Genetic testing for inherited cardiovascular diseases. A position statement of the Polish Cardiac Society endorsed by Polish Society of Human Genetics and Cardiovascular Patient Communities.

According to the latest guidelines of European and American medical societies, genetic testing (GT) is essential in cardiovascular diseases for establishing diagnosis, predicting prognosis, enabling initiation of disease-modifying therapy, and preventing sudden cardiac death. The GT result may be relevant for cascade GT in the patient's relatives, for planning his/her profession and physical activity, and for procreative counseling. This position statement has been prepared due to the scarcity of GT in cardiovascular diseases in Poland and the need to expand its availability. We give a concise description of the genetic background of cardiomyopathies, channelopathies, aortopathies, familial hypercholesterolemia, pheochromocytomas, and paragangliomas. The article discusses various aspects of GT in specific populations, such as children or athletes, and also presents prenatal genetic diagnostics. We propose recommendations for GT and counselling, which take into account Polish needs and capabilities. We give an outline of legal regulations, good clinical practice in GT with respect for patient rights, the role of cardiologists and clinical geneticists in GT planning and post-test counseling, and the requirements for laboratories performing genetic tests. The Polish Cardiac Society and Polish Society of Human Genetics experts speak with one voice with cardiovascular patient communities to underline the need for a law on GT and increasing the availability of GT for cardiovascular patients.

Lead Extraction in Children and Young Adults: When is the Best Time for Lead/System Replacement?

The best strategy for lead management in children is a matter of debate, and our experiences are limited. This is a retrospective single-center study comparing difficulties and outcomes of transvenous lead extraction (TLE) implanted ich childhood and at age < 19 years (childhood-implanted-childhood-extracted, CICE) and at age < 19 (childhood-implanted-adulthood-extracted, CIAE). CICE patients-71 children (mean age 15.1 years) as compared to CIAE patients (114 adults (mean age 28.61 years) were more likely to have VVI than DDD pacemakers. Differences in implant duration (7.96 vs 14.08 years) appeared to be most important, but procedure complexity and outcomes also differed between the groups. Young adults with cardiac implantable electronic device implanted in childhood had more risk factors for major complications and underwent more complex procedures compared to children. Implant duration was significantly longer in CIAE patients than in children, being the most important factor that had an impact on patient safety and procedure complexity. CIAE patients were more likely to have prolonged operative duration and more complex procedures due to technical problems, and they were 2-3 times more likely to require second-line or advanced tools compared to children, but the rates of clinical and procedural success were comparable in both groups. The difference between the incidence of major complications between CICE and CIAE patients is very clear (MC 2.9 vs 7.0%, hemopericardium 1.4 vs 5.3% etc.), although statistically insignificant. Delay of lead extraction to adulthood seems to be a riskier option than planned TLE in children before growing up.

Transvenous Lead Extraction in Pediatric Patients　- Is It the Same Procedure in Children as in Adults?

BACKGROUND: Cardiac implantable electronic devices (CIED) are very rare in the pediatric population. In children with CIED, transvenous lead extraction (TLE) is often necessary. The course and effects of TLE in children are different than in adults. Thus, this study determined the differences and specific characteristics of TLE in children vs. adults.Methods and Results: A post hoc analysis of TLE data in 63 children (age ≤18 years) and 2,659 adults (age ≥40 years) was performed. The 2 groups were compared with respect to risk factors, procedure complexity, and effectiveness. In children, the predominant pacing mode was a single chamber ventricular system and lead dysfunction was the main indication for lead extraction. The mean implant duration before TLE was longer in children (P=0.03), but the dwell time of the oldest extracted lead did not differ significantly between adults and children. The duration (P=0.006) and mean extraction time per lead (P<0.001) were longer in children, with more technical difficulties during TLE in the pediatric group (P<0.001). Major complications were more common, albeit not significantly, in children. Complete radiographic and procedural success were significantly lower in children (P<0.001). CONCLUSIONS: TLE in children is frequently more complex, time consuming, and arduous, and procedural success is more often lower. This is related to the formation of strong fibrous tissue surrounding the leads in pediatric patients.

Transvenous Lead Extraction in Adult Patient with Leads Implanted in Childhood-Is That the Same Procedure as in Other Adult Patients?

BACKGROUND: Lead management in children and young adults is still a matter of debate. METHODS: To assess the course of transvenous lead extraction (TLE) in adults with pacemakers implanted in childhood (CIP) we compared 98 CIP patients with a control group consisting of adults with pacemakers implanted in adulthood (AIP). RESULTS: CIP patients differed from AIP patients with respect to indications for TLE and pacing history. CIP patients were four-eight times more likely to require second-line or advanced tools. Furthermore, CIP patients more often than AIP were prone to developing complications: major complications (MC) (any) 2.6 times; hemopericardium 3.2 times; severe tricuspid valve damage 4.4 times; need for rescue cardiac surgery 3.7 times. The rate of procedural success was 11% lower because of 4.8 times more common lead remnants and 3.1 times more frequent permanently disabling complications. CONCLUSIONS: Due to system-related risk factors TLE in CIP patients is more difficult and complex. TLE in CIP is associated with an increased risk of MC and incomplete lead removal. A conservative strategy of lead management, acceptable in very old patients seems to be less suitable in CIP because it creates a subpopulation of patients at high risk of major complications during TLE in the future.

Usefulness of long-term telemetric electrocardiogram monitoring in the diagnosis of tachycardia in children with a medical history of palpitations.

BACKGROUND: In children, palpitations, which may result from a life­threatening tachyarrhythmia, are one of the most common causes of cardiac visits and hospitalizations. Effective diagnosis is essential in this population of patients. AIMS: This study aimed to assess the usefulness of long­term telemetric electrocardiograms compared with Holter monitoring in the diagnostic workup in children with palpitations. METHODS: A total of 350 children with undocumented palpitations were examined in a multicenter study. In 167 patients (47.7%), the TELE group, month­long continuous telemetric electrocardiogram monitoring (using the PocketECG system) was performed. In 183 patients (52.3%), the HOLT group, 24­hour Holter electrocardiography was carried out and repeated after a month if tachyarrhythmia was not recorded. RESULTS: A total of 152 children (43.4%) reported palpitations, and 36.2% of them had sinus tachycardia during palpitations. Tachyarrhythmias were recorded in 68 patients (40.7%) in the TELE group and in 7 (3.8%) in the HOLT group after the second examination (P <0.001); the mean time to record tachycardia was 15.8 (8.7) days versus 25.4 (11.1) days (P = 0.004). In the TELE group, we noted a greater number of children with palpitations during recording (62.9% vs 18%), tachycardia with normal QRS complexes (21.6% vs 1.6%), ventricular tachycardia (11.4% vs 0.5%), and asymptomatic arrhythmias than in the HOLT group. CONCLUSIONS: In children, long­term telemetric electrocardiogram monitoring using the PocketECG system is well tolerated and has a high diagnostic efficacy. In young patients with palpitations, telemetric cardiac monitoring lasting up to a month increased the number of patients with recorded tachyarrhythmia by almost 10-fold compared with the analysis of 2 Holter electrocardiograms. We found that a large number of children have asymptomatic cardiac arrhythmias.

Bipolar ablation of epicardial posteroseptal accessory pathway.

We present a case of a 16-year-old male with WPW syndrome, referred for ablation after being resuscitated from cardiac arrest. Bipolar transseptal RF ablation successfully destroyed rapidly conducting epicardial posteroseptal accessory pathway after three failed attempts of endo- and epicardial ablation.

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry.

Aims: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes. Methods and results: This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities. Conclusion: This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.

Radiofrequency catheter ablation of accessory pathways in patients with Ebstein's anomaly: At 8 years of follow-up.

BACKGROUND: Data regarding long-term follow-up of radiofrequency catheter ablation (RFCA) of accessory pathways (APs) in patients with Ebstein's anomaly (EA) are limited. The procedures are challenging due to multiple or wide APs. METHODS: Analysis was performed on clinical and periprocedural data of patients with EA referred to the centre in order to perform catheter ablation of AP. The group consisted of 22 patients (female 40.9%, mean age 33.6 ± 19.1 years). The follow-up utilized electrocardiogram and Holter monitoring. RESULTS: Twenty-two patients had 33 accessory pathways (8 patients had multiple APs, 11 patients broad AP). Twenty-nine different arrhythmias were ablated: 20 orthodromic atrioventricular reciprocating tachycardia (O-AVRT), 5 antidromic atrioventricular reciprocating tachycardia (A-AVRT), 3 slow/ fast atrioventricular nodal reentry tachycardia (s/f AVNRT) and 1 cavotricuspid-isthmus-dependent atrial flutter (CTI-AFL). In 3 (13.6%) patients multiple ablation targets for RFCA ablation were observed. The acute procedural success rate after the first RFCA performed was: 100% for AVNRT, 77.3% for APs and 50.0% for CTI-AFL ablation. Follow-up (mean 95.7 ± 49.8 months) was completed in 86.4% of patients. One patient had paroxysmal atrial fibrillation not targeted during ablation. One patient died due to heart failure 12 years after RFCA. Three patients who underwent RFCA of accessory pathways in the mid-1990s were lost in follow-up. CONCLUSIONS: Radiofrequency ablation in patients with EA is challenging but safe and have a high short-term as well as long-term success rate.

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated. We sought to define treatment outcomes in children with catecholaminergic polymorphic ventricular tachycardia. METHODS AND RESULTS: This is a Pediatric and Congenital Electrophysiology Society multicenter, retrospective cohort study of catecholaminergic polymorphic ventricular tachycardia patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (interquartile range, 6.8-13.2) years with a delay to diagnosis of 0.5 (0-2.6) years. Syncope (P<0.001), cardiac arrest (P<0.001), and treatment failure (P=0.008) occurred more often in probands. ß-Blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least 1 treatment failure event. Implantable cardioverter defibrillators were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and left cardiac sympathetic denervation in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years. CONCLUSIONS: This study demonstrates a malignant phenotype and lengthy delay to diagnosis in catecholaminergic polymorphic ventricular tachycardia. Probands were typically severely affected. ß-Blockers were almost universally initiated; however, treatment failure, noncompliance and subtherapeutic dosing were often reported. Implantable cardioverter defibrillators were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. Left cardiac sympathetic denervation was not uncommon although the indication was variable.

Andersen-Tawil syndrome: report of 3 novel mutations and high risk of symptomatic cardiac involvement.

INTRODUCTION: Andersen-Tawil syndrome (ATS) is a potassium channelopathy affecting cardiac and skeletal muscle. Periodic paralysis is a presenting symptom in some patients, whereas, in others, symptomatic arrhythmias or prolongation of QT in echocardiographic recordings will lead to diagnosis of ATS. Striking intrafamilial variability of expression of KCNJ2 mutations and rarity of the syndrome may lead to misdiagnosis. METHODS: We report 15 patients from 8 Polish families with ATS, including 3 with novel KCNJ2 mutations. RESULTS: All patients had dysmorphic features; periodic paralysis affected males more frequently than females (80% vs. 20%), and most attacks were normokalemic. Two patients (with T75M and T309I mutations) had aborted sudden cardiac death. An implantable cardioverter-defibrillator was utilized in 40% of cases. CONCLUSIONS: KCNJ2 mutations cause a variable phenotype, with dysmorphic features seen in all patients studied, a high penetrance of periodic paralysis in males and ventricular arrhythmia with a risk of sudden cardiac death.

Idiopathic ventricular arrhythmia in children and adolescents: early effectiveness of radiofrequency current ablation.

BACKGROUND AND AIM: The aim of the study was to evaluate early effectiveness of radiofrequency (RF) current ablation for idiopathic ventricular arrhythmia (iVA) in children and to identify factors affecting treatment results. METHODS: Among over 600 children, 30 ablation procedures were performed for iVA. Patient age ranged from 2.0 to 17.9 years (mean 14.7 ± 3.1). We analysed arrhythmia recurrences at 24 h and the effect of patient age, arrhythmia location, type of anaesthesia, and the presence of spontaneous arrhythmia during the procedure on the treatment results. RESULTS: Sixteen (53%) children had right ventricular (RV) arrhythmia, including RV outflow tract arrhythmia in 9 of them (56%). In 14 (47%) children, arrhythmia was located in the left ventricle (LV), including LV outflow tract in 2 children, and the posterior fascicle in 4 children. The procedure was effective in 13 (81%) children in the RV arrhythmia group and in 11 (78%) children in the LV arrhythmia group, including all children with fascicular tachycardia. The only variable that affected the treatment results was the presence of spontaneous arrhythmia during the procedure (p = 0.012). No procedural complications were noted. CONCLUSIONS: RF current ablation of iVA is a safe procedure with high early effectiveness. The only variable that affected the treatment results was the presence of spontaneous arrhythmia during the procedure.

Persistent multifocal atrial tachycardia in infant with encephalocraniocutaneous lipomatosis: a case report.

UNLABELLED: Encephalocraniocutaneous lipomatosis (ECCL, Haberland syndrome, Fishman syndrome) is a very rare congenital disorder, involving skin, eye, bone and central nervous system malformations. In this paper we present a case of a 2-month-old boy with encephalocraniocutaneous lipomatosis diagnosed on the basis of characteristic clinical manifestations and neuroimaging findings. Neurologically, the child presented only with mild physical and mental retardation. 24-h Holter monitoring revealed asymptomatic multifocal atrial tachycardia. Initial therapy with digoxin and metoprolol was not effective. Introduction of propafenone resulted in supression of supraventricular arrhythmia. During the 3- years follow-up, sinus rhythm persisted, but neurological status deteriorated. CONCLUSION: Supraventricular arrhythmia may be associated with Haberland syndrome. It seems that propafenone is most effective in this condition.

Ventricular fibrillation risk factors in over one thousand patients with accessory pathways.

BACKGROUND: Published data concerning risk factors of VF in WPW patients are inconsistent or contradictory. METHODS AND RESULTS: We included 1007 patient (pts) (mean age 35 years; 45% female) with an accessory pathway (AP) referred for non pharmacological treatment. Group 1 consisted of 56 pts (42M, aged 34 ± 15 yrs) with an AP and documented VF and Group 2-951 pts (513M, aged 35 ± 15 yrs) with an AP and without VF. Univariate predictors of VF were: overt pre-excitation, male gender, multiple AP, large AP. Multivariate predictors were: overt pre-excitation, male gender and MAP. The mean shortest pre-excited RR interval during AF was significantly shorter in Group 1: 205 ± 27 vs. 243 ± 64, P=0.019. VF as an end point of the first arrhythmia episode (AVRT or AF) was observed in 20 pts (15M, 5F). Primary VF (no documented arrhythmia prior to aborted SCD) occurred in 16 pts (13M, 3F). The mean age of primary VF pts was significantly lower than of pts with history of AVRT or AVRT and/or AF (24.5 vs. 36.5 vs. 38 yrs., P<0.005 and P=0.002, respectively). Age at VF occurrence shows a bi-modal distribution with peak occurrences in the 2-nd/3-rd and 5-th decades. CONCLUSION: In patients with an accessory pathway, overt pre-excitation, male gender and multiple AP constitute independent risk factors of VF episodes. Young patients in the 2-nd/3-rd and older patients in the 5-th decade might be at higher risk of VF occurrence.

Does atrioventricular reentry tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) in children affect their cognitive and emotional development?

The current study sought to assess cognitive and emotional functions among children and adolescents with atrioventricular reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT). 113 patients (62 girls and 51 boys ages, 9-18 years) scheduled for radiofrequency ablation due to AVRT or AVNRT underwent neuropsychologic examination. The study excluded patients who had experienced cardiac arrest, congenital heart defects, neurologic disorders, or other diseases affecting cognitive or emotional development. Standardized tests for examining verbal and visual memory as well as visual-spatial functioning were performed. For patients exhibiting deficits in two or more tests, a diagnosis of "cognitive deficits" was determined. Levels of anxiety were tested using the State-Trait Anxiety Inventory. Cognitive deficits were found in 47.8 % of the patients. The age at first arrhythmia attack was related to memory dysfunction. The mean age at which the first symptoms occurred was significantly lower for patients with deficits (8.3 years) than for patients who had no deficit (10.2 years) (t = 2.15; p = 0.03). Boys exhibited a significantly higher level of trait anxiety than girls (t = 3.42; p = 0.0009). A significant negative correlation was found between anxiety and the age at appearance of the first symptoms (r = -0.26; p = 0.005). These findings led us to conclude that cognitive and emotional developments can be negatively affected by AVNRT and AVRT, particularly if tachycardia appears early in life.