CRAS study guide
CRAS · Work through your exam, one topic at a time.
The Certified Registered Arrhythmia Specialist (CRAS) is a professional credential intended for clinicians whose work centers on cardiac rhythm care - nurses and allied professionals in electrophysiology labs, device clinics, telemetry units, and arrhythmia practices. It signals that a candidate can interpret rhythms accurately, explain arrhythmia mechanisms, and reason through pharmacologic and device-based management in realistic clinical scenarios. The CRAS study guide has 9 sections and about 2,359 words.
01Basic Cardiac Anatomy and Physiology
Know the conduction pathway in order: SA node → internodal/atrial pathways → AV node → bundle of His → right and left bundle branches → Purkinje network. The SA node sits at the junction of the superior vena cava and right atrium and normally fires at 60–100 bpm; the AV node (40–60 bpm) and Purkinje system (20–40 bpm) are subsidiary pacemakers.
325 words, about 2 min02Electrophysiology and Arrhythmia Mechanisms
Normal myocardial cells have a resting membrane potential near −90 mV maintained largely by the Na+/K+ pump; the fast-response action potential has phases 0 (rapid Na+ influx), 1 (transient K+ efflux), 2 (plateau from Ca2+ influx balancing K+ efflux), 3 (K+ efflux repolarization), and 4 (resting). Pacemaker cells (SA node) lack a stable phase 4 and instead show spontaneous depolarization driven by the funny current (If) and Ca2+ currents - this automaticity is why they fire without external stimulus.
293 words, about 1 min03ECG Interpretation and Rhythm Recognition
Use a systematic method every time: rate, rhythm (regular/irregular), P waves and their relationship to QRS, PR interval, QRS width, axis, and ST/T changes. Rate can be estimated by the 300-150-100-75-60-50 sequence for regular rhythms or by counting QRS complexes in a 6-second strip × 10.
278 words, about 1 min04Diagnostic Testing and Monitoring
Match the test to the question. A 12-lead ECG answers "what is the rhythm now." A Holter monitor (24–48 h continuous) captures frequent or daily symptoms; an event monitor or patch is better for symptoms every few days to weeks; an implantable loop recorder suits infrequent, unexplained syncope or palpitations over months to years.
256 words, about 1 min05Pharmacologic Therapy for Arrhythmias
Know the Vaughan-Williams classes and their prototypical agents and toxicities. Class I (Na+ channel blockers): IA (quinidine, procainamide - prolong repolarization, torsades risk), IB (lidocaine, mexiletine - shorten repolarization, useful in ischemic VT), IC (flecainide, propafenone - avoid in structural heart disease).
277 words, about 1 min06Device Therapy: Pacemakers and ICDs
Pacemakers treat bradyarrhythmias; ICDs treat life-threatening ventricular arrhythmias. Know the NASPE/BBG code: first letter chamber paced (A, V, D), second chamber sensed, third response (I inhibited, T triggered, D dual), fourth rate modulation.
269 words, about 1 min07Catheter Ablation and Electrophysiology Procedures
Catheter ablation destroys arrhythmogenic tissue with radiofrequency (heat) or cryoenergy (cold) to cure or control arrhythmias. It is first-line or strongly favored for symptomatic AVNRT, AVRT (WPW), typical atrial flutter (cavotricuspid isthmus ablation), and increasingly for atrial fibrillation (pulmonary vein isolation).
262 words, about 1 min08Patient Care, Education, and Follow-Up
Care of the arrhythmia patient spans assessment, education, and longitudinal follow-up. Assess symptoms (palpitations, syncope, dyspnea, chest pain), hemodynamic stability, and reversible contributors.
208 words, about 1 min09Safety, Quality, and Professional Practice
Safety and quality underpin arrhythmia care. Know infection prevention for device implantation (preprocedural antibiotics, sterile technique), radiation safety (ALARA, shielding, dose tracking during EP procedures), and procedural time-outs.
191 words, under 1 min