-QRS relation during initial control electrophysiologic studies, and in all 19 patients, electrophysiologic studies suggested that junctional reentry was the mechanism of supraventricular tachycardia. Seven of the 19 patients developed atrioventricular (AV) block during initiation of supraventricular tachycardia or after induction of supraventricular tachycardia following various drug administrations in subsequent studies. In three patients, second degree block within the His bundle or block distal to the His bundle recording site occurred after administration of quinidine. In one patient it occurred after procainamide, and in another patient it occurred after atropine. In one patient, 2:1 block proximal to the His deflection occurred after verapamil. In the remaining patient, a transient Wenckebach block proximal to the His deflection was noted after adenosine triphosphate. In this latter patient, 2:1 AV block was also noted after propranolol and digoxin. The site of reentry in these seven patients with AV block during supraventricular tachycardia was confined to the AV node area. Their supraventricular tachycardia did not involve a slowly conducting paraseptal accessory pathway because the distal AV node, His bundle and ventricle were not found to be necessary links in the tachycardia circuit.     

Serial testing of anti-arrhythmia preparations using the intracardiac electrophysiological study of patients with reciprocal paroxysmal tachycardias

Diagnostic investigation of 36 patients with reciprocal paroxysmal tachycardias, using intracardiac electrophysiologic tests, revealed supraventricular paroxysmal tachycardia in 29 patients, and ventricular paroxysmal tachycardia in 7. Serial trials of antiarrhythmic drugs in acute experiments with simultaneous electrophysiologic studies made possible efficient medication in 80% of the patients. A high correlation was demonstrated between the results of acute antiarrhythmic drug tests and subsequent long-term treatment. Ritmilen proved particularly effective in patients with paroxysmal tachycardias in the presence of the ventricular pre-excitation syndrome, while cordarone and etmozin were most effective antiarrhythmic drugs for reciprocal ventricular tachycardias. No preferential antiarrhythmic agent could be established for patients with reciprocal paroxysmal tachycardias due to double atrioventricular conduction.     

Comparison of adenosine effects on atrioventricular node reentry and atrioventricular reciprocating tachycardias

Background: Adenosine is an established first line therapy for the treatment of narrow complex tachycardias. The two most common etiologies of paroxysmal supraventricular tachycardia (SVT) are atrioventricular node reentry tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). Hypothesis: We postulated that adenosine might have different effects on the termination of AVNRT vs. AVRT, and that these differences might assist in the noninvasive differentiation between these diagnoses. Methods: Fifty-nine patients referred for the diagnosis and treatment of SVT were included in the study. All patients had SVT induced during electrophysiology testing, and each patient received adenosine during SVT. The adenosine dose, time to tachycardia termination, and site of tachycardia termination were recorded. Seventeen patients required isoproterenol administration to initiate SVT. This subset of patients was compared with those not requiring isoproterenol. Results: There was no statistically significant difference in the adenosine dose or time to tachycardia termination when comparing patients with AVNRT with those with AVRT. All patients with AVNRT had termination of tachycardia in the antegrade direction with final activation in the atria. Patients requiring isoproterenol for tachycardia initiation experienced tachycardia termination significantly faster than those not requiring isoproterenol, although there was no difference in the dose of adenosine required for termination. Conclusion: These data demonstrate that patients with dual AV node physiology and AVNRT do not have altered sensitivity to adenosine compared with patients with AVRT and normal AV nodes. Further investigation will be required to determine the clinical utility of the significantly shorter time to tachycardia termination for patients receiving isoproterenol.     

A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory

OBJECTIVE: The purpose of this study was to determine if the atrial response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction during paroxysmal supraventricular tachycardia is a useful diagnostic maneuver in the electrophysiology laboratory. BACKGROUND: Despite various maneuvers, it can be difficult to differentiate atrial tachycardia from other forms of paroxysmal supraventricular tachycardia. METHODS: The response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction was studied during four types of tachycardia: 1) atrioventricular nodal reentry (n = 102), 2) orthodromic reciprocating tachycardia (n = 43), 3) atrial tachycardia (n = 19) and 4) atrial tachycardia simulated by demand atrial pacing in patients with inducible atrioventricular nodal reentry or orthodromic reciprocating tachycardia (n = 32). The electrogram sequence upon cessation of ventricular pacing was, categorized as "atrial-ventricular" (A-V) or "atrial-atrial-ventricular" (A-A-V). RESULTS: The A-V response was observed in all cases of atrioventricular nodal reentrant and orthodromic reciprocating tachycardia. In contrast, the A-A-V response was observed in all cases of atrial tachycardia and simulated atrial tachycardia, even in the presence of dual atrioventricular nodal pathways or a concealed accessory atrioventricular pathway. CONCLUSIONS: In conclusion, an A-A-V response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction is highly sensitive and specific for the identification of atrial tachycardia in the electrophysiology laboratory.     

Effects of standing on the induction of paroxysmal supraventricular tachycardia

To evaluate the effects of standing on induction of paroxysmal supraventricular tachycardia, electrophysiologic studies were performed in both the supine and standing positions in 22 patients with atrioventricular (AV) reciprocating tachycardia and in 11 with AV node reentrant tachycardia. AV reciprocating tachycardia was induced in 9 of the 22 patients with AV reciprocating tachycardia when they were in the supine position and in 17 when standing. The effective refractory period of the AV node markedly shortened, from 275 +/- 72 to 203 +/- 30 ms (n = 16, p less than 0.005) after standing. The effective refractory period of the accessory pathway shortened slightly, from 293 +/- 75 to 278 +/- 77 ms (n = 8, p less than 0.005), after standing. AV node reentrant tachycardia was induced in 3 of the 11 patients with AV node reentrant tachycardia when they were in the supine position and in 6 when standing. The effective refractory periods of the slow pathway and fast pathway shortened markedly, from 293 +/- 72 to 216 +/- 40 ms (n = 6, p less than 0.025) and from 416 +/- 85 to 277 +/- 50 ms (n = 10, p less than 0.005), respectively, after standing. Plasma norepinephrine levels increased during standing both in patients with AV reciprocating and in those with AV node reentrant tachycardia (n = 11, p less than 0.005, n = 8, p less than 0.005, respectively). In conclusion, standing, which is associated with increased sympathetic tone, changed the electrophysiologic properties of the reentrant circuits, facilitating induction of AV reciprocating tachycardia and AV node reentrant tachycardia.