Treatment of cardiac arrhythmia with electrical ablation. False-colour digital angiogram (X-ray image) of the heart, showing the position of various catheters used for ablation - the treatment of arrhythmia (abnormal heart rhythm) by the selective destruction of small sections of heart muscle (myocardium) with an electric current. The heart is highlighted in yellow. The outlines of various catheters are visible: those with fine, S-shaped tips are used to introduce contrast medium; the others are for gathering electrocardiography (ECG) data & for delivering electrical current to the heart muscle. Yellow heart on blue background.