Cannon A waves on a CVP tracing are characteristic of which condition?

Cannon A waves on a central venous pressure (CVP) tracing indicate the presence of a significant atrioventricular (AV) dissociation, which is often associated with conditions affecting the heart's rhythm and function. The correct answer reflects that cannon A waves can occur in the context of pulmonary hypertension due to the increased pressure in the pulmonary arteries, which leads to changes in the dynamics of right atrial contraction.

In conditions like pulmonary hypertension, the right atrium may contract against a higher resistance, and when there is dissociation between the atria and ventricles (as can occur in certain arrhythmias), this will result in cannon A waves, which are prominent and occur simultaneously with the ventricular contraction rather than following it.

The other choices reflect different pathophysiological mechanisms that do not specifically lead to the occurrence of cannon A waves in the same way. Tricuspid stenosis, for example, can cause elevated right atrial pressure but is more likely to lead to a different wave form profile, primarily steep A waves due to impaired filling of the right ventricle. Atrial fibrillation also typically presents with irregularly timed and absent A waves on CVP tracing, rather than the pronounced cannon A waves associated with AV