A call to move away from 'out of the box' programming for cardiac resychronisation therapy (CRT) - an observational analysis of rate adaptive pacing in the United States

Cardiac Resynchronisation Therapy (CRT) improves exercise capacity, promotes reversal of adverse cardiac remodelling and improves survival for people with heart failure and significant conduction delay. Whilst guidelines exist to standardise implantation and anti-tachyarrhythmia programming, there is a little guidance for when and in whom to enable rate adaptive pacing, or the optimal upper tracking rate. Emerging evidence suggests that personalised programming of rate adaptive pacing parameters can improve exercise capacity in patients with heart failure and pacemaker devices.

We aimed to describe the standard practice in anti-bradycardia device programming in a large, unselected cohort of CRT-defibrillator (CRT-D) implants from a single device manufacturer in the United States using a remote monitoring platform. We provide exploratory analysis of the changes made to device programming over a period of four years.

All patients who underwent CRT-D implantation from a single device manufacturer with remote monitoring downloads in the United States between 2001 and 2004 were included. Patients under the age of 18 years and those with no remote transmission data were excluded. Data regarding age, sex, pacing mode at first device transmission and over the study period, programmed base rate, rate adaptive pacing status and upper tracking rate were collated. The association between upper tracking rate and age were assessed using simple, unadjusted linear regression. The changes in pacing mode over a period of four years were visualised using a Sankey diagram.

4.8 million remote transmissions were received from 352,795 CRT-D devices in 280,250 individuals. The median age was 71 (IQR 63-78 years) and 195,695 (71%) were male. At first device transmission 102,128 (36%) were programmed DDD, 137,650 (49%) were programmed DDDR, 32,930 (12%) were programmed VVIR and 3,607 (1%) were programmed VVI. There was little temporal change in the initial pacing mode programmed at the time of implant per individual patient over the study period. The changes to pacing mode over the study period are displayed in Figure 1.

Rate adaptive pacing was activated in 227,760 (81%) patients following the first transmission. Figure 2 demonstrates the poor relationship between patient age at transmission and upper tracking rate using simple linear regression (R2 0.07). The only guide to upper tracking rate (the Astrand formula (220-age)), is therefore not utilised.

There is significant variation in the initial programming of CRT-D devices in the heart failure population. The endemic issues of lack of pacemaker optimisation and the default position of using ‘out of the box’ settings, which rarely changes over the course of time is highlighted in this large cohort. These data should serve to remind clinicians and allied health professionals to consider device optimisation at every clinical encounter.Figure 1

- Sankey diagram