p.59 抽出テキスト

..................................................................................................... with usual or mirror-image atrial arrangement. Abnormal base-apex orientation, especially dextrocardia (apex of the heart pointed to the right), is common (20%). Associated lesions are common (8090%): VSD (70%), PS (40%), dysplastic systemic TV (e.g. Ebstein-like malformation).

The position of the AV node (sometimes multiple AV nodes), and the course of the bundle of His, are often abnormal and lead to AV conduction abnormalities. The anterior and lateral displacement of a fragile His bundle is important to recognize during EP studies and catheter interventions.

4.13.2 Clinical presentation and natural history The natural history and clinical presentation are determined by associated malformations. Patients with associated lesions reaching adulthood have either been operated upon [closure of VSD, relief of PS or (rarely) TV repair or replacement] or have a balanced physiology. Patients with isolated ccTGA rarely develop complications before adulthood.

Late complications are: • Systemic RV dysfunction and failure. • Progressive TR (systemic AV valve). • LVOTO. • Complete AV block (2% loss of AV conduction per year); it is more common after VSD repair and/or TV replacement and may occur during pregnancy. • VTs (extremely rare). Life expectancy is reduced: 50% of patients with associated lesions were alive at the age of 40 years; without associated lesions, 50% of patients were alive at the age of 60 years. Patients die from congestive heart failure or die suddenly, presumably due to VT/VF, regardless of the presence of advanced heart failure.

4.13.3 Diagnostic work-up See section 3.3 for general principles. • Clinical findings may include murmurs of TR, VSD, and/or PS. • ECG may reveal a prolonged PR interval or a complete heart block. Early septal activation from right to left may cause deep Q waves in II, III, aVF, and V1V3. Reversal of the normal precordial progression may be seen as a QR pattern in V1 and rS in V6. Wolff ParkinsonWhite syndrome is present in 24% of patients. • Chest X-ray may show an abnormally straight left heart border due to the leftward and anterior position of the ascending aorta, dextroposition with apex to the right (20%), or mesocardia (relatively common). • Echocardiography is the key diagnostic modality, demonstrating double discordance and identifying associated anomalies (Ebstein-like malformation of the TV and TR, VSD, LVOTO, and PS). Systolic RV and LV function and severity of TR can be qualitatively assessed. • CMR provides intracardiac and great vessel anatomy and is indicated for quantification of ventricular volumes, mass, and EF, especially since echocardiographic assessment of systolic function in systemic RVs is difficult and less reliable. • Holter monitoring, event recorder, and EP testing may be indicated for detection of arrhythmias, progressive AV block, and for risk assessment for SCD. • Cardiac catheterization is indicated when non-invasive assessment is inconclusive, or PH requires evaluation (see section 3.4.5).

4.13.4 Medical treatment There are no data to support the hypothesis that ACE inhibitors, ARBs, beta blockers or aldosterone antagonists, alone or in combination, improve outcome.280 Routine prescription of these medications to prevent heart failure/improve outcome is not recommended. • Diuretics may provide relief of symptoms if overt heart failure is present. Although there is no proven benefit from heart failure medical therapy, in terms of outcome in patients with systemic RVs, ‘classical’ heart failure medications or ARBs may provide some benefit in more symptomatic patients.289 A systemic RV morphology is not a contraindication for a ventricular assist device. The coarse trabecularization of the RV apex may deserve special consideration, since it may block the inflow cannula. Selective myomectomy should be considered.

4.13.5 Surgical/catheter interventional treatment Catheter intervention may be recommended for PA stenosis or conduit stenosis, which can be dilated or stented. However, a residual LVOTO may have a beneficial effect on the dilated subaortic RV and subaortic AV (tricuspid) valve regurgitation because of the septal shift. If complete heart block occurs, AV sequential pacing is the standard. Fixation of the pacemaker wire in the smooth-walled LV is difficult and requires a screw-in electrode. There are some data suggesting that biventricular pacing with a second ventricular wire through the (normally connecting) coronary sinus behind the subaortic RV may lead to a better preservation of RV systolic function than LV pacing alone.290

Recommendations for intervention in congenitally corrected transposition of the great arteries

Recommendations Classa Levelb

In symptomatic patients with severe TR and preserved or mildly impaired systemic RV systolic function (EF >40%), TV replacement is indicated. I C In asymptomatic patients with severe TR and progressive systemic RV dilatation and/or mildly impaired systemic RV systolic function (EF >40%), TV replacement should be considered. IIa C Biventricular pacing should be considered in case of complete AV block or >40% ventricular pacing requirement. IIa C In symptomatic patients with severe TR and more than mildly reduced systemic RV systolic function (EF <_40%), TV replacement may be considered. IIb C

AV = atrioventricular; EF = ejection fraction; RV = right ventricle/ventricular; TR = tricuspid regurgitation; TV = tricuspid valve. aClass of recommendation. bLevel of evidence. Downloaded from academic.oup.com/eurheartj/article/42/6/563/5898606 by guest on 07 October 2026