Introduction: Structural changes of myocardium, such as myocardial fibrosis, in hypertrophic cardiomyopathy (HCM) are associated with electrophysiological abnormalities, eg. pathological Q-wave or fragmented QRS (fQRS). Cardiac magnetic resonance (CMR) is the only non-invasive method used to detect and quantify the myocardial fibrosis.
Purpose: Aim of our study was to investigate the correlation between fQRS, Q wave and CMR characteristics in HCM, and their prognostic role.
Methods: In this study we investigated 85 consecutive patients (47 male; 48.4±16.2 years) with HCM, who underwent CMR with late gadolinium enhancement and standard 12-lead ECG. Using cine short-axis images we evaluated left ventricular ejection fraction, volumes, mass and maximal end-diastolic wall thickness (MaxEDWT). On delayed contrast enhancement images the myocardial fibrosis was quantified. Standard 12-lead ECG records of patients with HCM were analysed, we examined the presence of pathological Q-wave and fQRS. During clinical follow-up adverse cardiac events and cardiac complaints were recorded.
Results: Pathological Q-wave was detected in 23 (27%) patients, fQRS was present in 35 (41%) patients. fQRS was present most frequently in inferior leads (21 cases), followed by lateral (15 cases) and anterior leads (13 cases). Patients with fQRS had more myocardial fibrosis (26.1±30.5 vs. 14.6±20.3 g, p<0.05) and higher MaxEDWT (22.8±5.7 vs. 19.9±5.6 mm, p<0.05). There was no difference in the amount of fibrosis and MaxEDWT between patients with and without pathological Q-wave.
During clinical follow-up (881±619 days) one patient died, two patients had adequate ICD therapy, 17 further patients were hospitalized because of arrhythmia, heart failure, syncope or chest pain. Patients with fQRS had more often syncope compared to patients without fQRS (53.3% vs. 9.5%, p<0.01).
Conclusion: Although pathological Q-wave is traditionally considered a myocardial scar marker, we found no difference in the amount of fibrosis between patients with and without pathological Q-wave. In contrast, patients with fQRS had significantly higher amount of fibrosis. fQRS was also associated with higher maximal end-diastolic wall thickness and more frequent syncope.