For the client experiencing severe chest pain and shortness of breath, what is the immediate intervention required?

In a scenario where a client is experiencing severe chest pain and shortness of breath, the immediate intervention should focus on obtaining a clear and rapid assessment of the heart's electrical activity. A 12-lead ECG is crucial because it helps to identify any abnormalities in the heart rhythm, potential ischemia, or signs of a myocardial infarction (heart attack). This real-time data is essential for initiating appropriate treatments and interventions.

While other options may be relevant later in the diagnostic and treatment process, they are not the immediate focus. For instance, a CT scan is useful for visualizing structural issues but does not provide the urgent cardiac information required in this acute situation. Cardiac catheterization is an invasive procedure used to diagnose and treat specific heart conditions, but it cannot be performed without prior assessment through an ECG, and it is not immediate. Placement of an IV may be needed for medication administration, but it does not provide critical information about the heart's condition.

Therefore, the prompt acquisition of a 12-lead ECG allows healthcare professionals to swiftly evaluate the heart and respond accordingly, making it the most appropriate immediate intervention in this context.