Rubenstein Jason C, Freher Mark, Kadish Alan, Goldberger Jeffrey J
Division of Cardiology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Pacing Clin Electrophysiol. 2010 Aug;33(8):911-9. doi: 10.1111/j.1540-8159.2010.02725.x. Epub 2010 Mar 26.
Inappropriate sinus tachycardia (IAST) is a supraventricular tachycardia originating from the sinus node. Proposed etiologies for this symptom complex include autonomic dysfunction, abnormal automaticity, or hypersensitivity of the sinus node.
Patients with IAST were identified by symptomatic tachycardia, with P-wave morphology consistent with origination from a sinus location. A matched set of control subjects was included. Hourly heart rate (HR) was measured as the average HR during each one hour period on an ambulatory 24-hour Holter monitor. Patients were further divided into two subgroups based on average daily HR < or = 80 and >80 bpm. Harmonic analysis was used to evaluate diurnal variation.
The mean HR was 86.0 +/- 12.8 beats per minute (bpm) in the IAST group and 73.9 +/- 8.6 bpm in the control group (P = 0.056). There was an increased overall heart rate for the IAST group, which appeared to be more prominent in the morning hours. In the IAST subgroup with average daily HR < or = 80, hourly HR appears similar to controls for the period 8 pm-8 am. However, in the late AM, the IAST group had an increase in HR not seen in the control subjects. In the IAST subgroup with average HR > 80, there appeared to be a fixed difference in HR compared to the control group, without hourly change.
Patients with IAST and elevated average daily HR exhibit normal diurnal variation around a higher mean HR. In contrast, patients with IAST and lower average daily HR had an exaggerated morning rise in HR. These diurnal patterns may be useful to classify the pathophysiology of IAST.
不适当窦性心动过速（IAST）是一种起源于窦房结的室上性心动过速。该症状复合体的推测病因包括自主神经功能障碍、异常自律性或窦房结超敏反应。
通过症状性心动过速识别IAST患者，其P波形态与起源于窦房位置一致。纳入一组匹配的对照受试者。每小时心率（HR）通过24小时动态心电图监测仪上每个一小时时间段的平均HR来测量。患者根据平均每日HR≤80和>80次/分钟进一步分为两个亚组。采用谐波分析评估昼夜变化。
IAST组的平均HR为86.0±12.8次/分钟（bpm），对照组为73.9±8.6 bpm（P = 0.056）。IAST组的总体心率增加，在早晨时段似乎更为明显。在平均每日HR≤80的IAST亚组中，晚上8点至早上8点期间每小时HR与对照组相似。然而，在上午晚些时候，IAST组的HR出现了对照组未出现的增加。在平均HR>80的IAST亚组中，与对照组相比，HR似乎存在固定差异，且无每小时变化。
平均每日HR升高的IAST患者在较高平均HR周围表现出正常的昼夜变化。相比之下，平均每日HR较低的IAST患者早晨HR升高更为明显。这些昼夜模式可能有助于对IAST的病理生理学进行分类。
