Cardioversion of atrial fibrillation in heart failure with left atrial appendage thrombus — case discussion

Abbreviations

Scenario

Practice case (not a real patient). A 68-year-old man with hypertension, type 2 diabetes and HFrEF (LVEF 35% on a recent echocardiogram) presents with breathlessness on exertion and an irregular pulse. The palpitations began at least three days ago, possibly earlier; he cannot say exactly when. ECG: AF at 105 beats per minute, no pre-excitation, normal QTc. Blood pressure 118/76 mmHg; he is alert, warm and not in respiratory distress. He takes no anticoagulant and has not had cardiac surgery or an LAA occlusion procedure. Thyroid function is normal. His CHA2DS2-VASc score is 4.

1. Is this an emergency cardioversion?

• No. ESC 2024 recommends electrical cardioversion for AF with acute or worsening haemodynamic instability, to improve immediate patient outcomes (Class I, Level C), and ACC/AHA 2023 says immediate electrical cardioversion should be performed to restore sinus rhythm when instability is attributable to AF (COR 1, LOE C-LD); he is haemodynamically stable. For stable patients, ACC/AHA 2023 says electrical cardioversion can be performed as initial rhythm-control strategy or after unsuccessful pharmacological cardioversion (COR 1, LOE B-R).^[1][2]
• The 2026 ESC heart failure guideline recommends urgent cardioversion in the setting of decompensated heart failure in patients presenting with rapid ventricular rates and haemodynamic instability, to restore sinus rhythm (Class I, Level C); he is not haemodynamically unstable, so that row does not apply either.^[3]
• If his AF is persistent (ESC 2024 Table 5: AF episodes which are not self-terminating; many intervention trials have used 7 days as a cut-off), ESC 2024 says cardioversion of AF (either electrical or pharmacological) should be considered in symptomatic patients with persistent AF as part of a rhythm control approach (Class IIa, Level B), and ACC/AHA 2023 says that with reduced LV function and persistent (or high burden) AF, a trial of rhythm control should be recommended to evaluate whether AF is contributing to the reduced LV function (COR 1, LOE B-R).^[1][2]
• Diagnostic cardioversion: ESC 2024 says electrical cardioversion as a diagnostic tool should be considered in patients with persistent AF where there is uncertainty about the value of sinus rhythm restoration on symptoms, or to assess improvement in left ventricular function (Class IIa, Level C); the 2026 ESC heart failure guideline has an otherwise identically worded row that says it may be considered (Class IIb, Level C). ACC/AHA 2023: in patients with AF where symptoms associated with AF are uncertain, a trial of rhythm control (eg, cardioversion or pharmacological therapy) may be useful to determine what if any symptoms are attributable to AF (COR 2b, LOE C-LD).^[1][3][2]
• ACC/AHA 2023 also says that in patients with symptomatic AF, rhythm control can be useful to improve symptoms (COR 2a, LOE B-R), and that in patients with AF and HF, rhythm control can be useful for improving symptoms and improving outcomes, such as mortality and hospitalisations for HF and ischaemia (COR 2a, LOE B-R); if his HFrEF were a new diagnosis, arrhythmia-induced cardiomyopathy should be suspected, and an early and aggressive approach to AF rhythm control is recommended (COR 1, LOE B-NR).^[2]
• The scenario does not say when his AF was first diagnosed. With a recent diagnosis of AF (under 1 year), ACC/AHA 2023 says rhythm control can be useful to reduce hospitalisations, stroke and mortality (COR 2a, LOE B-R), and ESC 2024 says implementation of a rhythm control strategy should be considered within 12 months of diagnosis in selected patients with AF at risk of thromboembolic events, to reduce the risk of cardiovascular death or hospitalisation (Class IIa, Level B).^[2][1]

2. Can he be cardioverted today?

• Not without anticoagulation cover or imaging. ESC 2024: early cardioversion is not recommended without appropriate anticoagulation or TOE if AF has lasted longer than 24 h (Class III, Level C). ACC/AHA 2023: with AF of 48 hours or more, 3 weeks of uninterrupted therapeutic anticoagulation or imaging to exclude intracardiac thrombus is recommended before elective cardioversion (COR 1, LOE B-R).^[1][2]
• The ESC also warns that the definite onset of AF is often not known, which applies to his uncertain history.^[1]
• Anticoagulant: ESC 2024 recommends DOACs in preference to VKAs in eligible patients with AF undergoing cardioversion, for thromboembolic risk reduction (Class I, Level A). The 2026 ESC heart failure guideline recommends DOACs in preference to VKAs in patients with HF to prevent stroke and thromboembolism (Class I, Level B1), except with moderate or severe mitral stenosis or mechanical prosthetic heart valves, where VKAs are recommended. ACC/AHA 2023: in patients with AF who do not have a history of moderate to severe rheumatic mitral stenosis or a mechanical heart valve, and who are candidates for anticoagulation, DOACs are recommended over warfarin to reduce the risk of mortality, stroke, systemic embolism and intracranial haemorrhage (COR 1, LOE A).^[1][3][2]
• ESC 2024 Recommendation Table 7 also recommends DOACs in preference to VKAs to prevent ischaemic stroke and thromboembolism, except in patients with mechanical heart valves or moderate-to-severe mitral stenosis (Class I, Level A).^[1]
• Two routes: at least 3 weeks of therapeutic OAC (adherence to DOACs or INR 2.0 or more for VKAs) is recommended before scheduled cardioversion, to prevent procedure-related thromboembolism (ESC 2024, Class I, Level B); if this has not been provided, TOE is recommended to exclude cardiac thrombus and enable early cardioversion (ESC 2024, Class I, Level B). The team chooses a TOE-guided approach and starts a DOAC now. ESC 2024 says initiation of therapeutic anticoagulation should be considered as soon as possible in the setting of unscheduled cardioversion, to prevent procedure-related thromboembolism (Class IIa, Level B). ACC/AHA 2023 says therapeutic anticoagulation should be established before cardioversion and continued for at least 4 weeks afterwards without interruption, to prevent thromboembolism (COR 1, LOE B-NR).^[1][2]

3. The TOE shows LAA thrombus

• Cancel the cardioversion: the ACC/AHA says detected intracardiac thrombus should prompt cancellation of planned cardioversion. His DOAC was started only at the TOE decision; continue therapeutic anticoagulation, as the next step sets out.^[2]
• ESC 2024 text: therapeutic anticoagulation for a minimum of 4 weeks, then repeat TOE to ensure thrombus resolution; ACC/AHA 2023: therapeutic anticoagulation should be instituted for at least 3 to 6 weeks, after which imaging should be repeated before cardioversion (COR 1, LOE C-LD).^[1][2]
• Counsel that resolution is not certain: in anticoagulant-naïve patients cited by the ACC/AHA, 61.2% had resolution 3 to 12 weeks after starting a VKA, and 41.5% after 6 weeks of rivaroxaban.^[2]

4. Six weeks later: repeat TOE shows no thrombus

• ESC 2024: repeat TOE before cardioversion should be considered if thrombus was identified on initial imaging, to ensure thrombus resolution and prevent peri-procedural thromboembolism (Class IIa, Level C); his repeat TOE is clear.^[1]
• Electrical cardioversion: sedation with intravenous midazolam, propofol or etomidate, with blood pressure monitoring and oximetry, and atropine, isoproterenol or transcutaneous pacing available for post-cardioversion bradycardia (ESC 2024 text).^[1]
• ACC/AHA 2023: energy delivery should be confirmed to be synchronised to the QRS to reduce the risk of inducing VF (COR 1, LOE C-LD), and for elective electrical cardioversion, biphasic energy of at least 200 J as initial energy can be beneficial to improve success of the initial shock (COR 2a, LOE B-R).^[2]
• If a drug were preferred instead: with HFrEF, ESC 2024 recommends intravenous amiodarone when cardioversion is desired, accepting there may be a delay in cardioversion (Class I, Level A), and excludes HFrEF from its intravenous flecainide, propafenone and vernakalant rows.^[1]
• The 2026 ESC heart failure guideline says amiodarone is recommended in HFrEF requiring pharmacological cardioversion, and that propafenone, flecainide and dronedarone are associated with poorer outcomes in HFrEF and should be avoided; the ACC/AHA says ibutilide is best avoided with LVEF 40% or less.^[3][2]
• ACC/AHA 2023: intravenous amiodarone is reasonable for pharmacological cardioversion, although time to conversion is generally longer than with other agents (8–12 hours) (COR 2a, LOE A).^[2]

5. After cardioversion

• ESC 2024: OAC is recommended for at least 4 weeks in all patients after cardioversion and long-term in patients with thromboembolic risk factor(s), irrespective of whether sinus rhythm is achieved, to prevent thromboembolism (Class I, Level B). He has hypertension, diabetes and heart failure, each a CHA2DS2-VA risk factor in ESC 2024 Table 10, so the ESC text says long-term OAC should be instituted irrespective of the rhythm outcome.^[1]
• ACC/AHA 2023: therapeutic anticoagulation should be established before cardioversion and continued for at least 4 weeks afterwards without interruption, to prevent thromboembolism (COR 1, LOE B-NR). For the long-term plan, its general AF rows: patients with AF should be evaluated for their annual risk of thromboembolic events using a validated clinical risk score, such as CHA2DS2-VASc (COR 1, LOE B-NR); with an estimated annual risk of stroke or thromboembolic events of 2% or more, selection of therapy to reduce the risk of stroke should be based on the risk of thromboembolism, regardless of whether the AF pattern is paroxysmal, persistent, long-standing persistent or permanent (COR 1, LOE B-R); for patients with AF and an estimated annual thromboembolic risk of 2% or more per year (eg, CHA2DS2-VASc score of 2 or more in men and 3 or more in women), anticoagulation is recommended to prevent stroke and systemic thromboembolism (COR 1, LOE A); and in patients with AF at risk for stroke, reevaluation of the need for and choice of stroke risk reduction therapy at periodic intervals is recommended to reassess stroke and bleeding risk, net clinical benefit and proper dosing (COR 1, LOE B-NR). His CHA2DS2-VASc score is 4.^[2]
• ESC 2024 Recommendation Table 6: oral anticoagulation is recommended in patients with clinical AF at elevated thromboembolic risk, to prevent ischaemic stroke and thromboembolism (Class I, Level A); a CHA2DS2-VA score of 2 or more is recommended as an indicator of elevated thromboembolic risk for decisions on initiating oral anticoagulation (Class I, Level C), and his is 4 (heart failure, hypertension, diabetes and age 65–74 years); individualised reassessment of thromboembolic risk is recommended at periodic intervals in patients with AF, to ensure anticoagulation is started in appropriate patients (Class I, Level B); using the temporal pattern of clinical AF (paroxysmal, persistent or permanent) is not recommended to determine the need for oral anticoagulation (Class III, Level B); and antiplatelet therapy is not recommended as an alternative to anticoagulation in patients with AF to prevent ischaemic stroke and thromboembolism (Class III, Level A). The 2026 ESC heart failure guideline likewise recommends oral anticoagulation in patients with clinical AF at elevated thromboembolic risk, as determined by CHA2DS2-VA score, to prevent ischaemic stroke and thromboembolism (Class I, Level A). ACC/AHA 2023 says that in patients with AF who are candidates for anticoagulation and without an indication for antiplatelet therapy, aspirin either alone or in combination with clopidogrel as an alternative to anticoagulation is not recommended to reduce stroke risk (COR 3: Harm, LOE B-R).^[1][3][2]
• Bleeding risk scores should not decide it on their own. ESC 2024 Recommendation Table 12: assessment and management of modifiable bleeding risk factors is recommended in all patients eligible for oral anticoagulation, as part of shared decision-making, to ensure safety and prevent bleeding (Class I, Level B); use of bleeding risk scores to decide on starting or withdrawing oral anticoagulation is not recommended in patients with AF, to avoid under-use of anticoagulation (Class III, Level B). ACC/AHA 2023: patients with AF should be evaluated for factors that specifically indicate a higher risk of bleeding, such as previous bleeding and use of drugs that increase bleeding risk, in order to identify possible interventions to prevent bleeding on anticoagulation (COR 1, LOE B-NR); in patients deemed at high risk for stroke, bleeding risk scores should not be used in isolation to determine eligibility for oral anticoagulation but instead to identify and modify bleeding risk factors and to inform medical decision-making (COR 3: No Benefit, LOE B-NR).^[1][2]
• LV function after sinus rhythm restoration: the ESC text says that in some cases of persistent AF with no clear relationship between the arrhythmia and symptoms, restoring sinus rhythm by ECV might be useful to assess the impact of AF on LV function in HFrEF; this is the diagnostic cardioversion row in step 1 (ESC 2024 Class IIa, Level C; ESC heart failure 2026 Class IIb, Level C).^[1][3]

Teaching points

• ESC 2024 uses 24 h and ACC/AHA 2023 uses 48 hours; his AF has lasted at least three days, with an uncertain onset, so both point to anticoagulation cover or imaging before cardioversion.^[1][2]
• A thrombus on TOE cancels the cardioversion; anticoagulate (ESC: at least 4 weeks; ACC/AHA: at least 3 to 6 weeks) and re-image before trying again.^[2][1]
• The TOE route does not replace anticoagulation: ESC 2024 says initiation of therapeutic anticoagulation should be considered as soon as possible in unscheduled cardioversion, to prevent procedure-related thromboembolism (Class IIa, Level B), and ACC/AHA 2023 says it should be established before cardioversion and continued for at least 4 weeks afterwards without interruption, to prevent thromboembolism (COR 1, LOE B-NR).^[1][2]
• In HFrEF, ESC 2024 recommends intravenous amiodarone when cardioversion is desired, accepting there may be a delay in cardioversion (Class I, Level A).^[1]