Sinus rhythms

Heart rhythm comes from sinoatrial node and is normal.

• Sinus tachycardia (fast heartbeat),
• Sinus bradycardia (slow heartbeat),
• Sinus arrhythmia (the heart rate fluctuates form beat to beat, with respiration).

Blocks

There is an interruption or "blockage"of the conduction process thus extending the time period.

• 1st degree (No change in heart rate occurs & treatment is unnecessary),
• 2nd degree (partial), when some atrial impulses fail to reach the ventricles,
• 3rd degree (Complete) atrial impulses are not conducted to the ventricles, which beat independently at 40 beats/min,
• Bundle branch block (R &/or L bundles are affected and conduction is slowed). Can be symptomless, L bundle branch block tends to be more serious than R.

Sinus node disease (delay)

Caused by degeneration of the sinus node.

• Leads to dropped beats, fainting or collapse.

Premature beats

Focus of electrical activity occurs early. Known as ectopic beats or extrasystoles.

(see below).*

• Atrial ectopic beats (focus in atria),
• Ventricular ectopic beats (focus in ventricles).

Supraventricular Arrhythmias

occur above the ventricles.

• Supraventricular tachycardia (fast heartbeat),
• Atrial flutter (regular and fast),
• Atrial fibrillation (irregular and fast),
• Wolff-Parkinson - White syndrome (fast heartbeat through extra pathway).

Ventricular Arrhythmias

occur in the ventricles, a dangerous situation.

• Ventricular tachycardia (fast heartbeat usually assoc. with severe heart disease),
• Ventricular fibrillation (a type of cardiac arrest, & death will ensue without defibrillation).