|Year : 2021 | Volume
| Issue : 2 | Page : 93-94
Case report: A regular wide QRS complex tachycardia with fusion beats?
State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
|Date of Submission||30-Oct-2021|
|Date of Decision||09-Nov-2021|
|Date of Acceptance||10-Nov-2021|
|Date of Web Publication||28-Dec-2021|
Dr. Haiyang Xie
State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005
Source of Support: None, Conflict of Interest: None
A patient suffered from recurrent episodes of palpitations and documented wide QRS complex tachycardia. Echocardiography revealed no obvious abnormal heart structure. A diagnostic electrophysiological study was performed and fast-slow atrioventricular nodal reentrant tachycardia with aberrancy was diagnosed. Successful slow pathway ablation rendered the tachycardia noninducible.
Keywords: Aberrant ventricular conduction, catheter ablation, electrophysiological study, wide complex tachycardia
|How to cite this article:|
Xie H. Case report: A regular wide QRS complex tachycardia with fusion beats?. Int J Heart Rhythm 2021;6:93-4
| Introduction|| |
Several arrhythmias can manifest as wide QRS complex tachycardias (WCTs), such as ventricular tachycardia (VT), supraventricular tachycardia with aberrancy, supraventricular tachycardias with bystander preexcitation, and antidromic atrioventricular reentrant tachycardia. This study reported a case of WCT in a patient with subtle QRS morphological changes that seem like fusion beats, which ultimately achieved the differential diagnosis and required successful ablation.
| Case Report|| |
A 37-year-old male underwent a diagnostic electrophysiologic test because of recurrent episodes of palpitations and documented WCT with left bundle branch block morphology. Baseline electrocardiogram revealed no preexcitation [Figure 1]a. Echocardiography revealed no obvious abnormal heart structure. Quadripolar catheters were placed in the His bundle and right ventricle apex. A decapolar catheter was placed in the coronary sinus. The His-ventricular (HV) interval was 50 ms [Figure 1]c. Retrograde activation was concentric and decremental when ventricular extrastimulus testing, and the earliest atrial activation site in the bundle of His region could change to the proximal coronary sinus when burst pacing [Figure 1]d. Maximum 1:1 conduction at a tachycardia cycle length of 240 ms was observed. Atrial extrastimulation elicited no dual anterograde AV nodal conduction and preexcitation.
|Figure 1: Electrophysiological study of the patient. (a) A baseline electrocardiogram showed no preexcitation. (b) Electrocardiogram of the documented wide complex tachycardia. (c) The His-ventricular (HV) interval was 50 ms during sinus rhythm. (d) The earliest atrial activation site in the bundle of His region could change to the proximal coronary sinus when burst pacing. (e) A fixed HV interval of 50 ms was seen during the wide complex tachycardia (WCT). (f) Atrial pacing reset the WCT. (g) Ventricular overdrive pacing reset the WCT and revealed a “V-A-V” pattern|
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Burst ventricular pacing easily and reproducibly induced the WCT at a tachycardia cycle length of 268 ms [Figure 1]b. A fixed HV interval of 50 ms was seen during the WCT [Figure 1]e. Atrial pacing at a tachycardia cycle length of 250 ms could reset the WCT [Figure 1]f. Repeat right ventricle apex pacing could not reset the WCT, except for one, which revealed a “V-A-V” pattern [Figure 1]g.
Overall, fast-slow atrioventricular nodal reentrant tachycardia with aberrancy was diagnosed, which successfully ablated the slow pathway rendering the WCT noninducible.
| Discussion|| |
Several arrhythmias can present as WCTs, such as VT, supraventricular tachycardia with aberrancy, supraventricular tachycardias with bystander preexcitation, and antidromic atrioventricular reentrant tachycardia.
In this case, WCT did not meet most of Brugada algorithm or positive aVR criterion to diagnose VT, but subtle QRS morphological changes seem like fusion beats, which might not rule out VT. During the electrophysiologic study, decremental ventriculoatrial conduction and the absence of preexcitation excluded the diagnosis of supraventricular tachycardias with bystander preexcitation and atrioventricular reentrant tachycardia with aberrancy. Then, the HV interval during the WCT was the same as the sinus rhythm. In addition, atrial overdrive pacing could reset the WCT. Therefore, VT was excluded. To be noted, ventricular overdrive pacing several times could not reset the WCT, which might suggest AT with aberrancy. Para-Hisian pacing was tried to perform, but could not capture the His bundle. However, repeat ventricular pacing eventually reset the WCT. Considering the underlying problem of the Purkinje system, therefore, ventricular pacing intruded into the Purkinje system might not be easy. Para-Hisian pacing or repeat ventricular pacing in a different place would be helpful. Actually, in this case, the narrow beats should not be considered as fusion beats due to the identical morphology. However, aberrant ventricular conduction could well explain the subtle QRS morphological changes.
Institutional review board statement
This study was approved by the Institutional Review Board of Fuwai Hospital. The research reported in this paper adhered to the Helsinki Declaration as revised in 2013.
Declaration of patient consent
The author certifies that he has obtained the appropriate patient consent form. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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