If you are keen for your baby to be introduced to swimming before he is six weeks old your partner, or someone else, can take him. Some private baby swim classes start as early as four weeks but most classes at public pools begin at around 4 months.
Electrocardiogram (EKG, ECG) General Description. As the heart undergoes depolarization and repolarization, the electrical currents that are generated spread not only within the heart, but also throughout the body. This electrical activity generated by the heart can be measured by an array of electrodes placed on the body surface.
For nerve and skeletal muscle cells, it is the opening (also called activation) of voltage-gated Na+ channels that produces the rapid upstroke (also called the rising phase or depolarizing phase) of the action potential. This is also true for ventricular and atrial cardiac muscle cells.