| I40 | Acute myocarditis |
| I40.0 | Infective myocarditis |
| I40.1 | Isolated myocarditis |
| I40.8 | Other acute myocarditis |
| I40.9 | Acute myocarditis, unspecified |
| I41 | Myocarditis in diseases classified elsewhere |
| I42 | Cardiomyopathy |
| I42.0 | Dilated cardiomyopathy |
| I42.1 | Obstructive hypertrophic cardiomyopathy |
| I42.2 | Other hypertrophic cardiomyopathy |
| I42.3 | Endomyocardial (eosinophilic) disease |
| I42.4 | Endocardial fibroelastosis |
| I42.5 | Other restrictive cardiomyopathy |
| I42.6 | Alcoholic cardiomyopathy |
| I42.7 | Cardiomyopathy due to drug and external agent |
| I42.8 | Other cardiomyopathies |
| I42.9 | Cardiomyopathy, unspecified |
| I43 | Cardiomyopathy in diseases classified elsewhere |
| I44 | Atrioventricular and left bundle-branch block |
| I44.0 | Atrioventricular block, first degree |
| I44.1 | Atrioventricular block, second degree |
| I44.2 | Atrioventricular block, complete |
| I44.3 | Other and unspecified atrioventricular block |
| I44.30 | Unspecified atrioventricular block |
| I44.39 | Other atrioventricular block |
| I44.4 | Left anterior fascicular block |
| I44.5 | Left posterior fascicular block |
| I44.6 | Other and unspecified fascicular block |
| I44.60 | Unspecified fascicular block |
| I44.69 | Other fascicular block |
| I44.7 | Left bundle-branch block, unspecified |
| I45 | Other conduction disorders |
| I45.0 | Right fascicular block |
| I45.1 | Other and unspecified right bundle-branch 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 |
| I45.8 | Other specified conduction disorders |
| I45.81 | Long QT syndrome |
| I45.89 | Other specified conduction disorders |
| I45.9 | Conduction disorder, unspecified |
| I46 | Cardiac arrest |
| I46.2 | Cardiac arrest due to underlying cardiac condition |
| I46.8 | Cardiac arrest due to other underlying condition |
| I46.9 | Cardiac arrest, cause unspecified |
| I47 | Paroxysmal tachycardia |
| I47.0 | Re-entry ventricular arrhythmia |
| I47.1 | Supraventricular tachycardia |
| I47.2 | Ventricular 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 flutter |
| I48.0 | Paroxysmal atrial fibrillation |
| I48.1 | Persistent atrial fibrillation |
| I48.11 | Longstanding persistent atrial fibrillation |
| I48.19 | Other persistent atrial fibrillation |
| I48.2 | Chronic atrial fibrillation |
| I48.20 | Chronic atrial fibrillation, unspecified |
| I48.21 | Permanent atrial fibrillation |
| I48.3 | Typical atrial flutter |
| I48.4 | Atypical atrial flutter |
| I48.9 | Unspecified atrial fibrillation and atrial flutter |
| I48.91 | Unspecified atrial fibrillation |
| I48.92 | Unspecified atrial flutter |
| I49 | Other cardiac arrhythmias |
| I49.0 | Ventricular fibrillation and flutter |
| I49.01 | Ventricular fibrillation |
| I49.02 | Ventricular flutter |
| I49.1 | Atrial premature depolarization |
| I49.2 | Junctional premature depolarization |
| I49.3 | Ventricular premature depolarization |
| I49.4 | Other and unspecified 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 |