中西 弘毅¹, 福田 祥大², 尾辻 豊²

Koki NAKANISHI¹, Shota FUKUDA², Yutaka OTSUJI²

¹コロンビア大学循環器科, ²産業医科大学第2内科

¹Division of Cardiology, Department of Medicine, Columbia University, ²Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine

キーワード : cardiomyopathy, dyssynchrony, ischemic heart disease, strain imaging, valvular heart disease

ストレイン心エコー図法は心臓の局所および全体の機能を客観的，定量的に評価する方法として急速な発展を遂げてきた．ストレインは組織ドプラ法または，二次元スペックルトラッキング法によって得ることができる．ストレインエコーに基づく定量的評価は，虚血性心疾患，心室内同期不全，各種心筋症や拡張機能障害，さらに弁膜症による心筋障害の病態解明に大きな役割を果たしてきた．またストレインエコーは化学療法に伴う早期の心筋障害の検出にも利用されている．さらにストレインエコーは左室のみならず右室や左房にも応用され，近年では技術の進歩に伴い三次元スペックルトラッキング法が出現した．しかし，ストレインエコーの結果に基づいた臨床判断が心疾患の患者の予後を改善させるか否かは十分な検討がなされておらず，今後の臨床研究が必要である．ストレインエコーは現在もなお発展途上であり，その長所・短所を十分に理解したうえで使用すれば，我々の日常臨床において，重要な役割を果たす可能性がある．

Echocardiographic strain imaging, known as deformation imaging, has been developed as a means to objectively quantify regional and global myocardial function. Strain can be obtained with tissue Doppler imaging or with 2D speckle tracking. Strain imaging has been used to gain greater understanding into the pathophysiology of ischemic heart disease, dyssynchrony, cardiomyopathies, the effects of valvular disease on myocardial function even at the subclinical stage, and diastolic heart failure. Strain imaging has also been used for the evaluation of cardiotoxicity to detect left ventricular (LV) dysfunction prior to fall in LV ejection fraction in patients undergoing chemotherapy. Strain imaging can be used to assess right ventricular and left atrial function. Further advances, such as 3D speckle tracking strain imaging, have emerged to provide even greater insight. Strain imaging is still undergoing development, and further clinical studies are required to determine if clinical decisions based on strain imaging result in better outcomes. With this important limitation in mind, strain may have great potential to play many roles in clinical practice.