According to many studies,<unk> s often register in all leads except V6, most frequently in V2 and V3 when the heart rate is greater than 96 beats per minute. Its amplitude is often 0.1–0.33 mV. Particularly difficult is the allocation of the boundaries of the<unk>  on the background of the<unk>  and<unk> , which may partial or complete (in the case of<unk>  the merger. Higher values of heart rate or hypocalcemia<unk>  are superimposed on the<unk>  and in tachycardia — merges with the R-wave of the next cardiac cycle. Prominent<unk> s<unk> s are described as prominent if they are more than 1-2 mm or 25% of the height of the<unk> .) are most often seen in hypokalemia but may be present in hypercalcemia, thyrotoxicosis, or exposure to digitalis, epinephrine and Class 1A and 3 antiarrhythmics, as well as in congenital long QT syndrome, and in the setting of intracranial hemorrhage. An inverted<unk>  may represent myocardial ischemia (and especially appears to have a high positive predictive accuracy for left anterior descending coronary artery disease ) or left ventricular volume overload. A<unk>  can sometimes be seen in normal younger, athletic individuals. The<unk>  increases in adults that are older and less athletic.
U wave
J wave
Delta wave
P wave 
QRS complex
T wave
Mu wave
Delta Wave