激症型急性心筋炎の継続的心内膜心筋生検による検討—LOSに対し血管拡張剤とカテコラミンの併用療法が著効を示した1例

A study employing serial endomyocardial biopsy in a case of acute myocarditis

　急性ウイルス性心筋炎には自覚症のほとんどない軽症型から，Adams-Stokes発作や重症心不全を伴う激症型まで様々である。心電図異常が本症診断の糸口となるが，ST-T異常．異常Q波・房室ブロックなどを示し，臨床症状や酵素学的所見からも急性心筋梗塞症と鑑別が困難な例がある。近年，ウイルス学の発達により本症の診断の向上がみられているが，それによる診断率は必ずしも高くはない。

　我々は臨床的に急性心筋炎を疑ったが，急性心筋梗塞症も否定しえなかった例に継時的に心内膜心筋生検を施行し，その診断と病態の推移について新しい知見を得たので報告する。また本症に伴う重症心不全に対する治療法はジギタリス・利尿剤など従来の方法によるのがまだ一般的であるが，それでは難行する場合がある。我々は本例のlow output syndrome（以下LOS）に対し，血管拡張剤とDopamineの併用療法を用い著効を得たので併せて報告する。

A case of acute idiopathic myocarditis with Adams-Stokes attack and low output syndrome was reported. A 50 year old male with high fever for 3 days was admitted to our hospital by ambulance with Adams-Stokes attack. ECG revealed complete A-V block and ventricular asystole, so temporary external cardiac pacing was applied immediately. But low output syndrome (LOS) was not improved by cardiac pacing only. Hemodynamic parameters using Swan-Ganz catheter and thermodilution method were recorded. First, nitroglycerin ointment was applied in order to reduce preload and after-load of the heart. This treatment was too mild to improve LOS in this case, so, another vasodilator (phentolamine) and catecholamine (dopamine) were administrated. This combined therapy decreased preload and afterload further and increased cardiac output. The clinical symptoms of LOS were markedly improved by this treatment.

It was difficult to differentiate acute myo-carditis from acute myocardial infarction because clinical symptoms, ECG abnormalities and ele-vated serum enzymes are similar. To confirm the diagnosis, 3 serial endomyocardial biopsies were performed from the right ventricle. The first biopsy was done on the 6th hospital day, and microscopic findings showed an acute in-flammatory state of the myocardium. On the 14th day, a second biopsy revealed hypertrophied myocytes and mild inflammation. The 3rd biopsy of 26th day showed that inflammation was dis-appearing and that the myocytes were almost normal, along with some interstitial fibrosis. These biopsies confirmed the diagnosis of acute myocarditis and demonstrated its healing process.