Summary
Summary: Around 40% of patients implanted with a pacemaker to treat bradycardia have or develop cardiac dysfunction (Gierula et al., 2015). Currently we have particularly limited insight into which patients are at high risk of adverse cardiac remodeling and impairment. Some clinical characteristics have been associated previously, such as known ischaemic heart disease and presence of atrial fibrillation (Gierula et al., 2015, Begg et al., 2011), however, we still cannot predict who’s cardiac function will deteriorate prior to implant. If we could, we could be able to potentially implant a more sophisticated cardiac device, such as cardiac resynchronization therapy, or implant via the His bundle in these patients so as to avoid right ventricular pacing entirely. Currently, it is too expensive to provide every patient with these alternate methods of pacemaker therapy, and clinical trials have not shown a benefit in doing so, likely because of the heterogenous response to right ventricular pacing (Curtis et al., 2007).
We aim to use advanced echocardiographic imaging techniques, which are now becoming routinely available, although rarely utilised, in clinical practice. We have shown changes in these measures in patients with forced right ventricular pacing compared to during episodes of their own intrinsic rhythm. We believe particularly strain measures and myocardial work may provide subclinical information and have predictive power for this patient cohort in terms of cardiac deterioration.
References
BEGG, G., GIERULA, J., WALDRON, Z. & WITTE, K. 2011. 154 Patients receiving standard pacemaker generator replacements frequently have impaired left ventricular function and exercise intolerance, related to the percentage of right ventricular pacing. Heart, 97, A86-A86.
CURTIS, A. B., ADAMSON, P. B., CHUNG, E., JOHN SUTTON, M. S., TANG, F. & WORLEY, S. 2007. Biventricular versus right ventricular pacing in patients with AV block (BLOCK HF): clinical study design and rationale. Journal of cardiovascular electrophysiology, 18, 965-971.
GIERULA, J., CUBBON, R. M., JAMIL, H. A., BYROM, R. J., WALDRON, Z. L., PAVITT, S., KEARNEY, M. T. & WITTE, K. K. 2015. Patients with long-term permanent pacemakers have a high prevalence of left ventricular dysfunction. Journal of Cardiovascular Medicine, 16, 743-750.
