ICD-10-CM 2027
ICD-10 code for QT interval prolonged
From the official ICD-10-CM alphabetic index entry “Prolonged, prolongation (of) › QT interval”. Page updated September 29, 2026.
About coding QT interval prolonged
The ICD-10-CM code for QT interval prolonged is R94.31 (Abnormal electrocardiogram [ECG] [EKG]).
Within R94.3 (abnormal results of cardiovascular function studies), R94.31 is specifically for abnormal electrocardiogram [ECG] [EKG]. Related codes cover result of cardiovascular function study, unspecified (R94.30) and result of other cardiovascular function study (R94.39).
Don't report R94.31 together with the conditions in its Excludes1 note: long QT syndrome (I45.81).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Don't confuse with (Excludes1 for R94.31)
- long QT syndrome (I45.81)
Common questions about QT interval prolonged ICD-10 codes
What is the ICD-10 code for QT interval prolonged?
- R94.31 — Abnormal electrocardiogram [ECG] [EKG].
Is R94.31 billable?
- Yes. R94.31 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R94.31 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R94.31 as a principal diagnosis.
Is R94.31 a CC or MCC?
- No. R94.31 is neither a CC nor an MCC under MS-DRG v44.0.