2318/C73 - Long-term Outcomes in
Patients with Abnormal Microvolt T Wave Alternans - Comparison Between
Ischemic Heart Disease and Non-Ischemic Heart Disease- |
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Keywords: |
Ventricular
tachycardia, Sudden death, Electrocardiography, Clinical trials,
Electrophysiology |
Disclosure Block: |
K. Tanno, None; H. Ito, None; F. Miyoshi, None; Y. Minoura, None; M. Kawamura, None; T. Asano, None; Y. Kobayashi, None. |
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Abstract:
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Although
patients with negative microvolt T wave Alternans (MTWA) has been considered
to be better outcomes than patients with positive or indeterminate (abnormal)
MTWA, long-term outcomes in such patients is not clear. Methods: The
subject was the patients who underwent MTWA test from January, 1998 to July,
2004. The Number of patients was 1891, 60±15 years, female/male: 452/1439. Of
1891 patients, 926 patients had ischemic heart disease (IHD), 407 patients
had non-ischemic heart disease (non-IHD) and the 558 patient had no
structural heart disease. MTWA recordings were made with the CH2000 system
(Cambridge Heart, MA). MTWA was considered positive when alternans voltage
was more than 1.9 microvolt and the alternans ratio was greater than 3 for
more than 1 minute in VM, X, Y, Z, or two adjacent precordial leads without
artifact at a heart rate of less than 110 bpm. MTWA was considered negative
if the criteria for a positive test were not met, or if there was no
significant alternans for 1 minute while the heart rate was greater than 100
bpm. Otherwise, TWA was considered indeterminate. The date of the MTWA test
was regarded as day 1 of the study, and patients were followed up
prospectively at our university hospital outpatient clinic. Results:
During a mean follow-up periods of 54 ± 29 months, 1816 of 1891 patients
could be followed up their clinical course. In 1816 patients, 63 patients
died of cardiac disease. Kaplan-Meier analysis revealed that the total
mortality in patients with negative MTWA was significantly lower than that of
patients with abnormal MTWA (p<0.01). In patients with IHD, 12 patients
died suddenly. Of whom, one patient was positive MTWA, 3 patients were
negative MTWA and 8 patients were indeterminate MTWA. Ventricular tachycardia
(VT) was documented in 73 patients, in whom 40 patients was positive MTWA, 12
patients was negative MTWA and 21 patients was indeterminate MTWA. In
patients with non-IHD, 8 patients was sudden cardiac death (SCD), of whom 6
patients were positive MTWA and 2 patients were negative MTWA. Fifty-four
patients suffered from VT, of whom 40 patients were positive MTWA and 4
patients were negative MTWA. Conclusion: This study suggested that negative
MTWA was associated with better prognosis than abnormal MTWA even in long-term
follow-up. |