Final answer:
In the context of a new diagnosis of pericarditis, the manifestation of cardiac tamponade is a paradoxical pulse, which is a notable symptom along with other signs like hypotension and distended neck veins.
Step-by-step explanation:
A client who has a new diagnosis of pericarditis and is showing signs of cardiac tamponade would exhibit certain specific symptoms. Cardiac tamponade occurs when excess fluid, often blood, accumulates in the pericardial space, exerting pressure on the heart and impeding its function. Manifestations of cardiac tamponade include hypotension, distended neck veins, muffled heart sounds, and a paradoxical pulse, which is a significant drop in blood pressure during inspiration by more than 10 mmHg.