Myocardial bridging is associated with exercise‐induced ventricular arrhythmia and increases in QT dispersion

Abstract

BackgroundA myocardial bridge (MB) has been associated with ventricular arrhythmia and sudden death during exercise. QT dispersion (QTd) is a measure of abnormal repolarization and may predict ventricular arrhythmia. We investigated the frequency of ventricular arrhythmias during exercise and the QTd at rest and after exercise, in patients with an MB compared to a normal cohort.MethodsWe studied the rest and stress ECG tracings of patients with an MB suspected by focal septal buckling on exercise echocardiography (EE) (Echo‐MB group, N = 510), those with an MB confirmed by another examination (MB group, N = 110), and healthy controls (Control group, N = 198).ResultsThe frequency of exercise‐induced premature ventricular contractions (PVCs) was significantly higher in the Echo‐MB and MB groups compared with the Control group (both p < .001). In all, 25 patients (4.9%) in the Echo‐MB group, seven patients (6.4%) in the MB group and no patients in the Control group had exercise‐induced non‐sustained ventricular tachycardia (NSVT). There was no difference in the baseline QTd between the groups. In the Echo‐MB and MB groups, QTd postexercise increased significantly when compared with baseline (both p < .001). Patients with NSVT had a higher frequency of male gender and an even greater increase in QTd with exercise compared with the non‐NSVT group.DiscussionThere is an increased frequency of exercise‐induced PVCs and NSVT in patients with MBs. Exercise significantly increases QTd in MB patients, with an even greater increase in QTd in MB patients with NSVT. Exercise in MB patients results in ventricular arrhythmias and abnormalities in repolarization.

Highly increased Troponin I levels following high-intensity endurance cycling may detect subclinical coronary artery disease in presumably healthy leisure sport cyclists: The North Sea Race Endurance Exercise Study (NEEDED) 2013

“…A study by Kramer et alThere is limited knowledge on the consequences of myocardial bridging and the risk of sport-related cardiac events. Exercise-induced premature ventricular complexes and non-sustained ventricular arrhythmias have also been described to be more frequent in subjects with myocardial bridging(208), as well as case-reports of myocardial infarction and sudden death(209). It is interesting that both of our subjects had highly elevated cTn following the race, and this might suggest a supplydemand mismatch in these individuals.…”

The Myocardial Bridge: Potential Influences on the Coronary Artery Vasculature

“…MB is reportedly associated with several types of cardiomyopathy 69–73 or arrhythmia. 74–76 MB-induced focal myocardial ischemia may account for the prognosis of hypertrophic cardiomyopathy 69 and the development and prognosis of takotsubo cardiomyopathy. 71–73 In terms of the association between MB and arrhythmia, exercise-induced QT dispersion has been shown to be increased in patients with MB, which suggests that MB-induced focal myocardial ischemia leads to arrhythmia.…”

“…71–73 In terms of the association between MB and arrhythmia, exercise-induced QT dispersion has been shown to be increased in patients with MB, which suggests that MB-induced focal myocardial ischemia leads to arrhythmia. 74–76…”

A case of myocardial infarction due to myocardial bridging alone

“…1,2 MB without critical stenosis is generally considered as a harmless clinical anomaly in coronary angiography (CAG), but in some cases myocardial ischaemia, infarction, vasospasm, cardiac arrhythmias, ventricular rupture and sudden cardiac death have been reported. [3][4][5][6][7] We describe an acute myocardial infarction in a premenopausal woman due to MB alone, confirmed in a series of angiographic examinations, including optical coherence tomography (OCT).…”