med-hints

Most heart attacks-- myocardial infarctions occur when a portion of the heart can’t get enough oxygen and it is dying.   One of the arteries, the pipe that brings blood to part of the ventricle is blocked, and the chamber that pumps the blood to the body and brain stops receiving oxygen.   Arteries are long muscular tubes with smooth inner linings.   As we age fatty plaques, “speed bumps” develop.   Most heart attacks start when one of the plaques rupture and gunk starts spilling out.   Platelets then cover the opening and a clot forms.   If the clot is large enough to prevent blood flow, and a second (collateral) artery doesn’t supply blood to the area, a portion of the heart muscle dies.   Then blood stops flowing to the body and brain. At times the electrical system of the heart is disrupted. The muscular fibrils that normally contract simultaneously, begin to quiver and twitch erratically and the ventricle stops pumping blood.   We call ...

  On January 2023 a football player for the Buffalo Bills named Damar Hamlin was tackling an opponent and the opposing player’s shoulder struck his chest.   Both players fell.   When Hamlin stood he took a few steps, then collapsed.   His heart had stopped working.   One of the team’s health people came onto the field, began CPR, and, using an AED shocked the heart. A moment later the heart muscle started pumping blood to the man’s body. The ventricles of the heart are finely woven assemblages of small muscle fibrils that contract in unison.   They propel oxygen containing blood to the brain and the rest of the body.   When the heart is traumatized by a blow or a myocardial infarction, the fibrils can stop working as a team.   Then start quivering or contracting independently, and the ventricle doesn’t compress.   Blood stops flowing.   We call the accompanying EKG electrical pattern ventricular fibrillation.   The cells of the ...