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Author
Block:
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Naoki
Fujimoto, Chikaya
Omichi, Takafumi Koji, Atsushi Kawasaki, Shigeki Kato, Atsunobu Kasai,
National Mie Central Hospital, Hisai, Japan
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Background:
Brugada syndrome
is characterized by a right bundle branch block pattern and ST segment
elevation in the right precordial leads. The Brugada-type
electrocardiographic (ECG) pattern can be observed in asymptmatic healthy
patients (pts) or conditions other than true Brugada syndrome. The mechanisms
of Brugada-type ECG pattern are not fully understood.
Methods: We performed percutaneous coronary intervention (PCI) of
proximal right coronary artery (RCA) for ischemic heart diseases in 12 pts.
No significant stenosis was observed in left coronary arteries in all pts.
The ST changes were evaluated during PCI. Angiographical changes were
carefully observed from major branches of RCA to small branches during PCI.
We measured ST elevation in right precordial leads with class I
antiarrhythmic drug administration: pilsicainide 50 mg (pure sodium channel
blocker) after PCI. ST changes were compared with true Brugada syndrome
(n=5).
Results: Brugada-type ECG was observed in 5 pts (42%) but not in 7 pts
(58%) during PCI of proximal RCA. All 5 pts who had Brugada-type ECG
demonstrated ST segment alternans from coved shape to saddle back shape
during PCI. These ECG changes returned to normal after PCI. These pts who had
Brugada-type ECG with ST alternans demonstrated selective small RV branch
occlusion or vasospasm during PCI, which perfused RV anterior wall or RV
outflow. However pts without Brugada-type ECG did not show RV branch
occlusion. The class I antiarrhythmic drug administration showed no
significant ST elevation both in pts with Brugada-type ECG and in pts without
Brugada-type ECG (0.70±0.54mv, vs 0.46±0.21mv, p=NS). There was a significant
difference in ST elevation between pts with Brugada-type ECG during PCI and
pts with true Brugada syndrome. (0.70±0.54mv, vs 2.86±0.61mv, p<0.05)
Conclusions: The pts who had RV branch occlusion during PCI showed
Brugada-type ECG and ST alternans. Sodium channel impairment was not
associated with these ECG changes. ST alternans might be considered as
prerequisites before developing ventricular arrhythmia. These data suggest
that merely ischemia of small RV branch could be one of the different
entities showing Brugada-type ECG from true Brugada syndrome.
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