ELECTROPHYSIOLOGY
Recurrent fascicular ventricular tachycardia in myotonic dystrophy
Kaiser Permanente Regional Arrhythmia Center, Los Angeles Medical Center, 4867 Sunset Blvd. Building H, Los Angeles, CA 90027, USA
Manuscript submitted 10 October 2005. Accepted after revision 10 February 2006.
* Corresponding author. E-mail address: mfnageh{at}scal.kp.org
Conduction system disease and ventricular tachycardia (VT) are known to occur in myotonic dystrophy (MD) patients. The most commonly reported VT is bundle branch reentry;1
however, there are reports of other types including fascicular VT.2–5 This is a case report of recurrent fascicular VT, originating from two separate sites within the posterior fascicle in an adult patient diagnosed with MD.
A 32-year-old male diagnosed with MD presented with sustained palpitations associated with shortness of breath and dizziness. In the emergency room, he was found to have sustained wide complex tachycardia rate >220 bpm (Figure 1), which was treated with procainamide intravenously, that slowed the rate but did not terminate it, so an external cardioversion was performed.
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Echocardiogram (ECG) revealed mildly depressed left ventricular (LV) function, and the ECG in sinus rhythm showed intraventricular conduction delay.
The patient underwent an electrophysiology study (EPS) and was noted to have prolonged HV interval >70 ms. With isoprenaline (I) infusion and atrial programmed stimulation, a sustained monomorphic VT cycle length of 270 ms was induced, with similar morphology to his clinical tachycardia. VT induction was highly reproducible. The VT morphology of right bundle branch block with left anterior hemiblock and induction with atrial stimulation on I and with negative HV interval during tachycardia were all consistent with posterior fascicular VT.
Activation mapping (using the CARTO system), as well as mapping for Purkinje potentials were performed. The VT focus was localized at the distal postero-septal LV wall. During RF application, VT terminated and became non-inducible (Figure 2). In view of the high risk for other types of VT, as well as conduction system disease, the patient underwent dual chamber defibrillator implantation.
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One year later, the patient presented with ICD shocks for a rapid VT, and a second EPS was performed.
A sustained monomorphic fascicular VT was inducible with I infusion and atrial programmed stimulation. Activation mapping and Purkinje potential mapping localized VT focus to a more proximal postero-septal LV area, near the origin of the posterior fascicle. With RF applications, VT terminated and was not inducible.
During the next 3 years of follow-up, the patient had no further VT episodes. Although there are only few reports of fascicular VT in MD,4,5 this case of recurrent fascicular VT originating from different sites, together with the previous case reports, confirms an association between fascicular VT and MD, most likely secondary to involvement of the fascicles in this disease.
Conduction system disease has been linked to the mechanism of bundle branch reentry VT in MD patients.1,6 This also can be the underlying mechanism for micro re-entry in fascicular VT and can explain the recurrences from other sites within the posterior fascicle.
Fascicular VT should be included along with bundle branch reentry VT in the differential diagnosis of wide complex tachycardia in this patient population.
Finally, the higher risk of other forms of VT, possible progression to infranodal conduction block, and deterioration of LV function warrant consideration of ICD implantation in this high-risk patient population.7
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[1] Merino JL, Carmona JR, Fernandez-Lozano I, Peinado R, Basterra N, Sobrino JA. Mechanism of sustained ventricular tachycardia in myotonic dystrophy: implications for catheter ablation. Circulation 1998; 98: 541–6.
[2] Shiraishi H, Shiramama T, Inoue K, et al. Successful catheter ablation against ventricular tachycardia associated with myotonic dystrophy. Intern Med 2000; 39: 39–44.[Medline]
[3] Tamura K, Tsuji H, Matsui A, et al. Sustained ventricular tachycardia associated with myotonic dystrophy. Clin Cardiol 1996; 19: 647–7.
[4] Berger RD, Orias D, Kasper EK, Calkins H. Catheter ablation of coexistent bundle branch and interfascicular reentrant ventricular tachycardia. J Cardiovasc Electrophysiol 1996; 7: 341–7.[Web of Science][Medline]
[5] Ng KS, Ng WL, Chia BL. Left posterior fascicular ventricular tachycardia in myotonic dystrophy. Int J Cardiol 2000; 74: 93–4.[Medline]
[6] Muraoka H, Negoro N, Terasaki F, et al. Re-entry cicuit in ventricular tachycardia due to focal fatty-fibrosis in a patient with myotonic dystrophy. Intern Med 2005; 44: 129–35.[Medline]
[7] Lazarus A, Varin J, Babuty D, Anselme F, Coste J, Duboc D. Long term follow-up of arrhythmias in patients with myotonic dystrophy treated by pacing: a multicenter diagnostic pacemaker study. J Am Coll Cardiol 2002; 40: 1645–52.
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