Division of Cardiovascular Medicine, Lahey Hospital & Medical Center, Burlington, Massachusetts.
Division of Cardiovascular Medicine, Lahey Hospital & Medical Center, Burlington, Massachusetts.
Am J Cardiol. 2021 May 1;146:89-94. doi: 10.1016/j.amjcard.2021.01.026. Epub 2021 Jan 30.
Diagnosing cardiac amyloidosis is challenging and requires a high index of suspicion in patients with an increased left ventricular wall thickness (LVWT). Low QRS voltage on electrocardiogram (ECG) has been regarded as the hallmark ECG finding in cardiac amyloidosis; however, the presence of low voltage can range from 20-74% and the voltage/mass ratio carries a greater diagnostic accuracy than QRS voltage alone. Patients with cardiac amyloidosis can have conduction system infiltration and this may result in a BBB. Therefore, the ECG or mass/voltage criteria established for patients with a narrow QRS in the diagnosis of cardiac amyloidosis may not be applicable in patients with a BBB. We sought to identify criteria to aid in the diagnosis of cardiac amyloidosis in patients with increased LVWT on echocardiogram and with a BBB on ECG. We calculated the total QRS score/LVWT, limb lead QRS score/LVWT, R in lead aVL/LVWT, R in lead I/LVWT, and Sokolow index/LVWT. In patients with an increase in LVWT and BBB, total QRS voltage that is indexed to wall thickness can help distinguish between patients with increased wall thickness who have cardiac amyloidosis from those who have LVH related to a pressure overload state. A unique index of Total QRS Score/LVWT is the best predictor of cardiac amyloidosis with a cutoff value of 92.5 mV/cm which is 100% sensitive and 83% specific for the diagnosis of cardiac amyloidosis. This may be a useful screening tool in patients with an increased wall thickness to raise diagnostic suspicion for cardiac amyloidosis.
诊断心脏淀粉样变具有挑战性，需要在左心室壁增厚（LVWT）增加的患者中高度怀疑。心电图（ECG）上的低 QRS 电压被认为是心脏淀粉样变的标志性 ECG 发现；然而，低电压的存在范围为 20-74%，并且电压/质量比比单独的 QRS 电压具有更高的诊断准确性。心脏淀粉样变患者可能会有传导系统浸润，这可能导致 BBB。因此，用于诊断心脏淀粉样变的窄 QRS 患者的 ECG 或质量/电压标准可能不适用于 BBB 患者。我们试图确定标准，以帮助诊断超声心动图上 LVWT 增加且 ECG 上 BBB 的患者的心脏淀粉样变。我们计算了总 QRS 评分/LVWT、肢体导联 QRS 评分/LVWT、aVL 导联的 R 波/LVWT、I 导联的 R 波/LVWT 和 Sokolow 指数/LVWT。在 LVWT 增加和 BBB 的患者中，与壁厚度指数化的总 QRS 电压可以帮助区分患有心脏淀粉样变的壁厚度增加患者和患有与压力超负荷状态相关的 LVH 的患者。总 QRS 评分/LVWT 的独特指数是心脏淀粉样变的最佳预测指标，截断值为 92.5 mV/cm，对心脏淀粉样变的诊断具有 100%的敏感性和 83%的特异性。对于壁厚度增加的患者，这可能是一种有用的筛查工具，可以提高对心脏淀粉样变的诊断怀疑。
