First Real-Life Data on the Diving Response in Healthy Children

Swimming and diving are popular recreational activities, representing an effective option in maintaining and improving cardiovascular fitness in healthy people. To date, only little is known about the cardiovascular adaption to submersion in children. This study was conducted to improve an understanding thereof. We used a stepwise apnea protocol with apnea at rest, apnea with facial immersion, and at last apnea during whole body submersion. Continuous measurement of heart rate, oxygen saturation, and peripheral resistance index was done. Physiologic data and analysis of influencing factors on heart rate, oxygen saturation, and peripheral vascular tone response are reported. The current study presents the first data of physiologic diving response in children. Data showed that facial or whole body submersion leads to a major drop in heart rate, and increase of peripheral resistance, while the oxygen saturation seems to be unaffected by static apnea in most children, with apnea times of up to 75 s without change in oxygen saturation.

Accuracy of the Apple Watch Oxygen Saturation Measurement in Adults and Children with Congenital Heart Disease

As new customer health devices have been spread throughout the consumer market in recent years, it now needs to be evaluated if they also fulfill the requirements of clinical use. The Apple Watch Series 6 provides a new health feature with its oxygen saturation measurement. The aim of this prospective, investigator-initiated, single-arm study was to compare transcutaneous oxygen saturation measurements using the Apple Watch 6 with the conventional method of pulse oximetry in patients with congenital heart disease. Patients of any age presenting at the Leipzig Heart Center, Department for pediatric cardiology, were included. After obtaining informed consent, the routine oxygen saturation measurement with the pulse oximeter was taken and simultaneously three measurements with the Apple Watch. A total of 508 patients were enrolled. Comparing children and adults in terms of measurement success shows a statistically significant difference with a higher proportion of unsuccessful measurements in children, but no difference concerning correct versus incorrect Apple Watch measurements. Noticeable, strapping on the watch properly around the patient's wrists significantly improved the measurements compared to a watch only laid on. The study demonstrated that oxygen saturation measurement with the Apple Watch 6 is not yet up to the medical standard of pulse oximetry, too large a proportion of the measurements remain either unsuccessful or incorrect. While a high proportion of unsuccessful measurements in children can be attributed to movement, the cause in adults usually remains unclear. Further influencing factors on a correct, or successful measurement could not be found.

Use of the Apple Watch iECG in adult congenital heart disease patients

Introduction

This study evaluates the accuracy of iECGs in comparison to the gold standard ECG in adult patients with congenital heart disease and recommends the appropriate iECG derivation based on the patient's characteristics.

Methods

In 106 adults (51 female, 55 male) with congenital heart disease, a gold standard 12-lead ECG was recorded, followed by three iECGs with the Apple Watch series 4, which correspond to Einthoven leads I, II, and III. Two experienced and independent cardiologists analyzed the time intervals, amplitudes, and polarities of the ECG parameters as well as the rhythm type and correlated the patient characteristics with the iECG parameters.

Results

The iECG parameters of all three iECG leads correlate strongly with those of the gold standard ECG, with exception of the P and T wave durations. We demonstrated that the informative value of the individual iECGs was independent of the patient's characteristics, in particular the heart axis, anatomy, and situs, even if the quality of the Einthoven III-like derivation was partially inadequate. The automatic rhythm analysis of the Apple Watch and the heart rhythm classification of a standard ECG analyzed manually by a cardiologist corresponded in 77%.

Conclusion

iECG recordings of adults with congenital heart disease provide comparable results with Einthoven recordings I, II, and III of the 12-lead ECG and current data encourage the use of the Apple Watch not only in patients with structurally normal hearts but also in patients with congenital heart disease.

Performance of pacemaker leads in alternative lead positions after tricuspid valve replacement

BACKGROUND

Bradycardic arrhythmias requiring pacemaker (PM) implantation are still common in patients in need of tricuspid valve replacement (TVR). Leaving an existing PM lead in an extravalvular position may represent a helpful alternative in special situations like the implantation of a mechanical TV. This study aimed to examine the short- to mid-term outcome of paravalvular leads concerning lead survival and prosthesis dysfunction in patients after TVR.

METHODS

A retrospective case-control study of patients with TVR and ventricular pacing was conducted. Patients from the database of the Leipzig Heart Center were included. Data of the paravalvular lead group (PVG) and coronary sinus lead group (CSG) were compared to a control group with conventional transvalvular leads (TVG).

RESULTS

Eighty patients with TVR and cardiac PM (TVG [n = 13], PVG [n = 40], and CSG [n = 27]) were included. The mean follow-up was 2.8 years. The rate of lead revisions (TVG 15.4%, PVG 2.5%, and CSG 7.5%) was lower in PVG but without significance (P = .286). The CSG demonstrated significantly higher pacing thresholds (1.4 V/0.8 ms) than TVG (0.5 V/0.4 ms), P = .004. However, the deterioration of threshold amplitudes during follow-up was similar in CSG (7.4%) and PVG (7.5%) compared with controls (7.7%). Function of TV prosthesis regarding development of stenosis or regurgitation showed a similarity between the groups (regurgitation PVG P = .692, CSG P = 1; stenosis PVG P = .586, CSG P = 0.69).

CONCLUSION

Paravalvular positioning of PM leads seems to represent a reasonable alternative to the conventional transvalvular lead positioning concerning the lead and Tricuspid Valve prosthesis's function and durability in selected patients.

Junctional ectopic tachycardia in neonatal enterovirus myocarditis

Differential diagnosis is challenging in poor conditioned neonates referred to the emergency room. Infectious disease is common, yet tachycardia should alert the clinician to look for cardiac arrhythmia and comprise. Tachycardia can lead to cardiomyopathy and should warrant further diagnostics for myocarditis, especially in rare or unusual combination of arrhythmias.

Different habitus but similar electrocardiogram: Cardiac repolarization parameters in children - Comparison of elite athletes to obese children

Introduction:

The standard 12-lead electrocardiogram (ECG) remains a widely used tool in the basic cardiac evaluation of children and adolescents. With the emergence of inherited arrhythmia syndromes, the period of cardiac repolarization has been the focus of attention. So far, data on cardiac repolarization and its normal variants in healthy children are scarce. This may cause uncertainties in the differentiation between pathologies and normal variants. As abnormal autonomic regulation seems to be a major influencing factor on cardiac repolarization, this study aimed to evaluate the parameters of cardiac repolarization of children in extremely good physical shape to obese children to improve knowledge about cardiac repolarization in these subgroups of pediatric patients that are vastly affected by the alterations of autonomic regulation.

Methods:

A total of 426 pediatric volunteers (84 lean, healthy controls; 130 obese healthy pediatric volunteers; and 212 elite athletes) were enrolled in the study, and the parameters of cardiac repolarization were determined in 12-lead ECG.

Results:

Most importantly, there were no pathological findings, neither in the healthy controls nor in the obese or athletes. Athletes showed overall shorter corrected QT intervals than children from the other groups. This is also true if a correction of the QT interval is performed using the Hodges formula to avoid bias due to a tendency to lower heart rates in athletes. Athletes showed the shortest Tpeak-to-end ratios between the groups. The comparison of athletes from primarily strength and power sports versus those from endurance sports showed endurance-trained athletes to have significantly longer QT intervals.

Conclusions:

This study suggests that neither obesity nor extensive sports seems to result in pathological cardiac repolarization parameters in healthy children. Therefore, pathology has to be assumed if abnormal repolarization parameters are seen and might not be simply attributed to the child's habitus or an excellent level of fitness.

Use of the Abbott EnSite Precision three-dimensional mapping system for the placement of an atrial pacemaker lead in a patient with congenital heart disease

We report the use of the Abbott three-dimensional mapping system (EnSite Precision) for the placement of an atrial pacemaker lead in a patient after modified Fontan procedure. The mapping system was used for the identification of a promising pacing site in the complexly modified right atrium and to visualize the successful placement of an atrial lead at the same spot.

Drug-Induced Loss of Preexcitation in Pediatric Patients with WPW Pattern During Electrophysiologic Study

Ablation of accessory pathways (AP) is one of the most often performed procedures in pediatric electrophysiology. In pediatric patients these procedures are mostly performed in anaesthesia or sedation. In some of these patients who are referred for electrophysiologic (EP) study, we could observe disappearance of the preexcitation, i.e. antegrade conduction of an AP during introduction of sedation. As a suppression of AP conduction capacities has been reported as negative side effect of propofol and other anaesthetics, the aim of this study was to evaluate risk factors for drug-induced suppression of AP conduction properties. Consecutive, pediatric patients with Wolff-Parkinson-White (WPW) pattern referred for EP study in the period of 2016-2017 were reviewed in retrospect. Patients with complex congenital heart disease were excluded. An entire chart review including ECG, bicycle stress testing, and periprocedural data was performed. In 4 of 37 patients included into the study, loss of preexcitation could be observed during sedation. Data analysis showed weaker conduction capacities of the AP as a risk factor (p = 0.009). Interestingly, absolute (p = 0.11) or adjusted to body weight (p = 0.92) drug doses were not a relevant risk factor. Patients with WPW and weaker conduction capacities of the AP, as implied by an early disappearance of preexcitation during exercise stress testing, seem to be more prone to drug-induced suppression of an AP.

A novel technique for lead sparing tricuspid valve replacement in the case of a transvenous ICD lead

Tricuspid valve (TV) surgery represents a complex consideration regarding lead management in patients with a transvenous ICD. The presented case shows favorable short-term results after lead sparing TV replacement, leaving an ICD lead in a paravalvular position. The described technique can be used in challenging cases of TV replacement.

QRS Width as a Predictor of Right Ventricular Remodeling After Percutaneous Pulmonary Valve Implantation

Recent data showed a right ventricular dyssynchrony in patients with tetralogy of Fallot (TOF). Percutaneous pulmonary valve implantation (PPVI) has become an important procedure to treat a pulmonary stenosis and/or regurgitation of the right ventricular outflow tract in these patients. Despite providing good results, there is still a considerable number of nonresponders to PPVI. The authors speculated that electrical dysfunction of the right ventricle plays an underestimated role in the outcome of patients after PPVI. This study aimed to investigate the influence of right ventricular electrical dysfunction, i.e., right bundle branch block (RBBB) on the RV remodeling after PPVI. The study included consecutive patients after correction of TOF with or without RBBB, who had received a PPVI previously at the Heart Center of the University of Leipzig, Germany during the period from 2012 to 2015. 24 patients were included. Patients without RBBB, i.e., with narrow QRS complexes pre-intervention, had significantly better RV function and had smaller right ventricular volumes. Patients with pre-interventionally QRS width below 150 ms showed a post-interventional remodeling of the right ventricle with the decreasing RV volumes (p = 0.001). The parameters of LV function and volume as well as RV ejection fraction remained unaffected by RBBB. The presented data indicate that the QRS width seems to be a valuable parameter in the prediction of right ventricular remodeling after PPVI, as it represents both electrical and mechanical functions of the right ventricle and may serve as an additional parameter for optimal timing of a PPVI.

Rate Control by Transoesophageal Atrial Overdrive Pacing for Refractory Supraventricular Tachycardia with Severe Ventricular Dysfunction: A Bridge to Recovery

Tachyarrhythmia-induced cardiomyopathy (TIC) is a rare, yet life-threatening phenomenon in children. TIC has been defined as myocardial dysfunction that is entirely or partially reversible after control of the responsible tachyarrhythmia and is typically caused by an incessant supraventricular tachycardia. In cases of unsuccessful termination of the tachycardia, cardiogenic shock may occur. Several authors favour the use of mechanical circulatory support in such cases. Particularly with regard to these partly severe cases, the authors would like to present the option of transoesophageal overdrive pacing (TOP) as a tool for initial heart rate control and hemodynamic stabilization of patients with TIC refractory to conventional strategies of tachycardia termination. Chart review for patients receiving TOP during the last 5 years in two centres was performed. A case series of successful TOP including technique and outcomes is depicted. Rate control through TOP is a safe and effective option to restore acceptable hemodynamics in infants with refractory supraventricular tachycardia and severe impairment of ventricular function. It presents the possibility of immediate heart rate control and offers time for myocardial recovery and safe implementation of antiarrhythmic drug therapy.

Improved quality of life after treatment of prolonged asystole during breath holding spells with a cardiac pacemaker

Objectives:

To validate the physical and psychological effectiveness of cardiac pacing in pediatric patients with breath-holding spells (BHS) and prolonged asystole.

Materials and Methods:

The records and clinical data of all the patients with BHS who presented to our center in the period of 2001–2013 were reviewed. All patients who received cardiac pacemaker implantation for prolonged asystole during BHS were included. In addition, the parents were asked to fill out a standardized quality of life (QOL) questionnaire.

Results:

Seven patients were identified. The mean onset of symptoms was 7 month (1–12 months) of age, documented asystole was 12–21 seconds, and a permanent cardiac pacemaker device was implanted at a mean age of 23 months (8 months–3.9 years). No pacemaker related adverse events were recorded. Follow up showed immediate resolution from spells in four cases (4/7). Two patients (2/7) showed significant reduction of frequency and severity of spells, with complete elimination of loss of consciousness (LOC). One patient (1/7) with an additional neurologic disorder continued to have minor pallid BHS and eventually switched from pallid to cyanotic spells without further detection of bradycardia or asystole in holter examination. QOL questionnaire revealed significant reduction in subjective stress levels of patients (P = 0.012) and parents (P = 0.007) after pacemaker implantation.

Conclusion:

Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed.

Ryanodine receptor mutations presenting as idiopathic ventricular fibrillation: a report on two novel familial compound mutations, c.6224T>C and c.13781A>G, with the clinical presentation of idiopathic ventricular fibrillation

Idiopathic ventricular fibrillation (IVF) is a rare genetically determined disease causing unexpected cardiac death in otherwise healthy individuals. This study identified two novel, functional heterozygous mutations in the ryanodine receptor 2 (RyR2) gene in a family with IVF. In the presented case all the patients received a thorough diagnostic workup to exclude structural heart disease. Blood was drawn from the patients, and genetic testing was performed including amplification and sequencing of splice locations in two exons of the RyR2 gene. The mutations were detected in five symptomatic family members. The genetic status of the five affected family members remains unclear. No clinically affected patient is without mutation. At this writing, one family member with confirmed mutation is asymptomatic. The differentiation between catecholaminergic polymorphic ventricular tachycardia (CPVT) and IVF remains a difficult issue, mainly based on clinical characteristics and gross genetic classification. In our case, the family history, exercise testing, and epinephrine stress testing do not suggest an association of arrhythmia and adrenergic triggers, which makes CPVT rather unlikely despite the fact that genetic testing showed RyR2 mutations. Currently, knowledge concerning the functional meaning of genetic mutations is growing. Future exploration of these functional aspects might give further impetus to allocation of these patients to a specific diagnosis.

Performance of steroid eluting bipolar epicardial leads in pediatric and congenital heart disease patients: 15 years of single center experience

Objective

Cardiac pacing is sometimes required for patients with congenital heart disease for various reasons. Because of complex anatomy, repetitive previous heart surgery and patient size, epicardial leads are of special importance in these patients. Using epicardial leads has been discussed controversly regarding pacing performance and lead survival. The aim of this study was to review the long-term data on pacing performance as well as lead survival of epicardial leads implanted in our center.

Methods

Retrospective chart review and review of the literature.

Results

82 consecutive pediatric patients or adult patients with congenital heart disease with 158 epicardial leads (Medtronic 4968, bipolar, steroid - eluting) were included. We found 1.2% pacemaker-related early postoperative complications. The incidence of lead dysfunction was 7.5% (12/158) for primary (i.e. directly related to the lead itself) lead dysfunction and 3.2% (5/158) of lead abandonment for reasons not directly related to the lead itself. Primary lead dysfunction occured after a median of 3.83 years. Lead survival at 2, 5 and 10 years was 98.7%, 93% and 92.4%. There were no infections reported. Stable median measurements for impedance (RA/RV/LV of 577/483/610 Ohm), sensing threshold (RA/RV/LV of 2.0/11.0/10.0 mV) and pacing threshold (RA/RV/LV of 0.75 V at 0.4 ms/1.0 V at 0.49 ms/1.0 V at 0.45 ms) indicated a good mid- to longterm performance. The only risk factor for primary lead dysfunction was young age at implantation.

Conclusion

The use of epicardial leads in pediatric and adult patients with congenital heart disease shows good longterm outcomes in terms of pacing performance and lead survival. The authors encourage using epicardial leads in patients with congenital heart disease based on the patient‘s individual characteristics.

Pharmacologic cardiac resynchronization of a 1-year-old boy with severe left ventricular dysfunction

Postero-septal accessory pathways (AP) are a rare cause of intraventricular dyssynchrony and severe LV dysfunction in children. Beside the common treatment with radiofrequency ablation of septal substrates we present the case of a successful pharmacologic resynchronization in a 13/12 years old male toddler with Wolff-Parkinson-White syndrome (WPW) and severe LV dysfunction (left ventricular biplane EF of 31 %) due to intraventricular dyssynchrony with septal to posterior wall motion delay (SPWMD) of 350 ms. Interventricular mechanical delay (IVMD) was 65 ms. Using propafenone, pharmacologic cardiac resynchronization could be achieved. Pharmacologic resynchronization should be considered as safe and effective alternative to catheter ablation in very young children.

Atrioventricular conduction time in fetuses assessed by Doppler echocardiography

We performed measurement of mechanical atrioventricular conduction time intervals in human fetuses assessed by Doppler echocardiography and provided reference values. We found that atrioventricular conduction time interval was prolonged with gestational age and decreased with increasing fetal heart rate. No correlation between gestational age and heart rate was found. Using normal limits established by this study, mechanical atrioventricular interval >135 ms in the 20(th) week and/or >145 ms in the 26(th) week of gestation could be suspected of having the first-degree AV block. We compared reference values with fetuses of mothers with anti-SSA Ro/SSB La autoantibodies, being in risk of isolated congenital heart block development. One of 21 fetuses of mothers with positive autoantibodies was affected by prolonged atrioventricular interval according to the established limits, with sinus rhythm after the birth.

Cardiac resynchronisation therapy in paediatric and congenital heart disease: differential effects in various anatomical and functional substrates

Background:

Cardiac resynchronisation therapy (CRT) is increasingly used in children in a variety of anatomical and pathophysiological conditions, but published data are scarce.

Objective:

To record current practice and results of CRT in paediatric and congenital heart disease.

Design:

Retrospective multicentre European survey.

Setting:

Paediatric cardiology and cardiac surgery centres.

Patients:

One hundred and nine patients aged 0.24–73.8 (median 16.9) years with structural congenital heart disease (n = 87), congenital atrioventricular block (n = 12) and dilated cardiomyopathy (n = 10) with systemic left (n = 69), right (n = 36) or single (n = 4) ventricular dysfunction and ventricular dyssynchrony during sinus rhythm (n = 25) or associated with pacing (n = 84).

Interventions:

CRT for a median period of 7.5 months (concurrent cardiac surgery in 16/109).

Main outcome measures:

Functional improvement and echocardiographic change in systemic ventricular function.

Results:

The z score of the systemic ventricular end-diastolic dimension decreased by median 1.1 (p<0.001). Ejection fraction (EF) or fractional area of change increased by a mean (SD) of 11.5 (14.3)% (p<0.001) and New York Heart Association (NYHA) class improved by median 1.0 grade (p<0.001). Non-response to CRT (18.5%) was multivariably predicted by the presence of primary dilated cardiomyopathy (p = 0.002) and poor NYHA class (p = 0.003). Presence of a systemic left ventricle was the strongest multivariable predictor of improvement in EF/fractional area of change (p<0.001). Results were independent of the number of patients treated in each contributing centre.

Conclusion:

Heart failure associated with ventricular pacing is the largest indication for CRT in paediatric and congenital heart disease. CRT efficacy varies widely with the underlying anatomical and pathophysiological substrate.

Resynchronization pacing is a useful adjunct to the management of acute heart failure after surgery for congenital heart defects

The acute hemodynamic effect of atrioventricular (AV) and inter/intraventricular (IV) resynchronization accomplished by temporary pacing using multiple epicardial pacing wires was evaluated in 20 children (aged 3.4 months to 14.0 years) after surgery for congenital heart defects fulfilling the following criteria: (1) presence of AV and/or IV conduction delay, and (2) need for inotropic support. AV resynchronization (n = 13) was achieved by AV delay optimization during atrial synchronous right ventricular outflow tract pacing. IV resynchronization (n = 14) was accomplished by atrial synchronous pacing from the right ventricular lateral wall in 7 patients with right bundle branch block and normal AV conduction and by atrial synchronous multisite ventricular pacing in another 7 patients with previously performed AV resynchronization. Compared with baseline values, AV resynchronization resulted in an increase in arterial systolic, mean, and pulse pressures by 7.2 +/- 8.3% (p <0.01), 8.6 +/- 8.1% (p <0.005), and 6.9 +/- 13.5% (p = NS), respectively. IV resynchronization used either alone or added to previously performed AV resynchronization led to a pressure increase of 7.0 +/- 4.7%, 5.9 +/- 4.7%, and 9.4 +/- 7.8%, respectively (p <0.001 for all). The combined effect of AV and IV resynchronization resulted in a systolic, mean, and pulse pressure increase of 10.2 +/- 5.0% (range 4.0 to 19.1), 8.6 +/- 5.4% (range 0.8 to 14.8), and 15.2 +/- 8.5% (range 6.1 to 33.3), respectively (p <0.001 for all). The increase in systolic arterial pressure after IV resynchronization was positively correlated with the initial QRS duration (r = 0.62, p <0.05) and extent of QRS shortening (r = 0.66, p <0.05). In conclusion, resynchronization pacing led to a significant increase in arterial blood pressure and was a useful adjunct to the treatment of acute postoperative heart failure in patients with AV and/or IV conduction delay.