- 學位論文
嚴重主動脈瓣狹窄病患之心律複雜度分析
Heart Rhythm Complexity Analysis in Patients with Severe Aortic Stenosis
摘要
[背景]主動脈瓣狹窄是一種進行性的疾病，一旦嚴重度加劇而開始產生症狀，病患預後迅速變差，對於嚴重主動脈瓣狹窄的病患，心因性猝死更是令人忌憚的問題，而自律神經系統功能異常與心律不整和猝死的發生可能有相關性。在過去的研究中，心率變異度藉由自律神經系統調節，可應用於評估心血管疾病病患之死亡及心律不整風險，然而心率變化呈現高度不規則卻非隨機的特性，傳統線性分析方法著重在測量心跳的變異度，這樣的方法用以描述心律複雜度是不夠的，非線性方法被運用來進一步了解生理訊號長時間的關聯性，其中去趨勢波動分析及多尺度熵是目前最常用的非線性分析方法，過去文獻中對於嚴重主動脈瓣狹窄病患的心律複雜度研究不甚完整，此類病患可能在心律複雜度上產生異常，影響其預後，在本研究中，針對嚴重主動脈瓣狹窄的病患，除了線性分析外，我們也將利用上述兩種非線性分析方式以了解其心律複雜度的變化。 [方法]我們收錄經由胸前心臟超音波確診為嚴重主動脈瓣狹窄的病患，對照組為年齡性別配對且無主動脈瓣狹窄之健康族群，所有試驗參與者接受24小時連續性心電圖記錄，針對每一個參與者選擇四小時穩定的日間心跳間期用以分析，我們利用傳統線性分析、去趨勢波動分析及多尺度熵來分析心律複雜度。 [結果]共有35位嚴重主動脈瓣狹窄病患及70位對照組被收錄到本研究做最終的分析，在線性分析的指數中，主動脈瓣狹窄病患的低頻/高頻比值顯著較低，然而其餘線性指數皆無顯著差異，去趨勢波動分析中，主動脈瓣狹窄病患的DFAα1顯著較低，而在多尺度熵分析中，短時間尺度及長時間尺度的指數(slope 1-5, area 1-5,及 area 6-20)皆顯著地在主動脈瓣狹窄病患中較低，非線性指數用於嚴重主動脈瓣狹窄的鑑別度是可接受的(ROC曲線下面積DFAα1: 0.639, slope 1-5: 0.622, area 1-5: 0.627, 及area 6-20: 0.696)。 [結論]本研究藉由非線性方法中的去趨勢波動分析及多尺度熵發現嚴重主動脈瓣狹窄病患有較差的心律複雜度，而頻域分析的低頻/高頻比值亦有顯著差異。
並列摘要
Background: Aortic stenosis is a progressive disease, and the prognosis declines drastically once the severity increases and symptoms develop. Sudden cardiac death is a particular concern for patients with severe aortic stenosis. Autonomic dysfunction may play a role in the occurrence of arrhythmia and sudden death. Heart rate variability (HRV), an estimation of cardiac autonomic modulation, has been reported to predict the risk of mortality and arrhythmia in people with cardiovascular disease. Conventional linear HRV variables measure the variation in heart rate alone and are insufficient to describe the complexity of heart rhythm. Nonlinear methods are used to better understand the long-range correlations of physiological signals, of which detrended fluctuation analysis (DFA) and multiscale entropy (MSE) are the most frequently used. The information of heart rhythm complexity in severe aortic stenosis is inadequate form previous literature. These aortic stenosis patients may have impaired heart rhythm complexity, affecting long term outcome. In this study, in addition to linear HRV analysis, we investigated heart rhythm complexity using DFA and MSE in patients with severe aortic stenosis. Methods: Patients meeting the definition of severe aortic stenosis by transthoracic echocardiography were enrolled. Age- and sex-matched participants without significant aortic stenosis were enrolled as healthy controls. All participants received 24-hour ambulatory Holter ECG recording. A stable 4-hour daytime period of RR intervals was selected for analysis. Heart rhythm complexity was analyzed using conventional linear methods, DFA and MSE. Results: A total of 35 patients with severe aortic stenosis and 70 control subjects were enrolled. In the time domain variables, low frequency/high frequency (LF/HF) ratio was significantly lower in the aortic stenosis group. There were no significant differences among the other variables in linear analysis between the aortic stenosis and control groups. In DFA analysis, DFAα1 was significantly lower in the aortic stenosis group. In MSE analysis, slope 1-5, area 1-5 (area under the MSE curve for scale 1 to 5) and area 6-20 (area under the MSE curve for scale 6 to 20) in the aortic stenosis group were significantly lower than those in the control group. The discriminative power for severe aortic stenosis, which was quantified using areas under receiver operating characteristic curves, was modest (DFAα1: 0.639, slope 1-5: 0.622, area 1-5: 0.627, and area 6-20: 0.696). Conclusions: The patients with severe aortic stenosis had worse heart rhythm complexity (DFA and MSE) and LF/HF ratio than the patients without aortic stenosis.