Introduction
Hypertrophic cardiomyopathy (HCM) is a hereditary disease and the most common cause leading to sudden cardiac death in young people. This disease is characterized by abnormal left ventricular hypertrophy resulted from abnormal array of the myocardial fibers1,2. Ventricular arrhythmias due to irregular arrangements of myofibrils are not only an important cause of mortality in HCM patients but also consequent atrial arrhythmias may result in morbidity and impaired quality of life 3,4. Left ventricular hypertrophy and impaired myocardial relaxation lead to the development of diastolic dysfunction. Elevated left ventricular pressure is reflected back, causing an increase in left atrial pressure. Especially in HCMs accompanied by obstructive and/or systolic anterior motion (SAM)-related mitral regurgitation, the impairment in left atrial functions is more pronounced 5. While increased contractility is observed in the left atrium due to the initial increase in the pressure load; during disease progression, dilatation and fibrosis develop in the left atrium wall over time, called atrial remodeling. Structural remodeling contributes to the development of atrial arrhythmias, especially atrial fibrillation (AF), by causing electrical remodeling over time 6. Previous studies have found out that left atrial enlargement, left atrial volume index (LAVi), and age are predictive of the development of AF in HCM patients7. In addition to the classical echocardiography parameters, the parameters of speckle tracking echocardiography (STE) have been started to be used for the evaluation of left atrial functions. In the paroxysmal atrial fibrillation (PAF) patient group; STE-based left atrial strain was correlated with fibrosis distribution as evaluated by cardiac magnetic resonance imaging (MRI) and, in another study, it was correlated with low voltage areas observed during radiofrequency mapping 8,9.
Myocardial electrical dispersion has been found to be predictive of the development of ventricular arrhythmias in HCM patients as well as in other patient populations. 10,11. In a study conducted by Kawakami et al. on patients at risk for the development of heart failure or AF, atrial dispersion based on STE evaluations was found to be predictive of the development of AF 12.
Structural changes occurring in the left atrium in HCM patients cause electrical dispersion in the left atrium wall and may cause the development of atrial fibrillation. In our study; we investigated the effects of classic parameters (age, the left atrial volume), left atrial strain, and left atrial dispersion; which is a new echocardiography parameter, on AF development in HCM patients.