CCT Cheat Sheet 2026

The 30 highest-yield CCT facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which of the following lead groups provides the primary view of the inferior wall of the left ventricle? → II, III, aVF
2. To reduce somatic tremor artifact in an anxious or cold patient, the technician should FIRST: → Reassure the patient, ensure warmth, and allow time to relax before recording
3. Torsades de Pointes (TdP) is a specific form of polymorphic VT associated with which underlying ECG abnormality? → Prolonged QT interval (congenital or acquired)
4. A patient taking amiodarone is most likely to show which ECG finding? → Prolonged QT interval
5. Blood returning from the lungs enters the heart through which structure? → Pulmonary veins into the left atrium
6. True posterior MI is best confirmed on a 12-lead ECG by which finding in the standard leads? → Tall broad R waves and ST depression in V1-V2 (mirror of posterior STEMI)
7. Hyperkalemia is most associated with which ECG change? → Peaked, tall T waves
8. A left bundle branch block (LBBB) on a 12-lead ECG is characterized by which set of findings? → Broad notched R in I, aVL, V5-V6 and deep QS or rS in V1, QRS ≥120 ms
9. In a standard 12-lead ECG, lead aVR views the heart from which angle? → Right shoulder, looking toward the heart's base from above-right
10. A 24-hour Holter recording reveals 847 premature ventricular contractions (PVCs). Which characteristic would make this finding most concerning? → PVCs occurring in runs of 3 or more (non-sustained VT)
11. Which antiarrhythmic drug is most commonly used to chemically cardiovert atrial fibrillation with a rapid onset IV formulation in a hospital setting in the US? → Ibutilide
12. A patient undergoing Holter monitoring is instructed to keep a diary. What is the primary purpose of this diary? → To correlate the patient's symptoms with the ECG recording.
13. Which of the following are considered the standard bipolar limb leads, forming the basis of Einthoven's triangle? → I, II, III
14. Ambulatory Holter monitoring is particularly effective for diagnosing which of the following conditions? → Intermittent or paroxysmal arrhythmias.
15. Which valve separates the left atrium from the left ventricle? → Mitral (bicuspid) valve
16. Which of the following frequently reduces the utility of Holter monitoring as a diagnostic tool? → Patient noncompliance with keeping track of events
17. A CCT performing a 12-lead ECG notes a regular wide-complex tachycardia at 180 bpm with AV dissociation. What is the most likely diagnosis? → Ventricular tachycardia (VT)
18. A CCT notices a patient's rhythm changes from sinus tachycardia to a regular narrow-complex tachycardia at 160 bpm after IV adenosine. What has likely occurred? → Adenosine unmasked atrial flutter with 2:1 block
19. Which layer of the heart wall is composed of cardiac muscle and is primarily responsible for the heart's pumping action? → Myocardium
20. Which ECG pattern is described as diffuse concave ('saddle-back') ST elevation in most leads with PR depression, without reciprocal changes? → Pericarditis
21. Which of the following ions contributes most to the depolarizing current in pacemaker cells? → Calcium
22. ST elevation in leads V1-V4 combined with a new right bundle branch block most strongly suggests: → Anterior MI with septal involvement
23. Which of the following heart conditions is brought on by the parasympathetic nervous system's actions? → Decreased rate of SA node pacing
24. What is the correct intercostal space and anatomical location for electrode V4? → 5th intercostal space at the midclavicular line
25. Which of the following describes how action potentials should travel through the heart? → SA node → AV node → bundle branches → Purkinje fibers
26. On a standard ECG tracing, which waveform represents the electrical activation and depolarization of the ventricular myocardium? → QRS complex
27. Which precordial lead is typically located at the 4th intercostal space, right sternal border? → V1
28. When monitoring a patient on quinidine therapy, a CCT should be most alert to which dangerous ECG change? → QT interval exceeding 500 ms
29. Which electrolyte abnormality is most likely responsible for a prolonged QT interval combined with U waves and muscle cramps? → Hypomagnesemia combined with hypokalemia
30. Tricyclic antidepressant (TCA) overdose is most dangerous on the ECG because it causes: → QRS widening greater than 100 ms indicating high risk of arrhythmia