Wide QRS Complex Tachycardia Research Articles

Wide QRS Complexes: Electrophysiologic Basis of a Common Electrocardiographic Diagnosis

Wide QRS Complexes. Wide QRS complex tachycardia is a commonly encountered arrhythmia and its appropriate diagnosis often poses a challenge to most physicians. The origin of a wide QRS complex is either supraventricular with abnormal ventricular activation or ventricular. This review addresses the main electrophysiologic mechanisms involved in the genesis of a wide QRS complex and its maintenance as a sustained arrhythmia. (J Cardiovasc Electrophysiol, Vol. 3, pp. 365–393, August 1992)

Comparison of a vectorcardiographically derived 12-lead electrocardiogram with the conventional electrocardiogram during wide QRS complex tachycardia, and its potential application for continuous bedside monitoring

Previous investigators published conflicting reports comparing a vectorcardiographically derived electrocardiogram (ECG D) with the conventional 12-lead one (ECG). Prior comparisons were obtained in adults during sinus rhythm, but never in patients with wide QRS complex tachycardia. The ECG D was evaluated during baseline rhythms in patients with varying cardiac diagnoses, and the diagnostic accuracy of the 2 methods was compared during 64 episodes of wide QRS complex tachycardia in 49 patients during cardiac electrophysiologic study. All leads of the 12-lead ECG D closely resembled the conventional ECG in baseline and tachycardia tracings, except leads V 3 and V 4. QRS voltages were less in the ECG D, resulting in an inability to detect left ventricular hypertrophy in one third of patients with that diagnosis. There was excellent agreement between the ECG D and ECG in diagnosing prior myocardial infarction (92%), ventricular preexcitation patterns (100%), bundle branch and fascicular blocks (100%), and axis deviation. The ECG D was equally as valuable as the ECG in the diagnosis of wide QRS complex tachycardia. There was perfect agreement between the 2 lead systems in application of the morphologic criteria differentiating supraventricular tachycardia with aberration from ventricular tachycardia in leads V 1, V 2 and V 6, and for criteria requiring axis determination and measurement of RS intervals in the precordial leads. The ECG D tracings contained less muscle artifact during body movements (e.g., after direct-current defibrillation). In conclusion, the ECG D's close correlation with the ECG, and its technical superiority and simple 5 torso-positioned electrode configuration make it worth pursuing as an option for continuous bedside monitoring.

Wide QRS complex tachycardia.

Electrocardiographic monitoring for dysrhythmias is a major responsibility of critical care nurses, and patients with wide QRS complex tachycardias present a challenge. Criteria for differentiating the impulse origin as ventricular or supraventricular are well documented: QRS duration, QRS morphology, QRS axis, and presence of atrioventricular dissociation. However, definitive diagnosis can only be made by invasive electrophysiologic studies. Knowledge of treatment protocols is important to prevent hemodynamic deterioration. Procainamide is effective for treating ventricular and supraventricular dysrhythmias and is the drug of choice unless certainty of impulse origin exists.

Bidirectional Bundle Branch Reentry Tachycardia Associated with Ebstein's Anomaly: Cured by Extensive Cryoablation of the Right Bundle Branch

A 30-year-old woman with Ebstein's anomaly presented with a sustained, wide QRS complex tachycardia exhibiting a left bundle branch block morphology. Serial electrophysiological studies revealed right and left bundle branch reentry tachycardias refractory to many conventional antiarrhythmic drugs. Radiofrequency and direct current catheter ablation of the right bundle branch failed to control the tachycardias. The patient subsequently underwent extensive endocardial cryoablation to the right bundle branch resulting in cure of her arrhythmia.

Hypothesis Testing as an Approach to the Analysis of Complex Tachycardias-an Illustrative Case of a Preexcitation Variant

The correct elucidation of the electrophysiological substrate and mechanism(s) responsible for a complex arrhythmia requires a systematic approach to the analysis of the electrophysiological data. One approach calls for the formulation of a set of hypotheses that could explain the data obtained during the study. The hypotheses are then tested for compatibility with phenomena observed and the one that agrees with the majority of the findings would represent the most tenable explanation. We present the case of a young girl with a wide QRS complex tachycardia and a history of ventricular preexcitation that illustrates this approach. The complexities were resolved only after intraoperative analysis and surgical ablation of a right-sided accessory pathway with decremental properties, and provides further insight into our understanding of the nodoventricular Mahaim fiber.

Value of electrocardiographic leads MCL1, MCL6and other selected leads in the diagnosis of wide QRS complex tachycardia

To compare the modified precordial leads MCL1and MCL6with the conventional precordial leads V1and V6and assess the diagnostic accuracy of selected leads for continuous bedside electrocardiographic (ECG) monitoring, 121 wide QRS complex tachycardias were recorded from 92 patients during cardiac electrophysiologic study. As ascertained from intracardiac recordings, 86 tachycardias were ventricular and 35 were supraventricular with aberrant conduction. Early or late peaking of the predominant QRS deflection in lead MCL6or V6proved valuable in diagnosing wide complex tachycardia. An interval of ≤ 50 ms from the onset of the QRS complex to the predominant peak (or nadir) indicated supraventricular tachycardia; an interval of ≥ 70 ms indicated ventricular tachycardia. The QRS complexes in leads MCL1and MCL6were comparable to those in leads V1and V6during sinus rhythm.Significant discrepancies in QRS configuration occurred between the modified and conventional precordial leads during ventricular tachycardia, especially between leads MCL1and V1; however, these differences did not affect diagnostic accuracy. A single MCL1, V1, MCL6or V6lead was equally valuable in the diagnosis of wide complex tachycardia and far superior to a single lead II. A combination of leads (MCL1+ MCL6), (V1+ V6), (V1+ I + aVF) or (V1+ V6+ I + aVF) was superior to a single lead or the routinely monitored lead V1+ II combination.

Bedside diagnosis of wide QRS complex tachycardia

Assistant Professor Department of Physiological Nursing University of California, San Francisco San Francisco, California

Supraventricular tachycardia

The various forms of supraventricular tachycardia can be differentiated by careful review of a patient's electrocardiogram. If reentrant tachycardia involves the atrioventricular node, intravenous adenosine (Adenocard) provides a rapid means of converting the tachycardia to sinus rhythm. Adverse effects of adenosine, though common, are mild and of brief duration. Wide QRS complex tachycardia of ventricular origin is usually not affected by the drug.

Value of MCL1MCL6and selected ECG leads in the diagnosis of wide QRS complex tachycardia

Value of MCL1MCL6and selected ECG leads in the diagnosis of wide QRS complex tachycardia

Intravenous adenosine triphosphate during wide QRS complex tachycardia: Safety, therapeutic efficacy, and diagnostic utility: Sharma AD, Klein GJ, Yee R Am J Med 88:337–343 Apr 1990

Intravenous adenosine triphosphate during wide QRS complex tachycardia: Safety, therapeutic efficacy, and diagnostic utility: Sharma AD, Klein GJ, Yee R Am J Med 88:337–343 Apr 1990

Adenosine: a new drug for acute termination of supraventricular tachycardia

Adenosine, recently released for the acute termination of supraventricular tachycardia, is potentially the drug of first choice for this indication. Its notable effects are transient slowing of the sinus rate and atrioventricular nodal block. Adverse effects are transient and clinically insignificant, primarily because of the ultra-short half-life of the drug. Preliminary investigations suggest that adenosine may also be useful in the differential diagnosis of wide QRS complex tachycardias.

Intravenous adenosine triphosphate during wide QRS complex tachycardia: Safety, therapeutic efficacy, and diagnostic utility

purpose: Inappropriate administration of intravenous verapamil to patients with wide QRS complex tachycardia due to ventricular tachycardia or atrial fibrillation with Wolff-Parkinson-White syndrome occurs frequently because of misdiagnosis, and may precipitate a cardiac arrest. We evaluated the safety and the diagnostic and therapeutic utility of adenosine triphosphate administered to a consecutive series of 34 patients during wide QRS complex tachycardia due to a variety of mechanisms. patients and methods: Patients who had a hemodynamically and electrically stable, monomorphic, wide (greater than 120 msec) QRS complex tachycardia induced during an invasive cardiac electrophysiologic test were studied. Hemodynamic stability was defined by a systolic blood pressure greater than 80 mm Hg and no clinical evidence of cerebral or myocardial ischemia. Adenosine triphosphate, 20 mg, was administered as a rapid intravenous bolus via a peripheral vein during wide QRS complex tachycardia. Five surface electrocardiogram leads, at least three intracardiac electrograms, and blood pressure were monitored. results: Ventricular tachycardia was present in 14 patients (mean age 50.6 ± 19 years, cycle length 326 ± 67 msec) and adenosine triphosphate terminated the arrhythmia in one case. Ventricular tachycardia cycle length did not change. Among 10 patients with supraventricular tachycardia with mechanisms not involving the AV node (average ventricular cycle length 346 ± 82 msec), one case of ectopic atrial tachycardia was terminated. The ventricular rate was transiently increased in patients with Wolff-Parkinson-White syndrome and atrial fibrillation (average R-R interval 351 ± 84 msec in control and 317 ± 82 msec after adenosine triphosphate, p <0.001). Reentrant tachycardias involving the AV node (cycle length 302 ± 52 msec) terminated in seven of 10 patients. The drug was well tolerated, and no patient developed hemodynamic compromise necessitating cardioversion as a result of adenosine triphosphate.

Incessant Ventricular Tachycardia with a Right Bundle‐Branch Block Pattern and Left Axis Deviation Abolished by Catheter Manipulation

A 22-year-old man underwent electrophysiological evaluation for incessant wide QRS complex tachycardia with a pattern of right bundle-branch block and left axis deviation. The right and left ventricles were enlarged and hypokinetic consistent with dilated cardiomyopathy. Ventricular tachycardia was diagnosed by demonstrating capture and fusion beats, atrioventricular dissociation, and His potential activation that began after the onset of each QRS complex. Atrial extrastimuli and rapid atrial pacing failed to terminate the tachycardia and, although ventricular stimulation was successful, the tachycardia spontaneously restarted after one or two sinus beats. The tachycardia was unexpectedly abolished during catheter manipulation in the left ventricle and has not recurred during three-years of follow-up. The picture of a cardiomyopathy resolved. The ease with which the tachycardia was abolished by catheter manipulation implicate a therapeutic potential for catheter ablation of this type of tachycardia.

Wide QRS complex tachycardia: Reappraisal of a common clinical problem: Akhtar M, Shenasa M, Jazayeri M, et al Ann Intern Med 109; 905–912 Dec 1988

Wide QRS complex tachycardia: Reappraisal of a common clinical problem: Akhtar M, Shenasa M, Jazayeri M, et al Ann Intern Med 109; 905–912 Dec 1988

Lack of effectiveness of lidocaine for sustained, wide QRS complex tachycardia.

Records of 31 episodes of sustained, wide QRS complex tachycardia treated with IV boluses of lidocaine in 20 consecutive patients were reviewed. Most of the episodes were managed in the emergency department. Patient ages ranged from 18 to 91 years (mean +/- SD, 64 +/- 17), and 17 of 20 were men. All but three had coronary artery disease. Although 19 of 20 patients were admitted with a diagnosis of "rule out acute myocardial infarction," only two had this diagnosis confirmed. Seventeen patients had ventricular tachycardia, and three had wide QRS complex supraventricular tachycardia. Patients were given one to three boluses of lidocaine totaling 75 to 400 mg (127 +/- 64 mg). Termination of the tachycardia was temporally related to lidocaine administration in only six of 31 episodes (19%) occurring in five of 20 patients. In three of these five patients, lidocaine was given again for a recurrence of the tachycardia and was ineffective. A similarly low efficacy was seen in 20 episodes initially managed in the hospital compared with 11 episodes initially managed by paramedics. Thus, although lidocaine is widely considered the drug therapy of first choice for sustained wide QRS complex tachycardia, it was not usually effective in our study. Patients presenting to the ED with this rhythm disturbance rarely prove to have acute myocardial infarction. Although this small retrospective study should not be the basis for a change in standard medical practice, the recommendation of lidocaine as initial therapy for such patients should be reexamined.

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 electro-physiologic 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.

Analytic Reviews: Electrophysiologic Testing in the Intensive Care Unit

The role of electrophysiologic concepts and procedures in managing patients with potentially life-threatening ar rhythmias in the intensive care unit is discussed. These patients may be survivors of sudden cardiac arrest or myocardial infarction or may be admitted for syncope or sustained or nonsustained ventricular tachycardia. The value of electrophysiologic testing is discussed in terms of the distinction between wide QRS complex tachycardias that are supraventricular or ventricular in origin and those in which preexcitation syndromes may be important. Drug-induced ventricular arrhythmias are discussed, with specific emphasis on torsades de pointes. Finally, the use of His bundle recordings in pa tients with atrioventricular conduction disturbances is discussed. The methodology of electrophysiologic test ing, including stimulation protocols and interpretation of results, is described.

Computer detection of atrioventricular dissociation from surface electrocardiograms during wide QRS complex tachycardias.

Differentiation of wide QRS complex tachycardias on surface electrocardiograms is difficult for physicians and computers due in part to their inability to identify atrial activity, specifically atrioventricular (AV) dissociation. We studied 20 examples of AV associated rhythms and 17 examples of AV dissociated ventricular tachycardia. We applied an algorithm consisting of subtraction of a mean beat from each individual beat in leads II and V1 to generate remainder electrocardiograms. The remainder electrocardiograms were visually inspected for the presence of P wave candidates and then autocorrelated. AV dissociated P wave candidates were evident on visual inspection of remainder electrocardiograms in none of 20 AV associated and 15 of 17 AV dissociated rhythms. Atrial cycle length and the presence of AV dissociation were automatically detected by applying a peak selection algorithm to the autocorrelation function. AV association was detected in all 20 AV associated rhythms and AV dissociation was detected for 11 of 17 AV dissociated rhythms (sensitivity 65%, specificity 100%, positive and negative predictive accuracy 100%, 77%). The correlation coefficient of detected vs true atrial cycle length for the 11 correctly detected AV dissociated rhythms was r = .98. Visual inspection of the remainder electrocardiograms along with the original electrocardiogram may increase the ease with which human readers can identify the presence of AV dissociation and thus diagnose ventricular tachycardia. Computer diagnosis of wide QRS complex tachycardias should be significantly improved by use of this algorithm.

Electrical alternans in wide complex tachycardias

The occurrence of electrical alternation of 0.1 mV or greater of the QRS or T wave was analyzed in 156 electrocardiograms that showed wide QRS complex tachycardias from 91 patients. One hundred thirty-six ventricular tachycardias (VT) were recorded from 74 patients and 20 supraventricular tachycardias (SVT) from 17 patients. Alternans was present in 42 tracings (27%) from 35 patients (38%) and was equally frequent in the patients with VT (39%) and those with SVT (35%). Alternans occurred in 36 VTs (27%) and 6 SVTs (30%). Tachycardias with alternans had a shorter mean cycle length than tachycardians without alternans (339 ± 53 vs 368 ± 85 ms, p < 0.05), but were not associated with a particular QRS morphology or axis. Alternans was most frequent in leads V 2 and V 3 and was seen in more leads during SVT than VT (7.2 ± 2.6 vs 3.7 ± 2.5, p < 0.005). All SVTs with alternans incorporated an atrioventricular bypass tract. Electrical alternans occurs frequently in wide QRS tachycardias. Alone, it does not help differentiate VT from SVT. SVTs utilizing bypass tracts frequently show alternans even if the QRS is wide, and this finding may be useful in determining the mechanism of SVTs with aberrant intraventricular conduction.

Diagnostic potential for verapamil in wide QRS complex tachycardia

Differentiation of ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrancy or a preexisting bundle branch block is difficult, 1–4 particularly if 1:1 retrograde atrioventricular (AV) conduction is present. 4 We describe a previously unreported and potentially diagnostic effect of verapamil when administered in the management of a wide QRS complex tachycardia.