Cardiac Arrhythmias and Heart Block ICD-10-CM codes

I49.9 is cardiac arrhythmia unspecified and should only be used when no specific rhythm is documented. Common specific codes are I49.1 premature atrial contractions, I49.3 premature ventricular contractions, I49.5 sick sinus syndrome (including tachycardia-bradycardia syndrome), and I49.01 ventricular fibrillation. Atrial fibrillation and flutter are coded from I48 and are covered in a separate guide.

Paroxysmal tachycardia is I47. Supraventricular tachycardia is I47.10 (unspecified), I47.11 (inappropriate sinus tachycardia), or I47.19 (other SVT such as AVNRT). Ventricular tachycardia is I47.20 (unspecified), I47.21 (torsades de pointes), or I47.29 (other). Sinus tachycardia (R00.0), bradycardia (R00.1), and palpitations (R00.2) are symptom codes from chapter 18; they are not reported when a definitive arrhythmia is diagnosed.

Conduction disorders are I44 and I45. AV block is coded by degree: I44.0 first degree, I44.1 second degree (Mobitz I or II), I44.2 complete (third degree), and I44.30 when the degree is not stated. Left bundle branch block is I44.7, right bundle branch block is I45.10, bifascicular block is I45.2, trifascicular block is I45.3, long QT syndrome is I45.81, and Wolff-Parkinson-White is I45.6. Add Z95.0 for a patient with a pacemaker in place.

Cardiac arrest is I46.-: I46.2 when due to an underlying cardiac condition, I46.8 for another underlying condition, and I46.9 when the cause is unknown. When arrest occurs during an admission for another condition, the arrest is a secondary diagnosis; if the patient is resuscitated and the cause is never established, I46.9 may be principal.