Value of the 12-lead electrocardiogram in discriminating atrioventricular nodal reciprocating tachycardia from circus movement atrioventricular tachycardia utilizing a retrograde accessory pathway

The value of the 12-lead electrocardiogram for distinguishing atrioventricular (AV) nodal reciprocating tachycardia from circus movement AV tachycardia utilizing a retrograde accessory pathway was studied in 100 patients with narrow QRS complex tachycardia. Intracardiac electrograms showed AV nodal reciprocating tachycardia in 40 patients and circus movement AV tachycardia in 60. The 12-lead electrocardiograms recorded during tachycardia were randomly sorted and reviewed by 4 experienced cardiac electrophysiologists who were blinded to the diagnosis associated with each tracing, the relative proportion of each arrhythmia and the hypotheses to be tested. Each reviewer was asked to indicate the location of the P wave relative to the QRS complex, electrical axis of the P wave in the frontal and horizontal planes and presence or absence of QRS alternation, and to interpret the most likely mechanism. The performance of published electrocardiographic criteria to differentiate AV nodal reciprocating tachycardia from circus movement AV tachycardia was evaluated. The overall accuracy of the reviewers' interpretations was 75%, similar to the accuracy of the predefined criteria when applied by these observers (71% correct, difference not significant). Interobserver agreement of reviewer interpretations was 76% and the intraobserver agreement was 78%. Features associated with circus movement AV tachycardia by univariable analysis were P waves after the QRS complex, faster tachycardia rates and QRS alternation. Multivariable analysis showed that only the location of the P wave relative to the QRS complex was independently associated with the mechanism of tachycardia (p = 0.002). QRS alternation was found by multivariate analysis to be associated with the rate but not the mechanism of the tachycardia.     

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.     

Differentiating atrioventricular nodal reentrant tachycardia from tachycardia via concealed accessory pathway

Studies analyzing the diagnostic value of 12-lead electrocardiographic criteria differentiating slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) from atrioventricular reentrant tachycardia (AVRT) due to concealed accessory pathway have shown inconsistent results. In 97 patients (50 with AVNRT, 47 with AVRT) 12-lead electrocardiograms (ECGs) were recorded during sinus rhythm and tachycardia (QRS <120 ms). The ECGs were blinded for diagnosis and patient and analyzed independently by 2 electrophysiologists. The studied criteria differentiating AVNRT from AVRT included pseudo-r'/S, the presence of a retrograde P wave, RP interval, ST-segment depression >/=2 mm with the number and location of the affected leads, QRS amplitude, and cycle length alternans.     

Clinical usefulness of the 12-lead electrocardiogram in the Wolff-Parkinson-White syndrome

When used with insight, the 12-lead electrocardiogram can provide a considerable amount of useful data in patients with the Wolff-Parkinson-White syndrome. The 12-lead electrocardiogram during tachycardia usually provides excellent clues as to the mechanism of tachycardia, with the most valuable feature being the relationship of the P wave to the QRS complex. The observation of intermittent loss of preexcitation or loss of preexcitation with late atrial extrasystoles is an indicator of a long anterograde refractory period of the accessory pathway, a clue to a benign prognosis in the event of atrial fibrillation. The preexcited morphology as assessed by the electrocardiogram can provide an accurate first approximation to accessory-pathway location using a few simple guidelines.     

Usefulness of ST-segment elevation in lead aVR during tachycardia for determining the mechanism of narrow QRS complex tachycardia

In the present study, we analyzed ST-segment elevation in lead aVR during tachycardia to differentiate the narrow QRS complex tachycardia. A total of 338 12-lead electrocardiograms during narrow QRS complex tachycardia were analyzed. Each patient underwent a complete electrophysiologic study. There were 161 episodes of atrioventricular nodal reentrant tachycardia (AVNRT), 165 episodes of atrioventricular reciprocating tachycardia (AVRT), and 12 episodes of atrial tachycardia (AT). The prevalence of aVR ST-segment elevation was 71% for AVRT, 31% for AVNRT, and 16% for AT. For ST-T changes in different leads, logistic regression analysis showed aVR ST-segment elevation was the only significant factor to differentiate the types of narrow QRS complex tachycardia (p <0.001 for AVRT and AVNRT; P = 0.02 for AVRT and AT). The sensitivity, specificity, and accuracy of aVR ST-segment elevation to differentiate AVRT from AVNRT and AT were 71%, 70%, and 70%, respectively. Among 117 episodes of AVRT with aVR ST-segment elevation, there were 76 (65%) left side, 23 (20%) right side, 14 (12%) posterior septal, and 4 (3%) antero- and mid-septal accessory pathways (p = 0.002). In conclusion, aVR ST-segment elevation during narrow QRS complex tachycardia favors the atrioventricular reentry through an accessory pathway as the mechanism of the tachycardia.     

Signal averaging of the electrocardiogram in the remote differential diagnosis of broad complex tachycardias

The diagnosis of the origin of a broad complex tachycardia may be difficult, especially in the absence of a 12-lead electrocardiogram of the tachycardia. This study investigates the value of signal averaging in the differential diagnosis of broad complex tachycardia. Signal averaging during sinus rhythm was performed in 102 consecutive patients who presented with broad complex tachycardia (QRS width greater than 110 ms), in whom a definitive electrophysiological diagnosis was made. The presence of late potentials was determined on the basis of two definitions, the second including total QRS duration. The patients studied included 75 with ventricular tachycardia; 33 of these patients had suffered previous myocardial infarction, five had dilated cardiomyopathy, and 37 had a 'normal' heart. Of the 27 patients with supraventricular tachycardia, 22 had an atrioventricular accessory pathway (seven with a delta wave in sinus rhythm), three had atrioventricular nodal tachycardia and two had atrial tachycardia. The sensitivity of late potentials for the diagnosis of ventricular tachycardia was low utilizing both definitions (28% and 45%) although specificity was high (96% and 95%). The sensitivity for the diagnosis of ventricular tachycardia was higher for patients with ischaemic heart disease (43% and 70%) but very low for patients with ventricular tachycardia and a normal heart (16% and 22%). In conclusion, signal averaging in the remote diagnosis of broad complex tachycardia is specific but not sensitive for ventricular tachycardia, which limits its usefulness in selecting patients for electrophysiological study.     

TRANSESOPHAGEAL ELECTROCARDIOGRAPHY AND ATRIAL PACING IN ACUTE CARDIAC CARE: DIAGNOSTIC AND THERAPEUTIC VALUE

The utility of transesophageal electrocardiography using a bipolar 'pill electrode' was assessed in 17 consecutive patients with tachycardia presenting to our casualty department. Standard 12-lead electrocardiography showed regular narrow QRS tachycardia in 12 patients, and five patients had wide QRS tachycardia. Esophageal atrial electrogram recordings were obtained in 14 patients (82%), and these were helpful in determining the mechanism of tachycardia in 11 patients (78%). Of these 11, seven patients fulfilled criteria for atrioventricular junctional (AVJ) tachycardia based on measurement of the minimum interval between the onset of ventricular depolarisation and earliest atrial (esophageal) activity. One of these patients had presented with a wide QRS tachycardia. The other four patients were diagnosed as having ventricular tachycardia (VT) following diagnosis of AV dissociation. Atrial overdrive pacing, via the pill electrode, successfully reverted four of the nine patients (44%) with narrow QRS tachycardia but no patient with VT. Esophageal recording during tachycardia is a simple, relatively non-invasive technique which is helpful in suggesting the mechanism of tachycardia both in patients with narrow and wide QRS tachycardia, and may have a therapeutic role in patients with AVJ tachycardia. (Aust NZ J Med 1989; 19: 11–15.)     

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。     

Spectrum of regular tachycardias with wide QRS complexes in patients with accessory atrioventricular pathways

Reciprocating tachycardia and atrial flutter or fibrillation are the rhythm disorders most frequently documented in patients with accessory atrioventricular (A-V) pathways. Reciprocating tachycardia typically results in a regular tachycardia (140 to 250/min) with a normal QRS pattern, although on occasion bundle branch block aberration occurs. Atrial flutter or fibrillation may result in an irregular ventricular response, with the QRS configuration being normal or exhibiting bundle branch block or various degrees of ventricular preexcitation, or both. Although much less common than either reciprocating tachycardia or atrial flutter/fibrillation, regular tachycardias with a wide QRS complex suggestive of ventricular preexcitation are observed in patients with accessory pathways. Excluding functional or preexisting bundle branch block, several arrhythmias may cause these electrocardiographic findings which may mimic those of ventricular tachycardia.In the present study a variety of arrhythmias that resulted in tachycardias with a wide QRS complex were examined in 163 patients with accessory pathways who underwent clinical electrophysiologic study for evaluation of recurrent tachyarrhythmias. Twenty-six patients (15 percent) manifested a regular tachycardia with a wide QRS complex suggesting ventricular preexcitation. Atrial flutter with 1:1 anterograde conduction over an accessory pathway (15 of 26 patients, 58 percent) was the most frequent arrhythmia and was usually associated with a heart rate of 240/min or greater (12 of 15 patients). Reciprocating tachycardia with conduction in the anterograde direction over an accessory pathway (antidromic reciprocating tachycardia) occurred in 7 of 26 patients (27 percent), and resulted in a slower ventricular rate than atrial flutter (217 ± 22 versus 262 ± 42, P < 0.01). Other arrhythmias included reciprocating tachycardia with reentry utilizing a fasciculoventricular or nodoventricular connection (two patients, 8 percent), reciprocating tachycardia with reentry in the atrium or A-V node and anterograde accessory pathway conduction (one patient, 4 percent) and ventricular tachycardia (one patient, 4 percent).In this study the clinical electrophysiologic diagnostic features of several arrhythmias which cause tachycardias with a wide QRS compex suggesting ventricular preexcitation are outlined. It is apparent that definitive arrhythmia diagnosis during these tachycardias is often complex and usually requires careful study using intracardiac electrode catheter techniques.     

Flutrer-like P waves in a case of atrioventricular reciprocating tachycardia

Typical atrial flutter is characterized by its sawtooth flutter wave in leads II, III, aVF, and V1. Atrioventricular reciprocating tachycardia is characterized by its small retrograde P wave after completion of QRS complex, where sawtooth flutter-like P waves are rarely seen in the electrocardiogram during atrioventricular reciprocating tachycardia. We report on a 62-year-old patient who presented the characteristic sawtooth flutter-like P waves in the electrocardiogram during attack of supraventricular tachycardia. By electrophysiologic study, the mechanism of his supraventricular tachycardia was atrioventricular reciprocating tachycardia using the left posterior lateral concealed accessory pathway for retrograde conduction. The accessory pathway was successfully ablated by radiofrequency ablation therapy.     

A transcardiac lead system for identification and termination of supraventricular and ventricular tachycardia

The value of a transcardiac lead system (coronary sinus to right ventricular apex) to record atrial and ventricular electrical activity and its pacing capabilities was assessed in 20 patients with a variety of tachycardias (atrial tachycardia in 3 patients, atrial flutter in 4, intranodal tachycardia in 6, circus movement tachycardia using an accessory pathway in 1 patient, and ventricular tachycardia in 9). The transcardiac lead invariably showed both atrial and ventricular electrical activity during sinus rhythm and tachycardias, allowing application of the same criteria as used when analyzing cardiac rhythm on the surface electrocardiogram. Atrial complexes had a mean amplitude of 4.2 mV during sinus rhythm and varied from 3.0 to 4.1 mV during the different types of tachycardia. Ventricular complexes had a mean amplitude of 9.8 mV during sinus rhythm, 13.8 mV during supraventricular tachycardia and 16.1 mV during ventricular tachycardia. The duration of the QRS complex on the transcardiac lead was equal to the duration of the QRS complex on the surface electrocardiogram during tachycardias with a small or wide QRS complex. By varying the intensity of current delivered through the transcardiac lead, only right ventricular pacing (mean current intensity 1.2 +/- 0.4 mA) or simultaneous atrioventricular pacing (mean current intensity 4.7 +/- 3.3 mA) could be achieved. Termination of all episodes of tachycardia was achieved with either ventricular pacing or simultaneous atrioventricular pacing. This transcardiac lead system allows clear identification of atrial and ventricular events, is suitable for tachycardia analysis using simple surface electrocardiographic algorithms and allows pacing termination of a variety of tachycardias.     

射频消融治疗具有快频率依赖性室房逆传特性的旁道

目的报道具有快频率依赖性室房逆传特性的房室旁道电生理检查及射频消融结果。方法4例患者,均有阵发性心悸史,且发作时心电图均显示为窄QRS波心动过速,按常规方法接受心脏电生理检查及射频消融治疗。结果4例均证实存在旁道的快频率依赖性室房逆传,且均诱发了房室折返性心动过速,室房逆传最早激动部位均为左房。于快频率心室刺激下标测消融靶点,消融均获成功。结论旁道的快频率依赖性传导为一种少见电生理现象,可伴发房室折返性心动过速。     

Wide QRS complex tachycardia in patients with Chagas’ disease: Sustained ventricular tachycardia until proven otherwise

Algorithms used for the differential diagnosis of wide QRS complex tachycardia are extremely important in clinical practice, but they have limitations and should be applied with caution. We describe a case of a patient with positive serology for Chagas disease and normal echocardiogram who presented an episode of wide QRS complex tachycardia. It was initially diagnosed as sustained ventricular tachycardia using the Brugada and Vereckei algorithms and it was sent to the reference service for the implant of a cardioverter defibrillator. However, the clinical history, electrocardiogram in sinus rhythm and the electrophysiological study were fundamental to the correct diagnosis and treatment of a posterolateral atrioventricular accessory pathway.     

Reciprocal tachycardias using accessory pathways with long conduction times.

Three patients with reentrant tachycardia are described who had an accessory pathway with a very long conduction time that was incorporated in the tachycardia circuit. The accessory pathway was able to conduct in one direction only, in retrograde manner in two patients and in anteriograde manner in the remaining patient. Evidence is presented that reveals that in the first two patients the accessory pathway was septally located, had completely bypassed the normal atrioventricular (A-V) conduction system, had properties of decremental conduction, and had an atrial exit close to the coronary sinus and a ventricular exit relatively far from the atrioventricular A-V ring. In the third patient, who manifested wide QRS complex during tachycardia, the ventricular end of the accessory pathway seemed to be located close to the right ventricular apex. The atrial end of the pathway could not be localized exactly.     

Wide complex irregularly regular tachycardia with QRS alternation

A 44-year-old white man was referred to our service because of a history of symptomatic rapid palpitations that had begun on January 2007. He had no previous history of syncope or family history of sudden cardiac death. The patient was otherwise well and had not been taking any medications. The electrocardiogram (ECG) recorded during sinus rhythm was within normal limits. A 12-lead ECG was performed during the last episode on July 2007 while he was working at his office. An irregular wide complex tachycardia with varying QRS morphology (left bundle-branch block with an alternating pattern) was documented.The differential diagnoses based on the 12-lead electrocardiogram (ECG) were supraventricular tachycardia with aberrant conduction and QRS alternans, atrial tachycardia with anterograde conduction over an accessory pathway, or ventricular tachycardia. An electrophysiology study was performed and the results are discussed.     

Ventricular tachycardia masquerading as supraventricular tachycardia: A wolf in sheep''s clothing

It is generally assumed that if a wide QRS complex tachycardia has the same morphology on the 12-lead electrocardiogram as during sinus rhythm, the tachycardia is supraventricular. The author presents unique electrocardiographic data on four patients with QRS complex morphologies that are nearly identical during ventricular tachycardia and during sinus rhythm. The QRS complex duration during sinus rhythm was 140-180 msec and was the same as that of the tachycardia. The QRS complex morphology on the electrocardiogram was a right bundle branch block, left axis in three patients and right bundle branch block, normal axis in one patient. The mean ventricular tachycardia cycle length was 345 msec. The diagnosis of ventricular tachycardia was established by electrophysiologic testing in two patients and by atrial electrograms demonstrating AV dissociation in two patients. Thus, if the 12-lead electrocardiogram morphology of a wide QRS complex tachycardia is similar to that during sinus rhythm, it does not necessarily imply that the tachycardia is supraventricular. Ventricular tachycardia can occur with the same QRS complex morphology as occurs during sinus rhythm.     

Atrioventricular dissociation detected by suprasternal M-mode echocardiography: a clue to the diagnosis of ventricular tachycardia

Twenty-two patients were studied by suprasternal M-mode echocardiography during ventricular tachycardia (VT). Adequate echocardiograms were obtained from 19 patients. Thirteen patients showed atrioventricular (AV) dissociation and 6 patients a ventriculoatrial contraction pattern according to the left atrial (LA) contraction obtained from the suprasternal notch. In 1 of these 6 patients, a 2:1 block retrograde was found by echocardiography. In another patient, an intermittent block occurred in the retrograde direction. In 4 patients, a constant relation between the QRS complex and LA contraction soon after the beginning of the QRS complex was seen, demonstrating a 1:1 ventriculoatrial conduction. According to the LA contraction obtained from the suprasternal echocardiogram, 13 patients showed AV dissociation and 6 patients a retrograde conduction to the LA. From the analysis of the 12-lead standard electrocardiogram obtained simultaneously during VT, AV dissociation could be recognized in only 3 patients. Thus, AV dissociation during VT is more easily diagnosed with suprasternal M-mode echocardiography than with the standard electrocardiogram.     

Electrocardiographic differentiation of typical atrioventricular node reentrant tachycardia from atrioventricular reciprocating tachycardia mediated by concealed accessory pathway in children

The value of the electrocardiogram (ECG) in children with supraventricular tachycardia (SVT) is unclear. The noninvasive differentiation of typical atrioventricular node reentrant tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT) mediated by concealed accessory pathway conduction is clinically important, as it helps in counseling and potentially facilitates ablation procedures. One hundred forty-eight ECGs showing narrow QRS complex SVT were obtained from children before successful radiofrequency catheter ablation. An initial 102 ECGs were analyzed by 3 blinded observers to assess the utility of various electrocardiographic findings. No electrocardiographic criteria were found to discriminate between SVT mechanisms on 1- to 3-channel Holter/event recorder tracings (n = 32); their interpretation mainly (55%) resulted in an incorrect SVT diagnosis. On 12-lead ECGs (n = 70), the 2 arrhythmias were accurately diagnosed in 76% of patients; 5 findings were found to be discriminators of tachycardia mechanism. Predictors of AVRT were visible P waves in 74% of cases (sensitivity 92%; specificity 64%), RP intervals of > or =100 ms in 91% (sensitivity 84%; specificity 91%), and ST-segment depression of > or =2 mm in 73% of cases (sensitivity 52%; specificity 82%). Pseudo r' waves in lead V(1) and pseudo S waves in the inferior leads during tachycardia predicted AVNRT in 100% of cases (sensitivity 55% and 20%, respectively; specificity 100% for both). Based on these results, we developed a new diagnostic 12-lead electrocardiographic algorithm for pseudo r'/S waves, RP duration, and ST-segment depression during tachycardia. Two observers tested the algorithm in 46 (21 AVNRT; 25 AVRT) additional cases; they correctly diagnosed the SVT mechanism in 91% and 87%, respectively. Thus, the stepwise use of diagnostically relevant 12-lead electrocardiographic parameters helps to more accurately differentiate mechanisms of reentrant SVT.     

Spontaneous automaticity of an atriofascicular accessory pathway.

In a 12-year-old girl with history of recurrent palpitation, an ambulatory 24 h Holter electrocardiogram showed a wide QRS complex rhythm with atrioventricular dissociation. During an electrophysiology study, an atriofascicular pathway was diagnosed with an inducible antidromic atrioventricular re-entrant tachycardia. At slower heart rates, the patient had a wide QRS complex escape rhythm similar to the tachycardia and the pre-excited QRS complex morphology. This indicates the presence of pacemaker-like cells in the atriofascicular accessory pathway giving rise to the wide QRS complex escape rhythm at a slower heart rate.     

Clinical,electrocardiographic and electrophysiologic observations in patients with paroxysmal supraventricular tachycardia

Seventy-nine patients without ventricular preexcitation but with documented paroxysmal supraventricular tachycardia were analyzed. Electrophysiologic studies suggested atrioventricular (A-V) nodal reentrance in 50 patients, reentrance utilizing a concealed extranodal pathway in 9, sinus or atrial reentrance in 7 and ectopic automatic tachycardia in 3. A definite mechanism of tachycardia could not be defined In 10 patients (including 7 whose tachycardia was not inducible). The three largest groups with inducible tachycardias were compared in regard to age, presence of organic heart disease, rate of tachycardia, functional bundle branch block during tachycardia and relation of the P wave and QRS complex during tachycardia. A-V nodal reentrance was characterized by a narrow QRS complex and a P wave occurring simultaneously with the QRS complex during tachycardia. Reentrance utilizing a concealed extranodal pathway was characterized by young age, absence of organic heart disease, fast heart rate, presence of bundle branch block during tachycardia and a P wave following the QRS complex during tachycardia. Sinoatrial reentrance was characterized by frequent organic heart disease, a narrow QRS complex and a P wave in front of the QRS complex during tachycardia.In conclusion, a mechanism of paroxysmal supraventricular tachycardia could be defined in most patients. Observations of clinical and electrocardiographic features in these patients should allow prediction of the mechanism of the tachycardia.