Archive for the ‘Permanent pacemaker’ Category

Inserting an ICD  for  DCM  may a be great therapeutic success  for the physician  as well as the patient . But there is one big truth hidden behind the statistical screen.

Following  study  provides dramatic data from Maanhiem in Germany in about 561 patients who had ICD .The long term patient outcome after appropriate shocks were much worse  than those without    shocks .This was more pronounced in Ischemic DCM .

appropriate and inappropriate shocks ICD

Source : Streitner et al ,University Medical Centre Mannheim, Mannheim, Germany PLoS One. 2013 May 10;8(5):e6391

The fact that these patients continue to throw VT , some thing is wrong in the cellular  milieu or a fresh scar / fibrosis / ischemia is progressing .Further , the VTs and the  subsequent  shocks  set in temporary  hemodynamic instability .We have evidence , EF can be depressed for days  worsening the long-term out come.

While it is easy  to blame it on natural course of DCM , there are  solid reasons to believe  , shock induced myocardial damage is definitely contributing to this  excess mortality.

One important  clinical tip is to screen  all  these so called Idiopathic DCM  patients  who  had appropriate shocks.  They should be monitored for fresh signs of any systemic illness  , like a  connective tissue disorder , chronic granulomatous lesions  like sarcoid etc .To our surprise  some specific  myocardial disease may unmask themselves in the natural history. Identifying them may offer a dramatic cure .

Final message

Some where along our EP mind-set  we are conditioned to think  , as along as there is an ICD in situ and it appropriately  shocks, every thing is bliss ! Blame it  on semantics . The  word “appropriate”  inappropriately  soothes  our nerves.

The fact of the mater is , every appropriate shock is a  grim reminder  that the heart  in question  is restless electrically and VT continue to emanate  from diseased  myocardium  . It could  mean either the LV   is destabilising  , or the original  disease  is   progressing  or a new disease  is evolving .

Mean while, paradoxically , inappropriate shocks give us a quixotic comfort , since the  heart is not really  throwing any dangerous arrhythmia, after all it is  the device related  false alarm   that  could be easily  reprogrammed!


ICD appropriate and inappropriate shocks

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We expect LBBB in RV pacing . . .but if RBBB is recorded we are worried ! (Often times it may be neither  LBBB nor RBBB )

Is it really a panic situation ?

  • Not necessarily. The only issue is septal perforation .It is rare , can be recognised by echo or fluro .
  • In true RV apical pacing with tined leads , RBBB  is extremely uncommon .
  • If the lead  is fixed  in the septum and para hisian  area ,  there is  definite  possibility of  deviation from typical LBBB pattern . Screwing leads  that faces high septum  or outflow , RBBB  can be noted occasionally.
  • The commonest cause for RBBB pattern in RV pacing ,  is due to  screw tip going deeper into septal planes  and activating the fibers of left bundle early .
  • For LBBB pattern to occur right  bundle should be morphologically intact .In diffuse CHB  with bilateral bundle branch blocks  the relative contribution ( Impulse conduction ) will determine the QRS morphology . If right bundle is more damaged than left bundle ,RBBB pattern  may prevail  even in the midst of RV pacing !
  • In elderly men with sigmoid septum typical LBBBs are not observed.
  • Anther plausible mechanism would be , even though RV is paced , the pacemaker current’s  exit route may be from LV side .
  • Finally , always  think about coronary  sinus pacing .It is extremely common in blind temporary pacing.

What should we do if we encounter RBBB morphology after PPM ?

  • Analyse the ECG meticulosuly for capture or sensing failure .
  • Do an echocardiography in RV inflow view.
  • Screen the lead by fluroscopy
  • Check the pacing  parameters.
  • Do a holter if  you are really anxious .

If everything is fine , just forget the RBBB.Don’t split your hair for this apparent paradox. In medicine  impossibilities will always  galore !

This paper from Taiwan would vouch for this

RBBB during RV pacing safe ecg

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