Impact of common rhythm disturbances on echocardiographic measurements and interpretation

Transthoracic echocardiography (TTE) remains the workhorse of noninvasive cardiac imaging, allowing to easily obtain precise information on cardiac structure and function. Over time, Doppler interrogation of blood flow velocities, direction, and timing in several locations within the heart became the primary method for haemodynamic assessment, replacing cardiac catheterization in most clinical settings and providing valuable diagnostic and prognostic information on a wide spectrum of cardiac pathological processes. Abnormalities in heart rate, rhythm, and intracardiac electrical conduction are commonly encountered during the performance of echocardiographic studies. Up to now, only a modest attention has been given to the impact of these abnormalities on the reading and interpretation of echocardiographic examination and this assessment has not yet been carried out in a global and systematic way. Tachyarrhythmias, bradyarrhythmias and atrioventricular conduction disturbances influence cardiac structure and mechanics as well as Doppler flow patterns. For this reason, and to be able to avoid misinterpretation, echocardiographers must be aware of the consequences of these common rhythm disturbances on echocardiographic findings. This narrative review aims to describe the current knowledge on this topic, focusing on the expected mechanical effects and Doppler patterns observed on transthoracic echocardiography in patients with common rhythm (tachycardia and bradycardia, atrial flutter and fibrillation and ectopic beats) and conduction disturbances (namely, atrioventricular block).