Karaca Ilgin, Durukan Polat, Dagli Necati, Yavuzkir Mustafa, Ikizceli Ibrahim, Balin Mehmet
Department of Cardiology, Firat University Hospital, Elazig, Turkey.
Adv Ther. 2008 Dec;25(12):1303-14. doi: 10.1007/s12325-008-0120-0.
A sharp increase in blood pressure, increase in atrial pressure and atrial strain, left ventricular diastolic dysfunction, and left ventricular hypertrophy (LVH) lead to heterogeneity and instability in atrial conduction. The resulting physiopathological situation may elevate maximum Pwave duration (P(max)) and P-wave dispersion (PWD) in electrocardiography. The objective of our study was to explore the effect of the sudden change in atrial hemodynamics on P(max) and PWD, which may indicate the risk of atrial fibrillation (AF) development in hypertensive urgency.
The study included patients diagnosed as hypertensive urgency (systolic blood pressure > or =180 mmHg, diastolic blood pressure > or =110 mmHg). Nitroprusside was started at a dose of 0.2 microg/kg/min, and the ensuing dose was arranged according to blood pressure. Echocardiography and electrocardiography were used to noninvasively measure changes in diastolic function and PWD and P(max), respectively.
The study enrolled 102 patients (mean age 57.9+/-11.6 years; 32 [31.4%] males, and 70 [68.6%] females). P(max) decreased from 99.9+/-11.1 msec (95% confidence intervals [CI] 97.7, 102) to 88.5+/-9.3 msec (95% CI 86.6, 90.3) (P<0.001), while PWD decreased from 60.1+/-7.4 msec (95% CI 58.7, 61.6) to 43.9+/-6.7 msec (95% CI 42.5, 45.2) (P<0.001). In addition, most patients had LVH and diastolic dysfunction. After nitroprusside treatment improvements in indicators of diastolic functions such as E/A ratio, deceleration time, and isovolumetric relaxation time were observed.
The change observed in P(max) and PWD in hypertensive urgency may be associated with the rapid change in blood pressure and atrial strain, sympathetic nervous system activation, relative myocardial ischemia, and left ventricular diastolic dysfunction. Rapid regulation of blood pressure with nitroprusside brought about a marked decrease in P(max) and PWD in our patients. This improvement was interpreted as atrial conduction acquiring a stable and homogeneous character, which may reduce the risk of AF development in hypertensive urgency.
血压急剧升高、心房压力和心房应变增加、左心室舒张功能障碍以及左心室肥厚（LVH）会导致心房传导的异质性和不稳定性。由此产生的生理病理状况可能会使心电图中的最大P波时限（P(max)）和P波离散度（PWD）升高。我们研究的目的是探讨心房血流动力学的突然变化对P(max)和PWD的影响，这可能预示着高血压急症患者发生心房颤动（AF）的风险。
该研究纳入了被诊断为高血压急症（收缩压≥180 mmHg，舒张压≥110 mmHg）的患者。硝普钠起始剂量为0.2 μg/kg/min，随后根据血压调整剂量。分别使用超声心动图和心电图无创测量舒张功能以及PWD和P(max)的变化。
该研究共纳入102例患者（平均年龄57.9±11.6岁；男性32例[31.4%]，女性70例[68.6%]）。P(max)从99.9±11.1毫秒（95%置信区间[CI] 97.7，102）降至88.5±9.3毫秒（95% CI 86.6，90.3）（P<0.001），而PWD从60.1±7.4毫秒（95% CI 58.7，61.6）降至43.9±6.7毫秒（95% CI 42.5，45.2）（P<0.001）。此外，大多数患者存在LVH和舒张功能障碍。硝普钠治疗后，观察到舒张功能指标如E/A比值、减速时间和等容舒张时间有所改善。
高血压急症中观察到的P(max)和PWD变化可能与血压和心房应变的快速变化、交感神经系统激活、相对性心肌缺血以及左心室舒张功能障碍有关。硝普钠对血压的快速调节使我们研究中的患者P(max)和PWD显著降低。这种改善被解释为心房传导获得了稳定且均匀的特性，这可能会降低高血压急症患者发生AF的风险。
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