Clinical Assessment and CRT Trouble-shooting

Many of the problems associated with CRT devices are those of conventional pacemakers and ICDs (if that function is also present). These have previously been covered.

The major extra problem to consider is that the epicardial LV lead is much more vulnerable to displacement than the intra-cardiac leads.

For the huge majority of patients with CRT, LV pacing is achieved through epicardial stimulation. Of these, the majority have a highly mobile thin lead delivered through the venous system to the right atrium. From there, it is manipulated out through the coronary sinus, and into a branch of one of the epicardial cardiac veins.

Although displacement is generally a problem soon after implant, it can be delayed for weeks or months. Even a minor shift in the lead tip can lead to failed LV sensing or pacing, and should be considered if patients present with decompensated heart failure after an initial improvement from CRT.

A CXR and ECG performed in the ED will be appropriate in patients in whom failed CRT is suspected; these investigations will be difficult to interpret and expert advice should be sought.