Sudden cardiac death in adults with congenitally corrected transposition of the great arteries

Clinical Factors Affecting Survival in Patients with Congenitally Corrected Transposition of the Great Arteries: A Systematic Review and Meta-Analysis

Background: Congenitally corrected transposition of the great arteries (cc-TGA) is a defect characterized by arterio-ventricular and atrioventricular disconcordance. Most patients have co-existing cardiac abnormalities that warrant further treatment. Some patients do not require surgical intervention, but most undergo physiological repair or anatomical surgery, which enables them to reach adulthood. Aims: We aimed to evaluate mortality risk factors in patients with cc-TGA. Results: We searched the PubMed database and included 10 retrospective cohort studies with at least a 5-year follow-up time with an end-point of cardiovascular death a minimum of 30 days after surgery. We enrolled 532 patients, and 83 met the end-point of cardiovascular death or equivalent event. As a risk factor for long-term mortality, we identified New York Heart Association (NYHA) class ≥III/heart failure hospitalization (OR = 10.53; 95% CI, 3.17-34.98) and systemic ventricle dysfunction (SVD; OR = 4.95; 95% CI, 2.55-9.64). We did not show history of supraventricular arrhythmia (OR = 2.78; 95% CI, 0.94-8.24), systemic valve regurgitation ≥moderate (SVR; OR = 4.02; 95% Cl, 0.84-19.18), and pacemaker implantation (OR = 1.48; 95% Cl, 0.12-18.82) to affect the long-term survival. In operated patients only, SVD (OR = 4.69; 95% CI, 2.06-10.71) and SVR (OR = 3.85; 95% CI, 1.5-9.85) showed a statistically significant impact on survival. Conclusions: The risk factors for long-term mortality for the entire cc-TGA population are NYHA class ≥III/heart failure hospitalization and systemic ventricle dysfunction. In operated patients, systemic ventricle dysfunction and at least moderate systemic valve regurgitation were found to affect survival.

External Validation of a Risk Score Model for Predicting Major Clinical Events in Adults After Atrial Switch

BACKGROUND

A risk model has been proposed to provide a patient individualized estimation of risk for major clinical events (heart failure events, ventricular arrhythmia, all-cause mortality) in patients with transposition of the great arteries and atrial switch surgery. We aimed to externally validate the model.

METHODS AND RESULTS

A retrospective, multicentric, longitudinal cohort of 417 patients with transposition of the great arteries (median age, 24 years at baseline [interquartile range, 18-30]; 63% men) independent of the model development and internal validation cohort was studied. The performance of the prediction model in predicting risk at 5 years was assessed, and additional predictors of major clinical events were evaluated separately in our cohort. Twenty-five patients (5.9%) met the major clinical events end point within 5 years. Model validation showed good discrimination between high and low 5-year risk patients (Harrell C index of 0.73 [95% CI, 0.65-0.81]) but tended to overestimate this risk (calibration slope of 0.20 [95% CI, 0.03-0.36]). In our population, the strongest independent predictors of major clinical events were a history of heart failure and at least mild impairment of the subpulmonary left ventricle function.

CONCLUSIONS

We reported the first external validation of a major clinical events risk model in a large cohort of adults with transposition of the great arteries. The model allows for distinguishing patients at low risk from those at intermediate to high risk. Previous episode of heart failure and subpulmonary left ventricle dysfunction appear to be key markers in the prognosis of patients. Further optimizing risk models are needed to individualize risk predictions in patients with transposition of the great arteries.

Endocardial substrate of ventricular tachycardia in an adult patient with congenitally corrected transposition of great arteries without surgical repair

Congenitally corrected transposition of the great arteries (CCTGA) is a rare congenital heart disease which may present sudden cardiac death presumably due to malignant ventricular tachycardia (VT). In patients with congenital heart disease, knowledge of arrhythmogenic substrate is crucial for planning an ablation procedure. We present the first description of the arrhythmogenic endocardial substrate of a non-iatrogenic scar-related VT in a patient with CCTGA.

Long-term outcome of patients with transposition of the great arteries and a systemic right ventricle: A systematic review and meta-analysis

BACKGROUND

Patients with a transposition of the great arteries (TGA) and a systemic right ventricle are at risk of heart failure (HF) development, arrhythmia and early mortality. Prognostic evaluations in clinical studies are hampered by small sample sizes and single-centred approaches. We aimed to investigate yearly rate of outcome and factors affecting it.

METHODS

A systematic literature search of four electronic databases (PubMed, EMBASE, Web of Science and Scopus) was conducted from inception to June 2022. Studies reporting the association of a systemic right ventricle with mortality with a minimal follow-up of 2 years during adulthood were selected. Incidence of HF hospitalization and/or arrhythmia were captured as additional endpoints. For each outcome, a summary effect estimate was calculated.

RESULTS

From a total of 3891 identified records, 56 studies met the selection criteria. These studies described the follow-up (on average 7.27 years) of 5358 systemic right ventricle patients. The mortality incidence was 1.3 (1-1.7) per 100 patients/year. The incidence of HF hospitalization was 2.6 (1.9-3.7) per 100 patients/year. Predictors of poor outcome were a lower left ventricular (LV) and right ventricular ejection fraction (RVEF) (standardized mean differences (SMD) of -0.43 (-0.77 to -0.09) and - 0.85 (-1.35 to -0.35), respectively), higher plasma concentrations of NT-proBNP (SMD of 1.24 (0.49-1.99)), and NYHA class ≥2 (risk ratio of 2.17 (1.40-3.35)).

CONCLUSIONS

TGA patients with a systemic right ventricle have increased incidence of mortality and HF hospitalization. A lower LVEF and RVEF, higher levels of NT-proBNP and NYHA class ≥2 are associated with poor outcome.

End-stage heart failure in congenitally corrected transposition of the great arteries: a multicentre study

BACKGROUND AND AIMS

For patients with congenitally corrected transposition of the great arteries (ccTGA), factors associated with progression to end-stage congestive heart failure (CHF) remain largely unclear.

METHODS

This multicentre, retrospective cohort study included adults with ccTGA seen at a congenital heart disease centre. Clinical data from initial and most recent visits were obtained. The composite primary outcome was mechanical circulatory support, heart transplantation, or death.

RESULTS

From 558 patients (48% female, age at first visit 36 ± 14.2 years, median follow-up 8.7 years), the event rate of the primary outcome was 15.4 per 1000 person-years (11 mechanical circulatory support implantations, 12 transplantations, and 52 deaths). Patients experiencing the primary outcome were older and more likely to have a history of atrial arrhythmia. The primary outcome was highest in those with both moderate/severe right ventricular (RV) dysfunction and tricuspid regurgitation (n = 110, 31 events) and uncommon in those with mild/less RV dysfunction and tricuspid regurgitation (n = 181, 13 events, P < .001). Outcomes were not different based on anatomic complexity and history of tricuspid valve surgery or of subpulmonic obstruction. New CHF admission or ventricular arrhythmia was associated with the primary outcome. Individuals who underwent childhood surgery had more adverse outcomes than age- and sex-matched controls. Multivariable Cox regression analysis identified older age, prior CHF admission, and severe RV dysfunction as independent predictors for the primary outcome.

CONCLUSIONS

Patients with ccTGA have variable deterioration to end-stage heart failure or death over time, commonly between their fifth and sixth decades. Predictors include arrhythmic and CHF events and severe RV dysfunction but not anatomy or need for tricuspid valve surgery.

Successful transvenous implantable cardioverter-defibrillator implantation supported by preceding 3D electro-anatomical mapping for a ventricular fibrillation survivor with surgically repaired congenitally corrected transposition of the great arteries: a case report

Background

The atrial sites suitable for lead placement are limited after complex surgical atrial procedures, and lead placement can be challenging in patients with congenitally corrected transposition of the great arteries (ccTGA) after intracardiac repair.

Case summary

A 34-year-old man with ccTGA, who had undergone a double-switch operation with combined Senning and Jatene operations at the age of 14 was transferred to us. He experienced faintness and suffered cardiopulmonary arrest, and electrocardiography revealed ventricular fibrillation. After conversion to sinus rhythm by urgent external defibrillation, sinus bradycardia was revealed. Electrophysiological study was done using a three-dimensional (3D) mapping system (Ensite®) to evaluate the electrical condition of atria and to decide whether atrial lead can be transvenously placed. The electrical potential of the functional right atrium was good in the lateral or posterior wall, but the threshold was high. By contrast, the roof of the functional right atrium beyond cavoatrial junction was characterized by low voltage, but in a limited region of the roof of right atrium, the threshold was satisfactory and the electrical potential was normal. Thus, 3 weeks later, we implanted a transvenous implantable cardioverter-defibrillator (ICD). We used a 3D mapping system to place the atrial lead in the limited region of the roof of the right atrium mentioned above, the threshold was 0.7 V.

Discussion

Electrophysiological examination using a 3D mapping system before implantation of a dual-chamber ICD is useful because atrial sites suitable for lead placement are limited in patients.

Narrative review of: risk stratification and implantable cardioverter-defibrillator therapy in adults with congenital heart disease

Fortunately, the population of adults with congenital heart disease (ACHD) is growing due to improved operation techniques. Life expectancy is continuously rising, nevertheless, sudden cardiac death is one of the leading causes of mortality in ACHD late after initial diagnosis. Risk stratification in ACHD remains challenging as large study results are missing, congenital defects and operation methods differ considerably between individual patients and results from acquired heart diseases are often not conferrable. The purpose of this narrative review is to objectively summarize the current knowledge on arrhythmogenic risk of ACHD and to give an overview on implantable cardioverter-defibrillator (ICD) therapy in this collective. Remarkable progress has been made in electrophysiological understanding of critical areas of slow conduction especially in patients with Tetralogy of Fallot (ToF). In patients with transposition of the great arteries after atrial baffling (Mustard/Senning procedure) atrial arrhythmias play a crucial role in sudden cardiac death. ICD therapy in ACHD may pose special technical challenges due to limited access for intracardiac leads. The introduction of the totally subcutaneous ICD improved therapeutic options for ACHD especially when contraindications for transvenous leads are present. Risk stratification in ACHD has to be seen as a team approach, requires thorough understanding of congenital heart defects and the operation techniques and needs unconventional technical approaches in some cases.

QT interval variability and heart rate turbulence are associated with clinical characteristics in congenital heart disease patients with a systemic right ventricle

BACKGROUND

QT interval variability (QTV) and heart rate turbulence (HRT) are measures of cardiac autonomic function, which, when abnormal, are correlated with ventricular arrhythmias and worse clinical outcome. This study aims to evaluate QTV and HRT in patients with a systemic right ventricle (RV) and to assess correlations with clinical characteristics.

METHODS

In a retrospective cohort study, QTV and HRT were derived from 24-h Holter registrations of patients with a systemic RV and healthy controls. QTV and HRT were compared between groups. In patients, the association between QTV, HRT, and clinical characteristics was assessed.

RESULTS

Holter recordings from 40 patients (mean age 40 years, 16 females) and 37 healthy controls (mean age 42 years, 21 females) were analyzed. Groups were comparable in terms of age and sex. QTV was increased in patients compared with controls (p < 0.001), HRT did not differ significantly between the groups. Increased QTV and decreased HRT correlated with medication use, especially of diuretics, and with clinical events, particularly supraventricular arrhythmias. Increased QTV correlated with reduced systemic RV function. Decreased HRT was independently associated with a larger number of past clinical events (estimate -0.33, 95% CI -0.63 to -0.02, p = 0.037). QTV was higher in women in both patients and controls (p = 0.041 and p = 0.034, respectively).

CONCLUSIONS

QTV and HRT are associated with clinical factors and events in patients with a systemic RV. Further studies are mandatory to confirm their prognostic value.

Implantable cardiac electronic device therapy for patients with a systemic right ventricle

The systemic right ventricle (SRV), defined as the morphological right ventricle supporting the systemic circulation, is relatively common in congenital heart disease (CHD). Our review aimed at examining the current evidence, knowledge gaps and technical considerations regarding implantable cardiac electronic device therapy in patients with SRV. The risk of sinus node dysfunction (SND) after atrial switch repair and/or complete heart block in congenitally corrected transposition of great arteries requiring permanent pacing increases with age. Similar to acquired heart disease, indication for pacing includes symptomatic bradycardia, SND and high degree atrioventricular nodal block. Right ventricular dysfunction and heart failure also represent important complications in SRV patients. Cardiac resynchronisation therapy (CRT) has been proposed to improve systolic function in SRV patients, although indications for CRT are not well defined and its potential benefit remains uncertain. Amongst adult CHD, patients with SRV are at the highest risk for sudden cardiac death (SCD). Nevertheless, risk stratification for SCD is scarce in this cohort and implantable cardioverter-defibrillator indication is currently limited to secondary prevention. Vascular access and the incidence of device-related complications, such as infections, inappropriate shocks and device system failure, represent additional challenges to implantable cardiac electronic device therapy in patients with SRV. A multidisciplinary approach with tertiary expertise and future collaborative research are all paramount to further the care for this challenging nonetheless ever increasing cohort of patients.

Sudden death in patients with Ebstein anomaly

Aims

Ventricular dysfunction or structural alteration of either ventricle is a well-established risk factor for sudden death (SD). Ebstein anomaly (EA) can present with both right and left heart abnormalities; however, predictors of SD have not been described. We therefore sought to characterize the incidence and risk factors of SD among a large cohort of patients with EA.

Methods and results

All EA patients who underwent evaluation at a high-volume institution over a 4-decade period were retrospectively reviewed. Clinical variables, cardiovascular surgical procedure(s), and cause of death were recorded. Sudden death incidence from birth and following tricuspid valve (TV) surgery were estimated using the Kaplan-Meier method. Cox regression analysis was used to identify clinical and surgical predictors of SD. The cohort comprised of 968 patients [mean age 25.3 years, 41.5% male; 79.8% severe EA, 18.6% accessory pathway, 0.74% implantable cardioverter-defibrillator (ICD) placement]. The 10-, 50-, and 70-year cumulative incidences of SD from birth were 0.8%, 8.3%, and 14.6%, respectively. Prior ventricular tachycardia [hazard ratio (HR) 6.37, P < 0.001)], heart failure (HR 5.64, P < 0.001), TV surgery (HR 5.94, P < 0.001), syncope (HR 2.03, P = 0.019), pulmonic stenosis (HR 3.42, P = 0.001), and haemoglobin > 15 g/dL (HR 2.05, P = 0.026) were multivariable predictors of SD. In a similar subgroup analysis of patients who underwent TV surgery, all of the above factors except syncope were significantly associated with post-operative SD on multivariable analysis.

Conclusion

Patients with EA are at significant risk for SD. Key clinical SD predictors identified can aid in risk stratification and potentially guide primary prevention ICD implantation.

Ventricular fibrillation in congenitally corrected transposition of great arteries treated with pacing: a case report

Background

Congenitally corrected transposition of the great arteries (CCTGA) is a rare form of congenital heart disease which may present with sudden death from malignant arrhythmias including complete heart block and ventricular tachyarrhythmias as late complications. Only few cases about ventricular tachyarrhythmias, usually in those with markedly depressed systemic ventricular function, have been reported.

Case summary

A 26-year-old woman with a known history of CCTGA presented to the emergency department with palpitations and breathlessness for 3–4 weeks and worsening symptoms for 8 h. She had a history of ventricular septal defect repair 14 years ago. Her initial presentation electrocardiogram demonstrated high degree atrioventricular block with a ventricular rate of 44 b.p.m. She had two episodes of complete syncope during this hospitalization, both required external defibrillation due to documented bradycardia-dependent ventricular fibrillations. Her two-dimensional echocardiography study confirmed the diagnosis of CCTGA with preserved systolic ventricular function. She underwent urgent temporal pacing wire placement with a paced ventricular rate at 90 b.p.m. Having thoroughly reviewed the arrhythmia events and discussed with the patient about the option of defibrillator vs. pacemaker therapy a decision was made upon her request for dual-chamber pacemaker implantation. She was discharged home uneventfully 3 days after hospital presentation and has been physically active at 3-, 6-, and 9-month follow-ups.

Discussion

Our case illustrates the individualized clinical decision making in choosing device therapy for a rare congenital heart disease presented with malignant arrhythmia. Careful history taking, open communication, and closely planned long-term follow-up will be essential in caring for such patients.

Origins and consequences of congenital heart defects affecting the right ventricle

Congenital heart disease is a major health issue, accounting for a third of all congenital defects. Improved early surgical management has led to a growing population of adults with congenital heart disease, including patients with defects affecting the right ventricle, which are often classified as severe. Defects affecting the right ventricle often cause right ventricular volume or pressure overload and affected patients are at high risk for complications such as heart failure and sudden death. Recent insights into the developmental mechanisms and distinct developmental origins of the left ventricle, right ventricle, and the outflow tract have shed light on the common features and distinct problems arising in specific defects. Here, we provide a comprehensive overview of the current knowledge on the development into the normal and congenitally malformed right heart and the clinical consequences of several congenital heart defects affecting the right ventricle.