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JOSEPHSON AND WELLENS ECG LESSONS: A MONTHLY VISIT TO THE 12 LEAD ECG
Syncope in a patient with myotonic dystrophy Mark E. Josephson, MD,*† Hein J.J. Wellens, MD† From the *Division of Cardiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, and † Cardiovascular Research Institute, Maastricht, The Netherlands.
Syncope in a patient with myotonic dystrophy
Question
A 40-year-man presented with syncope that was preceded by palpitations. There was no history of preexcitation, supraventricular tachycardia, or ventricular arrhythmias. His electrocardiogram (ECG) showed left bundle branch block (LBBB) with a PR interval of 0.24 seconds and a QRS duration of 0.16 seconds. An echocardiogram showed an ejection fraction of 48% and no hypertrophy or valvular disease. A physical examination showed normal cardiac examination results but impaired relaxation of his hand after a handshake. A neuromuscular examination confirmed the diagnosis of myotonic dystrophy. While in the hospital he developed a wide complex tachycardia, which is shown with a sinus rhythm ECG in Figure 1.
What is the likely cause of the tachycardia and syncope?
Discussion Patients with myotonic dystrophy frequently have abnormal atrioventricular conduction, particularly in the His-Purkinje system. Our patient had an ECG demonstrating LBBB and left anterior hemiblock. Syncope could be related to atrioventricular block, sinus node dysfunction, or a tachyarrhythmia. In this case, a wide complex tachycardia with a morphology similar to sinus rhythm was associated with syncope. Atrioventricular dissociation was present (dark arrows), suggesting that this was ventricular tachycardia (VT). The morphology suggests that activation occurs over
Figure 1 Electrocardiogram in sinus rhythm and ventricular tachycardia. The left panel demonstrates left bundle branch block (LBBB) with left-axis deviation during sinus rhythm. During VT on the right, atrioventricular dissociation is present (arrows). The electrocardiogram looks similar to the sinus rhythm tracing.
Address reprint requests and correspondence: Dr Mark E. Josephson, Division of Cardiology, Beth Israel Deaconess Medical Center, 185 Pilgrim Rd, Baker 4, Boston, MA 02215. E-mail address: mjoseph2@bidmc. harvard.edu.
1547-5271/$-see front matter B 2015 Published by Elsevier Inc. on behalf of Heart Rhythm Society.
http://dx.doi.org/10.1016/j.hrthm.2015.04.032
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the right bundle branch as it does in sinus rhythm with LBBB. VTs with an LBBB-like morphology originating from the left ventricular myocardium typically have a slurred downstroke in lead V1-2 or an r wave in lead V1 Z0.04 seconds.1 Those with negative concordance usually have an anteroseptal infarction and have Q waves in leads I and aVL.2 There was no evidence of right ventricular cardiomyopathy. An electrophysiological study demonstrated an HV interval of 85 ms in sinus rhythm inducible bundle branch reentry and no other myocardial VTs. A nodofascicular accessory pathway could give rise to an LBBB tachycardia with activation of the heart over the RBB, but this was excluded by the HV interval of 85 ms. Moreover, this rare accessory pathway typically occurs in young, healthy people. Ablation of the RBB prevented induction of the arrhythmia, and the patient has been fine for 5 years.
Heart Rhythm, Vol 0, No 0, Month 2015 Bundle branch reentry is a macroreentrant ventricular tachycardia using either the right or left bundle for antegrade conduction and the contralateral bundle for retrograde conduction. It occurs typically in patients with severe cardiac dysfunction and/or in those with severe infranodal conduction disease. In dilated cardiomyopathies, valvular disease, and myotonic dystrophy, an LBBB pattern is more common, while in infarct-related cardiomyopathy, an RBBB pattern is more frequent. Our patient was fortunate not to have addition VTs induced, in which case ablation of a bundle branch would have been ineffective and an implantable defibrillator would be required. Moreover, this rare accessory pathway typically occurs in young, healthy people.
References 1. Kindwall, et al. Am J Cardiol 1988;61:1279–1283. 2. Miller, et al. Circulation 1988;77:759–766.
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JOSEPHSON AND WELLENS ECG LESSONS: A MONTHLY VISIT TO THE 12 LEAD ECG
Syncope in a patient with myotonic dystrophy Mark E. Josephson, MD,*† Hein J.J. Wellens, MD† From the *Division of Cardiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, and † Cardiovascular Research Institute, Maastricht, The Netherlands.
Syncope in a patient with myotonic dystrophy
Question
A 40-year-man presented with syncope that was preceded by palpitations. There was no history of preexcitation, supraventricular tachycardia, or ventricular arrhythmias. His electrocardiogram (ECG) showed left bundle branch block (LBBB) with a PR interval of 0.24 seconds and a QRS duration of 0.16 seconds. An echocardiogram showed an ejection fraction of 48% and no hypertrophy or valvular disease. A physical examination showed normal cardiac examination results but impaired relaxation of his hand after a handshake. A neuromuscular examination confirmed the diagnosis of myotonic dystrophy. While in the hospital he developed a wide complex tachycardia, which is shown with a sinus rhythm ECG in Figure 1.
What is the likely cause of the tachycardia and syncope?
Discussion Patients with myotonic dystrophy frequently have abnormal atrioventricular conduction, particularly in the His-Purkinje system. Our patient had an ECG demonstrating LBBB and left anterior hemiblock. Syncope could be related to atrioventricular block, sinus node dysfunction, or a tachyarrhythmia. In this case, a wide complex tachycardia with a morphology similar to sinus rhythm was associated with syncope. Atrioventricular dissociation was present (dark arrows), suggesting that this was ventricular tachycardia (VT). The morphology suggests that activation occurs over
Figure 1 Electrocardiogram in sinus rhythm and ventricular tachycardia. The left panel demonstrates left bundle branch block (LBBB) with left-axis deviation during sinus rhythm. During VT on the right, atrioventricular dissociation is present (arrows). The electrocardiogram looks similar to the sinus rhythm tracing.
Address reprint requests and correspondence: Dr Mark E. Josephson, Division of Cardiology, Beth Israel Deaconess Medical Center, 185 Pilgrim Rd, Baker 4, Boston, MA 02215. E-mail address: mjoseph2@bidmc. harvard.edu.
1547-5271/$-see front matter B 2015 Published by Elsevier Inc. on behalf of Heart Rhythm Society.
http://dx.doi.org/10.1016/j.hrthm.2015.04.032
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the right bundle branch as it does in sinus rhythm with LBBB. VTs with an LBBB-like morphology originating from the left ventricular myocardium typically have a slurred downstroke in lead V1-2 or an r wave in lead V1 Z0.04 seconds.1 Those with negative concordance usually have an anteroseptal infarction and have Q waves in leads I and aVL.2 There was no evidence of right ventricular cardiomyopathy. An electrophysiological study demonstrated an HV interval of 85 ms in sinus rhythm inducible bundle branch reentry and no other myocardial VTs. A nodofascicular accessory pathway could give rise to an LBBB tachycardia with activation of the heart over the RBB, but this was excluded by the HV interval of 85 ms. Moreover, this rare accessory pathway typically occurs in young, healthy people. Ablation of the RBB prevented induction of the arrhythmia, and the patient has been fine for 5 years.
Heart Rhythm, Vol 0, No 0, Month 2015 Bundle branch reentry is a macroreentrant ventricular tachycardia using either the right or left bundle for antegrade conduction and the contralateral bundle for retrograde conduction. It occurs typically in patients with severe cardiac dysfunction and/or in those with severe infranodal conduction disease. In dilated cardiomyopathies, valvular disease, and myotonic dystrophy, an LBBB pattern is more common, while in infarct-related cardiomyopathy, an RBBB pattern is more frequent. Our patient was fortunate not to have addition VTs induced, in which case ablation of a bundle branch would have been ineffective and an implantable defibrillator would be required. Moreover, this rare accessory pathway typically occurs in young, healthy people.
References 1. Kindwall, et al. Am J Cardiol 1988;61:1279–1283. 2. Miller, et al. Circulation 1988;77:759–766.
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