Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, M5G1X8, Canada.
J Cardiovasc Magn Reson. 2011 Aug 24;13(1):43. doi: 10.1186/1532-429X-13-43.
Diastolic dysfunction of the right ventricle (RV) is common after repair of tetralogy of Fallot. While restrictive physiology in late diastole has been well known, dysfunction in early diastole has not been described. The present study sought to assess the prevalence and mechanism of early diastolic dysfunction of the RV defined as delayed onset of the tricuspid valve (TV) flow after TOF repair.
The study population consisted of 31 children with repaired TOF (mean age ± SD, 12.3 ± 4.1 years) who underwent postoperative cardiovascular magnetic resonance (CMR). The CMR protocol included simultaneous phase-contrast velocity mapping of the atrioventricular valves, which enabled direct comparison of the timing and patterns of tricuspid (TV) and mitral (MV) valve flow. The TV flow was defined to have delayed onset when its onset was > 20 ms later than the onset of the MV flow. The TV and MV flow from 14 normal children was used for comparison. The CMR results were correlated with the findings on echocardiography and electrocardiography.
Delayed onset of the TV flow was observed in 16/31 patients and in none of the controls. The mean delay time was 64.81 ± 27.07 ms (8.7 ± 3.2% of R-R interval). The delay time correlated with the differences in duration of the TV and MV flow (55.94 ± 32.88 ms) (r = 0.90, p < 0.001). Delayed onset was associated with prolongation of the RV ejection time in 9 and delayed onset and cessation of the pulmonary arterial flow in 4. Delayed onset was not associated with timing changes in the pulmonary artery in 3. The patients with delayed onset showed reduced RV ejection fraction (p = 0.01). However, the two groups did not show significant differences in TV E/A ratio, ventricular end-diastolic volumes, left ventricular ejection fraction, pulmonary regurgitant fraction, heart rate, PR interval and QRS duration.
Early diastolic dysfunction with delayed onset of TV flow is common after TOF repair, and is associated with reduced RV ejection fraction. It is a further manifestation of interventricular dyssynchrony and represent an additional mechanism of ventricular diastolic dysfunction.
右心室（RV）舒张功能障碍在法洛四联症修复后很常见。虽然人们已经熟知晚期舒张期的限制生理现象，但早期舒张功能障碍尚未被描述。本研究旨在评估 RV 早期舒张功能障碍的患病率和机制，该障碍定义为法洛四联症修复后三尖瓣（TV）血流的起始延迟。
研究人群包括 31 名接受过术后心血管磁共振（CMR）检查的修复后的法洛四联症患儿（平均年龄 ± 标准差，12.3 ± 4.1 岁）。CMR 方案包括房室瓣的相位对比速度映射的同步进行，这使 TV 和 MV 瓣流的时间和模式的直接比较成为可能。当 TV 血流的起始延迟大于 MV 血流的起始 20ms 时，定义为 TV 血流的起始延迟。比较了 14 名正常儿童的 TV 和 MV 血流。CMR 结果与超声心动图和心电图的结果相关。
在 16/31 例患者中观察到 TV 血流的起始延迟，而在对照组中均未观察到。平均延迟时间为 64.81 ± 27.07ms（8.7 ± 3.2%的 R-R 间期）。延迟时间与 TV 和 MV 血流持续时间的差异相关（55.94 ± 32.88ms）（r = 0.90，p < 0.001）。9 例 RV 射血时间延长，4 例肺动脉血流起始和终止延迟与延迟起始相关。在 3 例患者中，肺动脉的起始时间无变化。延迟起始的患者 RV 射血分数降低（p = 0.01）。然而，两组在 TV E/A 比值、心室舒张末期容积、左心室射血分数、肺动脉反流分数、心率、PR 间期和 QRS 持续时间方面无显著差异。
法洛四联症修复后 TV 血流起始延迟的早期舒张功能障碍很常见，与 RV 射血分数降低有关。它是室间隔不同步的进一步表现，代表心室舒张功能障碍的另一种机制。
