肥大型心筋症の左室病態評価における心尖拍動図A波率の有用性

Usefulness for evaluation of the left ventricular disorders by apexcardiographic A-wave ratio in patients with hypertrophic cardiomyopathy

　〔目的〕肥大型心筋症（HCM）において心尖拍動図A波による左室病態評価の有用性を検討すること。〔対象〕HCM48例をA波率（A波高／心尖拍動波高）15％以下，16〜29％，30％以上の3群に分類。〔方法〕A波率と左心カテーテル所見との関連および3群における臨床所見を対比した。〔結果〕A波率とTime constant T（r＝＋0.71），LVEDP（r＝＋0.46），atrial kick（r＝＋0.55）とはいずれも正相関を認めた。A波率30％以上の群は15％以下の群に比し，負荷心プールシンチで運動時EFが有意に低下した（p＜0.05）。トレッドミル負荷で前者は血圧上昇度が低くST下降例も多かった（いずれもp＜0.05）。負荷心筋シンチで前者は灌流欠損を30％の例に認めた。〔結語〕A波率が高値な例は，左室拡張期機能の異常が著しく，運動時の左室収縮期機能障害や血行動態の異常，心筋障害との関連が示された。心尖拍動図A波率はHCMにおける左室病態の評価に有用な指標になりうると思われた。

Usefulness for evaluation of left ventricular dis-orders by apexcardiographic A-wave ratio was studied in 48 patients with hypertrophic cardiomyo-pathy.

These subjects were divided into 3 groups : A-wave ratio≦115% (group 1), 16≦A-wave ratio≦29 % (group 2), and A-wave ratio≧30% (group 3).

A-wave ratio was found to have a positive correla-tion with Time constant T (r=+O.71), left ventricu-lar end-diastolic pressure (r= 0.46), and left ven-tricular atrial kick (r=+0.55).

During exercise, ejection fraction decreased sig-nificantly (p＜0.05) in group 3 as compared to group 1.

During treadmill exercise test, rise of systolic blood pressure was significantly (p＜0.05) poor, and there was a large number of ST depression (p＜0.05) in group 3.

It was recognized by exercise thallium-201 myoca-rdial scintigraphy, that the frequency of perfusion defect was 30% in group 3.

In conclusion, high A-wave ratio may strongly suggest impaired left ventricular diastolic function, and, there was correlated to abnormal hemodynamic state during exercise.

Apexcardiographic A-wave ratio proved to be use-ful in patients with hypertrophic cardiomyopathy. It is useful for evaluation of left ventricular disorders.