Yi G, Elliott P, McKenna W J, Prasad K, Sharma S, Guo X H, Camm A J, Malik M
Department of Cardiological Sciences, St. George's Hospital Medical School, London, United Kingdom.
Am J Cardiol. 1998 Dec 15;82(12):1514-9. doi: 10.1016/s0002-9149(98)00696-1.
This study examines the relation of QT dispersion (QTd) on a surface electrocardiogram (ECG) to clinical features and established risk factors of sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HC). One hundred fifty-six consecutive patients with HC (91 men, mean age 41+/-15 years, range 7 to 79) and 72 normal subjects (41 men, mean age 39+/-9 years, range 20 to 60) were studied. Standard 12-lead ECGs were recorded from each subject using a MAC VU electrocardiograph. Patients with nonsinus rhythm, atrioventricular conduction block, QRS duration > 120 ms, age < 15 years, and low amplitude T waves were excluded from the analysis (n=51). Another 22 patients who were receiving amiodarone and/or sotalol therapy were also excluded. QT interval and QTd were measured using automated analysis in the remaining 83 patients (46 men, age 40+/-14 years, range 16 to 76). QT interval (406+/-38 ms), QTc interval (432+/-27 ms), and QTd (43+/-25 ms) were significantly greater in patients with HC than in normal controls (386+/-31 ms, 404+/-16 ms, 26+/-16 ms, respectively) (p <0.0001). QTd was significantly greater in patients with HC with chest pain compared with asymptomatic or mildly symptomatic patients (50+/-28 ms vs 37+/-20 ms, p=0.02). Increased QTd was found in patients with dyspnea New York Heart Association functional classes II/III than in those with dyspnea New York Heart Association functional class I (50+/-27 ms vs 38+/-22 ms, p=0.04). QTd was weakly correlated with maximum left ventricular wall thickness (r=0.228, p=0.038). No significant association was found between QTd and any risk factors for SCD. Thus, patients with HC have increased QTd. The QTd correlates with symptomatic status. Assessment of QTd might provide complementary clinical characterization of patients with HC but its relation to SCD remains uncertain.
本研究探讨肥厚型心肌病（HC）患者体表心电图（ECG）上的QT离散度（QTd）与心脏性猝死（SCD）的临床特征及既定危险因素之间的关系。研究了156例连续性HC患者（91例男性，平均年龄41±15岁，范围7至79岁）和72例正常受试者（41例男性，平均年龄39±9岁，范围20至60岁）。使用MAC VU心电图仪记录每位受试者的标准12导联ECG。分析中排除了非窦性心律、房室传导阻滞、QRS时限>120 ms、年龄<15岁以及T波低振幅的患者（n = 51）。另外22例正在接受胺碘酮和/或索他洛尔治疗的患者也被排除。对其余83例患者（46例男性，年龄40±14岁，范围16至76岁）使用自动分析测量QT间期和QTd。HC患者的QT间期（406±38 ms）、校正QT间期（QTc，432±27 ms）和QTd（43±25 ms）显著高于正常对照组（分别为386±31 ms、404±16 ms、26±16 ms）（p<0.0001）。与无症状或轻度症状患者相比，有胸痛的HC患者QTd显著更高（50±28 ms对37±20 ms，p = 0.02）。纽约心脏协会功能分级为II/III级的呼吸困难患者的QTd高于纽约心脏协会功能分级为I级的呼吸困难患者（50±27 ms对38±22 ms，p = 0.04）。QTd与最大左心室壁厚度弱相关（r = 0.228，p = 0.038）。未发现QTd与SCD的任何危险因素之间存在显著关联。因此，HC患者的QTd增加。QTd与症状状态相关。QTd评估可能为HC患者提供补充性的临床特征描述，但其与SCD的关系仍不确定。
