Some people with<unk> s are born with this condition. Many others acquire it as a consequence of heart disease. People with<unk> s may still be quite active, and may have nothing more remarkable than an abnormal appearance to their ECG. However, when<unk><unk> s are complex and diffuse in the<unk>  systems, or are associated with additional and significant ventricular muscle damage, they may be a sign of serious underlying heart disease. In more severe cases, a pacemaker may be required to restore an optimal electrical supply to the heart muscle.
Bundle branch block
Right bundle branch block
Left bundle branch block
Sinoatrial block
Pre-excitation syndrome
Sinoatrial arrest
Left anterior fascicular block
Atrioventricular block