The diagnoses used in the ECG Quiz are organized in a hierarchy by diagnosis category. The following is the list of Diagnosis Categories used on the site with a couple of examples of each that are used in The ECG Quiz.

Conduction Abnormalities

These are conditions in which the heart’s electrical impulses are delayed or blocked as they travel through the conduction pathways. Examples of diagnoses in this category include:

• First-degree AV Block: Delayed conduction through the AV node.
• Bundle Branch Block (BBB): Delayed conduction through the ventricles.

Electrolytes and Drugs

These findings reflect changes in the heart’s electrical activity caused by imbalances in blood electrolytes or the effects of medications. Examples of diagnoses in this category include:

• Prominent U Waves, Consider Hypokalemia: Elevated potassium levels leading to prominent U waves.
• Short QT Interval, Consider Hypercalcemia: Elevated calcium levels leading to a shortening of the QT interval.

Hypertrophies

These are patterns indicating enlargement or thickening of the heart’s chambers, typically due to increased workload. Examples of diagnoses in this category include:

• Left Ventricular Hypertrophy (LVH): Thickening of the left ventricle, often seen with longstanding hypertension.
• Right Atrial Enlargement (RAE): Abnormal P-wave morphology due to enlargement of the right atrium.

Myocardial Infarctions

These signify tissue death in the heart muscle due to blocked coronary arteries, often characterized by specific ST-segment and Q-wave changes. Examples of diagnoses in this category include:

• Myocardial Infarction, Acute, Anterior: Infarction typically involving leads V1–V4.
• Myocardial Infarction, Acute, Inferior: Infarction typically involving leads II, III, and aVF.

Myocardial Ischemias

These are signs of insufficient blood supply to the heart muscle, seen before infarction occurs. Examples of diagnoses in this category include:

• ST&T Wave Changes, Consider Lateral Ischemia: Suggestive of ischemia in the lateral wall of the left ventricle (e.g., leads I, aVL, V5–V6).
• ST&T Wave Changes, Consider Anterior Ischemia: Suggestive of ischemia in the anterior wall of the left ventricle (e.g., anterior leads V1–V4).

Other ST and T Wave Abnormalities

These encompass ST or T wave changes not explicitly linked to classic ischemia or infarction.

• Early Repolarization: A benign ECG variant characterized by elevated J-points, ST-segment elevation, and prominent terminal QRS notching or slurring, typically in the inferior (II, III, aVF) and lateral (I, aVL, V4-V6) leads.
• Left Ventricular Strain: A pattern of myocardial deformation typically caused by chronic pressure overload or myocardial dysfunction.

Pacemakers

These findings show the presence and activity of artificial pacemakers that electrically stimulate the heart to maintain adequate rate and rhythm. Examples of diagnoses in this category include:

• Pacemaker Failure to Capture in Ventricles (RV, LV, or Both): When the pacemaker delivers an electrical stimulus, but the myocardium fails to depolarize and generate a paced response.
• Pacemaker Failure to Sense in Ventriclesr: When the pacemaker fails to detect intrinsic ventricular activity, leading to inappropriate pacing.

Rhythms

These diagnoses classify the overall heartbeat pattern or origin of impulses. Examples of diagnoses in this category include:

• Sinus Tachycardia: A fast rhythm originating from the sinoatrial (SA) node.
• Atrial Fibrillation: Irregularly irregular rhythm with absent P waves and varying R-R intervals.

Summary Features

This category offers a broad interpretation or overall impression of the ECG. Examples of diagnoses in this category include:

• Artifact: Noise in the ECG signal, such as Baseline Wander, Motion Artifact, and Muscle Artifact.
• Lead Malposition: An incorrect placement of electrodes during recording, potentially leading to misleading waveforms and erroneous interpretations of the heart’s electrical activity.