• atrial
  • The rub is best heard during the maximal movement of the heart within the pericardial sac, namely, during atrial systole, ventricular systole, and the filling phase of early ventricular diastole. (wikipedia.org)
  • occur
  • The effusion can occur rapidly (as in the case of trauma or myocardial rupture), or over a more gradual period of time (as in cancer). (wikipedia.org)