Abnormal Heart Rhythms

Abnormal heart rhythms may cause the heart to beat too slow or too fast, or they may disrupt the coordination between the top and bottom chambers of the heart.  This may cause a change in heart function leading to symptoms.  The symptoms associated with abnormal heart rhythms may include palpitations, skipped heart beats, rapid heartbeats, lightheadedness, dizziness, fainting, chest pain, chest pressure or chest discomfort.  Abnormal heart rhythms may be caused by abnormalities within the heart or problems outside of the heart.  Fever, anxiety, thyroid conditions and kidney malfunction are some conditions that may affect the heart rate and rhythm.

Abnormal Heart Rhythms

Types of Abnormal Heart Rhythms


Tachycardias occur when the heart beats too fast. This is usually thought to occur when the heart rate is above 100 beats a minute at rest. Fast heartbeats may originate from the top chambers of the heart, the bottom chambers of heart, or the conducting system of the heart which would include the sinus node, atrioventricular node and conducting bundles. Tachycardias may also occur due to duplication or lack of coordination within the conducting system of the heart.  Treatment for tachycardia may include medications or electrophysiological procedures such as cardiac ablations.


Bradycardias occur when the heart is beating too slowly such as when the heart rate is below 50 beats a minute while awake.  A slow heart rate may be due to either lack of impulse generation from the heart’s natural pacemaker called the sinus node, or reduced transmission of the cardiac impulse by the conduction system.

Heart Block

A disturbance of the conduction of the cardiac impulse from the top chambers to the bottom chambers of the heart is called heart block. When symptoms are severe, treatment may include a cardiac device such as a pacemaker or an implantable cardiac defibrillator.