ACHD general principles — practice case: a systemic right ventricle after the Mustard operation

Presentation

Practice case (not a real patient). A woman in her early thirties had a Mustard atrial switch operation for dextro-TGA in infancy, so her right ventricle is systemic. She was lost to follow-up after leaving paediatric care and now presents with palpitations.^[2][13] Her ECG shows atrial flutter and she is haemodynamically stable. Echocardiography shows moderate systemic ventricular dysfunction. She has no heart failure symptoms, her baseline resting oxygen saturation is normal, there is no pulmonary arterial hypertension, and she has had no heart failure hospitalization or endocarditis.^[1][2]

Step 1 — Classify her and place her care

Discussion:

• ACC/AHA 2025 Table 4 lists dextro-TGA after atrial switch (Mustard/Senning) operation in III: Great Complexity, and a systemic right ventricle is one of the conditions that can never be in physiological stage A.^[2]
• Moderate or severe ventricular dysfunction (systemic, pulmonic, or both) is a stage C feature; with no stage D feature, the “highest” feature rule makes her IIIC.^[2]
• ACC/AHA 2025: patients in ACHD AP classes IB–D, IIA–D, and IIIA–D should be evaluated and managed by or in collaboration with an ACHD cardiologist and, when indicated and accessible, an ACHD program to improve outcomes (COR 1, LOE B-NR).^[2]
• ESC 2020 lists transposition of the great arteries (except for patients with arterial switch operation) as severe, and in moderate and severe CHD complexity with documented arrhythmias, referral to a centre with a multidisciplinary team and expertise in ACHD patients and ACHD-related arrhythmia is indicated (Class I, Level C).^[1]

Step 2 — The atrial flutter

Discussion:

• ESC 2020: among the atrial tachycardias of congenital heart disease, the most frequently encountered is late intraatrial reentrant tachycardia (IART), in particular cavotricuspid isthmus-dependent atrial flutter, and atrial rates between 150 and 250 beats per minute may lead to rapid AV conduction, haemodynamic compromise, and sudden cardiac death (SCD).^[1]
• ESC 2024 (AF): oral anticoagulation should be considered in all adult congenital heart disease patients with AF/AFL and intracardiac repair, cyanosis, Fontan palliation, or systemic right ventricle to prevent ischaemic stroke and thromboembolism, regardless of other thromboembolic risk factors (Class IIa, Level C).^[5]
• ACC/AHA 2025: in adults with d-TGA and atrial switch who have sustained intra-atrial reentrant arrhythmias or atrial fibrillation, oral anticoagulation can be useful to prevent embolic events (COR 2a, LOE C-LD); whether her flutter is sustained decides whether this row applies.^[2]
• ESC 2020: if IART/AF is tolerated and lasting ≥48 h, cardiac thrombus needs to be ruled out (TOE) and/or appropriate anticoagulation (>3 weeks) and pharmacological rate control needs to be initiated before cardioversion using a beta blocker or calcium channel blocker (in patients with normal systemic ventricular function and absent preexcitation); her systemic ventricular function is not normal.^[1]
• Rhythm control is typically preferred over rate control for atrial arrhythmias in complex patients, such as those with a systemic right ventricle or Fontan circulation (ACC/AHA 2025), and maintenance of sinus rhythm is the aim in all CHD patients (ESC 2020).^[2][1]
• If the IART becomes symptomatic, sustained and recurrent, ESC 2020 says that in moderate and severe CHD catheter ablation should be considered for symptomatic, sustained recurrent SVT (AVNRT, AVRT, AT, and IART), or if SVT is potentially related to SCD, provided that the procedure is performed in experienced centres (Class IIa, Level C).^[1]

Step 3 — Heart failure

Some years later she has exertional breathlessness, and her systemic right ventricular function has worsened.^[1]

Discussion:

• Any haemodynamic abnormalities, including arrhythmias, potentially causing heart failure that can be addressed by intervention or surgery must be excluded and, if possible, treated first (ESC 2020).^[1]
• The ACC/AHA 2025 heart failure rows are written for patients with ACHD and heart failure symptoms who have systemic LV dysfunction and biventricular circulation: GDMT (with systemic LV systolic dysfunction) is reasonable to improve heart failure symptoms (COR 2a, LOE C-LD), CRT is reasonable to improve heart failure symptoms in those who otherwise meet accepted criteria for CRT (COR 2a, LOE B-NR), and a primary-prevention ICD is reasonable to prevent sudden cardiac death (SCD) in those who otherwise meet accepted criteria (COR 2a, LOE C-LD); her systemic ventricle is a right ventricle.^[2]
• ESC 2020 says that in a biventricular circulation patients with an impaired systemic LV are generally treated with conventional heart failure therapy, which is also applied in symptomatic patients with a failing systemic RV; it warns that, as the pathophysiology of cardiorespiratory dysfunction is often different from the failing circulation in acquired heart disease, extrapolation of results from published heart failure studies to ACHD patients is inappropriate, particularly in patients with a systemic RV, a failing subpulmonary ventricle, or a single ventricle physiology.^[1]
• On devices, ESC 2020 notes that the benefit of ICD therapy in primary prevention for single or systemic RVs is less well established, and ESC 2022 says that in patients with advanced single ventricle or systemic RV dysfunction with additional risk factors, ICD implantation may be considered (Class IIb, Level C); the table footnote to that row says data are sparse and risk factors may be lesion-specific, including non-sustained VT, NYHA II/III, severe AV valve regurgitation, and wide QRS ≥140 ms (transposition of the great arteries).^[1][3]
• ACC/AHA 2025: in patients with ACHD and heart failure, evaluation by specialists with medical and surgical experience in ACHD, as well as by specialists with expertise in advanced heart failure, is recommended to assess appropriateness for advanced heart failure therapies, such as heart transplantation or MCS (COR 1, LOE B-NR); it says the development of systemic ventricular dysfunction is associated with worse outcomes and would be an appropriate trigger for evaluation for advanced heart failure therapies, including transplantation.^[2]

Step 4 — She asks about pregnancy

With treatment she is in NYHA class II, but the ejection fraction of her systemic ventricle is below 40%. She would like to become pregnant.^[13]

Discussion:

• ESC 2025 (pregnancy): it is recommended that women with a systemic RV (Mustard/Senning or congenitally corrected TGA), in NYHA class III/IV, systemic ventricular dysfunction (EF <40%), or severe TR wishing to become pregnant are counselled by the Pregnancy Heart Team regarding the high risk of pregnancy-related adverse events (Class I, Level C); her EF <40% meets that row.^[13]
• ACC/AHA 2025 Table 10 lists a systemic right ventricle with at least moderately depressed ventricular function among the congenital heart conditions considered significantly high risk for maternal complications in pregnancy.^[2]
• Adults with congenital heart disease interested in pregnancy should receive preconception counseling, in collaboration with an ACHD cardiologist, about the maternal cardiac, obstetric, and fetal risks associated with pregnancy and the potential long-term risks to the pregnant individual (ACC/AHA 2025, COR 1, LOE B-NR).^[2]
• Patients with ACHD who have high risk for maternal morbidity and mortality should be counseled to avoid pregnancy and given guidance on effective contraception to improve outcomes (ACC/AHA 2025, COR 1, LOE C-LD).^[2]

Examiner criteria

• Pass (classification): classifies her as IIIC and explains why stage A is impossible with a systemic right ventricle.^[2]
• Pass (care): gives the ACC/AHA 2025 row that patients in ACHD AP classes IB–D, IIA–D and IIIA–D should be evaluated and managed by or in collaboration with an ACHD cardiologist and, when indicated and accessible, an ACHD program, to improve outcomes (COR 1, LOE B-NR), and the ESC 2020 row that in moderate and severe CHD complexity with documented arrhythmias, referral to a centre with a multidisciplinary team and expertise in ACHD patients and ACHD-related arrhythmia is indicated (Class I, Level C).^[2][1]
• Pass (atrial flutter): gives the ESC 2024 anticoagulation row (Class IIa, Level C) and the ACC/AHA 2025 d-TGA and atrial switch anticoagulation row (COR 2a, LOE C-LD), and notes that ACC/AHA 2025 says rhythm control is typically preferred over rate control for atrial arrhythmias in complex patients, such as those with a systemic right ventricle.^[5][2]
• Pass (heart failure): recognises that the ACC/AHA 2025 heart failure rows are written for systemic LV dysfunction and biventricular circulation, that ESC 2020 says extrapolation of results from published heart failure studies to ACHD patients is inappropriate, particularly with a systemic RV, and that the benefit of primary-prevention ICD therapy for systemic RVs is less well established.^[2][1]
• Pass (pregnancy): gives the ESC 2025 row (Class I, Level C) that it is recommended that women with a systemic RV (Mustard/Senning or congenitally corrected TGA), in NYHA class III/IV, systemic ventricular dysfunction (EF <40%), or severe TR wishing to become pregnant are counselled by the Pregnancy Heart Team regarding the high risk of pregnancy-related adverse events, and the ACC/AHA 2025 row (COR 1, LOE C-LD) that patients with ACHD who have high risk for maternal morbidity and mortality should be counseled to avoid pregnancy and given guidance on effective contraception to improve outcomes.^[13][2]
• Fail: assigns stage A or a moderate anatomic class, does not address oral anticoagulation, or applies the systemic LV heart failure rows to her without comment.^[2][5][1]