ペーシングカテーテルリードに起因する収縮期雑音を呈した2例

Pacemaker catheter induced systolic murmurs in two patients

　心内膜人工ペーシング施行時に過剰心音や収縮期雑音が出現することは古くから報告されている^1,3）。今回，ペーシング施行時に新たに高調な収縮期雑音を呈した2例を経験した。1例は一時的ペーシング施行時に聴取されたが，恒久型ペースメーカー（以下PM）植込み後には消失し，また，他の1例では恒久型PM植込み後に生じて持続した。今までこのような心雑音についての報告例は，一時的ペーシング時に見られたものであり，恒久型リードにより生じた例についての報告や，同一例において使用したペーシングワイヤーの差により雑音が出現・消退したことについての報告は，これまでわれわれの知る限りでは見当たらない。また，今回，これらの症例についてドプラー心エコー法を用い，この雑音と三尖弁逆流との関連も検討したので，その成因についての考察も加えて報告する。

Although extracardiac sounds secondary to cardiac pacing have been well known, the murmurs origina-ting in the heart after permanent pacemaker implan-tation and then disappearance after exchanging a temporary to permanent lead have rarely been reported. In this paper, two patients revealing a musical systolic murmur after placement of a trans-venous endocardial pacemaker in the absence of any complications were documented. Case 1 : A 43-year-old man with episodes of dizziness and brady-tachycardiac atrial fibrillation. Immediately after the implantation of a tempolary transvenous right ventricular pacemaker, a high-pitched systolic musical murmur was heard at the lower left sternal border. No murmur was however audible after a permanent pacemaker implantation in this case. Case 2 was a 83-year-old female with coronary heart disease associated with sick sinus syndrome to whom a permanent transvenous right ventricular pacemaker was inserted. A musical systolic murmur occurring immediately after the procedure was best audible at the apex. Although numerous papers concerning the mechanisms of these cardiac murmurs have been reported without reaching conclusive explanations, our data based on two cases examined with Doppler echocardiography did not support the idea of tricus-pid regurgitation as one of causative factors. In the first case, this murmur appeared only a temporary pacing was performed and disappeared after implan-tation of a permanent pacemaker lead. On the cont-rary, however, the 2nd case revealed after the im-plantation of the permanent pacemaker with a rela-tively rigid bipolar lead. It is concluded that these murmurs might be produced by vibrations caused by the pacing catheters and physical propeties could be related the mechanism of this phenomenon.