Myocardial work impairment in children with Wolff-Parkinson-White syndrome

Background

Wolf-Parkinson-White Syndrome (WPW) has been associated with reduced local myocardium deformation during systole. According to guidelines, when the left ventricle (LV) dysfunction is present catheter ablation of the accessory pathway may be required, even in asymptomatic patients.

Purpose

The study aimed to assess the diagnostic value of non-invasive myocardial work in predicting subtle myocardial abnormalities in children with WPW.

Methods

Eighty pediatric patients (age 7.91±3.2 years) were included in the study: 20 cases with manifest WPW and 60 age- and sex-matched controls (CTR). Global myocardial work index (MWI) was measured as the area of the LV pressure-strain loops. From MWI, global Constructive Work (MCW), Wasted Work (MWW) and Work Efficiency (MWE) were estimated. In addition, standard echocardiographic parameters of LV function were evaluated.

Results

Patients characteristics are summarized in the table. Despite normal LV EF and GLS, children with WPW had worse MWI (WPW 1292.90±307.67 mmHg% vs CTR 1658.73±241.74 mmHg%, p=0.0000005), MCW (WPW 1844.15±267.96 mmHg% vs CTR 2104.90±237.85 mmHg%, p=0.00009), MWW (WPW 101.5 [85–148.25] mmHg% vs CTR 72 [54.75–109.25] mmHg%, p=0.004) and GWE (WPW 94 [91.75–95] mmHg% vs 96 [95–97] mmHg%, p=0.00012) (table). In the WPW group, MWE (r=−0.6, p=0.009) and MWW (r=0.6, p=0.01) was found to correlate with a prolonged QRS (figure).

A multiple regression model was generated to identify the relation between abnormal myocardial work indices (worst interquartile range as dependent variable) and several independent variables. QRS was the best independent predictor of impaired myocardial work. In particular, a QRS>110 msec showed an 86% sensibility and 85% specificity for abnormal MWE (AUC of 0.85), and a 75% sensibility and 83% specificity for abnormal MWW (AUC of 0.83) (figure).

Conclusion

In children with WPW, myocardial work indices were found significantly reduced, even in presence of normal LV EF and GLS. Prolonged QRS independently predicted myocardial impairment. In pediatric patients with WPW, myocardial work may represent a sensitive measure of LV dysfunction and help in the decision-making.

Funding Acknowledgement

Type of funding sources: None.

COVID-19 vaccination in adults with congenital heart disease: results of 1-year prospective study

Background

Adults with congenital heart disease (ACHD) are a vulnerable population. Routine vaccination is the only strategy to prevent a life-threatening infection. However, concerns on the cardiac safety and efficacy of COVID-19 vaccines have been raised.

Aim

To assess safety and efficacy of available COVID-19 vaccines in ACHD patients.

Methods

Data on COVID-19 infection and vaccines including booster doses and any suspected or confirmed adverse events were prospectively collected for all ACHD patients attending our tertiary centre from the beginning of the vaccination campaign (March 2021). A group of 75 healthy volunteers, matched per age and sex, was included for comparison. Antispike IgG titre was routinely obtained at the ACHD clinic. Patients' attitude towards COVID-19 was explored with a questionnaire.

Results

As of February 2022, 498 ACHD patients (36.7±16 years, 54% male,69% with moderate-complex defects, 48% with advanced physiological stage) were enrolled. Four hundred and sixty-one (92%) were fully vaccinated: the type of vaccine was Pfizer-BioNTech for 399 (86%) patients, Moderna for 20 (4%) and AstraZeneca for 26 (6%), 9 received a mixed vaccine regimen (2%). Forty-two (9%) had a history of previous COVID-19 infection and therefore received only one dose. Two-hundred and sixty-nine (58%) patients received a booster dose. Adverse events were mainly mild and transient. One patient complaining of chest pain following administration of mRNA-based vaccination was diagnosed with acute pericarditis, which made full remission after appropriate therapy. Two patients reported a non-specific increment of inflammatory markers. No other severe adverse events were reported. Thirty-seven (7%) refused COVID-19 vaccination being scared of potential cardiac/extra-cardiac adverse events. Among those not-vaccinated, 9 (24%) had a history of previous mild COVID-19 infection. IgG titre was measured in 243 patients at 1915 [835–5934] BAU/ml, which was significantly higher compared to controls (1196 [827–2048] BAU/ml, p=0.002). Three ACHD patients contracted COVID-19 infection after the first dose, while 65 (14%) fully vaccinated patients tested positive for COVID-19, all with mild to moderate symptoms. COVID-19 symptoms duration was significantly longer in case of infection before vaccination (10 [2.7–15] vs 3 [1.2–7], p=0.03). One Fontan patient was tested positive for COVID-19 twice, before and after COVID-19 vaccination, requiring hospitalization in both cases. Four hundred and seven patients completed the questionnaire: 128 (31%) declared to be scared of potential cardiac effects of the vaccine and that the discussion with the ACHD cardiologist was crucial to decide to undergo COVID-19 vaccination.

Conclusions

Our data provide real-world evidence on COVID-19 vaccines safety and efficacy in ACHD patients. Patients' education from the ACHD team may play a key role in vaccine acceptance in this vulnerable population.

Funding Acknowledgement

Type of funding sources: None.

Effects of sacubitril/valsartan in patients with a systemic right ventricle

Background

Sacubitril/valsartan has been proved to reduce mortality in heart failure and reduced ejection fraction (EF) and is currently recommended as first-line therapy. However, effects in patients with a systemic right ventricle (sRV) have not been systematically investigated yet.

Purpose

We aimed to assess safety and efficacy of sacubitril/valsartan in patients with a sRV

Methods

From September 2020 to April 2021, all patients with congenitally corrected transposition of the great arteries (TGA) or TGA after Senning/Mustard repair attending our tertiary centre were prospectively enrolled. Inclusion criteria were: age ≥18 years, 3-months of optimal medical therapy including ACEi/ARB and sRV EF≤40%. Patients with univentricular physiology, systolic blood pressure (SBP) <90 mmHg, glomerular filtration rate (GFR) <30 ml/min or K >5.5 mEq/L were excluded. SBP and blood samples were obtained at 1-month of treatment. Other clinical and echocardiographic variables were reassessed at 6 and 12-month follow-up and the medication was progressively up-titrated to the highest tolerated dose.

Results

Fifty-one patients (38±11 years, 60% male, 34% ccTGA) were included. Up to March 2022, 48 (92%) patients were reviewed after 6 months of therapy and 35 (68%) completed the first year of follow-up. Baseline patients' characteristics are summarized in Table 1. At 1 month, treatment did not impact on the serum potassium values (4.5±0.3 vs 4.4±0.3 mEq/L, p=0.9) and GFR (112±33 vs 112±31 ml/min, p=0.3), while SBP dropped significantly (119±13 vs 108±18 mmHg, p=0.003). Two patients ceased the treatment due to symptomatic hypotension during the first month. One patient developed a nephrotic syndrome at 4 months of follow-up, which was likely unrelated to the treatment. No other major adverse events were reported. One patient was lost to follow-up after 3 months. Despite no significant change in the NYHA class (p=0.9), the 6-minute walking distance increased significantly at 6-month (Table 2). Nt pro BNP values were significantly decreased at 6-month, and returned to baseline at 12-month. Improved sRV systolic function was demonstrated at 6 and 12-month by significant increase in fractional area change, RV global longitudinal strain and sRV EF measured with 3D echocardiography.

Conclusions

Our mid-term results showed that sacubitril/valsartan is well tolerated in patients with a sRV and leads to signficant improvement of sRV systolic function, supporting its use in this complex population.

Funding Acknowledgement

Type of funding sources: None.

Blood flow vortices adapt their behaviour to the presence of kent accessory pathway

Funding Acknowledgements

Type of funding sources: None.

Background

Blood speckle imaging (BSI) is a new speckle-tracking-based technique for the evaluation of blood flow. Ventricular flow vortices have been studied in sinus rhythm in normal and dysfunctional hearts, however, data are lacking in patients with Kent accessory pathway (KAP) and short atrio-ventricular (AV) conduction.

Purpose

We aimed to evaluate the characteristics of left ventricle blood vortices in children with KAP.

Methods

Nineteen paediatric patients (age 7 ± 2.9 years) were included in the study: 13 patients with manifest KAP (KAP group) and 6 age and sex -matched controls with normal AV conduction (CTR group). A thorough echocardiographic evaluation with 2D, color doppler and BSI was performed in all the included patients. BSI was recorded in apical 3-chamber view with a 6S-D probe. Vortices characteristic were analysed during filling phase of the left ventricle. We focused on the anterior vortex generated by mitral valve, which persisted longer during the cardiac cycle and is assumed to contribute to optimizing cardiac function. A standard 12-lead ECG was also recorded for each child in KAP group to esteem KAP localization.

Results

According to Arruda criteria for KAP localization, all patients in KAP group manifested the accessory pathway in the septal region. All patients in CTR group presented one major anterior vortex during filling phase, while in KAP group 10 patients out of 13 (p= 0.009) lacked of this main anterior vortex, showing instead fragmented different vortices. There were no differences in term of left ventricle function (KAPg 59.8 ± 4.02% vs CTRg 59.0 ± 2.5%, p= 0.6) and global longitudinal strain (KAPg -18.6 ± 1.0% vs CTRg -19.6 ± 3.1%, p= 0.5) between the two groups.

Conclusion

In our preliminary analysis, in patients with septal KAP, blood vortices adapted their diastolic traces to the septal dyssynchrony showing a fragmented pattern. We speculate this fragmentation may contribute to impair the performance of the left ventricle. Abstract Figure. BSI in control vs patient with WPW

Myocardial work indices and ventricular dyssynchrony in adults with aortic coarctation

Funding Acknowledgements

Type of funding sources: None.

Background

Adults with coarctation of the aorta (CoA) may present residual aortic obstruction and develop arterial vasculopathy and subclinical left ventricular (LV) dysfunction. Myocardial work (MW) is a novel non-invasive index of myocardial efficiency calculated from echocardiographic LV pressure-strain loops, which yields incremental information over ejection fraction and global longitudinal strain. (GLS)

Purpose

Aim of the present study is to analyze LVMW in a cohort of adult patients with operated aortic CoA

Methods

CoA patients aged > 18 years who underwent transthoracic echocardiography between September 2020 and July 2021 at our tertiary centre were included. Exclusion criteria were significant recoarctation, impaired LVEF, significant valvular disease and suboptimal image quality. A group of healthy individuals with no cardiac abnormalities. GLS and peak strain dispersion(PSD) were measured. MW indices were calculated using the blood pressure measured in the right arm at the time of the exam.

Results

Sixty patients (26[22-33]years, 66%male) were included. Data on previous medical history, clinical status at last assessment and Coa-related echocardiographic findings are showed in table 1. No significant differences in traditional parameters of LV systolic and diastolic function were found between groups (EF 60[57-64] vs 57[53-61],p = 0.6), however Coa patients had higher LVmass (84[75-97] vs 68[56-75]g). GLS and MW indices in the study population and in the control group  are reported in table 2. Coa group showed lower GLS values and higher PSD (p < 0.0001 for both). Global work index(GWI) and global constructive work(GCW) values were not significantly different between groups, whereas CoA group showed significant increase of global wasted work(GWW) and impaired global work efficiency(GWE,p = 0.003 and 0.0005 respectively). Spearman’s linear method illustrated that both GCW and GWI had a moderate positive relation with mean gradient across the descending aorta at continuous wave Doppler. PSD was positively related to GWW and inversely related to GWE(Figure 1). Using linear regression model with the log of GWE values as dependent variable,PSD,age(β:-0.002,p = 0.03) and LVmass(β:-0.06,p = 0.004)were related to GWE. However, only PSD retained a significant relation on multivariable analysis(β:-0.002,p > 0.0001).

Conclusion

MW indices assessment is feasible in Coa patients may provide a more comprehensive understanding of the overall myocardial mechanics and performance. In particular, MW demonstrated impaired LV efficiency, which was strongly related to increased mechanical dispersion in Coa patients. Abstract Figure.  Abstract Figure.

Impaired myocardial work in paediatric patients with wolff-parkinson-white syndrome

Funding Acknowledgements

Type of funding sources: None.

Background

Wolff-Parkinson-White Syndrome (WPW) has been associated with reduced local myocardium deformation during systole. Left ventricle (LV) dysfunction due to electrical dyssynchrony may require catheter ablation of the accessory pathway, even in asymptomatic patients.

Purpose

The study aimed to assess the diagnostic value of non-invasive myocardial work in predicting subtle myocardial abnormalities in patients with WPW.

Methods

Forty-four paediatric patients (age 8.2 ± 4.3 years) were included in the study: 12 cases with manifest WPW and 32 age-, sex- and arterial pressure- matched controls (CTR). LV ejection fraction (EF) and global longitudinal strain (GLS) were evaluated. Global myocardial work index (MWI) was measured as the area of the LV pressure-strain loops. From MWI, global Constructive Work (MCW), Wasted Work (MWW) and Work Efficiency (MWE) were estimated.

Results

Despite normal LV systolic function by standard echocardiographic parameters, patients with WPW had lower MWI (1233.5 ± 281.6 mmHg% in WPW vs 1624.0 ± 305.8 mmHg% in CTR, p = 0.0004), MCW (1833.4 ± 257.9 mmHg% in WPW vs 2069.0 ± 319.9 mmHg% in CTR, p= 0.03), MWW (187.6 ± 117.7 mmHg% in WPW vs 90.9 ± 58.9 mmHg% in CTR, p= 0.0008) and GWE (90.5 ± 4.8% in WPW vs 95.2 ± 2.2% in CTR, p= 0.00006). There were no significant differences in GLS and EF between patients with WPW and controls.

Conclusion

Myocardial work indices were found significantly reduced in patients with WPW, even in presence of normal LV EF and GLS. In patients with WPW, MWI may represent a sensitive measure of myocardial dysfunction and help in the decision-making for catheter ablation. Abstract Figure. Myocardial work in WPW  Abstract Figure. Myocardial work in control patient

Effects of sacubitril/valsartan in patients with a systemic right ventricle: early evidence of exercise tolerance and systolic function improvement

Background

Sacubitril/valsartan has been shown to reduce mortality and morbidity inpatients with heart failure and reduced systolic function. However, the effects of this novel association in patients with congenital heart disease and a systemic right ventricle (sRV) have not been investigated yet.

Purpose

We aimed to assess tolerability and efficacy of sacubitril/valsartan in patients with a sRV

Methods

From September 2020 to March 2021, 38 patients with congenitally corrected transposition of the great arteries or transposition of the great arteries after Senning or Mustard repair were prospectively enrolled. Inclusion criteria were: age ≥18 years, optimal medical therapy including ACEi/ARB for at least 6 months and EF of the sRV ≤40%. Patients with univentricular physiology, systolic blood pressure (SBP) <90mmHg, glomerular filtration rate (GFR) <30ml/min or K >5.5mEq/L were excluded. RV systolic function was assessed on echocardiography using a multiparametric evaluation. The study protocol contemplates serial assessments at 1, 3, 6 and 12 months after treatment initiation.

Results

Up to March 31th, 23 patients completed 1-month and 15 completed 3-month assessment after treatment initiation. Baseline patients' characteristics are summarized in table 1. The medication dose was up-titrated to the highest tolerated dose during follow-up. During early follow-up, no major adverse events were reported. Treatment did not impact significantly on the values of serum potassium (basal K+ 4.4 [4.2–4.6] mEq/L, K+ at 3 months 4.4 [4.3–4.6] mEq/L, p=0.7) and GFR (basal GFR 113.9±35ml/min, GFR at 3 months 107.8±21 ml/min, p=0.7). Although SBP did not change significantly (114±12 vs 113.9±19 mmHg at 1-month and 117.3±12 mmHg at 3 months; p=0.9 for both), 2 (5%) patients ceased the treatment due to symptomatic hypotension during the first month of treatment. There was no significant change in the NYHA class. However, the 6-minute walking distance increased significantly after 3 months (365±120 vs 498.3±71 min; p=0.01). Furthermore, while traditional echocardiographic parameters of RV systolic function (TAPSE, s wave and FAC) did not change significantly, RV global longitudinal strain (GLS) and RV free wall GLS demonstrated subclinical improvement in right ventricular systolic function (table 2).

Conclusions

Our short-term results from an ongoing prospective study showed that sacubitril/valsartan is well tolerated in patients with a sRV with early evidence of improvement in exercise tolerance and sRV systolic function. Longer follow-up is warranted to confirm these data.

Funding Acknowledgement

Type of funding sources: None. Table 1Table 2

Prognostic relevance of thyroid disease in adults with congenital heart disease

Background

Adults with congenital heart disease (ACHD) are frequently affected by thyroid diseases (TD). However, the clinical relevance of TD in ACHD remains unknown.

Purpose

We aimed to describe the prevalence of TD in the ACHD population and to ascertain whether TD are associated with worse outcome.

Methods

Clinical data on all consecutive patients aged >18 years attending our ACHD unit for a day-case between 2014 and 2019 were retrospectively collected. For statistical analysis, a composite endpoint was created combining the following events at follow-up: hospitalization for heart failure, new-onset tachyarrhythmic or bradyarrhythmic events and death.

Results

Four hundred ninety-five ACHD patients with a median age of 32.2 [24.5–45.6] years (46% male) were included. There was an overall prevalence of patients with moderate or complex lesions (414=84%). Compared to the group with no history of TD, patients in the TD were older, (41.9 [29.7–53.5] vs 30.2 [24.3–39] years; p<0.0001) and mainly female (77% vs 46%; p<0.0001) and more likely to have undergone at least two cardiac catheterization procedures (29 vs 13%; p<0.0001). Genetic disorders including Down syndrome were more prevalent in the group with TD (p<0.0001). Moreover, at last follow-up, those with TD had higher pro-BNP-nt values (243.5 [96.5–523] pg/ml Vs 94 [45–207] pg/ml; p<0.0001) and were in a more advanced NYHA class (27% vs 13% in class III-IV; p=0.0002). Echocardiography showed lower EF in the TD group (55 [55–60]% vs 60 [55–65]%; p=0.0002).

Median follow-up was 9.4 [4.5–13.1] years. Patients with TD had a higher unadjusted mortality rate, with a trend towards statistical significance (p=0.07). Sixty-four (42%) patients in the TD group and 43 (12.5%) met our composite endpoint, leading to a 10-year survival free from events of 53.7% Vs 86.5%, respectively (p<0.0001, Figure1). Multivariate analysis showed that age, ejection fraction, previous surgical palliation, advanced physiological stage and TD were independent predictors of our composite endpoint, even after stratification for genetic disorders as reported in table1. After adjustment for baseline differences between groups with propensity matching score using age, sex, disease complexity, physiological stage, previous palliative or reparative surgery, normal or reduced systemic ventricle ejection fraction, pulmonary arterial hypertension, cyanosis and presence of systemic right ventricle as independent variables, TD remained a strong predictor of cardiac events at follow-up with an hazard ratio of 4.47 (95% CI 2.42–8.28; p<0.0001).

Conclusion

TD is a strong predictor of adverse outcome in the ACHD population after exclusion of potential confounding factors, being related to a fourfold increased risk of events at follow-up.

Funding Acknowledgement

Type of funding sources: None. Figure 1Table 1

P1446 Correlation of B-Type natriuretic peptide with LV and RV function assessed by echocardiography in adults congenital heart diseases patients

Introduction

Brain natriuretic peptide (BNP) is a well-established marker for heart failure in the general population however limited data are available on the value of BNP as a diagnostic and prognostic marker in adults with congenital heart disease (ACHD). The purpose of our study is to evaluate the relation between BNP levels and biventricular systolic and diastolic function in patients with ACHD.

Methods

We evaluated clinically stable ACHD patients who underwent echocardiography from May 2015 until January 2018. We studied the correlation of BNP with the degree of systolic and diastolic dysfunction of the left ventricle. Moreover we also investigate the relation of BNP with the right tricuspid annular plane systolic excursion (TAPSE), the fractional area change (FAC) and the pulmonary arterial systolic pressure (PASP).

Results

In total, 385 patients were included in our study (median age, 43 ±12 years; 61% male). Of the 385 patients, 193 (50%) had tetralogy of Fallot, 94 (24%) had systemic RV, including patients with transposition of the great arteries (TGA) after atrial switch operation (Mustard or Senning) and congenitally corrected TGA -ccTGA , 43 (11%) had univentricular hearts and Fontan physiology, 55 (14%) had other lesions. BNP levels were 66 ± 26 pg/mL and 93, ±31pg/mL, for patients with EF > 50% and 50%> EF >35% respectively (p = 0.003). BNP levels correlate with parameters reflecting LV filling pressure, including transmitral early diastolic velocity (E) 81 ± 29pg/mL and its ratio to early diastolic annular myocardial tissue velocity (E/Ea) 77 ± 17pg/mL. (r=-0.607, p = 0.003 r=-0.598, p = 0.005, respectively) BNP levels were also significantly higher in patients with impaired tricuspid annular plane systolic excursion 87 ± 21 pg/mL (TAPSE < 14mm; p = 0.002) and decreased RV FAC 81 ± 18 pg/mL (FAC <35% P= 0.004) and in patients with PASP≥35 mmHg (p = 0.003). The ROC curve and logistic regression analysis spotted the role of BNP in identifying systolic and diastolic dysfunction patterns in ACHD patients. Conclusion: In clinical stable ACHD patiens BNP levels correlate well with LV systolic dysfunction as well as with impaired diastolic function. Furthermore patients with impaired RV function and increased PASP have raised BNP levels. Therefore monitoring BNP levels plays an important role in management of clinical stable ACHD patients

P3654Location of the coronary origins in transposition patients following anatomical repair: Implications for invasive coronary angiography and intervention

Background

Surgical repair of transposition of the great arteries (TGA) is most commonly via the arterial switch operation (ASO). This involves translocation of the aorta and pulmonary trunk, typically with anastomosis of the branch pulmonary arteries anteriorly (LeCompte manoeuvre) and re-implantation of the coronary arteries onto the posterior neo-aorta. As such, the position of the coronary ostia may differ from their expected locations.

Purpose

To use ECG-gated CT angiography to describe the anatomic position of coronary ostia in post-switch TGA patients guiding potential catheter interventions in this population.

Methods

All post ASO patients who underwent CT imaging between 2008–2018 were identified. Patients with complex anatomy such as double outlet right ventricle were excluded. The positions of the coronary ostia were measured in degrees from vertical on a double-oblique reconstruction in the aortic valve plane. Ostium positions were compared to those of patients with no congenital heart disease via Watson's two-sample test of homogeneity for circular data. Angular dispersion was compared between groups via the Wallraff test. P<0.05 indicated statistical significance.

Results

Of 206 adult patients with TGA and ASO followed in our adult congenital heart disease centre, 38 (18.4%) had CT imaging available for analysis during the study period (mean age 24±6.8, 75% male).

The control group consisted of 15 patients investigated for chest pain (mean age 54±15.1, 73% male). In the control group, the right and left coronary ostia arose at a mean angle of −19 and +125 degrees from vertical (figure 1a). This was significantly different to the mean ASO coronary ostia clustered at mean angles of −70 and +29 degrees from vertical (Watson p<0.001) (figure 1b, with stenosis at the left coronary anastomosis).

There was no significant difference in spread of left ostia (Rho 0.9 vs 0.99, p=0.12), but right ostia were significantly more variable in ASO patients than controls (0.71 vs 0.96, p=0.003).

Figure 1

Conclusions

Coronary ostial positions in the neo-aorta of post-ASO patients differ significantly from those of normal controls, with considerable variability, especially in right coronary position. CT can demonstrate coronary ostia in 3D space and derive appropriate tube angles to guide catheterisation in post-operative congenital cardiac patients, optimise catheter selection, reduce catheterisation tome, radiation and contrast dose.

2401Cardiac resinchronization therapy for the systemic right ventricle: a single center experience

Introduction

Cardiac resynchronization therapy (CRT) has become a treatment of choice in patients with chronic heart failure (HF). About 25% of patients with systemic right ventricle (SRV) progress to symptomatic HF, which may be refractory to drug therapy and is commonly associated with significant morbidity and mortality. For these reasons, CRT has been emerging as an effective treatment strategy for patients with SRV failure and electrocardiographic signs of ventricular dyssynchrony. Few studies have reported the acute and long - term effects of CRT in SRV subjects, with different findings. Our study aimed to describe the experience with CRT in SRV patients in a single tertiary centre.

Purpose

Assess the long term efficacy of CRT in patient with SRV

Materials and methods

All consecutive SRV patients who underwent CRT implantation and/or upgrading between 1994 and 2018 at our tertiary centre were included. Clinical and echocardiographic parameters before and after CRT implantation were collected and analyzed.

Results

A total of 21 patients (mean age 47.8±14.8 years, 13 M) were implanted with CRT-P (12, 57%) or CRT-D (9,43%) during the study period. 90% of patients showed an anatomy of congenitally corrected transposition of the great arteries (CCTGA), whereas 9.5% underwent Mustard procedure for transposition of the great arteries (TGA). Among CCTGAs, 11 (52.5%) subjects underwent previous surgical procedures, including implant of a conduit between the left ventricle (LV) and the pulmonary artery (PA) in 8 (38%) patients, tricuspid valve repair in 2 (9.5%) and surgical closure of atrial septal defect in 1 (5%). Before CRT implant/upgrading, 10 (48%) patients had a moderate to severe reduction in the SRV ejection fraction (EF) and 7 (33%) had a moderate to severe tricuspid regurgitation (TR). Overall, 15 (71%) patients referred a NYHA II or III. After a median follow up of 57 months (IQR 35–83), 43% of patients showed an improvement in their functional status, which was associated with an improvement of SRV EF and TR only in 22% and 33% of these patients. On the contrary, no patient reported a worsening in NYHA class, while SRV EF decreased in 28.5% and the grade of TR worsen in 23.8% of patients.

Conclusions

CRT is emerging as an effective treatment for SRV dysfunction. However, criteria for implantation are not well defined and the deterioration of SRV function related to subpulmonary univentricular pacing should be considered. Moreover, TR did not improve in this study, suggesting that concurrent tricuspid valve interventions may be necessary in patients with severe TR and may facilitate the improvement in RV function achieved with CRT. Proper planning, tertiary expertise and international collaborations are all paramount in this field.