エコーによりペースメーカーリードの最良の設置部位が得られる

TARGET：個々の患者について評価することにより心臓再同期療法の結果が向上する
TARGET: Individualized assessment improves results of cardiac resynchronization therapy
ペースメーカーリードの設置部位決定を心エコーガイド下で行うことの有益性を報告した初めての無作為化臨床試験の結果、左室機能を解析しリードワイヤの設置位置をガイドするソフトウェアを用いた患者ごとのアプローチ法により臨床上の有益性が上昇することが示されたと第60回American College of Cardiology学会で発表された。研究者らはスペックルトラッキング法（STE）を用いて、心臓再同期療法を予定されている患者220人の心臓評価を行った。試験群に無作為に割り付けられた患者110人においてはリードワイヤの左室内埋め込みをSTE計測ガイド下で行った。コントロール群のリードは STEデータを参照せずに従来通りの方法で行った。左室のリバースリモデリング率（70%対55%）、心不全に関する標準的な尺度の改善（83%対 65%）などの臨床上のエンドポイントにおいて試験群の方がコントロール群よりも結果が良好であった。リードが適切であった（リードがちょうど標的部位に設置された）患者は総死亡および心不全による入院の合計の発現率が最も低く（8%）、全体的な結果において良好であった。リード位置が最良位置近傍であった患者においてはその確率は倍（16%）であり、最良部位から離れていた患者においては4.5倍高かった（36%）。
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In the first randomized clinical trial to report the benefits of using echocardiography - the most common non-invasive tool for diagnostic imaging of the heart - to guide placement of pacemaker leads, researchers found that a patient-tailored approach using software to analyze left ventricle function and guide placement of lead wires can significantly boost clinical benefits from pacemakers, according to research presented at the American College of Cardiology's 60th Annual Scientific Session.

"Optimal placement of pacemaker leads is determined by the location of cardiac scar tissue and areas of delayed heart muscle contraction, which vary considerably among patients," said Fakhar Z. Khan, M.D., clinical research fellow, Cambridge University, Cambridge, U.K. "Our improved results with an individualized approach should change the way pacemaker leads are implanted in this population of patients."

Researchers used speckle tracking echocardiography (STE) to conduct cardiac assessments of 220 patients scheduled for cardiac resynchronization therapy. STE is a technological advance that refines echocardiography. Several studies have confirmed that STE is a simple, inexpensive, quick and accurate way to measure strain and function in the myocardium.

For the 110 patients randomly assigned to the test group, STE measurements guided placement of the lead wire implanted in the left ventricle. Leads for the control group were implanted conventionally, without reference to the STE data. The test group had better results than the control group on all clinical endpoints, including rates of response by reverse remodeling of the left ventricle, a measure of improvement in heart function (70 percent vs. 55 percent), and improvement on a standard scale for heart failure (83 percent vs. 65 percent).

Clinical results correlate with degree of success in directing the lead to the optimal site identified by STE. Across both groups, patients with a concordant lead - placed exactly at the target site - had the lowest combined rate of death from any cause and hospitalization related to heart failure (8 percent) and better results overall. That rate was doubled (16 percent) for patients with a lead adjacent to the optimal site and 4.5 times higher (36 percent) for those with a lead remote from the optimal site. A much higher proportion of patients in the test group had concordant lead placement (61 percent vs. 47 percent).

"STE software can be applied to any existing echocardiographic image at no additional risk to the patient," Khan said. "It makes targeting of the lead feasible at any facility that's already performing echocardiography and has the software in their system to analyze the images. That makes it widely accessible, even for small centers and non-university hospitals, where more and more pacemakers are being implanted."

Study participants were recruited from Papworth and Addenbrooke's Hospitals, Cambridge, U.K, and will continue to have ongoing follow-up. The study was sponsored by Papworth Hospital Foundation Trust and funded through charitable funds and the UK National Institute for Health Research.