POAF remains one of the most frequent complications post-cardiac surgery. Despite patients being discharged in sinus rhythm and frequently receiving antiarrhythmic therapies such as amiodarone and sotalol, recurrence rates within the first month ranged between 30% and 60% across studies [6, 13, 14, 15, 16, 17, 18]. Continuous monitoring tools, including implantable loop recorders and handheld ECGs, revealed that many episodes were asymptomatic and would have gone entirely undetected if monitoring devices were not used [6, 19].

The surveillance for early atrial fibrillation recurrence after cardiac surgery (SEARCH-AF) trial demonstrated that nearly 20% of patients had atrial fibrillation recurrences lasting over 6 minutes when monitored continuously with a wearable ECG patch, compared to only 1.7% detection in those followed through usual care [20]. These findings show that relying only on symptoms is not enough and that early rhythm monitoring can be very useful, especially for high-risk patients. Without this, silent recurrences with potential thromboembolic consequences may be missed. Several studies reported that AF episodes tended to recur within the first 30 days, although late recurrences (up to a year) were also observed [1, 14]. While these later episodes were often shorter in duration, their clinical significance remains under debate. Even more concerning is that although approximately 80% of postoperative patients met the criteria for anticoagulation, only 20% were treated [19], suggesting a major gap in post-surgical stroke prevention. Altogether, these findings show that AF requires closer, long-term surveillance. Integrating continuous monitoring into routine post-discharge care may be essential to identify silent recurrences and adapt treatment strategies accordingly.

Although the distinction between rate and rhythm control is clinically less significant in cardiac surgery patients due to the high rates of spontaneous conversion to sinus rhythm, the management of POAF often still involves a decision between both options. Rate control (beta-blockers) is generally favored as a first-line strategy due to their safety profile. In fact, beta-blockers reduce atrial ectopy by decreasing automaticity, which directly lowers the incidence of atrial fibrillation. However, this choice is not always straightforward. Most patients spontaneously convert to sinus rhythm post-op, making rate control sufficient in most cases. However, this assumption does not universally hold, especially in those with structural heart disease, recurrent symptoms, or prolonged AF episodes [21, 22, 23].

Several trials support a rate-first approach, emphasizing that rhythm control does not significantly improve short-term outcomes such as recurrence rates, length of stay, or mortality in the average postoperative patient [8, 11, 22]. 95.9% of patients, regardless of treatment strategy, maintained sinus rhythm 60 days post-operation, suggesting that spontaneous recovery is common and aggressive rhythm control is often unnecessary [8].

That being said, a few special cases still need to be considered. In high-risk patients, particularly those with left ventricular heart failure, rhythm control through catheter ablation accompanied by medical therapy has demonstrated substantial benefits, including reduced mortality and hospitalizations compared to rate control alone [21, 24]. These findings, although not exclusive to surgical patients, suggest that rhythm control may be the main choice in some populations, such as patients with paroxysmal AF as well as patients at risk of cognitive decline. When rhythm control is prioritized medically, the choice often lies between amiodarone and sotalol. Although no randomized controlled trial has directly compared these two drugs in POAF, the sotalol amiodarone atrial fibrillation efficacy trial (SAFE-T) trial in patients with prevalent AF (non-surgical population) showed that amiodarone was more effective than sotalol in maintaining sinus rhythm [16, 25, 26]. However, its use still requires vigilance due to potential hepatic, thyroid, and pulmonary toxicity. Sotalol, while in terms of drug interactions is cleaner and metabolized renally, is also contraindicated in patients with reduced left ventricular ejection fraction (LVEF) or with left ventricular hypertrophy (LVH) and carries a five percent risk of torsades de pointes with corrected QT interval (QTc) prolongation. This explains sotalol’s disappearance from most recent guidelines. The primary differences between amiodarone and sotalol are shown in Fig. 2 (Ref. [5, 25, 27]). Some evidence suggests that early rhythm intervention, particularly in symptomatic or persistent cases, may prevent long-term complications and reduce the frequency of arrhythmia [28].

Fig. 2.

Comparison of sotalol and amiodarone for rhythm control in postoperative atrial fibrillation. Data adapted from SAFE-T trial [25] and subsequent guideline summaries [5, 27]. The table contrasts key clinical features, efficacy, contraindications, and safety considerations relevant to the postoperative context. SAFE-T, sotalol amiodarone atrial fibrillation efficacy trial; QTc, corrected QT interval.

Finally, it is worth considering additional strategies that may help reduce the burden of postoperative AF in select patients. Mineralocorticoid receptor antagonists like spironolactone can be valuable in supporting atrial remodeling and hemodynamic stability, especially in patients with underlying hypertension or renal dysfunction. When it comes to beta-blockers, tailoring their choice and dosing schedule is crucial. Metoprolol, though commonly used, may not offer consistent coverage throughout the day, particularly in patients with rapid metabolism. In contrast, bisoprolol, when given twice daily, seems to provide more stable rate control with less hypotension, making it a practical option in the early postoperative period. Some surgical teams have also integrated left atrial appendage exclusion as a preventive measure, recognizing its potential to reduce thromboembolic risk even in patients without pre-existing AF. These approaches reflect a shift toward more individualized, physiology-based prevention strategies.

Ultimately, the decision between rate and rhythm control should not be rigid but flexible according to patient-specific factors. In reality, the decision is often shaped by chance and how the clinical course unfolds. A 3-month period can act as a blinding phase, after which a strategy can be defined. This highlights the importance of 3-month follow-up and clear communication between surgery, cardiology, and primary care.

Effective stroke prevention is essential in POAF, which has been linked to higher rates of late stroke and subsequent long-term mortality [29]. Preventing stroke in the context of POAF requires careful risk stratification rather than a one-size-fits-all approach. Short-term stroke rates are significantly elevated in patients with POAF compared to those in sinus rhythm, with the risk particularly pronounced after valve surgery or combined procedures [2]. As illustrated in Fig. 3 (Ref. [2]), the absolute risk of stroke in the POAF group reached 4.5%, nearly doubling that of the non-POAF population at 2.5%. Although the long-term absolute stroke risk is lower, it remains elevated compared to non-POAF patients, suggesting that the risk extends beyond hospitalization [30, 31].

Fig. 3.

Incidence of stroke incidence in patients with and without POAF after CABG and valvular surgery. Data adapted from Wang et al. [2]. Short-term refers to 30 days post-surgery, long term refers to $>$1 year follow up. Error bars represent 95% confidence intervals.

Risk stratification in POAF is far from straightforward. While the CHA₂DS₂-VASc score remains a cornerstone in guiding anticoagulation for general atrial fibrillation, its reliability in the postoperative context is less certain. Although stroke risk increases significantly once the CHA₂DS₂-VASc score reaches 4 or more [7], this threshold may carry a different significance in surgical patients. For example, a postoperative cardiac surgery patient with a CHA₂DS₂-VASc of 4 has an estimated annual stroke risk of only 2.3%, which corresponds to a score of 2 in the general AF population where anticoagulation is usually recommended. This suggests that postoperative patients may require a higher score to derive a similar net benefit from anticoagulation, and relying on the same cutoffs used in the general population may underestimate thromboembolic risk in this setting.

Adding to this complexity is the presence of SCAF, often detected only through implantable monitors or pacemakers. As shown in Fig. 4 (Ref. [32]), only SCAF episodes exceeding 24 hours clearly raise the risk of stroke [32, 33, 34], while shorter episodes appear less concerning. However, the apixaban for the reduction of thrombo-embolism in patients with device-detected subclinical atrial fibrillation (ARTESiA) trial showed that in high-risk patients, even briefer episodes might justify anticoagulation if the bleeding risk is acceptable. This aligns with findings from the SEARCH-AF study, previously discussed in the section Recurrence Patterns of POAF, which revealed that a substantial number of patients develop subclinical AF after cardiac surgery. In practice, there is a growing trend to anticoagulate SCAF based on increasingly shorter episodes. These findings demonstrate that CHA₂DS₂-VASc alone is not enough; it must be interpreted within a broader clinical context [35].

Fig. 4.

Stroke risk in subclinical atrial fibrillation (SCAF) by episode duration and CHADS₂ score. Stroke risk associated with SCAF, showing that only episodes lasting $>$24 h significantly increase ischemic stroke risk. Annual stroke risk is also stratified by CHADS₂ score, with higher scores corresponding to greater risk. Data adapted from the ASSERT trial [32]. CHADS, score for stroke risk in atrial fibrillation (mentioned above); ASSERT, asymptomatic stroke and systemic embolism in patients with recorded tachyarrhythmias.

Moreover, anticoagulation is underused. Fewer than 30% of eligible patients receive treatment within the first 30 days, even with evidence of increased stroke risk and a low number needed to harm (NNH) [36]. Clinicians remain caught between minimizing bleeding and preventing embolic complications [37].

Large observational studies report that only 25% to 30% of patients receive oral anticoagulation after cardiac surgery, a rate that is strikingly low given the perceived stroke risk in this population [9, 38]. This cautious approach reflects the ongoing uncertainty regarding the true benefit of anticoagulation in POAF, especially when weighed against its potential bleeding harms. In clinical practice, the decision to initiate anticoagulation is often influenced by the surgeon, who may be particularly hesitant due to the risk of complications such as tamponade, which can lead to reoperation and may be viewed as a failure of the surgery itself. In addition, variability arises from differences between surgical centers, surgeon preference, patient comorbidities, and the absence of POAF-specific recommendations in major guidelines.

As shown in Fig. 5 (Ref. [39]), the role of anticoagulation in POAF is anything but clear-cut. In cardiac surgery patients, a meta-analysis of ten retrospective studies showed that oral anticoagulation lowered the risk of thromboembolic events by 32% (OR 0.68, 95% CI: 0.47–0.96), which seems promising on the surface. But that benefit came with a trade-off: a significantly higher risk of major bleeding, nearly four times as high as those not anticoagulated (OR 4.30, 95% CI: 3.69–5.02). And when it came to overall survival, there was no meaningful improvement (OR 0.93, 95% CI: 0.70–1.22). In non-cardiac surgical patients, the picture was even less reassuring. There was not even a statistically significant reduction in thromboembolic events, despite the same elevated bleeding risk.

Fig. 5.

Major outcomes in anticoagulated patients with atrial fibrillation (general AF population). Comparison of dabigatran, rivaroxaban, and apixaban versus warfarin in randomized trials of the general AF population (not POAF-specific). Outcomes include stroke, major bleeding, intracranial bleeding, and total mortality. Results are provided as relative risk (RR) with 95% confidence intervals. Blue shading indicates statistical significance. Adapted from [39]. This figure is included to provide contextual evidence, as large-scale randomized trials specifically in POAF are lacking.

The inconsistency across studies and the absence of randomized trials show the limitations of current evidence. While a few studies hint at the benefit of anticoagulation, the overall picture remains mixed. For instance, a large retrospective study of over 254,000 patients with POAF found that anticoagulation led to a 0.8% absolute reduction in thromboembolic events, translating to eight strokes prevented per 1000 patients. However, it also reported an additional five bleeding events per 1000 patients [38]. Similarly, in the Fragão-Marques meta-analysis of over 15,000 POAF patients, anticoagulation did not significantly reduce stroke rates and only showed a non-significant trend toward reduced mortality [9]. Bleeding risks were inconsistently reported, adding further uncertainty.

Interestingly, among patients not anticoagulated but discharged on amiodarone alone, the stroke and bleeding rates remained low, suggesting that short-term anticoagulation may not always be necessary when rhythm control is used. Even more compelling, those discharged on both amiodarone and anticoagulation experienced a 35% reduction in early stroke without an increase in bleeding, pointing to a potential synergistic benefit when the two therapies are combined [10].

When anticoagulation is initiated in POAF, the choice of agent requires careful consideration. Warfarin, while historically the standard anticoagulant agent, is less favorable in a cardiac postoperative setting due to challenges maintaining therapeutic International Normalized Ratio (INR) and its association with early tamponade events [40, 41]. Direct oral anticoagulants (DOACs) have increasingly replaced it, offering more predictable pharmacokinetics and fewer monitoring requirements [26, 42]. Among them, apixaban consistently shows the most favorable safety profile, significantly reducing both major and intracranial bleeding compared to warfarin, while preserving stroke protection as seen in Fig. 6 (Ref. [39]). However, apixaban’s antidote (andexanet alfa) can interfere with anticoagulation monitoring during surgery, which presents a challenge if urgent reoperation is needed. In contrast, dabigatran’s antidote (idarucizumab) can be used safely in surgical settings, as recognized by European anesthesiology guidelines. It is important to note that the comparative data presented in Fig. 5 and Fig. 6 are derived from a non-specific POAF population and thus should be interpreted as contextual rather than direct evidence for the postoperative setting. In addition, patients with mechanical valves require lifelong warfarin therapy, limiting the applicability of DOACs to CABG or bioprosthetic valve patients.

Fig. 6.

Adjusted bleeding risks in dabigatran vs apixaban (general AF population, real-world data). Forest plot comparing adjusted bleeding risks between dabigatran and apixaban in the general AF population. Outcomes include major bleeding, intracranial hemorrhage (ICH), gastrointestinal bleeding (GI), clinically relevant non-major bleeding (CRNM), and overall bleeding events. Data adapted from registry-based real-world evidence [39]. This analysis provides contextual safety insights relevant to anticoagulant selection but should not be interpreted as POAF-specific evidence.

Dabigatran, on the other hand, provides even stronger stroke prevention, but at a cost: it significantly increases the risk of gastrointestinal bleeding, with a number needed to harm (NNH) of approximately 200 over two years. In real-world studies, as shown in Fig. 6, patients on dabigatran experienced 24% more gastrointestinal bleeding (GI) bleeds compared to those on apixaban. Additionally, some data suggest that apixaban may carry a slightly higher risk of venous or arterial thrombosis compared to dabigatran, particularly in the early postoperative period.

Cardiac tamponade is a serious but under-recognized complication of anticoagulation therapy following cardiac surgery. It typically presents in two forms: early tamponade and late tamponade. Early tamponade is bleeding-related and often triggered by anticoagulation, while late tamponade, also called post pericardiotomy syndrome, is inflammatory in nature and may also involve pericardial effusions [43]. The risk is particularly relevant in the first month postoperatively. Recent data suggest that early use of DOACs, particularly apixaban, may lower bleeding-related complications compared to warfarin and thereby reduce tamponade risk [12]. Beyond anticoagulant selection, anti-inflammatory strategies may offer additional protection. The COPPS-2 trial demonstrated that colchicine reduced the incidence of postpericardiotomy syndrome with a number needed to treat (NNT) of 10, although its effect on postoperative atrial fibrillation and effusions was more modest [44]. While gastrointestinal intolerance was more frequent, serious adverse events were rare, reinforcing colchicine’s role as a potentially useful adjunct in high-risk patients [23, 45].