11.6 EKG and Cardiovascular Reference Checklist

EKG Reference

A 12-lead electrocardiogram (EKG/ECG) uses 10 electrodes - 4 limb and 6 chest - to record 12 views of the heart. EKG questions are high yield because they fuse anatomy, patient prep, troubleshooting, urgent symptoms, and scope. Verify the order and identity, explain the test, expose and prep the skin (dry, clip excess hair, abrade lightly), preserve privacy, place leads precisely, and route the tracing per policy.

Limb Lead Placement (Mnemonic)

"Snow over grass" (white over green on the right), "smoke over fire" (black over red on the left) keeps limb leads straight. Reversing RA/LA inverts lead I and mimics pathology.

Chest Lead Landmarks (Memorize Exactly)

Standard paper speed is 25 mm/sec with calibration at 10 mm/mV; one small box = 0.04 sec, one large box = 0.2 sec. Mention these only if the stem references them - the CCMA sets them, the provider interprets.

Artifact Troubleshooting

Red Flags = Immediate Escalation

Chest pressure, radiating pain, severe dyspnea, syncope, cyanosis, diaphoresis, pallor, or sudden confusion: stop adjusting electrodes and notify the provider or activate the emergency protocol. Never tell the patient the tracing is "normal" or name a cardiac diagnosis - that is outside CCMA scope.

Last-Minute Self-Test

Reading the Strip the CCMA Way

The CCMA does not diagnose, but recognizing basic waveform components helps you spot a usable tracing and describe artifact accurately. The P wave represents atrial depolarization, the QRS complex ventricular depolarization, and the T wave ventricular repolarization. A normal adult heart rate on the strip is 60-100 beats per minute; you can estimate rate quickly by counting large boxes between two R waves and dividing into 300 (one large box apart equals 300 bpm, two equals 150, three equals 100, and so on).

Recognizing that a tracing is too noisy to read - rather than interpreting the rhythm - is the appropriate CCMA skill and the reason artifact correction is emphasized.

Skin Prep and Lead Quality

Most poor tracings trace back to skin contact. Clean oily or lotioned skin with alcohol and let it dry, gently abrade dead skin if the device allows, and clip rather than shave excess hair so electrodes adhere. Use fresh, in-date electrodes with moist gel; dried-out electrodes are a top cause of wandering baseline. Place electrodes on flat, fleshy areas and keep lead wires untangled and off the floor to limit interference. Ensure the patient is warm, relaxed, lying still with arms and legs supported, because shivering and muscle tension create somatic-tremor artifact that no amount of filtering fully removes.

Ambulatory and Stress Monitoring Scope

Beyond the resting 12-lead, the CCMA may set up a Holter monitor (continuous recording over 24-48 hours) or an event monitor (patient-activated over weeks), instructing the patient to keep a symptom diary and avoid getting electrodes wet. During a treadmill or pharmacologic stress test, the CCMA assists with monitoring and emergency readiness but never directs the protocol or interprets results. Across all of these, the scope rule is unchanged: the CCMA obtains a clean tracing, reports symptoms and red flags immediately, and routes the interpretation to the provider.

Cardiac Anatomy and Vocabulary the Exam Expects

A handful of cardiovascular terms recur in EKG stems and patient-communication items. Blood flows from the body into the right atrium, to the right ventricle, out the pulmonary artery to the lungs, back via the pulmonary veins to the left atrium, into the left ventricle, and out the aorta - the left ventricle is the thickest chamber because it pumps to the whole body. The electrical impulse normally starts in the sinoatrial (SA) node, the heart's natural pacemaker, travels to the atrioventricular (AV) node, and down the bundle of His and Purkinje fibers.

Recognize that tachycardia is a fast rate, bradycardia is slow, and arrhythmia or dysrhythmia is any irregular rhythm - terms you may chart from the monitor reading but never diagnose. Coronary arteries supply the heart muscle itself, which is why their blockage causes the chest pain that makes cardiac red flags so urgent.

Lead Reversal and Quality Checks Before You Print

Before handing a tracing to the provider, run a quick quality check: confirm all 10 electrodes are attached, that the limb leads are not reversed (a curiously inverted lead I or an upside-down P wave often means right and left arm electrodes are swapped), that the baseline is flat and free of the artifacts described above, and that the strip is labeled with the patient's name, date, and time. A common exam trap presents an abnormal-looking tracing whose real problem is a placement or reversal error rather than a cardiac event; the correct CCMA action is to recheck and re-run the lead, not to alarm the patient.

Clean placement, calm patients, and fresh electrodes prevent the majority of repeat tracings.