Cardio

–Atrial systole

• –Signal from SA node spreads through
• atria and depolarization begins

• –Correlates with phase 0 of
• myocardial action potential

• –Firing of AV node and ventricular
• depolarization

• –Atrial repolarization and
• diastole

• –Correlates with phase 1 of
• myocardial action potential

–Ventricular systole

–Contraction and ejection of blood

• –Correlates with phase 2 of
• myocardial action potential

–Ventricular repolarization

• –Immediately before ventricular
• diastole

• –Correlates with phase 3 of
• myocardial action potential

Genetic or acquired

Caused by drugs and electrolyte abnormalities

• –Antiarrhythmics, antipsychotics, antibiotics,
• methadone

–Hypokalemia, hypomagnesemia

• Procedure to open blocked or narrowed coronary arteries
• Done during the left cardiac catheterization
• Balloon angioplasty alone or with stent placement

Coronary artery bypass grafting

nOpen heart surgery

nGrafts harvested from legs, chest, or arms

nGrafts are used as a “detour” around the blocked portion of the coronary artery