The electrocardiogram
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Assistant Editor-in-Chief: Rim Halaby
Fundamentals of EKG
Fundamentals of EKG
Basic Principles of Interpretation of an EKG
- Introduction to EKG
- How to read an EKG
- Normal sinus rhythm
- QRS axis and voltage
- Overall overview on electrocardiography
EKG Complexes
EKG Intervals
Abnormal Findings on the EKG
- Delta wave
- H wave
- K wave
- Low QRS voltage
- Nonspecific ST-segment and T-wave changes
- NSSTW changes
- Osborn wave
- P wave alternans
- Poor R wave progression
- PR interval alternans
- QRS complex alternans
- QT prolongation
- Retrograde P wave
- Sine wave pattern
- T wave alternans
- T wave inversion
- Tombstone ST elevation
- U wave
Tachyarrhythmias
Tachyarrhythmias
Atrial Arrhythmias
- Atrial fibrillation
- Atrial flutter
- Ectopic atrial rhythm
- Multifocal atrial tachycardia (MAT)
- Paroxysmal atrial tachycardia (PAT) with block
- Premature atrial contractions (PAC)
- Sinus tachycardia
- Supraventricular tachycardia
- Wandering atrial pacemaker
Ventricular Arrhythmias
Bradycardia and Conduction Abnormalities
Bradycardia and Conduction Abnormalities
EKG Findings in Diseases
EKG Findings in Diseases
Cardiac Hypertrophy and Dilatation
- Left ventricular hypertrophy (LVH)
- Right ventricular hypertrophy (RVH)
- Biventricular hypertrophy
- Left atrial enlargement
- Right atrial enlargement
- Biatrial enlargement
Acute Myocardial Infarction
Pre-excitation Syndromes
Cardiomyopathies
Congenital Heart Diseases
- Dextrocardia
- Atrial septal defect
- Ventricular septal defect
- Tetralogy of Fallot
- The heart in conjoined twins
- Congenital heart block
Inherited Diseases
Other Heart Diseases
EKG in Other Disease States
EKG Abnormalities in Electrolyte Disturbances
EKG Abnormalities in Electrolyte Disturbances
EKG Abnormalities in Normal Pregnancy (Physiological Changes)
EKG Abnormalities in Normal Pregnancy (Physiological Changes)
- Left axis deviation
- Right axis deviation
- Q wave in lead III
- T wave inversion
- Increased R/S ratio in V1 and V2
- ST-segment depression (usually after anesthesia for C-section)
Drug Effects on the EKG
Drug Effects on the EKG
Technical Issues and Potential Errors in Interpretation
Technical Issues and Potential Errors in Interpretation
Additional Information
Additional Information
Looking for the patient version?
© 2026 MyEClinic – IFTM Institut für Telematik in der Medizin GmbH