ECG Interpretation Lessons

The atrial heart rate is rapid (250-350 bpm), but ventricular rate is often slower. ECG heart rhythm will be regular or irregular. P wave and PR interval are not observable, but saw-toothed flutter waves are present. The QRS complex will typically be normal (0.06-0.10 sec).

In a bundle branch block ECG, the P wave features should be normal and the PR interval is normal (0.12-0.20 sec). The QRS complex will usually be wide, over 0.12 sec.

The P wave will be normal while the PR interval is prolonged, over 0.20 sec. The QRS complex will typically be normal (0.06-0.10 sec). A first degree atrioventricular (AV) block occurs when electrical impulses moving through the AV node are delayed, but not blocked. The adjective first degree signifies that conduction is only slowed with no missed beats.

The ECG rhythm will be regular with a very slow heart rate of about 20-40 bpm. The PR interval is not measurable while the P wave will be absent. The QRS complex will typically be over 0.10 sec (wide) and will have a bizarre appearance.

Heart rate will usually be slow (40-60 bpm) and the ECG rhythm will appear regular. The P wave will be present before, during (hidden) or after QRS. When visible the P wave is inverted. The PR interval is not measurable. The QRS complex will typically be in the range of 0.06-0.10 sec (normal). Learn more about junctional rhythms.

The ECG rhythm will appear regular with a fast heart rate (100-180 bpm). The P wave can appear before, during (hidden) or after QRS. When visible it will be inverted. The PR interval is short or absent. The QRS complex will typically be 0.06-0.10 sec (normal).

The ECG rhythm will appear irregular with a fast heart rate over 100 bpm. The P wave features often change shape and size from beat to beat with at least three differing forms. Observe that the PR interval is variable. The QRS complex will typically be normal (0.06-0.10 sec). In addition, the T wave can be distorted.

A normal (60-100 bpm) heart rate and an ECG regular. The P wave appears normal and before each QRS. The PR interval is normal (0.12-0.20 sec). The QRS complex will also be normal (0.06-0.10 sec).

The ECG rhythm will appear irregular with heart rate that is slow or normal. Observe that the pacemaker spikes are not followed by p waves or QRS complexes.

The ECG rhythm will appear irregular and pacemaker spikes do not appear or appear irregularly.

Normal heart rate and ECG rhythm will be present. The P wave and PR interval will both be normal. The QRS complex is also normal. Pacemaker spikes will precede the P wave on the ECG tracing.

The ECG rhythm will appear irregular with heart rate that is usually normal but depends on underlying rhythm. The P wave will appear premature, positive and a shape that is abnormal. Observe that the PR interval is normal or longer. The QRS complex will typically be 0.10 sec or less.

The ECG rhythm will appear regular with premature beats with heart rate that is the underlying rate. The P wave is present before, during (hidden) or after QRS. If the P wave is visible, it is inverted. Observe that the PR interval is absent or short. The QRS complex will typically be normal (0.06-0.10 sec).

The ECG rhythm will appear irregular with heart rate that is the underlying rate. The P wave features absent. Observe that the PR interval is not measurable. The QRS complex will typically be wide (> 0.10 sec) with a bizarre appearance.

The ECG rhythm will appear irregular with an absent P wave and the PR interval is not measurable. The QRS complex will typically be wide (> 0.10 sec) with a bizarre appearance. The PVC appears on every second beat.

The ECG rhythm will be irregular. The PR interval is not measurable and the P wave is absent. The QRS complex will typically over 0.10 sec (wide) and bizarre in appearance. The PVC appears every fourth beat.

The ECG rhythm will be irregular. The PR interval is not measurable and the P wave is absent. The QRS complex will typically over 0.10 sec (wide) with a bizarre appearance. The PVC appears every third beat.

The ECG rhythm will appear irregular but with progressively longer pr interval lengthening. The P wave is normal. Observe that the PR interval becomes progressively longer until a QRS complex is missed, then cycle repeats. The QRS complex will typically be normal (0.06-0.10 sec).

The ECG rhythm will appear regular (atrial) and irregular (ventricular) with heart rate that is characterized by atrial rate that is usually faster than ventricular rate (usually slow). The P wave has a normal form, but more P waves than QRS complexes. The PR interval is normal or prolonged. The QRS complex will typically be normal or wide.

The ECG rhythm will appear irregular. Sinoatrial block occurs with a normal or slow heart rate. The P wave will be normal and the PR interval will be normal (0.12-0.20 sec). The QRS complex will typically be normal (0.06-0.10 sec). The pause time is an integer multiple of the p-p interval.

A sinus arrest or sinus pause ECG rhythm will appear irregular due to a pause with heart rate that is normal to slow. The P wave is normal. The PR interval is normal (0.12-0.20 sec). An ECG sinus arrest QRS complex will typically be normal (0.06-0.10 sec). Pause time is not an integer multiple of the p-p interval.

The ECG rhythm will appear irregular, varying with respiration with heart rate that is normal (60-100 bpm) and rate may increase during inspiration. The P wave is normal and the PR interval is also normal (0.12-0.20 sec). The QRS complex will typically be normal (0.06-0.10 sec). Heart rate frequently increases with inspiration, decreasing with expiration.

Sinus bradycardia is characterized by a slow heart rate (under 60 bpm). The ECG rhythm will be regular. The P wave and the PR interval are normal. The QRS complex will typically be normal (0.06-0.10 sec).

Sinus tachycardia is characterized by a fast heart rate of over 100 bpm. The ECG rhythm will be regular. The P wave is normal but may merge with T wave at very fast rates. Observe that the PR interval is normal (0.12-0.20 sec). The QRS complex will typically be normal (0.06-0.10 sec). The QT interval shortens with increasing heart rate.

The ECG rhythm will appear regular and heart rate that will be fast (150-250 bpm). The P wave will be merged with T wave. The PR interval is normal (0.12 sec) but can be difficult to measure. The QRS complex will typically be normal (.10 sec).

The ECG rhythm will appear regular, but atrial and ventricular rhythms are independent. Heart rate is characterized by atrial rate usually normal but faster than the ventricular rate. The P wave will have normal shape and size but may appear within QRS complexes. The PR interval is absent: the atria and ventricles beat independently. The QRS complex will typically be normal, but wide if junctional escape focus.

The ECG rhythm will appear highly irregular with an unmeasurable heart rate. The P wave is absent, the PR interval is not measurable and no QRS complex. The ECG tracings is a wavy line.

The ECG rhythm will appear regular with heart rate that is fast (100-250 bpm). The P wave is absent and the PR interval is not measurable. The QRS complex will typically be wide (>0.10 sec) with a bizarre appearance.

The ECG rhythm will appear regular with a fast (100-250 bpm) heart rate. The P wave is absent and the PR interval is not measurable. The QRS complex will typically be wide (>0.10 sec) and bizarre looking.

The ECG rhythm will appear regular or irregular with heart rate that is fast (100-300 bpm). The P wave is absent and the PR interval is not measurable. The QRS complex will typically be normal or wide (>0.10 sec) with a bizarre shape.

The ECG rhythm will appear irregular with heart rate that is fast (200-250 bpm). The P wave is absent and the PR interval is not measurable. The QRS complex will typically be wide (>0.10 sec). Its shape is characterized by a gradual change in the ECG amplitude and a twisting of the QRS complexes around a line.

The ECG rhythm will be irregular with a normal heart rate. The P wave can be observed changing shape and size from beat to beat (at least three different forms). The PR interval is variable in duration. The QRS complex will typically be normal (0.06-0.10 sec) and the T wave normal. If heart rate exceeds 100 bpm, then rhythm may be multifocal atrial tachycardia (MAT).

The ECG rhythm will appear regular unless atrial fibrillation is present. Heart rate is normal (60-100 bpm). The P wave is normal. Observe that the PR interval is can be short (less than 0.12 sec). The QRS complex will typically be wide (over 0.12 sec). A delta wave (positive or negative) distorts the early part of the QRS complex.