The  ECG  in  the  broader  picture  

Hypokalaemia  

Hypokalaemia  

•  The  characteris+c  abnormali+es  associated  with  a  low  potassium  are:  

•  Fla7ened  T  waves  •  U  waves  •  ST  depression  •  Peaked  p  waves  (p  pulmonale  like)  

Hypokalaemia  

•  Treatment  is  dependent  on  the  presence  or  absence  of  arrhythmia  

•  VT/VF  is  possible  with  very  low  levels  but  rare  •  Ideally  should  be  brought  up  gradually  with  causal  correc+on  

Hyperkalaemia  

•  Progressive  ECG  changes  usually  related  to  level  of  K  and  danger  of  arrythmia  

•  Ini+al  peaking  of  T  waves  •  Then  broadening  of  QRS  un+l  bundle  branch  block  sort  of  picture  

•  Finally  sinusoidal  looking  ECG  that  is  a  peri-­‐arrest  phenomenon  

Sinus  tachy  with  Potassium  9.1  This,  for  once,  was  not  VT.  CaCl  caused  the  complex  to  

narrow  immediately,  showing  sinus  rhythm  

Hyperkalaemia  –  what  it  usually  looks  like  

Hyperkalaemia  

•  Treatment  is  to  initally  give  CaCl  10mls  of  10%  •  Acts  as  myocardial  membrane  stabilising  agent  to  reduce  risk  of  arrythmia  

•  Then  goal  is  to  move  potassium  into  cells  •  Dextrose/insulin  •  Salbutamol  •  Then  to  remove  potassium  •  Stop  drugs/calcium  resonium/renal  replacement  

Hypocalcaemia  

Hypocalcaemia  

•  Prolonged  QTc  with  u  waves  •  Flat  T  waves  •  Can  also  cause  coronary  spasm  and  ST  eleva+on  

•  Unusual  cause  of  symptoms  or  arrythmia  

Digoxin  

•  Normal  levels  of  digoxin  can  produce  ECG  changes  

•  Changes  can  become  more  marked  during  toxicity  

 

Digoxin  

•  Can  induce  brady  or  tachycardia  •  Even  mildly  elevated  levels  can  be  dangerous  in  presence  of  addi+ve  factor:  

•  Hypokalaemia  •  Drugs  –  erythromycin,  ibuprofen,  quinindine  •  Can  induce  heart  block  

Pericardial  Effusion  

Pericardial  effusion  •  The  characteris+c  ECG  findings  are  those  of  small  

complexes  

PericardiGs  

PericardiGs  

•  Saddle-­‐shaped  ST  eleva+on  •  PR  depression  •  Usually  see  abnormali+es  in  most  if  not  all  leads  

•  Can  be  difficult  to  dis+nguish  from  benign  early  repolarisa+on  (history)  

•  Prone  to  accumula+ng  pericardial  fluid  •  Can  rarely  cause  tamponade  

PericardiGs  

Amyloid  •  Amyloid  is  an  infiltra+ve  

disorder  which  can  involve  the  heart  

•  ECG  changes  are  similar  to  those  seen  with  pericardial  effusion  

•  Le\  axis  devia+on  may  also  be  seen  in  heavily  hypertrophied  hearts  

•  Atrial  arrythmia  is  common  due  to  the  high  atrial  filling  pressures  caused  by  the  s+ff  ventricle  

Pulmonary  Embolus  

•  The  most  common  ECG  in  PE  is  sinus  tachycardia  

•  The  fabled  ‘S1Q3T3’  simply  represents  right  axis  devia+on  

•  Caused  by  strain  on  the  right  ventricle  from  the  clot  

Massive  Pulmonary  Embolus  can  rarely  cause  the  anterior  T  waves  to  flip  

Hypothermia  

•  Causes  bradycardia  and  J  point  eleva+on  33o

Hypothermia  –  during  warming  the  ‘Osbourne  wave’  gradually  disappears  

35o

38o