Optimal pacing sites for cardiac resynchronization therapy for patients with a systemic right ventricle with or without a rudimentary left ventricle.

AIMS: This study aims to assess the impact of pacing sites on the effectiveness of cardiac resynchronization therapy (CRT) in systemic right ventricle (sRV) patients with/without a rudimentary left ventricle (rLV). METHODS AND RESULTS: We evaluated 13 procedures in 11 sRV patients with a wide QRS (>150 ms). Based on the digitalization results of ventriculography, long-axis dyssynchrony (LD) was defined as extremely delayed right ventricular (RV) outflow tract movement: ≥100 ms delay from the RV apical contraction, and short-axis dyssynchrony (SD) was defined as a paradoxical contraction between the rLV and sRV caused by a conduction delay between the two ventricles. During the follow-up period (2.1 ± 1.9 years), the response rates were 71% (5/7) and 33% (2/6) in the sRV patients with and without an rLV, respectively (P = ns). Following the CRT, the QRS duration remained similar between the responders and nonresponders. Among five responders with an rLV, the leads were placed in the longitudinal RV direction in two with LD, longitudinal RV direction with fusion of the intrinsic QRS in two with LD + SD, and laterally on opposite sides of both ventricles in one with SD. Among two responders without an rLV, the leads were placed in the longitudinal RV direction in those two with LD. CONCLUSIONS: In sRV patients with LD with/without an rLV, the leads should be placed at furthest sites in the longitudinal RV direction. In patients with an rLV and SD, the leads should be placed laterally on opposite sides of both ventricles.

High Incidence of Dilated Cardiomyopathy After Right Ventricular Inlet Pacing in Patients With Congenital Complete Atrioventricular Block.

BACKGROUND: Some patients with congenital complete atrioventricular block (CCAVB) develop dilated cardiomyopathy (DCM) after pacemaker implantation (PMI). We evaluated the relationship between pacing site and DCM incidence. METHODS AND RESULTS: We retrospectively evaluated 38 patients with CCAVB; 8 (25%) of 32 patients who had PMI developed DCM/heart failure death (HFD) after PMI, although none of the 6 patients without PMI showed DCM/HFD. All DCM/HFD occurred within 50 months of PMI. Among the 32 patients with PMI, the DCM/HFD incidence was 55% (6/11) for right ventricular inlet (RVI), 18% (2/11) for RV apex (RVA), and 0% for left ventricle (LV) (P=0.013). At the endpoint, the LV ejection fraction and septal-to-posterior wall motion delay of patients with LV pacing were better than those for patients with other pacing sites. Among the 8 DCM/HFD patients, 2 in whom the pacing site was changed from RVI to LV apex or in whom therapy was upgraded to cardiac resynchronization remained alive with no heart failure symptoms, whereas the other 6 died of heart failure. CONCLUSIONS: A total of 25% of the patients who underwent PMI because of CCAVB, but none in the non-PMI group, developed DCM/HFD. DCM/HFD incidence was higher in patients with RVI pacing. Ventricular dyssynchrony related to pacing site may be one cause of DCM in patients with CCAVB. (Circ J 2016; 80: 1251-1258).

The clinical characteristics of sudden cardiac arrest in asymptomatic patients with congenital heart disease.

Sudden cardiac arrest (SCA) is a major cause of death in patients with congenital heart disease (CHD). Systemic ventricular dysfunction is a reported risk factor for SCA. We retrospectively analyzed the medical records of 46 patients (age >6 years) who experienced SCA. The following underlying cardiac defects were observed: biventricular repair with affected subpulmonary right ventricle (n = 18, 39 %), biventricular repair with systemic right ventricle and Eisenmenger syndrome (n = 6 each, 13 %), Fontan circulation and unrepaired CHD (n = 5 each, 11 %), and others (n = 6, 13 %). Twenty-one patients (46 %) had no history of arrhythmias, and 21 of 43 (49 %) showed systemic ventricular ejection fraction >55 %. According to the New York Heart Association classification, 18 patients (39 %) were class I and 28 (61 %) were class II/III. SCA occurred at a younger age in class I (16 ± 5 years) than in the other classes (23 ± 10 years; P = 0.004). QRS duration was similar between the groups (136 ± 38 vs. 141 ± 50 ms; P not significant). Seven patients in class I (15 % of all SCAs) had no history of arrhythmias or features of hemodynamic abnormalities. The proportion of patients with biventricular repair and affected subpulmonary right ventricle was higher than that of patients with other defects, and the majority of SCA patients had more complicated defects than a simple repaired ventricular septal defect or an atrial septal defect. No symptoms of heart failure, history of arrhythmias, or features of hemodynamic abnormalities were observed in 15 % of the patients who experienced SCA. Prolonged QRS duration might be a predictor of SCA even in asymptomatic CHD patients. Prevention of SCA in CHD patients may require more detailed evaluation than is typically considered necessary.

Efficacy of hemodynamic-based management of tachyarrhythmia after repair of tetralogy of Fallot.

BACKGROUND: Supraventricular and ventricular tachyarrhythmias (SVT, VT) are major concerns after repair of tetralogy of Fallot (TOF). This study evaluated the impact of comprehensive treatment, including hemodynamic interventions such as surgery, catheter-based intervention and pacemaker implantation (PMI), on tachyarrhythmia in repaired TOF patients. METHODS AND RESULTS: Of 66 repaired TOF patients with tachyarrhythmia (age at onset, 23±11 years), 29 patients had sustained SVT, 21 had sustained or non-sustained VT, and 16 had both (SVT+VT). Successful treatment with catheter-directed ablation and/or anti-arrhythmic drugs (AADs) alone was achieved in 31 (69%) and partially achieved in 6 (13%) of 45 patients. Surgery, catheter-based intervention, and/or PMI were performed in 21 (32%) of 66 patients and resulted in complete control of the arrhythmia in 8 (38%) and partial control in 7 (33%) of these 21 patients, 20 (95%) of whom were receiving AADs. Patients with successfully controlled tachyarrhythmia in response to catheter ablation and/or AADs without hemodynamic intervention had a significantly higher probability of absence of sinus node dysfunction (odds ratio [OR], 23.2; 95% confidence interval [CI], 1.8-845.2; P=0.02) and lone intra-atrial reentrant tachycardia (OR, 12.4; 95% CI: 1.3-278.7; P=0.03). CONCLUSIONS: Hemodynamic interventions resulted in an improvement in outcomes in repaired TOF patients with tachyarrhythmia. To effectively manage intractable tachyarrhythmia with hemodynamic abnormalities, it is essential to understand hemodynamics and consider hemodynamic intervention.

Computed tomography-based surgical strategy for total anomalous pulmonary venous connection.

OBJECTIVES: We used computed tomographic angiography (CTA)-based surgical planning to clarify the anatomical indications of sutureless repair technique for total anomalous pulmonary venous connection. The mid-term impact of the current surgical strategies was evaluated. METHODS: One hundred twelve patients underwent repair for total anomalous pulmonary venous connection. The study period was divided into era 1 (1996-2010, n = 56) and era 2 (2011-2018, n = 56). Patients with single ventricular heart (SVH) were included. In era 2, the indications for primary sutureless repair and branch pulmonary vein incision were based on CTA findings. RESULTS: For patients with biventricular heart, the 5-year survival was 69% and 97% in eras 1 and 2, respectively (P = 0.0024). For patients with SVH, the 5-year survival was 21% and 70% in eras 1 and 2, respectively (P = 0.0007). During the follow-up period, the evidence of post-repair pulmonary vein stenosis (PVS) was observed in 12 patients with biventricular heart [era 1, 8 patients (23%); era 2, 4 patients (13%)], and 14 patients with SVH [era 1, 6 patients (60%); era 2, 8 patients (36%)]. Using multivariable analysis, preoperative CTA was associated with improved survival in both biventricular heart and SVH and associated with post-repair PVS-free survival in SVH. Since 2011, 12 patients with post-repair PVS underwent multiple reintervention with 1 recorded death (5-year survival: 88%). CONCLUSIONS: CTA-based surgical strategy for total anomalous pulmonary venous connection provided significant survival benefit. Although post-repair PVS could occur in era 2, aggressive reintervention appeared to be associated with improved survival and vein patency.

Comorbid Epilepsy and Developmental Disorders in Congenital Long QT Syndrome With Life-Threatening Perinatal Arrhythmias.

OBJECTIVES: Given the association of long QT syndrome (LQTS) and neurological disorders, we speculated that the more severe LQTS phenotype, perinatal LQTS, would exhibit more frequent comorbid neurodevelopmental anomalies than LQTS without perinatal arrhythmias (nonperinatal LQTS). BACKGROUND: Congenital LQTS with life-threatening perinatal arrhythmias (perinatal LQTS) has a poor life prognosis. METHODS: Twenty-one consecutive LQTS patients diagnosed before 1 year of age at our institution and 3 previously reported perinatal LQTS patients with neurological seizures were enrolled. In total, the clinical course was evaluated in 24 patients. RESULTS: Among 21 infantile LQTS patients, 5 of 6 with perinatal LQTS (83%) were diagnosed with epilepsy and 4 (67%) with developmental disorders, but none with nonperinatal LQTS were. The total development quotient by Kinder Infant Development Scale scores was 17 to 72 (median 67) in 5 epileptic perinatal LQTS. In the 8 perinatal LQTS patients with neurological disorders, including 3 previously reported cases, epileptic seizures occurred at 2 days to 2.5 years of age and 5 had developmental disorders. Mutations in these 8 patients were located in the transmembrane loop of KCNH2, and D3/S4-S5 linker, D4/S4, or the D4/S6 segment of SCN5A. CONCLUSIONS: A high comorbidity of neurodevelopmental anomalies was observed in perinatal LQTS. Mutations in patients with neurological comorbidities were in loci linked to LQTS with a severe cardiac phenotype. These observations indicate the possibility that neurological disorders in perinatal LQTS are manifested as neurological phenotypes associated with severe cardiac phenotypes, while we could not completely exclude another possibility that those were caused by a brain perfusion injury.