Posts Tagged ‘refractory rv shock’

Right ventricular infarction (RVMI ) is a  common  cardiac emergency in coronary care units. It can be termed as a mechanical complication of infero-posterior STEMI .However ,  around 10 % of anterior  MI do develop this complication . Onset of refractory hypo-tension in spite of correcting hypovolemia  suggests  RVMI.RVMI generally comes under class 3  (Cidar Siani /Diamond -Forester classification of STEMI )  , ie   silent lung with systemic hypotension.       (RV shock requires an unique definition , as it can not be included in traditional  definition of cardiogenic shock as the PCWP is likely to be normal.

How to manage a full blown RVMI  who is not showing  signs of improvement ?

Following is an extract  from our coronary care unit experience

(do not ask for evidence for everything !)

  • Consider immediate angiogram  to know the  anatomy of the problem .Try opening the RCA which is most  likely to be  the culprit (Any associated critical  LCX /LAD lesion  must be attended too ! )If  the duration of MI is beyond 36 hours  culprit lesion may be  left untouched or at least not our primary target !
  • Inotropic support (Doubtamine continuous infusion is preferred .Milrinone  for the rich !)
  • There is no specific RV assist devices available.(LV  assist device has no role in RV )
  • Restrict fluid (Opposite  to RVMI guidelines) There have been instances of  overzealous fluid therapy resulting intra-cardiac  hypervolemia. IVS encroaching LV worsening the cardiac index .
  • Pacing is  definitely required in severe bradycardia or CHB .  Dual chamber pacing is the  ideal  choice to maintain AV synchrony as we desperately need  the  atrial booster pumb  for a failing RV . (Please realise , VVI  pacemakers ,  can still save lives as it takes care of extreme bradycardias  effectively )
  • PCWP in the setting  of RVMI is an  unreliable parameter of true cardiac function.(In almost 90 % of RVMi some degree of LVMI is present ) . In RVMI  PCWP is determined by a  delicate balance between LVEDP and the  onward stroke volume from a failing RV .) The alter tend to bring the PCWP down former would keep it high . Which component is  operating at a given point is a  wild guess  . The situation get quiet complex in the setting of multiple vaso-active drugs , pacemaker , ventilator
  • Balloon Atrial septostomy  /dilatation might help ( Hypoxia may worsen as elevated RA mean pressure may shunt right to left  however cardiac out put might improve)
  • Pericardiotomy  or simple splitting  of pericardial  layers has been tried   (Improves RV restriction effect)
  • If the patient is on ventilator keep the PEEP well below the standard recommendations (RV will struggle more ! )
  • Pacing catheters  can irritate the RVMI in their  raw zone and trigger recurrent ventricular arrhythmia .( Often  labelled wrongly  as Ischemic electrical storm !)
  • Call  Nephrologist  consult  if  renal function  deteriorates . Peritoneal  dialysis is preferred  .  It  is worthy to know , deaths have occurred on hemo dialysis  table.

Final message

RV shock  carries a dismal  outcome , almost  reaching  as that of an LV cardiogenic shock. Ironically ,the most important prognosticator  in RVMI  is the quantum of LV involvement !

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