Patients After Atrial Switch Operation for Transposition of the Great Arteries Can Not Increase Stroke Volume Under Dobutamine Stress as Opposed to Patients With Congenitally Corrected Transposition

Abstract

Consecutive outpatients who had undergone the atrial switch operation or who had ccTGA without previous heart surgery were invited to participate. Patients with a permanent pacemaker in situ were excluded. All patients received routine clinical evaluation in the outpatient clinic, including determination of the grade of tricuspid regurgitation by echocardiography. The degree of tricuspid regurgitation was qualitatively assessed by color Doppler imaging and graded as 0 (no regurgitation), I (mild regurgitation), II (moderate Circ J 2008; 72: 1130 -1135 (Received July 1, 2007 revised manuscript received February 6, 2008; accepted February 25, 2008 Background Patients after atrial switch operation for transposition of the great arteries have limited exercise performance. Rigid atrial baffles may cause a relative preload reduction. Previous studies have had suboptimal control groups, which ideally should consist of patients with congenitally corrected transposition of the great arteries (ccTGA) without previous heart surgery, having a systemic right ventricle, but lacking rigid atrial baffles. Therefore the aim of this study was to test the impact of atrial baffles by comparing 12 atrial switch patients with 11 ccTGA patients. Methods and ResultsSystemic right ventricular stroke volume (SV), heart rate, cardiac index, and other parameters were assessed during rest and dobutamine stress magnetic resonance imaging. The most important difference between the groups was that the atrial switch patients could not increase SV during stress, whereas ccTGA patients increased it significantly. There was no difference between groups in the rise of the cardiac index. Heart rate increased significantly more in atrial switch patients than in ccTGA patients. ConclusionsThe results support the hypothesis that atrial baffles restrict a rise in SV under dobutamine stress in patients after atrial switch operation for transposition of the great arteries. (Circ J 2008; 72: 1130 -1135

Relation of Diastolic and Systolic Function, Exercise Capacity and Brain Natriuretic Peptide in Adults after Mustard Procedure for Transposition of the Great Arteries

“…Second, surgically created atrial baffles may lead to inadequate ventricular filling at rest and during exercise. This hypothesis is supported by findings of Fratz et al They showed that after the Mustard procedure patients could not increase stroke volume index during stress [24]. This suggests that preload reduction caused by the rigid atrial baffles plays a powerful role in limiting exercise performance.…”

Arterial switch operation for transposition of great arteries: late results in adult patients

“…Further exercise parameters reflecting the superiority of ASO than atrial switch the higher increase in O2 pulse, which is the amount of oxygen transported by the circulatory system in a single heartbeat, which is considered a surrogate variable for peak stroke volume after AsO confirms that patients after atrial redirection cannot increase stroke volume under exercise, as they suffer not only from the burden of a systemic RV, but also from a reduced preload reserve due to stiff atrial baffles 62 . In addition, AsO patients have better blood pressure response to exercise compared to patients after atrial redirection.…”

Right Ventricle: Wrong Targets?

“…For example, after atrial redirection procedures it appears that, consequent on the conduit function of the baffles, it is a failure of atrioventricular coupling, with an inability to increase stroke volume with exercise or dobutamine stress 13,14 which limits stroke volume and cardiac output responses. Although this is demonstrably not an issue for those with ccTGA (who have normal stroke volume responses to exercise and dobutamine stress), 15 evidence for primary RV myocardial failure is similarly lacking. Indeed, in an analysis of long-term outcomes in patients with ccTGA, those devoid of significant tricuspid (systemic) valve insufficiency remained free heart failure for decades.…”