What is the hallmark of RV dysfunction associated with pulmonary embolism?

The hallmark of right ventricular (RV) dysfunction associated with pulmonary embolism is RV dilation. In the context of a significant pulmonary embolism, there is an acute increase in pressure in the right ventricle because it has to overcome increased resistance due to obstruction in the pulmonary arteries. This resistance leads to acute right ventricular strain and dilation as the RV accommodates the increased workload.

As the RV becomes dilated, it can also lead to impaired function. A significant RV dilation can sometimes be visualized on imaging studies like echocardiography, which can confirm the presence of RV dysfunction. This dilation is often associated with a drop in cardiac output and a subsequent rise in systemic venous pressure, which can lead to symptoms of right heart failure if the obstruction is significant and sustained.

Other possible symptoms, such as an increased heart rate, may occur as a compensatory mechanism in response to the decreased cardiac output. However, the definitive sign indicating the structural and functional changes in the RV due to a pulmonary embolism is the dilation of the right ventricle itself. Thus, RV dilation stands out as the most characteristic feature of RV dysfunction in this clinical setting.