Fearnot N E, Smith H J
Pacing Clin Electrophysiol. 1986 Nov;9(6):939-47. doi: 10.1111/j.1540-8159.1986.tb06651.x.
Exercise (rate) responsive pacemakers benefit patients by providing increased cardiac output when needed and permitting lower rate during rest. This paper briefly reviews trends in reported studies on rate responsive pacemakers. For patients with reliable atrial rhythms, atrial-triggered pacemakers (DDD) provide physiological ventricular rates unless complications arise. At low rates, A-V synchrony benefits patients with refractory cardiac decompensation; however, in patients with healthy myocardiums, achieving higher pacing rates is more significant than maintaining synchrony. If atrial rhythms are unreliable, an alternative sensor for determining pacing rate is indicated. Pacemakers that respond to changes in right ventricular blood temperature, respiratory rate, QT interval, body vibration (motion), and pH have been implanted in humans. Clinical evaluations have shown that increased pacing rate leads to increased exercise tolerance and cardiac output when needed, independent of the sensor type (DDD, QT, respiratory rate, etc.). The effectiveness of any sensor type to increase pacing rate appropriately requires reliable sensors that respond specifically to the need for increased pacing rate. Sensors for stroke volume, venous oxygen saturation, right atrial or ventricular pressure and catecholamines are also under preclinical investigation. The availability of a reliable, long-term sensor is a key limitation to several techniques including pH, stroke volume, oxygen saturation, pressure, and catecholamines. Sensor technology and clinical effectiveness are the keys to rate responsive pacing.
频率适应性起搏器通过在需要时增加心输出量并在休息时允许较低频率来使患者受益。本文简要回顾了有关频率适应性起搏器的报道研究趋势。对于具有可靠心房节律的患者，心房触发型起搏器（DDD）可提供生理性心室率，除非出现并发症。在低心率时，房室同步对难治性心脏代偿失调患者有益；然而，对于心肌健康的患者，达到更高的起搏频率比维持同步更重要。如果心房节律不可靠，则需要一种用于确定起搏频率的替代传感器。已将对右心室血温、呼吸频率、QT间期、身体振动（运动）和pH值变化作出反应的起搏器植入人体。临床评估表明，在需要时，无论传感器类型（DDD、QT、呼吸频率等）如何，增加起搏频率都会导致运动耐量和心输出量增加。任何传感器类型要适当增加起搏频率，其有效性都需要可靠的传感器，这些传感器能对增加起搏频率的需求作出特异性反应。每搏输出量、静脉血氧饱和度、右心房或心室压力以及儿茶酚胺的传感器也正在进行临床前研究。可靠的长期传感器的可用性是包括pH值、每搏输出量、血氧饱和度、压力和儿茶酚胺在内的几种技术的关键限制因素。传感器技术和临床有效性是频率适应性起搏的关键。
