Cardiac Testing Basics
Match the cardiac test to the clinical question — what each test answers, its limits, and what not to order.
Learning Objectives
- 1.Match the common cardiac tests to the clinical questions they answer.
- 2.Choose between stress modalities at a conceptual level.
- 3.Recognize the situations where a test is unsafe or low-yield.
Overview
The skill isn’t memorizing tests — it’s asking "what question am I answering?" and choosing the test that answers it. Reflexive panels waste time and money and can delay care.
The testing menu and what each answers
- •EKG — rhythm, ischemia, conduction, chamber clues; fast and first-line.
- •Ambulatory monitor (Holter/event/patch/loop) — symptom-rhythm correlation; choose duration by symptom frequency.
- •Echocardiogram — structure and function (EF, valves, wall motion, effusion, pulmonary pressures).
- •Stress testing — functional ischemia / risk stratification in stable patients.
- •Coronary CT angiography / calcium score — anatomy and plaque burden in selected stable patients.
- •Coronary angiography (cath) — definitive coronary anatomy and revascularization.
Choosing a stress test (concepts)
- •Can they exercise and has an interpretable baseline EKG? → exercise treadmill (± imaging).
- •Can’t exercise, or uninterpretable EKG (LBBB, paced, baseline ST changes)? → pharmacologic stress with imaging.
- •Imaging (nuclear/echo) adds localization and works when the EKG won’t be interpretable.
- •APPs select/order tests per guidelines; reading the images is the imager’s role.
Match test to question (examples)
- •Stable exertional chest pain, low-intermediate risk → stress test or coronary CTA.
- •Palpitations, infrequent → longer ambulatory monitor or loop recorder.
- •Dyspnea, ? heart failure → echo (plus BNP).
- •Suspected ACS / unstable → not a stress test; troponin, EKG, and admission/cath pathway.
When NOT to test (or to escalate instead)
- •Don’t stress-test a patient with suspected ACS or who is unstable — they need the acute pathway.
- •Don’t order an elective test that delays urgent evaluation of a high-risk presentation.
- •Consider renal function/contrast and pregnancy before certain tests.
Escalate
A high-risk or unstable presentation is a "stabilize and escalate" situation, not a "schedule an outpatient stress test" situation.
Limitations to remember
- •Every test has false positives/negatives; interpret with pretest probability.
- •A normal stress test doesn’t guarantee no disease, especially with a high-risk story.
- •Calcium score of 0 is reassuring in selected patients but is not used in acute chest pain.
Common beginner mistakes
- •Ordering an echo when the question is rhythm (needs a monitor), or vice versa.
- •Stress-testing the wrong (unstable/ACS) patient.
- •Ignoring pretest probability when interpreting results.
Nurse / MA workflow connection
- •MAs deliver prep instructions (NPO/caffeine/med holds) — confirm holds per protocol.
- •Nurses route results and flag abnormal/critical findings back to you.
Mini cases
Stable 55-year-old, exertional chest pressure, normal EKG, can walk, intermediate risk.
Reasonable next test?
Show answer
A functional stress test (exercise treadmill ± imaging) or coronary CTA is reasonable for stable intermediate-risk chest pain — not an immediate cath, and definitely not nothing.
A patient with rare palpitations (a few times a month), normal exam and EKG.
What test answers the question?
Show answer
Symptom-rhythm correlation over a longer window — an extended patch monitor or loop recorder sized to the symptom frequency — not a 24-hour Holter that may miss the events.