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Wide Complex Tachycardia Following Cardiac Valve Surgery
W ide Complex Tac hyc ardia F o l l o w i n g C a rd i a c Va l v e Surgery Wendy S. Tzou, MDa,*, Edward P. Gerstenfeld, MDb KEYWORDS Ventricular tachycardia Bundle branch reentry Catheter ablation
KEY POINTS A right bundle branch block pattern on the surface electrocardiogram may represent significant delay rather than a block in the right bundle. When ventricular tachycardia (VT) with a right bundle right inferior axis occurs in patients with nonischemic cardiomyopathy and conduction disease, one should consider antidromic bundle branch reentry. A His bundle recording in front of a left bundle branch VT with H-H driving V-V is diagnostic for orthodromic bundle branch reentry. Ablation of the right bundle branch is curative for bundle branch reentrant VT.
A 63-year-old man with a history of atrial fibrillation and bicuspid aortic valve with sinus of Valsalva aneurysm underwent complex aortic root replacement, hemiarch repair, pericardial aortic valve replacement, and mitral valve repair. Before surgery, he was in persistent atrial fibrillation with a narrow QRS. Immediately after surgery, he was noted to have developed a new right bundle branch block (RBBB) and first-degree atrioventricular (AV) conduction delay (Fig. 1A). His postoperative course was uncomplicated until 1 week later, when he experienced recurrent episodes of sustained, monomorphic ventricular tachycardia (VT) necessitating multiple external cardioversions (Fig. 1B). He was treated with intravenous amiodarone and lidocaine, which slowed the rate of the VT from 190 to 130 beats/min; however, the burden increased to the point that the VT became incessant. Because of the extent of his surgery involving the complex aortic valve reconstruction, the patient’s cardiothoracic surgeon advised against
any systemic anticoagulation or catheter manipulation in the newly reconstructed aortic root. However, after several days of incessant VT despite repeated amiodarone boluses, he was eventually referred for electrophysiology study and VT ablation.
CLINICAL COURSE The patient’s presenting rhythm to the electrophysiology laboratory was a right-bundle, right-axis, inferiorly directed VT with a cycle length of 410 milliseconds. During catheter placement in the apical right ventricle (RV), the VT terminated. Subsequent programmed stimulation or catheter ectopy from the RV reproducibly induced a left-bundle, rightaxis, inferiorly directed VT with the same cycle length (CL) as the presenting VT (Fig. 2). Question: What is the mechanism of this tachycardia, and the likely mechanism of the presenting tachycardia?
a University of Colorado, Anschutz Medical Campus, Cardiology, Electrophysiology Section, 12401 E. 17th Avenue, MS B136, Aurora, CO 80045, USA; b Cardiology Division, Department of Medicine, University of California at San Francisco, 500 Parnassus Avenue, MUE-434, Box 1354, San Francisco, CA 94143-1354, USA * Corresponding author. E-mail address: [email protected]
Card Electrophysiol Clin 4 (2012) 617–621 http://dx.doi.org/10.1016/j.ccep.2012.08.012 1877-9182/12/$ – see front matter Ó 2012 Published by Elsevier Inc.
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Fig. 1. (A) Electrocardiogram (ECG) obtained on postoperative day 1 showing sinus rhythm with prolonged PR interval and new right bundle branch block (RBBB). (B) Ventricular tachycardia 1 week following surgery, with RBBB and right inferior axis morphology.
DISCUSSION The presenting VT had an RBB/right-axis pattern, suggesting an exit from near the left anterior fascicle. Although “apparent” complete RBBB was present in sinus rhythm, the overall vector of the clinical VT was quite similar to the sinus rhythm axis. Termination of the VT with His bundle catheter placement led the surgeon to suspect that the RBB might also be involved in the tachycardia circuit. Ventricular programmed stimulation easily
induced a left bundle late transition VT at the exact same CL of the clinical VT. During this VT, RV apical activation occurred before the surface QRS. Placement of a catheter at the His and RBB positions demonstrated that variations in the VT CL were preceded by variations in the His-His interval (Fig. 3).1 Entrainment from a catheter recording an RBB potential demonstrated concealed fusion with a postpacing interval within 10 milliseconds of the tachycardia CL.
Tachycardia Following Cardiac Valve Surgery
Fig. 2. Surface 12-lead ECG together with intracardiac electrograms recorded from an ablation catheter positioned at the proximal RB (Abl), distal RB, and right ventricular apex. Abld, distal pole ablation catheter; Ablp, proximal pole ablation catheter; RB, right bundle potential; RBd, catheter positioned at distal right bundle branch; RVA, right ventricular apex catheter; V, ventricular electrogram.
Fig. 3. Surface 12-lead ECG together with intracardiac electrograms recorded from an ablation catheter positioned at the proximal RB (Abl), distal RB, and right ventricular apex. Variations in RB-RB intervals predicted variations in ventricular tachycardia cycle length. Abld, distal pole ablation catheter; Ablp, proximal pole ablation catheter; RB, right bundle potential; RBd, catheter positioned at distal right bundle branch; RVA, right ventricular apex catheter; V, ventricular electrogram.
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Tzou & Gerstenfeld Therefore, the diagnosis of orthodromic bundle branch reentry (BBR), with antegrade conduction occurring through the right bundle and retrograde conduction via the left bundle branch (LBB), was confirmed. With a 4-mm-tip ablation catheter positioned at the proximal RBB, VT terminated within 5 seconds. No other VTs were subsequently inducible with triple extra-stimuli delivered to the RV apex. Assessing whether complete block of the RBB was present was challenging given the patient’s underlying atrial fibrillation and “apparent” RBBB before the ablation, because the QRS duration following ablation was unchanged from baseline (160 milliseconds). After cardioversion to sinus rhythm, with the catheters maintained in the same position, a proximal His signal was identified and the RBB potential was noted to occur after the ensuing QRS. The sequence of activation demonstrated that His activation occurred in the anterograde direction and that the RBB was activated retrogradely, with earliest activation toward the apical RV (Fig. 4). It was thus evident that antegrade left ventricular activation conduction occurred via
the LBB, and that activation of the RV occurred retrogradely after transseptal penetration and retrograde activation of the distal RBB. This finding provided evidence that complete antegrade RBB had been achieved. In addition, the patient was noninducible for any VT with aggressive programmed stimulation. BBR typically occurs in individuals with significant disease in the His-Purkinje system. BBR after iatrogenic conduction disease induced by aortic valve surgery is uncommon, although it has been described.2 The ability to induce and sustain typical BBR indicates that the patient’s underlying RBB was incomplete, despite a baseline RBB block pattern with a QRS duration of 160 milliseconds. Such phenomena have been previously reported, although in the setting of interventricular conduction delay.3 This case serves as a reminder that one should consider antidromic BBR in patients with an RBB/right-axis VT, even in the presence of RBBB. Although it could not be proved that the original tachycardia was due to antidromic BBR, findings
Fig. 4. Following right bundle branch ablation and cardioversion to sinus rhythm, His activation during sinus rhythm is depicted on the left panel (solid red arrows). The right panel displays corresponding intracardiac activation (dotted red arrows), antegrade via the His bundle (Abld), and retrograde right bundle branch/RV activation. Ablp, proximal pole ablation catheter; AO, aorta; CS, coronary sinus; IVC, inferior vena cava; LBB, left bundle branch; LV, left ventricle; RA, right atrium; RBB, right bundle branch; RBd, catheter positioned at distal right bundle branch; RV, right ventricle; RVA, right ventricular apex catheter; SVC, superior vena cava.
Tachycardia Following Cardiac Valve Surgery favoring this diagnosis include: (1) recent valve surgeries with subsequent conduction system disease; (2) similar RBB morphology during baseline AV conduction and the presenting VT; (3) subsequent inducible orthodromic BBR VT with identical CL to the presenting VT; and (4) inability to induce the VT after RBB ablation. In this case, although the complex surgery limited access to the left ventricle to treat an RBB morphology VT, the patient was successfully cured with RBB ablation without the need for systemic anticoagulation and left ventricular access. Documenting completeness of the RBB following ablation was difficult in the setting of a preexisting RBB pattern. It was possible to record an anterograde His bundle activation during sinus rhythm, and retrograde distal RBB activation, presumably after anterograde conduction down the left fascicle with transseptal retrograde activation of the RBB. Transseptal catheterization to prove this activation sequence was not performed because of the patient’s recent surgery.
SUMMARY This article describes an unusual case of an incessant RBB VT in a patient who developed new RBB
after aortic valve surgery. The complex surgery limited access to the left ventricle for mapping, yet the patient’s arrhythmia was cured after a diagnosis of antidromic BBR was established. Proof of complete RBB after ablation was obtained using detailed mapping of RBB activation with a multipolar catheter. This case serves as a reminder that BBR should be considered in the case of postoperative VT occurring after apparent surgically induced BBB, even if the VT has an RBB morphology.
REFERENCES 1. Akhtar M, Gilbert C, Wolf FG, et al. Reentry within the His-Purkinje system. Elucidation of reentrant circuit using right bundle branch and his bundle recordings. Circulation 1978;58:295–304. 2. Narasimhan C, Jazayeri M, Sra J, et al. Ventricular tachycardia in valvular heart disease: facilitation of bundle-branch reentry by valve surgery. Circulation 1997;96:4307–13. 3. Mizusawa Y, Sakurada H, Nishizaki M, et al. Characteristics of bundle branch reentrant ventricular tachycardia with a right bundle branch block configuration: feasibility of atrial pacing. Europace 2009;11:1208–13.
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KEY POINTS A right bundle branch block pattern on the surface electrocardiogram may represent significant delay rather than a block in the right bundle. When ventricular tachycardia (VT) with a right bundle right inferior axis occurs in patients with nonischemic cardiomyopathy and conduction disease, one should consider antidromic bundle branch reentry. A His bundle recording in front of a left bundle branch VT with H-H driving V-V is diagnostic for orthodromic bundle branch reentry. Ablation of the right bundle branch is curative for bundle branch reentrant VT.
A 63-year-old man with a history of atrial fibrillation and bicuspid aortic valve with sinus of Valsalva aneurysm underwent complex aortic root replacement, hemiarch repair, pericardial aortic valve replacement, and mitral valve repair. Before surgery, he was in persistent atrial fibrillation with a narrow QRS. Immediately after surgery, he was noted to have developed a new right bundle branch block (RBBB) and first-degree atrioventricular (AV) conduction delay (Fig. 1A). His postoperative course was uncomplicated until 1 week later, when he experienced recurrent episodes of sustained, monomorphic ventricular tachycardia (VT) necessitating multiple external cardioversions (Fig. 1B). He was treated with intravenous amiodarone and lidocaine, which slowed the rate of the VT from 190 to 130 beats/min; however, the burden increased to the point that the VT became incessant. Because of the extent of his surgery involving the complex aortic valve reconstruction, the patient’s cardiothoracic surgeon advised against
any systemic anticoagulation or catheter manipulation in the newly reconstructed aortic root. However, after several days of incessant VT despite repeated amiodarone boluses, he was eventually referred for electrophysiology study and VT ablation.
CLINICAL COURSE The patient’s presenting rhythm to the electrophysiology laboratory was a right-bundle, right-axis, inferiorly directed VT with a cycle length of 410 milliseconds. During catheter placement in the apical right ventricle (RV), the VT terminated. Subsequent programmed stimulation or catheter ectopy from the RV reproducibly induced a left-bundle, rightaxis, inferiorly directed VT with the same cycle length (CL) as the presenting VT (Fig. 2). Question: What is the mechanism of this tachycardia, and the likely mechanism of the presenting tachycardia?
a University of Colorado, Anschutz Medical Campus, Cardiology, Electrophysiology Section, 12401 E. 17th Avenue, MS B136, Aurora, CO 80045, USA; b Cardiology Division, Department of Medicine, University of California at San Francisco, 500 Parnassus Avenue, MUE-434, Box 1354, San Francisco, CA 94143-1354, USA * Corresponding author. E-mail address: [email protected]
Card Electrophysiol Clin 4 (2012) 617–621 http://dx.doi.org/10.1016/j.ccep.2012.08.012 1877-9182/12/$ – see front matter Ó 2012 Published by Elsevier Inc.
cardiacEP.theclinics.com
CLINICAL HISTORY
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Tzou & Gerstenfeld
Fig. 1. (A) Electrocardiogram (ECG) obtained on postoperative day 1 showing sinus rhythm with prolonged PR interval and new right bundle branch block (RBBB). (B) Ventricular tachycardia 1 week following surgery, with RBBB and right inferior axis morphology.
DISCUSSION The presenting VT had an RBB/right-axis pattern, suggesting an exit from near the left anterior fascicle. Although “apparent” complete RBBB was present in sinus rhythm, the overall vector of the clinical VT was quite similar to the sinus rhythm axis. Termination of the VT with His bundle catheter placement led the surgeon to suspect that the RBB might also be involved in the tachycardia circuit. Ventricular programmed stimulation easily
induced a left bundle late transition VT at the exact same CL of the clinical VT. During this VT, RV apical activation occurred before the surface QRS. Placement of a catheter at the His and RBB positions demonstrated that variations in the VT CL were preceded by variations in the His-His interval (Fig. 3).1 Entrainment from a catheter recording an RBB potential demonstrated concealed fusion with a postpacing interval within 10 milliseconds of the tachycardia CL.
Tachycardia Following Cardiac Valve Surgery
Fig. 2. Surface 12-lead ECG together with intracardiac electrograms recorded from an ablation catheter positioned at the proximal RB (Abl), distal RB, and right ventricular apex. Abld, distal pole ablation catheter; Ablp, proximal pole ablation catheter; RB, right bundle potential; RBd, catheter positioned at distal right bundle branch; RVA, right ventricular apex catheter; V, ventricular electrogram.
Fig. 3. Surface 12-lead ECG together with intracardiac electrograms recorded from an ablation catheter positioned at the proximal RB (Abl), distal RB, and right ventricular apex. Variations in RB-RB intervals predicted variations in ventricular tachycardia cycle length. Abld, distal pole ablation catheter; Ablp, proximal pole ablation catheter; RB, right bundle potential; RBd, catheter positioned at distal right bundle branch; RVA, right ventricular apex catheter; V, ventricular electrogram.
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Tzou & Gerstenfeld Therefore, the diagnosis of orthodromic bundle branch reentry (BBR), with antegrade conduction occurring through the right bundle and retrograde conduction via the left bundle branch (LBB), was confirmed. With a 4-mm-tip ablation catheter positioned at the proximal RBB, VT terminated within 5 seconds. No other VTs were subsequently inducible with triple extra-stimuli delivered to the RV apex. Assessing whether complete block of the RBB was present was challenging given the patient’s underlying atrial fibrillation and “apparent” RBBB before the ablation, because the QRS duration following ablation was unchanged from baseline (160 milliseconds). After cardioversion to sinus rhythm, with the catheters maintained in the same position, a proximal His signal was identified and the RBB potential was noted to occur after the ensuing QRS. The sequence of activation demonstrated that His activation occurred in the anterograde direction and that the RBB was activated retrogradely, with earliest activation toward the apical RV (Fig. 4). It was thus evident that antegrade left ventricular activation conduction occurred via
the LBB, and that activation of the RV occurred retrogradely after transseptal penetration and retrograde activation of the distal RBB. This finding provided evidence that complete antegrade RBB had been achieved. In addition, the patient was noninducible for any VT with aggressive programmed stimulation. BBR typically occurs in individuals with significant disease in the His-Purkinje system. BBR after iatrogenic conduction disease induced by aortic valve surgery is uncommon, although it has been described.2 The ability to induce and sustain typical BBR indicates that the patient’s underlying RBB was incomplete, despite a baseline RBB block pattern with a QRS duration of 160 milliseconds. Such phenomena have been previously reported, although in the setting of interventricular conduction delay.3 This case serves as a reminder that one should consider antidromic BBR in patients with an RBB/right-axis VT, even in the presence of RBBB. Although it could not be proved that the original tachycardia was due to antidromic BBR, findings
Fig. 4. Following right bundle branch ablation and cardioversion to sinus rhythm, His activation during sinus rhythm is depicted on the left panel (solid red arrows). The right panel displays corresponding intracardiac activation (dotted red arrows), antegrade via the His bundle (Abld), and retrograde right bundle branch/RV activation. Ablp, proximal pole ablation catheter; AO, aorta; CS, coronary sinus; IVC, inferior vena cava; LBB, left bundle branch; LV, left ventricle; RA, right atrium; RBB, right bundle branch; RBd, catheter positioned at distal right bundle branch; RV, right ventricle; RVA, right ventricular apex catheter; SVC, superior vena cava.
Tachycardia Following Cardiac Valve Surgery favoring this diagnosis include: (1) recent valve surgeries with subsequent conduction system disease; (2) similar RBB morphology during baseline AV conduction and the presenting VT; (3) subsequent inducible orthodromic BBR VT with identical CL to the presenting VT; and (4) inability to induce the VT after RBB ablation. In this case, although the complex surgery limited access to the left ventricle to treat an RBB morphology VT, the patient was successfully cured with RBB ablation without the need for systemic anticoagulation and left ventricular access. Documenting completeness of the RBB following ablation was difficult in the setting of a preexisting RBB pattern. It was possible to record an anterograde His bundle activation during sinus rhythm, and retrograde distal RBB activation, presumably after anterograde conduction down the left fascicle with transseptal retrograde activation of the RBB. Transseptal catheterization to prove this activation sequence was not performed because of the patient’s recent surgery.
SUMMARY This article describes an unusual case of an incessant RBB VT in a patient who developed new RBB
after aortic valve surgery. The complex surgery limited access to the left ventricle for mapping, yet the patient’s arrhythmia was cured after a diagnosis of antidromic BBR was established. Proof of complete RBB after ablation was obtained using detailed mapping of RBB activation with a multipolar catheter. This case serves as a reminder that BBR should be considered in the case of postoperative VT occurring after apparent surgically induced BBB, even if the VT has an RBB morphology.
REFERENCES 1. Akhtar M, Gilbert C, Wolf FG, et al. Reentry within the His-Purkinje system. Elucidation of reentrant circuit using right bundle branch and his bundle recordings. Circulation 1978;58:295–304. 2. Narasimhan C, Jazayeri M, Sra J, et al. Ventricular tachycardia in valvular heart disease: facilitation of bundle-branch reentry by valve surgery. Circulation 1997;96:4307–13. 3. Mizusawa Y, Sakurada H, Nishizaki M, et al. Characteristics of bundle branch reentrant ventricular tachycardia with a right bundle branch block configuration: feasibility of atrial pacing. Europace 2009;11:1208–13.
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