Novel insights in pathophysiology of postoperative atrial fibrillation

Geranylgeranylacetone as Prevention for Postoperative Atrial Fibrillation (GENIALITY)

PURPOSE

Interestingly, 30-50% of patients undergoing elective cardiothoracic surgery develop postoperative AF (PoAF). Unfortunately, preventive PoAF therapy is still suboptimal. In our previous studies, we showed that oral Geranylgeranylacetone (GGA) administration increased cardioprotective heat shock protein (HSP) protecting against AF onset and progression in clinically relevant animal model studies.

METHODS

The GENIALITY study is a phase II single-center, double-blind, placebo-controlled randomized trial comparing the efficacy of GGA in preventing PoAF. Participants (N = 146) are adult patients, without any registered history of AF, undergoing elective open-heart surgery for valvular disease, coronary artery bypass grafting, or concomitant, and are allocated with ratio 1:1 in treatment or placebo groups. Daily administration of 300 mg of GGA or placebo starts 5 days before until 3 days after surgery. Cardiac rhythm will be monitored using a Holter monitoring post-surgery until hospital discharge. Additionally, blood samples, right atrial appendage tissue, and epicardial adipose tissue will be collected to assess proteostasis levels.

RESULTS

The primary endpoint is the assessment of PoAF incidence in the GGA group compared to the placebo group. Secondary endpoints include the evaluation of HSP levels through biochemical analysis in both blood and atrial tissue.

CONCLUSION

The GENIALITY study aims to reduce PoAF incidence in the GGA group compared to the placebo group. Herewith, we expect to obtain proof of concept for a beneficial effect of GGA in preventing PoAF in patients undergoing cardiothoracic surgery.  TRIAL REGISTRATION: Clinical Trial Information System (CTIS) registry: 2024-514743-28-00. Authorized on September 30th 2024.

Characterization of pre-existing arrhythmogenic substrate associated with de novo early and late postoperative atrial fibrillation

BACKGROUND

PoAF is the most common complication after cardiac surgery and may occur in patients with pre-existing arrhythmogenic substrate. Characterization of this substrate could aid in identifying patients at risk for PoAF. We therefore compared intra-atrial conduction parameters and electrogram morphology between patients without and with early- (≤5 days after surgery) and late- (up to 5 years) postoperative atrial fibrillation (PoAF).

METHODS AND RESULTS

Epicardial mapping of the right and left atrium and Bachmann's Bundle (BB) was performed during sinus rhythm (SR) in 263 patients (207male, 67 ± 11 years). Unipolar potentials were classified as single, short or long double and fractionated potentials. Unipolar voltage, fractionation delay (time difference between the first and last deflection), conduction velocity (CV) and conduction block (CB) prevalence were measured. Comparing patients without (N = 166) and with PoAF (N = 97), PoAF was associated with lower CV and more CB at BB. Unipolar voltages were lower and more low-voltage areas were found at the left and right atrium and BB in PoAF patients. These differences were more pronounced in patients with late-PoAF (6%), which could even occur up to 5 years after surgery. Although several electrophysiological parameters were related to PoAF, age was the only independent predictor.

CONCLUSIONS

Patients with de novo PoAF have more extensive arrhythmogenic substrate prior to cardiac surgery compared to those who remained in SR, which is even more pronounced in late-PoAF patients. Future studies should evaluate whether intra-operative electrophysiological examination enables identification of patients at risk for developing PoAF and hence (preventive) therapy.