MS-DRG 309 – Cardiac Arrhythmia and Conduction Disorders with CC
A Medical DRG in MDC 05 (Diseases & Disorders of the Circulatory System). Inpatient cases group to DRG 309 when the ICD-10-CM principal diagnosis is one of the 58 codes listed below and a secondary diagnosis on the complication or comorbidity (CC) list is present. Its FY 2026 relative weight is 0.7357 with a geometric mean length of stay of 2.3 days.
Severity family
The grouper first assigns the case to MDC 05 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here), then applies the severity split from secondary diagnoses: with MCC → 308; with CC → 309; without CC/MCC → 310.
Principal Diagnosis Codes 58 codes · 8 categories
I44 Atrioventricular and left bundle-branch block10 codes
- I44.0 Atrioventricular block, first degree
- I44.1 Atrioventricular block, second degree
- I44.2 Atrioventricular block, complete
- I44.30 Unspecified atrioventricular block
- I44.39 Other atrioventricular block
- I44.4 Left anterior fascicular block
- I44.5 Left posterior fascicular block
- I44.60 Unspecified fascicular block
- I44.69 Other fascicular block
- I44.7 Left bundle-branch block, unspecified
I45 Other conduction disorders11 codes
- I45.0 Right fascicular block
- I45.10 Unspecified right bundle-branch block
- I45.19 Other right bundle-branch block
- I45.2 Bifascicular block
- I45.3 Trifascicular block
- I45.4 Nonspecific intraventricular block
- I45.5 Other specified heart block
- I45.6 Pre-excitation syndrome
- I45.81 Long QT syndrome
- I45.89 Other specified conduction disorders
- I45.9 Conduction disorder, unspecified
I47 Paroxysmal tachycardia8 codes
- I47.0 Re-entry ventricular arrhythmia
- I47.10 Supraventricular tachycardia, unspecified
- I47.11 Inappropriate sinus tachycardia, so stated
- I47.19 Other supraventricular tachycardia
- I47.20 Ventricular tachycardia, unspecified
- I47.21 Torsades de pointes
- I47.29 Other ventricular tachycardia
- I47.9 Paroxysmal tachycardia, unspecified
I48 Atrial fibrillation and flutter9 codes
- I48.0 Paroxysmal atrial fibrillation
- I48.11 Longstanding persistent atrial fibrillation
- I48.19 Other persistent atrial fibrillation
- I48.20 Chronic atrial fibrillation, unspecified
- I48.21 Permanent atrial fibrillation
- I48.3 Typical atrial flutter
- I48.4 Atypical atrial flutter
- I48.91 Unspecified atrial fibrillation
- I48.92 Unspecified atrial flutter
I49 Other cardiac arrhythmias10 codes
- I49.01 Ventricular fibrillation
- I49.02 Ventricular flutter
- I49.1 Atrial premature depolarization
- I49.2 Junctional premature depolarization
- I49.3 Ventricular premature depolarization
- I49.40 Unspecified premature depolarization
- I49.49 Other premature depolarization
- I49.5 Sick sinus syndrome
- I49.8 Other specified cardiac arrhythmias
- I49.9 Cardiac arrhythmia, unspecified
Q24 Other congenital malformations of heart1 code
- Q24.6 Congenital heart block
R00 Abnormalities of heart beat3 codes
T82 Complications of cardiac and vascular prosthetic devices, implants and grafts6 codes
- T82.110A Breakdown (mechanical) of cardiac electrode, initial encounter
- T82.111A Breakdown (mechanical) of cardiac pulse generator (battery), initial encounter
- T82.120A Displacement of cardiac electrode, initial encounter
- T82.121A Displacement of cardiac pulse generator (battery), initial encounter
- T82.190A Other mechanical complication of cardiac electrode, initial encounter
- T82.191A Other mechanical complication of cardiac pulse generator (battery), initial encounter
Procedure Codes
Frequently Asked Questions
What is MS-DRG 309?
MS-DRG 309 (Cardiac Arrhythmia and Conduction Disorders with CC) is a medical DRG in MDC 05 (Diseases & Disorders of the Circulatory System). Its FY 2026 relative weight is 0.7357 with a geometric mean length of stay of 2.3 days.
What is the difference between DRG 308, 309, 310?
All 3 share the same base category; the severity of secondary diagnoses separates them: 308 (with MCC), 309 (with CC), 310 (without CC/MCC). A major complication or comorbidity (MCC) places the case in the highest-weighted DRG of the family; a CC in the middle; neither in the lowest.
How many diagnosis codes group to DRG 309?
58 ICD-10-CM principal diagnosis codes group to this DRG, spanning 8 three-character categories.
What is the relative weight of DRG 309?
The FY 2026 relative weight of this DRG is 0.7357, meaning reimbursement of roughly 0.74 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
