Statistics from Altmetric.com
A 67 year old patient with advanced congestive heart failure (CHF) caused by coronary artery disease (CAD) was referred for evaluation of cardiac resynchronisation therapy (CRT). After implantation of a dual chamber pacemaker six months earlier, the clinical status of the patient had worsened from New York Heart Association (NYHA) functional class III to IV with recurrent pulmonary oedema. Pacemaker implantation had been performed after the patient, already showing first degree atrioventricular (AV) block, exhibited a complete AV block during a coronary intervention. During cardiac catheterisation left ventricular (LV) haemodynamic response to different pacemaker settings was evaluated.
This figure shows recordings of the ECG and LV and aortic pressure, together with the rate of LV pressure development (dP/dt). The left panel exhibits the haemodynamic response with the original pacemaker settings—dual chamber pacing using the default AV delay of 170 ms—while the right panel illustrates right atrial pacing at the same rate. In conjunction with a first degree AV block (PQ time of 260 ms) the narrow QRS complex indicated undisturbed intraventricular conduction. Changing modes was accompanied by a remarkable increase in LV and aortic systolic pressure and an augmentation in LV maximal positive dP/dt by ∼76%.
Instead of CRT the patient received reprogramming of the current system. By setting the AV delay to 300 ms, unfavourable right ventricular stimulation could be minimised. Despite unchanged medication the patient’s clinical status improved to NYHA class III and remained stable during the following two years.
Obviously, the negative impact of artificial left bundle brunch block outweighed the benefits of corrected first degree AV block in this patient with CHF.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.