Lamendola Priscilla, Cambise Nello, Di Renzo Antonio, Tinti Lorenzo, De Vita Antonio, Tremamunno Saverio, Pastena Paola, Belmusto Antonietta, Montone Rocco, Rinaldi Riccardo, Villano Angelo, Lanza Gaetano A
Department of Cardiovascular Sciences, Fondazione Policlinico Universatario A Gemelli IRCCS Rome, Italy.
Facoltà di Medicina e Chirurgia, Università Cattolica del Sacro Cuore Rome, Italy.
Eur Cardiol. 2024 Jun 19;19:e09. doi: 10.15420/ecr.2024.03. eCollection 2024.
Detection of myocardial bridge (MB) at angiography suggests it has a role in ischaemic-related symptoms in patients with angina without obstructive coronary artery disease. However, evidence that MB may cause myocardial ischaemia is limited.
We studied 41 patients with MB of the left anterior descending coronary artery and otherwise normal coronary arteries. Fourteen patients with normal coronary arteries and without MB served as controls. All subjects underwent a maximal treadmill exercise stress test (EST) under ECG monitoring. Standard and speckle-tracking echocardiography were performed at baseline and immediately after peak EST.
EST duration and peak heart rate and systolic pressure were similar in the two groups. A positive EST (ST-segment depression .1 mm) was found in 18 patients in the MB group (43.9%) and none in the control group (p=0.001). No abnormalities in both left ventricle systolic and diastolic function were found between the two groups in the standard echocardiographic evaluation. Global and segmental (anterior, inferior) longitudinal strain (LS) did not differ at baseline between the groups. There was a small increase in global LS during EST in MB patients but not in the control group (p=0.01). Similar trends were found for regional LSs, with differences being significant for the medium (p=0.028) and apical (p=0.032) anterior segments. No differences in echocardiographic parameters and both global and segmental LSs were observed between MB patients with ischaemic ECG changes during EST versus those without.
Our findings do not support the notion that MB results in significant degrees of myocardial ischaemia during maximal myocardial work.
血管造影术中检测到心肌桥（MB）提示其在无阻塞性冠状动脉疾病的心绞痛患者的缺血相关症状中起作用。然而，心肌桥可能导致心肌缺血的证据有限。
我们研究了41例左前降支冠状动脉有心肌桥且冠状动脉其他部位正常的患者。14例冠状动脉正常且无心肌桥的患者作为对照。所有受试者在心电图监测下进行最大运动平板运动试验（EST）。在基线和EST峰值后立即进行标准和斑点追踪超声心动图检查。
两组的EST持续时间、峰值心率和收缩压相似。MB组18例患者（43.9%）EST结果为阳性（ST段压低>1mm），而对照组无一例阳性（p=0.001）。标准超声心动图评估显示两组左心室收缩和舒张功能均无异常。两组之间基线时整体和节段性（前壁、下壁）纵向应变（LS）无差异。MB患者在EST期间整体LS略有增加，而对照组未增加（p=0.01）。区域LS也有类似趋势，中前壁（p=0.028）和心尖前壁（p=0.032）差异显著。在EST期间有缺血性心电图改变的MB患者与无缺血性心电图改变的患者之间，超声心动图参数以及整体和节段性LS均未观察到差异。
我们的研究结果不支持心肌桥在最大心肌负荷期间导致显著程度心肌缺血的观点。
