The sinus node develops an abnormal rate or rhythm. A patient has a heart block. Heart block is a condition in which the electrical signal cannot travel normally down the special pathways to the ventricles. If there is no conduction, the beat generally originates from the ventricles and is very slow. There are many types of arrhythmias.
Ventricular arrhythmias begin in the ventricles.
In general, ventricular arrhythmias caused by heart disease are the most serious. Sometimes an arrhythmia can be detected by listening to the heart with a stethoscope. However, the electrocardiogram is the most precise method for diagnosing the arrhythmia. An arrhythmia may not occur at the time of the exam even though symptoms are present at other times. In such cases, tests will be done if necessary to find out whether an arrhythmia is causing the symptoms.