Tanabe A, Mohri T, Ohga M, Yoshiga O, Hidaka Y, Ikeda H, Hiyamuta K, Koga Y, Toshima H
Third Department of Internal Medicine, Kurume University School of Medicine, Japan.
Jpn Heart J. 1990 May;31(3):309-17. doi: 10.1536/ihj.31.309.
To assess the effects of pacing-induced left bundle branch block on left ventricular (LV) systolic and diastolic performance, we performed digital subtraction ventriculography while simultaneously measuring LV pressure with a catheter tip micromanometer. The subjects included 10 patients with a sinus rhythm, a normal QRS duration and PR interval within 0.22 sec. LV performance was assessed during both right atrial pacing (AP) and atrioventricular sequential pacing (AVP) at the same pacing rate. The atrioventricular pacing interval during AVP was adjusted to be the maximal interval that showed the QRS configuration seen during complete right ventricular pacing. LV end-diastolic pressure and volume during AVP did not differ from those during AP. Peak positive and negative dp/dt during AVP were significantly lower than those during AP. Time constants were also significantly longer during AVP. The QRS duration during AVP significantly correlated with end-systolic volume and time constants, and inversely correlated with ejection fraction and +dp/dt. These observations indicated that conduction disturbance per se, induced by AVP, could not only impair LV systolic performance but also diastolic performance, possibly due to asynchronous contraction and relaxation of the left ventricle.
为评估起搏诱发的左束支传导阻滞对左心室（LV）收缩和舒张功能的影响，我们进行了数字减影心室造影，同时用导管尖端微测压计测量左心室压力。研究对象包括10例窦性心律、QRS时限正常且PR间期在0.22秒以内的患者。在相同的起搏频率下，分别于右心房起搏（AP）和房室顺序起搏（AVP）期间评估左心室功能。将AVP期间的房室起搏间期调整为显示完全右心室起搏时所见QRS形态的最大间期。AVP期间的左心室舒张末期压力和容积与AP期间无差异。AVP期间的峰值正负dp/dt显著低于AP期间。AVP期间的时间常数也显著延长。AVP期间的QRS时限与收缩末期容积和时间常数显著相关，与射血分数和+dp/dt呈负相关。这些观察结果表明，AVP诱发的传导障碍本身不仅会损害左心室收缩功能，还会损害舒张功能，这可能是由于左心室收缩和舒张不同步所致。
