Different Characteristics of T Wave Alternans Between Polymorphic Ventricular Tachycardia and Monomorphic Ventricular Tachycardia

Presentation Time: Monday, 10:00 a.m. - 11:00 a.m.

Kaoru Tanno, Youichi Kobayashi, Takashi Katagiri, Showa University, Tokyo, Japan.

Presentation Number: 1093-109

Poster Board Number: 109

Keyword: Ventricular tachycardia, Repolarization

[Background] Microvolt T wave alternans (TWA) has been reported to be closely associated with polymorphic ventricular tachycardia (VT) in animal experiments. However, it is not clear whether monomorphic VT (monoVT) has relation to TWA as closely as polymorphic VT (polyVT). [Method] The subjects were 59 patients (male/female=51/8, mean age 60 ± 13 years) with organic heart disease and ventricular tachyarrhythmias. We compared TWA of patients with polyVT with that of patients with monoVT. Programmed ventricular stimulation was performed at right ventricular apex and outflow tract to induce sustained ventricular tachyarrhythmias. Recordings of TWA were made in sinus rhythm and with atrial pacing at 80, 90, 100, and 110 beat per minute if conducted without atrioventricular block for 3 minutes respectively with CH2000 system (Cambridge Heart Co. Boston, MA). TWA was considered positive when the alternans voltage (Valt) was >1.9mV and the alternans ratio was >3 for a period of more than 1 minute in VM, X, Y, Z, or two adjacent precordial leads.
[Results] Electrical stimulation induced polyVT in 13 patients and monoVT in 20 patients. TWA was positive in all patients in polyVT group, while 15 of 20 patients in monoVT group had positive TWA. Although onset heart rate was not significantly different between two groups, onset heart rate/target heart rate (220-age) of polyVT group was significantly lower than the other group (polyVT: 58 ± 11 vs. monoVT: 63 ± 8, None: 68 ± 9 %, p<0.05). Valt of polyVT group at X lead during 110 bpm was significantly higher than the other group (polyVT: 3.6 ± 2.4 vs. monoVT: 1.4 ± 1.3, None: 1.8 ± 1.9mV, p<0.05). During 29 ± 12 months follow-up periods, Vf recurred in 4 patients of polyVT group and VT recurred in 7 patients of monoVT group. All patients with recurrence of ventricular tachyarrhythmias were positive in TWA.
[Conclusion] Polymorphic VT could be more closely associated with TWA than monomorphic VT. Microvolt TWA might be a powerful tool for predicting recurrence of ventricular tachyarrhythmias in patients with organic heart disease.