Wide QRS Tachycardia Research Articles

Conversion from Irregular to Regular Wide QRS Tachycardia: What Is the Mechanism?

Journal of Cardiovascular ElectrophysiologyVolume 25, Issue 5 p. 553-555 Arrhythmia Rounds Conversion from Irregular to Regular Wide QRS Tachycardia: What Is the Mechanism? TOMOFUMI NAKAMURA M.D., Corresponding Author TOMOFUMI NAKAMURA M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanAddress for correspondence: Tomofumi Nakamura, M.D., Department of Cardiology, Yokohama Minami Kyosai Hospital, 1-21-1 Mutsuura-higashi, Kanazawa-ku, Yokohama, Kanagawa, Japan. Fax: +81-45-701-9159; E-mail: tomonakamura-tmd@umin.ac.jpSearch for more papers by this authorMITSUHIRO NISHIZAKI M.D., MITSUHIRO NISHIZAKI M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorMASATO SHIMIZU M.D., MASATO SHIMIZU M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorHIROYUKI FUJII M.D., HIROYUKI FUJII M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorNORIYOSHI YAMAWAKE M.D., NORIYOSHI YAMAWAKE M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorHARUMIZU SAKURADA M.D., HARUMIZU SAKURADA M.D. Tokyo Metropolitan Health and Medical Treatment Corporation Ookubo Hospital, Tokyo, JapanSearch for more papers by this authorMASAYASU HIRAOKA M.D., MASAYASU HIRAOKA M.D. Tokyo Medical and Dental University, Tokyo, JapanSearch for more papers by this author TOMOFUMI NAKAMURA M.D., Corresponding Author TOMOFUMI NAKAMURA M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanAddress for correspondence: Tomofumi Nakamura, M.D., Department of Cardiology, Yokohama Minami Kyosai Hospital, 1-21-1 Mutsuura-higashi, Kanazawa-ku, Yokohama, Kanagawa, Japan. Fax: +81-45-701-9159; E-mail: tomonakamura-tmd@umin.ac.jpSearch for more papers by this authorMITSUHIRO NISHIZAKI M.D., MITSUHIRO NISHIZAKI M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorMASATO SHIMIZU M.D., MASATO SHIMIZU M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorHIROYUKI FUJII M.D., HIROYUKI FUJII M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorNORIYOSHI YAMAWAKE M.D., NORIYOSHI YAMAWAKE M.D. Department of Cardiology, Yokohama Minami Kyosai Hospital, Kanagwa, JapanSearch for more papers by this authorHARUMIZU SAKURADA M.D., HARUMIZU SAKURADA M.D. Tokyo Metropolitan Health and Medical Treatment Corporation Ookubo Hospital, Tokyo, JapanSearch for more papers by this authorMASAYASU HIRAOKA M.D., MASAYASU HIRAOKA M.D. Tokyo Medical and Dental University, Tokyo, JapanSearch for more papers by this author First published: 27 November 2013 https://doi.org/10.1111/jce.12334Citations: 1 No disclosures. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume25, Issue5May 2014Pages 553-555 RelatedInformation

Fetal arrhythmias associated with cardiac rhabdomyomas

Primary heart tumors in fetuses are rare and mainly represent rhabdomyomas. The tumors have a variable expression and can be associated with arrhythmias, including both wide and narrow QRS tachycardia. Although multiple Doppler techniques exist to assess fetal heart rhythm, it can be difficult to record precise electrophysiological abnormalities in fetal life. Investigations defining precise electrophysiological diagnosis were performed by using fetal magnetocardiography (fMCG). In addition to routine fetal echocardiography, fMCG was used to investigate electrophysiological rhythm patterns in a series of 10 fetuses with cardiac rhabdomyomas. The mean gestational age of the fetuses was 28.6 ± 4.7 weeks. The multiple rhabdomyomas were mainly located in the right and left ventricles as well as around the atrioventricular groove. Arrhythmias or conduction abnormalities were diagnosed in all 10 patients, although only 6 of them were referred due to that indication. Remarkably, 80% (8 of 10) had associated Wolff-Parkinson-White pre-excitation. In addition, we found prominent P waves in 4 fetuses. In fetuses with rhabdomyomas, a disease where rhythm pathology is common, precise electrophysiological diagnosis can now be made by fMCG. fMCG is complimentary to echocardiography for rhythm assessment and can detect conduction abnormalities that are not possible to diagnose prenatally with M-mode or pulsed Doppler ultrasound. Risk factor assessment using fMCG can support pregnancy management and postnatal treatment and follow-up.

Bundle Branch Reentrant Ventricular Tachycardia With Wide and Narrow QRS Morphology

Bundle branch reentrant ventricular tachycardia (BBR-VT) is generally recognized as VT with wide QRS complexes that includes the His-Purkinje system and ventricle in its circuit. BBR-VT is well known to be commonly associated with structural heart diseases and left ventricular dysfunction.1 We report a rare case of BBR-VT displaying wide and narrow type QRS complexes in a patient without obvious structural heart disease or overt ventricular conduction disturbance. Editor’s Perspective see p e92 A 39-year-old man with episodes of wide QRS tachycardia was referred to our institution for electrophysiological study and catheter ablation. ECG during his clinical tachycardia showed left axis deviation and left bundle branch block (LBBB)–type morphology. Baseline 12-lead ECG showed sinus rhythm with no remarkable abnormalities, except for slight right axis deviation (Figure 1A). Transthoracic echocardiography was also normal, with normal values for left ventricular size (diastolic diameter, 46 mm) and systolic function (ejection fraction, 62%). There was nothing suggestive in the patient’s medical history, such as syncope, nor was there any family history of sudden cardiac death. Figure 1. Twelve-lead ECG of sinus rhythm and ventricular tachycardia (VT). A , Sinus rhythm showed slight right axis deviation. B , VT1 showed left bundle branch block pattern. C , VT2 had narrow QRS complexes and similar morphology to that of sinus rhythm. D , VT3 with right bundle branch block morphology was observed after spontaneous conversion from VT2. Diagnostic electrophysiological study demonstrated a normal A-H interval of 78 ms and an H-V interval of 48 ms during sinus rhythm. Programmed ventricular stimulation with single extrastimulus delivered from right ventricular apex revealed decremental ventriculoatrial conduction as S1S2 interval shortened, and V3 phenomenon was observed by an S1S2 interval of 280 ms.2 Sustained LBBB forms wide QRS tachycardia with QRS width of 144 ms and cycle length of 270 …

Atrial Flutter or Fibrillation is the Most Frequent and Life‐Threatening Arrhythmia in Myotonic Dystrophy

Several arrhythmias were reported in myotonic dystrophy (MD). To evaluate the prevalence of atrial fibrillation (AF) and atrial flutter (AFL) in MD and the clinical consequences. One hundred sixty-one patients, mean age 41 ± 14 years, were referred for a type 1 MD. All patients were asymptomatic except four patients and followed during 5 ± 4 years. Electrocardiogram (ECG), echocardiography assessing left ventricular ejection fraction, and Holter monitoring were obtained and repeated. Twenty-seven patients (17%) presented sustained (>1 hour) AF (n = 15) or AFL (n = 12); two of them presented syncope-related 1/1 AFL. In one of them, 16 years of age, cardiac defibrillator was implanted for a diagnosis of ventricular tachycardia, but the true diagnosis was established after inappropriate shocks. AFL ablation was performed in five patients, but four developed AF. The other seven patients with AFL developed AF. During the follow-up, 22 patients died (14%) from cardiac and respiratory failure; eight patients with AF/AFL died (30%) while only 14 without AF/AFL died (10%; P < 0.01). Univariate analysis indicated that age >40 years (death: 48 ± 14 vs 40 ± 8 in alive patients), abnormal ECG, and occurrence of AF/AFL were significant factors of death. At multivariate analysis, AF at ECG (odds ratio: 3.12) and age >40 (odds ratio: 3.14) were the sole independent variables predicting death. AF and AFL were frequent in MD and increased mortality. AFL could present as 1/1 AFL with a poor tolerance and a risk of misdiagnosis despite frequent conduction disturbances. This arrhythmia could explain wide QRS tachycardia occurring in MD and interpreted as VT.

Protocolo diagnóstico de las taquicardias de QRS ancho

Ventricular tachycardia is the commonest underlying mechanism for wide QRS tachycardia, representing between 80% to even 95% of patients with ischemic heart disease. Accurate differentiation of ventricular tachycardia from supraventricular tachycardia with aberrant conduction or preexcitation syndromes and pacemaker mediated supraventricular tachycardias, holds important implications in terms of prognosis and dysrhythmia management. Haemodynamic tolerance should not be considered diagnostic criterion. Careful study of the electrocardiogram during sinus rhythm and tachycardia provides diagnostic clue. Different diagnostic algorithms have been published, but their use is complicated and may lead to misdiagnosis. We believe it is essential to understand the criteria for the development of diagnostic algorithms rather than merely its application. When in doubt, common sense should prevail and ventricular tachycardia should be considered the default diagnosis in wide-QRS-complex tachycardias

Rapid palpitations: three of a kind?

The first part of the ECG shows a wide QRS tachycardia with a right bundle branch block (RBBB) morphology, an inferior axis and a heart rate of 240 bpm (tachycardia cycle length (TCL) of 250 ms). The middle part shows a narrow QRS tachycardia with an intermediate axis and the same heart rate of 240 bpm (TCL 250 ms). In the last part a wide QRS tachycardia is observed, although with a different, left bundle branch block (LBBB) morphology and horizontal axis. The heart rate decreased slightly to 195 bpm (TCL 310 ms). In the middle part, during tachycardia with a narrow QRS complex, a P wave can be suspected on top of the T wave with an RP interval longer than the PR. Especially leads aVR, lead I and the inferior leads permit the visualisation of the P waves. The morphology of the P wave is difficult to see, but a negative polarity in the inferior leads and positive polarity in aVR suggest the presence of a retrograde P wave. The differential diagnosis will be: orthodromic atrioventricular reentrant tachycardia (AVRT), atypical or fast-slow atrioventricular nodal reentrant tachycardia (AVNRT), or atrial tachycardia (AT). The pattern of QRS alternans during the narrow QRS tachycardia points towards the direction of an AVRT, although it does not rule out AT or AVNRT. The clue to the diagnosis is the change in QRS morphology during the ongoing tachycardia. During tachycardia with RBBB morphology, the same TCL as during the narrow QRS tachycardia is seen (250 ms). In contrast, changing to LBBB the tachycardia slows down with a TCL of 310 ms. In case of an AVNRT or AT the ventricles are not part of the reentrant circuit, so a conduction block in either of the bundle branches would not influence the heart rate. The fact that the heart rate slows during LBBB means that the slowed conduction towards the left ventricle influences the cycle length and proves that the ventricle is part of the circuit and an orthodromic AVRT using a left-sided accessory pathway (AP) is proven. The fact that during RBBB the heart rate remains unchanged confirms the diagnosis of the left-sided AP (Fig. 2). During the electrophysiology study the AP was located lateral on the mitral annulus and was successfully ablated. Afterwards no tachycardia could be induced. Fig. 2 a. AV conduction with RBBB does not influence the conduction time to the retrograde conducting AP. b. AV conduction without bundle blanch block. c. During LBBB the conduction time over the ventricle is longer because of the delayed right to left conduction ...

Rapid palpitations: three of a kind?

The first part of the ECG shows a wide QRS tachycardia with a right bundle branch block (RBBB) morphology, an inferior axis and a heart rate of 240 bpm (tachycardia cycle length (TCL) of 250 ms). The middle part shows a narrow QRS tachycardia with an intermediate axis and the same heart rate of 240 bpm (TCL 250 ms). In the last part a wide QRS tachycardia is observed, although with a different, left bundle branch block (LBBB) morphology and horizontal axis. The heart rate decreased slightly to 195 bpm (TCL 310 ms). In the middle part, during tachycardia with a narrow QRS complex, a P wave can be suspected on top of the T wave with an RP interval longer than the PR. Especially leads aVR, lead I and the inferior leads permit the visualisation of the P waves. The morphology of the P wave is difficult to see, but a negative polarity in the inferior leads and positive polarity in aVR suggest the presence of a retrograde P wave. The differential diagnosis will be: orthodromic atrioventricular reentrant tachycardia (AVRT), atypical or fast-slow atrioventricular nodal reentrant tachycardia (AVNRT), or atrial tachycardia (AT). The pattern of QRS alternans during the narrow QRS tachycardia points towards the direction of an AVRT, although it does not rule out AT or AVNRT. The clue to the diagnosis is the change in QRS morphology during the ongoing tachycardia. During tachycardia with RBBB morphology, the same TCL as during the narrow QRS tachycardia is seen (250 ms). In contrast, changing to LBBB the tachycardia slows down with a TCL of 310 ms. In case of an AVNRT or AT the ventricles are not part of the reentrant circuit, so a conduction block in either of the bundle branches would not influence the heart rate. The fact that the heart rate slows during LBBB means that the slowed conduction towards the left ventricle influences the cycle length and proves that the ventricle is part of the circuit and an orthodromic AVRT using a left-sided accessory pathway (AP) is proven. The fact that during RBBB the heart rate remains unchanged confirms the diagnosis of the left-sided AP (Fig. 2). During the electrophysiology study the AP was located lateral on the mitral annulus and was successfully ablated. Afterwards no tachycardia could be induced. Fig. 2 a. AV conduction with RBBB does not influence the conduction time to the retrograde conducting AP. b. AV conduction without bundle blanch block. c. During LBBB the conduction time over the ventricle is longer because of the delayed right to left conduction ...

Spontaneous Transition of Wide QRS Tachycardia: What Is the Mechanism?

Spontaneous Transition of Wide QRS Tachycardia: What Is the Mechanism?

Cardiomyopathy induced by incessant fascicular ventricular tachycardia

A 12-year-old girl with symptoms of fatigue, decreased exercise tolerance and progressive dyspnea (New York Heart Association functional class III) with a possible diagnosis of dilated cardiomyopathy secondary to viral myocarditis. Because of incessant wide QRS tachycardia refractory to antiarrhythmic drugs, she was referred for electrophysiological study. The diagnosis was idiopathic left ventricular tachycardia involving the posterior fascicle of the left bundle branch. After successful treatment with radiofrequency catheter ablation guided by a Purkinje potential radiological and echocardiographic evaluation showed complete reversal of left ventricular function in the first 3 months and no recurrence of arrhythmia during 2 years of follow up.

Taquicardias de complejo QRS ancho precedidas de espiga de marcapasos

The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral.

Myocardial delayed enhancement by magnetic resonance imaging in a patient with Duchenne muscular dystrophy and ventricular tachycardia

Received 17 December 2012; revision accepted for publication 27 February 2013. Cardiomyopathy is a significant component in Duchenne muscular dystrophy (DMD), and it is not necessarily related to the degree of skeletal myopathy. Cardiac death can result from progressive heart failure, due to ventricular dysfunction, or from sudden death, presumably caused by heart block or malignant arrhythmias. Although electrical abnormalities may occur in the absence of overt cardiac histopathology, electrical and functional abnormalities have been attributed to cardiac fibrosis1. As a representative example of this, we present the cardiovascular magnetic resonance (CMR) finding in a 19-year-old patient with DMD. Myocardial delayed enhancement showed multifocal fibrosis in the septal and lateral wall of the mid left ventricle. This patient had presented several syncopes and spells, with electrocardiographic documentation of repetitive episodes of ventricular tachycardia (VT). The ECG shows a monomorphic wide QRS tachycardia (240 bpm), with RBBB morphology, inferior axis and QS complex in lead I and aVL, suggestive of a basal lateral LV exit site, with, possibly, epicardial origin, compatible with the CMR findings mentioned above. Baseline ECG was representative of cardiac involvement, showing a short PR interval, R/S ratio > 1 in lead V1 V2 and Q waves in the lateral leads2. Myocardial delayed enhancement by magnetic resonance imaging in a patient with Duchenne muscular dystrophy and ventricular tachycardia

“Classical” Response in a Pre-excited Tachycardia

A 24-year-old patient presented with history of recurrent palpitation and was diagnosed as wide QRS tachycardia which was cardioverted. The sinus rhythm ECG and the tachycardia ECG are shown in Figure 1. During the electrophysiological study, 2 morphologies of tachycardia were inducible, 1 with right bundle branch block (RBBB) morphology (Figure 2A) and another with left bundle branch block (LBBB) morphology (Figure 2B), which was her clinical tachycardia. The LBBB type wide QRS tachycardia was faster (Figure 2B). During the RBBB morphology tachycardia, ventricular entrainment showed a V–A–V response and a His refractory ventricular extrastimulation advanced the retrograde atrial activation, resetting the tachycardia. Figure 1. Twelve-lead electrocardiograms of the patient in sinus rhythm ( A ) and during clinical tachycardia ( B ). Figure 2. Surface leads I, III, and V1 and intracardiac electrograms from right atrium (HALO 1, 2 at lateral right atrium to HALO 17, 18), His bundle (His bundle distal [HBED] and His bundle middle [HBEm]), the coronary sinus (coronary sinus distal [CSD] and coronary sinus proximal [CSP]) and right ventricular apex (RVA). A , The orthodromic tachycardia with right bundle branch block aberrancy. B , The left bundle branch block tachycardia of shorter cycle length and long ventricular–His of 80 ms with the same retrograde eccentric atrial activation as in the initial tachycardia. The LBBB morphology tachycardia showed variation in cycle length with a constant Ventriculo–Atrial (VA) interval. Atrial entrainment did not change the QRS morphology or VA relationship. An early premature atrial extrastimulation from the lateral right atrium showed an interesting finding (Figure 3). Very late atrial extrastimulus from the same location did not advance the V without affecting the septal A. What are the mechanisms of the two tachycardia? Figure 3. Surface leads I, III, and V1 and intracardiac electrograms from right atrium (HALO 1, 2 at lateral right atrium to HALO …

Answer to ECG Quiz no. 31

Regular, wide QRS tachycardia is usually VT, even in young people. QRS morphology is the key to differentiating VT from SVT with bundle branch block. P-waves may help to distinguish VT from pre-excited tachycardias. VT from the right ventricle (pseudo LBBB morphology) requires investigation for ARVC.

Atrial Fibrillation With Wide QRS Tachycardia and Undiagnosed Wolff-Parkinson-White Syndrome

A 10-year-old girl presented to the emergency department of a regional hospital with 1 episode of generalized tonic-clonic seizures. Postictal monitoring followed by a 12-lead electrocardiogram showed fast atrial fibrillation with intermittent wide QRS regular tachycardia. Immediately following this, her rhythm changed to wide QRS irregular tachycardia without hemodynamic compromise. She was suspected to have ventricular tachycardia and was treated with intravenous amiodarone with cardioversion to sinus rhythm. Subsequent electrocardiogram in sinus rhythm showed typical features of manifest Wolff-Parkinson-White (WPW) accessory pathway. This case illustrates the diagnostic and therapeutic dilemmas in patients with atrial fibrillation, wide QRS tachycardia, and undiagnosed WPW syndrome with antidromic conduction of atrial arrhythmias through the accessory pathway. Furthermore, this case demonstrates that undiagnosed wide QRS tachycardias need to be treated with drugs acting on the accessory pathway, thus keeping in mind underlying WPW syndrome as a possibility to avoid potentially catastrophic events.

Index of Suspicion

A previously healthy 18-year-old boy presents for the evaluation of palpitations and lightheadedness, which started after he drove home after finishing his regular work shift. His symptoms were relieved partially by vomiting but then reappeared and worsened progressively, leading to diaphoresis and dizziness, after which he has been brought to an ED. There is no history of fever, diarrhea, intake of coffee or caffeinated beverages, or use of illicit drugs. On arrival, his temperature is 37°C; heart rate, 180 beats per minute; respiratory rate, 22 breaths per minute; blood pressure, 100/50 mm Hg; and oxygen saturation, 99% in room air. His weight is 99 kg (>95th percentile), height 184 cm (75–90th percentile), and BMI, 29.2. He is uncomfortable due to the palpitations, but he is able to follow commands. His cardiac examination reveals tachycardia, regular rhythm, normal first and second heart sounds, no murmurs, and equal peripheral pulses. His breath sounds are clear bilaterally. There are no signs of injury or trauma. Family history is negative for any sudden cardiac deaths, arrhythmias, or structural heart disease. Laboratory evaluation reveals normal electrolyte levels, thyroid function tests, urine toxicology testing, and cardiac enzyme levels. His ECG reveals a left axis deviation (−84°), wide QRS tachycardia at 180 per minute, and right bundle branch block (Fig 1). With amiodarone infusion, he converts to a sinus rhythm. He is admitted to the intensive care unit, a specialist is consulted, and the diagnosis is established. Figure 1. Electrocardiogram reveals a left axis deviation (−84°), wide QRS tachycardia at 180 per minute, and right bundle branch block. A 4-year-old girl presents with worsening pain, swelling, and limited movement of the right elbow for 6 days and fever of 38.9°C for 1 day. No trauma or other joint abnormalities are reported. Her mother reports “pink eye” that began 2 …

711 Identification of Atrio-Ventricular Relationship With Echocardiography - A Useful Tool to Diagnose Tachycardia Mechanism

BackgroundEchocardiography can provide direct visualization of atrial and ventricular contraction and their timing. This should be especially useful in diagnosis of tachycardia of unknown mechanism when P waves are not readily apparent. Using paced rhythm as a surrogate for wide QRS tachycardia , we investigated whether echocardiography can identify atrio-ventricular (AV) dissociation in patients with implanted pacemakers.MethodsStandard echocardiography was performed during rapid ventricular pacing (100-120 bpm) to mimic ventricular tachycardia in 14 patients with pacemakers and no retrograde VA conduction. Three methods were tested: 1) pulse-wave Doppler in the superior / inferior vena cava (PW-VC) in the subcostal view, 2) M-mode over the right atrium (MM-RA) in the subcostal view, and 3) tissue Doppler over the left / right atrial wall (TDI-A) in the apical four chamber view. The diagnosis of AV dissociation with each method was confirmed by 2 independent, blinded investigators.ResultsAV dissociation was identified by echocardiography in at least one of the three methods in 11/14 patients (79%) (Figure). PW-VC and MM-RA correctly identified AV dissociation in the same 11/14 patients (79%). TDI-A was not useful identifying AV dissociation. There was 100% interobserver agreement of the echocardiographic data, Kappa statistic = 1.ConclusionThese preliminary data suggest that echocardiography can identify AV dissociation in a subset of patients with tachycardia of unknown mechanism. PW-VC and MM-RA appear to be the most useful in identifying AV dissociation. This technique may be especially relevant due to the expanding availability of portable echocardiography in practice. BackgroundEchocardiography can provide direct visualization of atrial and ventricular contraction and their timing. This should be especially useful in diagnosis of tachycardia of unknown mechanism when P waves are not readily apparent. Using paced rhythm as a surrogate for wide QRS tachycardia , we investigated whether echocardiography can identify atrio-ventricular (AV) dissociation in patients with implanted pacemakers. Echocardiography can provide direct visualization of atrial and ventricular contraction and their timing. This should be especially useful in diagnosis of tachycardia of unknown mechanism when P waves are not readily apparent. Using paced rhythm as a surrogate for wide QRS tachycardia , we investigated whether echocardiography can identify atrio-ventricular (AV) dissociation in patients with implanted pacemakers. MethodsStandard echocardiography was performed during rapid ventricular pacing (100-120 bpm) to mimic ventricular tachycardia in 14 patients with pacemakers and no retrograde VA conduction. Three methods were tested: 1) pulse-wave Doppler in the superior / inferior vena cava (PW-VC) in the subcostal view, 2) M-mode over the right atrium (MM-RA) in the subcostal view, and 3) tissue Doppler over the left / right atrial wall (TDI-A) in the apical four chamber view. The diagnosis of AV dissociation with each method was confirmed by 2 independent, blinded investigators. Standard echocardiography was performed during rapid ventricular pacing (100-120 bpm) to mimic ventricular tachycardia in 14 patients with pacemakers and no retrograde VA conduction. Three methods were tested: 1) pulse-wave Doppler in the superior / inferior vena cava (PW-VC) in the subcostal view, 2) M-mode over the right atrium (MM-RA) in the subcostal view, and 3) tissue Doppler over the left / right atrial wall (TDI-A) in the apical four chamber view. The diagnosis of AV dissociation with each method was confirmed by 2 independent, blinded investigators. ResultsAV dissociation was identified by echocardiography in at least one of the three methods in 11/14 patients (79%) (Figure). PW-VC and MM-RA correctly identified AV dissociation in the same 11/14 patients (79%). TDI-A was not useful identifying AV dissociation. There was 100% interobserver agreement of the echocardiographic data, Kappa statistic = 1. AV dissociation was identified by echocardiography in at least one of the three methods in 11/14 patients (79%) (Figure). PW-VC and MM-RA correctly identified AV dissociation in the same 11/14 patients (79%). TDI-A was not useful identifying AV dissociation. There was 100% interobserver agreement of the echocardiographic data, Kappa statistic = 1. ConclusionThese preliminary data suggest that echocardiography can identify AV dissociation in a subset of patients with tachycardia of unknown mechanism. PW-VC and MM-RA appear to be the most useful in identifying AV dissociation. This technique may be especially relevant due to the expanding availability of portable echocardiography in practice. These preliminary data suggest that echocardiography can identify AV dissociation in a subset of patients with tachycardia of unknown mechanism. PW-VC and MM-RA appear to be the most useful in identifying AV dissociation. This technique may be especially relevant due to the expanding availability of portable echocardiography in practice.

Wide-QRS tachycardia in a patient with left bundle branch block

Wide-QRS tachycardia in a patient with left bundle branch block

Diagnostic testing and the average absolute likelihood ratio: application to diagnosing wide QRS complex tachycardia and other ED diseases

The Bayesian approach to disease diagnosis in the emergency department is facilitated by the use of likelihood ratios (LRs) to evaluate diagnostic tests. The use of dichotomous, interval, and joint LRs for single and multiple tests is reviewed, and comparison is made to regression modeling.The clinical motivation for a single statistic to describe the average change in the odds of disease associated with the use of a particular test or series of tests is described. This new extension of the LR concept is termed the average absolute LR (AALR).Illustrative examples include the use of elevated electrocardiogram ST segment and troponin to diagnose acute myocardial infarction, and serum d-dimer and computed tomographic angiography to diagnose pulmonary embolism. Finally, a detailed example with original data demonstrating the use of the AALR to compare QRS duration, QRS axis, and the 2 tests combined to diagnose ventricular tachycardia in patients with stable sustained regular wide QRS tachycardia is provided. Application of both tests together to patients with wide QRS complex tachycardia changes the odds of ventricular tachycardia, on average, by a factor of 3.5 (95% confidence interval, 2.4-6.2). Challenges are described, and methods are provided to estimate the 95% confidence interval of the LR and AALR using bootstrapping techniques. The AALR is a test statistic that may be helpful for clinicians and researchers in evaluating and comparing diagnostic testing approaches.

Irregular wide QRS complex tachycardia without structural heart disease

A 64-year-old female presented to the emergency room with persistent dizziness that began early that morning. She had a 30-year history of palpitations and known electrocardiogram (ECG) abnormalities. Her pulse was irregular at 130–270 min 1 and blood pressure was 90/40 mmHg. There were no other abnormalities on physical examination. A chest X-ray was normal and without cardiomegaly. Echocardiography revealed normal left ventricular contraction without structural abnormalities. Blood chemistry evaluation, including electrolytes and cardiac enzymes, was within normal limits. Twelve-lead ECG showed irregular wide QRS tachycardia of various configurations (Fig. 1). How would you diagnose her tachycardia?

Ventricular tachycardia in a patient with double valve replacement and bilateral coronary artery fistulas

A young patient presented with hemodynamic instability due to wide QRS tachycardia occurring about 10 years after double valve replacement. Bilateral coronary artery fistulas draining into the pulmonary artery were documented by invasive coronary angiography as well as by computed tomography imaging. A calcified scar of the posterolateral left ventricle was considered to be the origin of the clinical ventricular tachycardia. Although additional pathological findings are rare in young patients with valvular heart disease, diagnostic imaging of the heart is mandatory prior to cardiac surgery.