Assessment of left atrial mechanics and left ventricular functions using 3D speckle-tracking echocardiography in patients with inappropriate sinus tachycardia

Purpose Inappropriate sinus tachycardia (IST) is defined as a sinus heart rate > 100 bpm at rest (with a mean 24-h heart rate > 90 bpm not due to primary causes) and is associated with distressing symptoms of palpitations. The effect of IST on left atrial (LA) and left ventricular (LV) myocardial dynamics is uncertain. Thus, the aim of this study was to identify early changes in LA mechanics and LV myocardial functions in patients with IST using 3D-STE. Methods Sixty patients with IST and 65 age- and gender-matched controls were enrolled into the study. Conventional 2D echocardiography and 3D-STE were performed, and LAS-r, LAS-active, LAS-passive, LAEF, LAEF-active, LAEF-passive, LV-GLS, LV-GCS, LV-GAS, and LV-GRS were obtained for every patient. Results The LAS-r and LAS-active were significantly decreased in the IST group than in the control group (p < 0.001, p = 0.004, respectively). The multivariate logistic regression models revealed that LAS-r (p = 0.008, Odds ratio (OR) 5.98, 95% confidence interval (CI) 2.36-11.18), and LAS-active (p = 0.032, OR 2.16, 95% CI 1.97-4.69) were found to be independent factors for predicting IST. Conclusions The present study is the first to evaluate the left atrial mechanics and left ventricular functions in the patients with IST using 3D-STE. We found that IST had a negative effect on left atrial mechanics. According to our findings, we can say that IST is not a completely innocent, benign clinical condition, but rather, it causes subclinical left atrial dysfunction.