Mechano-Electrical Interaction Late After Fontan Operation

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

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Arrhythmic and thromboembolic outcomes in adults with coarctation of the aorta

BACKGROUND

Adults with congenital heart disease (ACHD) experience a high prevalence of atrial arrhythmia (AA) and thromboembolic cerebrovascular complications. However, data on AA and associated long-term outcomes are limited in ACHD patients with coarctation of the aorta (CoA).

OBJECTIVES

This study aimed to characterize the prevalence and risk factors for AA and thromboembolic complications in adults with CoA.

METHODS

We conducted a retrospective cohort study in a tertiary ACHD care center and included consecutive CoA patients older than 18 years old with more than one year of follow-up.

RESULTS

Two hundred seventy patients with CoA were followed for 7.2 ± 3.95 years. The mean age was 35.3 ± 11.1 and 55.2% were male. Patients had a mean of 2.1 ± 1.8 cardiovascular surgical or transcatheter procedures. Thirty-five patients (13%) had AA. Ten subjects (3.8%) had a thromboembolic cerebrovascular event, of which four (1.4%) had AA. In univariate analysis, age (p = 0.005) and total intracardiac interventions (p = 0.007) were associated with the presence of AA. Age (p = 0.021), history of heart failure (p = 0.022), and dyslipidemia (p = 0.019) were associated with thromboembolism. In multivariate analysis, age (p < 0.001) and intracardiac interventions (p = 0.007) were associated with AA.

CONCLUSIONS

The rate of AA is higher in adults with CoA than in the general population but lower than in other ACHD. Increasing age and intracardiac interventions were associated with AA. The rate of thromboembolic events was low. Some traditional risk factors for stroke may apply. Larger studies are needed to validate predictors for stroke in this population.

Temporal progression of P wave abnormality in a patient with classical or atriopulmonary Fontan

We present the electrocardiographic findings in a 36-year-old female with tricuspid atresia with double-outlet right ventricle and malposition of great arteries who underwent classical or "atriopulmonary" Fontan procedure in childhood. Her electrocardiograms have consistently shown marked intra-atrial delay with an initial positive P wave deflection and terminal negative P deflection in all leads with progressive increase in P wave duration with time. She has had frequent episodes of intra-atrial tachycardia, atrial fibrillation and sinus and post ectopic pauses over the past few years. The findings in our patient, which have not been reported before, illustrate the atrial pathology, which is unique to Fontan physiology, particularly those with classical or atriopulmonary Fontan. We hope that the specific electrocardiographic findings presented will allow for their recognition.

Validation of Normal P-Wave Parameters in a Large Unselected Pediatric Population of North-Western Romania: Results of the CARDIOPED Project

AIMS

Reference values of the P-wave on 12 lead electrocardiograms are lacking for children and adolescents in Eastern Europe. Hence, the present study is aimed at determining the standard values of the P-wave in children and adolescents based on ECG data from the CARDIOPED project, a large-scale general population of children who participated in a screening program in Transylvania, Romania.

METHODS AND RESULTS

A total of 22,411 ECGs of participants aged 6 to 18 years old from a school-based ECG screening were obtained between February 2015 and December 2015 in Transylvania, Romania. Three pediatric cardiologists manually reviewed each ECG. P-wave duration, voltage, axis, and correlation with gender and age were analyzed. The mean P-wave duration was 88 ± 10.7 ms, with a maximum duration of 128 ms. P-wave showed a positive correlation with age but did not differ between sexes. There was a positive correlation between the P-wave duration and the heart rate, but not with the body max index. The mean P-wave axis was 40.4 ± 31.1, and the mean P-wave amplitude was 0.12 ± 0.03 mV.

CONCLUSION

In this study on many pediatric subjects, we have provided normal limits for the P-wave in Romanian children aged 6-18 years. Our findings are useful for creating interpretation guidelines for pediatric ECG.

P-Wave Area Predicts New Onset Atrial Fibrillation in Mitral Stenosis: A Machine Learning Approach

Introduction: Mitral stenosis is associated with an atrial cardiomyopathic process, leading to abnormal atrial electrophysiology, manifesting as prolonged P-wave duration (PWD), larger P-wave area, increased P-wave dispersion (PWDmax-PWDmin), and/or higher P-wave terminal force on lead V1 (PTFV1) on the electrocardiogram. Methods: This was a single-center retrospective study of Chinese patients, diagnosed with mitral stenosis in sinus rhythm at baseline, between November 2009 and October 2016. Automated ECG measurements from raw data were determined. The primary outcome was incident atrial fibrillation (AF). Results: A total 59 mitral stenosis patients were included (age 59 [54-65] years, 13 (22%) males). New onset AF was observed in 27 patients. Age (odds ratio [OR]: 1.08 [1.01-1.16], P = 0.017), systolic blood pressure (OR: 1.03 [1.00-1.07]; P = 0.046), mean P-wave area in V3 (odds ratio: 3.97 [1.32-11.96], P = 0.014) were significant predictors of incident AF. On multivariate analysis, age (OR: 1.08 [1.00-1.16], P = 0.037) and P-wave area in V3 (OR: 3.64 [1.10-12.00], P = 0.034) remained significant predictors of AF. Receiver-operating characteristic (ROC) analysis showed that the optimum cut-off for P-wave area in V3 was 1.45 Ashman units (area under the curve: 0.65) for classification of new onset AF. A decision tree learning model with individual and non-linear interaction variables with age achieved the best performance for outcome prediction (accuracy = 0.84, precision = 0.84, recall = 0.83, F-measure = 0.84). Conclusion: Atrial electrophysiological alterations in mitral stenosis can detected on the electrocardiogram. Age, systolic blood pressure, and P-wave area in V3 predicted new onset AF. A decision tree learning model significantly improved outcome prediction.

Impact of Transcatheter Device Closure of Atrial Septal Defect on Atrial Arrhythmias Propensity in Young Adults

Atrial septal defect (ASD) is a condition that requires early intervention because of the consequences over the right-side heart. Chronic atrial stretching promotes atrial conduction delay and the imbalance of the conduction homogeneity, which lead to the propensity to atrial arrhythmias (AA). We aim to evaluate the impact of transcatheter closure of ASD on atrial vulnerability markers leading to late AA in young adults. We conducted a prospective, longitudinal study in one hundred patients (mean age 25.2 ± 5.4 years) who underwent transcatheter closure of ASD at Cardiocentro Pediátrico William Soler. P-wave maximum (P_max) and P-wave dispersion (P_d) were analyzed from 12-lead electrocardiogram. Left-side and right-side intraatrial and interatrial electromechanical delay (EMD) were measured with tissue Doppler imaging. Both electrocardiographic and echocardiographic analyses were performed during the study period. Compared to baseline, there was a significant reduction in P max (p ≤ 0.001) and P_d (p ≤ 0.001) after 3 months of procedure. All atrial electromechanical coupling parameters significantly reduced at 6 months of ASD closure and tend to remain at lower values till the last evaluation. Over 9.2 ± 1.6 years of follow-up, 15 subjects (15%) developed AA, of which intraatrial reentrant tachycardia (66.6%) became the main rhythm disturbance. Intra-right atrial EMD ≥ 16 ms (HR 4.08, 95% CI 1.15-14.56; p = 0.03) and P_d 45 ms (HR 1.66, 95% CI 1.06-2.59; p = 0.02) were identified as predictors of late AA. Transcatheter device closure of ASD in young adults promotes a significant reduction of electrocardiographic and echocardiographic markers of AA vulnerability, which persist during the long-term follow-up. Nevertheless, P_d and interatrial EMD were identified as independent risk factors of AA.

Different characteristics of postoperative atrial tachyarrhythmias between congenital and non-congenital heart disease

PURPOSE

The chance of encountering tachyarrhythmias has been increasing in adult congenital heart disease (CHD) patients with previous open-heart surgery, along with the improvement of their longevity. However, the characteristics of these arrhythmias remain to be elucidated.

METHODS

We examined the characteristics of atrial tachyarrhythmias (ATs) in 26 consecutive CHD patients (M/F 17/9) referred for catheter ablation and compared them with 16 non-CHD patients with cardiac surgery (M/F 11/5).

RESULTS

The CHD group was younger and had a longer period from cardiac surgery until the occurrence of ATs compared with the non-CHD group (44.8 ± 19.5 vs. 67.6 ± 12.5 years old, and 23.3 ± 13.2 vs. 6.3 ± 4.9 years, respectively, both P < 0.05). Multiple ATs were equally induced in both groups, 12 in CHD (46.1%) and 5 in non-CHD (31.3%). Although the prevalence of macro-reentrant ATs (cavo-tricuspid isthmus-dependent atrial flutter (AFL) or intra-atrial reentrant tachycardia (IART)) was comparable, the mechanisms were different between the 2 groups (AFL and IART), 34% and 27% in CHD and 71% and 24% in non-CHD, respectively. Furthermore, focal AT (FAT) was noted in 9 patients (34.6%) in CHD but none in non-CHD (P < 0.05). Electroanatomical mapping showed that the surface area and low-voltage area (LVA) of the right atrium were significantly larger in CHD than in non-CHD (197.1 ± 56.4 vs. 132.4 ± 41.2 cm², and 40.8 ± 33.3 vs. 13.6 ± 9.0 cm², respectively, both P < 0.05). Ten out of 14 FATs (71.4%) were highly associated with LVA, especially near the crista terminalis.

CONCLUSIONS

The development of ATs in CHD patients could be associated with large atrial remodeling, resulting in complicated ATs.

Long-term outcomes after first-onset arrhythmia in Fontan physiology

OBJECTIVES

Patients living with a Fontan circulation are prone to develop arrhythmias. However, their prognostic impact has been seldom studied. As such, we aimed to determine the incidence and predictors of arrhythmias after the Fontan procedure and the long-term outcomes after the first onset of arrhythmias.

METHODS

Of the 1034 patients who have undergone a Fontan procedure as recorded in the Australian and New Zealand Fontan Registry, we identified those in whom a tachyarrhythmia or bradyarrhythmia developed. We evaluated the incidence and predictors of developing arrhythmias and their prognostic impact on late outcomes.

RESULTS

Arrhythmia developed in 195 patients. Tachyarrhythmia was present in 162 patients, bradyarrhythmia was present in 74 patients, and both forms were present in 41 patients. At 20 years, freedom from any arrhythmia, tachyarrhythmia, and bradyarrhythmia was 66% (95% confidence interval [CI], 59-72), 69% (95% CI, 62-75), and 85% (95% CI, 80-90), respectively. On multivariable analyses, patients with an extracardiac Fontan (hazard ratio [HR], 0.23; 95% CI, 0.10-0.51; P < .001) were less likely to develop an arrhythmia, whereas those with left atrial (HR, 3.18; 95% CI, 1.45-6.95; P = .004) and right atrial (HR, 4.00; 95% CI, 2.41-6.61; P < .001) isomerism were more likely to have an arrhythmia. After onset of any arrhythmia (tachyarrhythmia or bradyarrhythmia), 10- and 15-year survivals were 74% (65%-83%) and 70% (60%-80%), respectively, and freedom from Fontan failure was 55% (44%-64%) and 44% (32%-56%), respectively. The development of any arrhythmia (HR, 2.20; 95% CI, 1-44-3.34; P < .001), tachyarrhythmia (HR, 2.56; 95% CI, 1.60-4.11; P < .001), and bradyarrhythmia (HR, 1.85; 95% CI, 1.16-2.95; P = .01) were all independent predictors of late Fontan failure on multivariable analyses.

CONCLUSIONS

The development of an arrhythmia is associated with a heightened risk of subsequent failure of the Fontan circulation.

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

Outcomes of Fontan conversion for failing Fontan circulation: mid-term results

OBJECTIVES

We investigated the results of a revision of a previous Fontan connection to total cavopulmonary connection (TCPC) in patients with failing Fontan circulation.

METHODS

From July 1998 to April 2013, 21 patients who had failing Fontan circulation underwent revision of the previous Fontan operation to TCPC. The median age at TCPC conversion was 17.9 years (range, 4.6-38.1 years) and the median interval between initial Fontan operation and TCPC was 13.8 years (range, 2.1-25.4 years). There were 37 indications for Fontan revision in 21 patients. The indications were huge right atrium (n = 15), atrial arrhythmia (n = 8), intra-atrial thrombi (n = 6), protein-losing enteropathy (PLE) (n = 3) and more than mild atrioventricular valve regurgitation (n = 5). The previous Fontan operation was revised to extracardiac conduit replacement (n = 20) and intra-atrial lateral tunnel (n = 1). Concomitant surgery for atrial arrhythmia was performed in 8 patients. Fenestration was performed in 7 patients. The median follow-up duration was 7.1 years (range, 0.3-13.4 years).

RESULTS

There were no operative deaths and two late deaths occurred 7.9 and 8.1 years after operation. Actuarial 5- and 10-year survival rates were 92.3 and 83.1%, respectively. Postoperative complications included bleeding (n = 3), deep sternal infection (n = 1) and prolonged pleural effusion for more than 2 weeks (n = 5). During follow-up, atrial arrhythmia recurred in 6 patients, PLE recurred in 2 patients and pleural effusion recurred in 2 patients. All patients were classified as New York Heart Association Class I (n = 15) or Class II (n = 4).

CONCLUSIONS

Fontan conversion to TCPC in patients with failing Fontan circulation can be performed with low risk of morbidity and mortality. The procedure confers better quality of life and is functional for patients with failed Fontan circulation.

Fontan Conversion

Early survival after the Fontan operation has improved significantly leading to a lifetime of Fontan circulation for patients. There is a natural progression of pulmonary artery pressure during the human lifetime that is easily tolerated in two-ventricle physiology but is deleterious for single-ventricle physiology. Obstructions in the venous to pulmonary artery pathway and pulmonary venous return or ventricular outflow, atrioventricular valve dysfunction (regurgitation), pulmonary arteriovenous malformations, venous thrombosis, and the development of atrial arrhythmias can lead to reduced functional status. These complications have been demonstrated in older patients with largely atriopulmonary connections owing to time accrual and unfavorable flow characteristics. Various surgical and catheter interventions aimed at reducing morbidity and mortality have been attempted to treat these identifiable abnormalities. The purpose of this article is to review the extant literature on Fontan Conversion and to assess the lessons learned over 20 years.

Holter electrocardiography findings and P-wave dispersion in pediatric patients with transcatheter closure of atrial septal defects

BACKGROUND

This study aimed to determine the frequency of postintervention arrhythmia and factors associated with the development of arrhythmia, including the correlation between arrhythmia and P-wave dispersion, and the effects of the latter on transcatheter closure of atrial septal defects (ASDs).

METHODS

Holter ECG recordings were performed before and after the intervention and 6 and 12 months later in 47 of the 59 patients who had undergone transcatheter ASD closure and once in the healthy control subjects.

RESULTS

A statistically significant correlation was identified between the patients' arrhythmia grade according to Lown's system and each of the following: the number of defects, the size of the atrioventricular valve rim, the presence of an atrial septal aneurysm.

CONCLUSION

The frequency of arrhythmia increases after transcatheter ASD closure, gradually decreases within the next year, and is most frequently of a benign nature. Lown's arrhythmia grading of patients occluded with either the Amplatzer septal occluder (ASO) or the Cardio-O-Fix septal occluder (CSO) were compared, and the arrhythmia frequency was higher with the latter. One day after the intervention, the P maximum (Pmax ) and the P dispersion(Pdis ) values were not increased but in fact slightly reduced in patients occluded with either ASO or CSO. An improvement in the electrical system resulting from early anatomical and mechanical healing following transcatheter ASD occlusion may explain the reduction in the Pmax and Pdis values.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Identifying arrhythmias in adults with congenital heart disease by 24-h ambulatory electrocardiography

Adults with congenital heart disease (CHD) are at risk for the development of arrhythmias. This study aimed to assess the incidence of unsuspected arrhythmias among adults with CHD identified on electrocardiograms (ECGs) and 24-h ambulatory electrocardiographic monitoring (Holter monitoring). A review of the cardiology database at the authors' institution from July 2004 through December 2007 identified all clinic patients 18 years old or older who had a recent ECG and Holter monitoring. Data collection included diagnosis, ECG and Holter monitoring results, arrhythmias, and the presence or absence of symptoms. The review identified 140 patients. Analysis of the ECGs showed that 15% of the patients had an arrhythmia. These arrhythmias consisted of ectopy (6%), supraventricular tachycardia (SVT) (3%), pacemaker issues (2%), and previously unrecognized atrioventricular block (AVB) (1%). The majority of the patients with arrhythmias were asymptomatic (76%). Analysis of the Holter monitoring results showed that 31% of the patients had arrhythmias consisting of ectopy (17%), SVT (12%), ventricular tachycardia (7%), high-grade AVB (5%), and pacemaker issues (3%). Of the patients with arrhythmias, 80% were asymptomatic. Among the patients without arrhythmias on ECG, 26% had arrhythmias noted on Holter monitoring. Of the patients with multiple Holter monitorings performed, 34% had a new arrhythmia noted on repeat monitoring. In conclusion, arrhythmias were present in a significant number of adults with CHD, but the majority were asymptomatic. Among adults with CHD, even those with normal ECGs, arrhythmias were frequently detected on Holter monitoring. In addition, repeat Holter monitoring may identify significant arrhythmias over time.

Fontan conversion with concomitant arrhythmia surgery for the failing atriopulmonary connections: mid-term results from a single centre

OBJECTIVES

Classical Atriopulmonary Fontan connections tend to fail in the long term due to progressive anastomotic site obstruction, right atrial enlargement, and refractory atrial arrhythmias. Conversion to total cavopulmonary connection with concomitant arrhythmia surgery is a promising treatment but optimal timing of the procedure remains controversial.

METHODS

Between the years 2002 and 2009, 15 patients with a median age of 26.2 (12-43) years underwent Fontan conversion operation with concomitant arrhythmia surgery. All were symptomatic and 14 out of the 15 patients had refractory arrhythmias. The duration of pre-operative arrhythmia and the outcome of surgery were correlated to study the impact of delay in surgical intervention on post-operative survival and arrhythmia control.

RESULTS

There were two patients who died in the early post-operative period (13.3%). At the mid-term follow-up, 53 (20-86) months, late atrial arrhythmias had recurred in two of the 13 surviving patients (15.30%) and one patient developed late sinus node dysfunction. The need for anti-arrhythmic drugs decreased considerably from 93.5% to 15.3% on mid-term follow-up. There was no late death or need for cardiac transplantation. The duration of arrhythmia before surgery was prolonged for more than 10 years in patients who died as well as in those who had complications like late recurrence of arrhythmias, dependence on anti-arrhythmic medications, and worsening of ventricular dysfunction.

CONCLUSIONS

Fontan conversion is a well-established treatment option for salvaging the failing atriopulmonary connections. Concomitant arrhythmia surgery effectively resolves the refractory atrial arrhythmias and improves survival, but we need to optimise the timing of Fontan conversion to improve the long-term outcome.

Prevalence of interatrial block in healthy school-aged children: definition by P-wave duration or morphological analysis

BACKGROUND

P waves > or = 110 ms in adults and > or = 90 ms in children are considered abnormal, signifying interatrial block, particularly in the first case.

METHODS

To evaluate the prevalence of interatrial block in healthy school-aged children, we obtained 12-lead digital ECGs (Cardioperfect 1.1, CardioControl NV, Delft, The Netherlands) of 664 healthy children (349 males/315 females, age range 6-14 years old). P-wave analysis indices [mean, maximum and minimum (in the 12 leads) P-wave duration, P-wave dispersion, P-wave morphology in the derived orthogonal (X, Y, Z) leads, as well the amplitude of the maximum spatial P-wave vector] were calculated in all study participants.

RESULTS

P-wave descriptor values were: mean P-wave duration 84.9 + or - 9.5 ms, maximum P-wave duration 99.0 + or - 9.8 ms, P dispersion 32.2 + or - 12.5 ms, spatial P amplitude 182.7 + or - 69.0 microV. P-wave morphology distribution in the orthogonal leads were: Type I 478 (72.0%), Type II 178 (26.8%), Type III 1 (0.2%), indeterminate 7 (1%). Maximum P-wave duration was positively correlated to age (P < 0.001) and did not differ between sexes (P = 0.339). Using the 90-ms value as cutoff for P-wave duration, 502 (75.6%) children would be classified as having maximum P-wave duration above reference range. The 95th and the 99th percentiles were in the overall population 117 ms and 125 ms, respectively. P-wave morphology type was not in any way correlated to P-wave duration (P = 0.715).

CONCLUSIONS

Abnormal P-wave morphology signifying the presence of interatrial block is very rare in a healthy pediatric population, while widened P waves are quite common, although currently classified as abnormal.

Atrial remodeling after the Fontan operation

The hemodynamics after Fontan surgery are notable for hypertension and dilation of the right atrium (RA). The effect of this stress on atrial cytoarchitecture has not been systematically studied and might be relevant to arrhythmias and their treatment. Morphologic and histopathologic analyses were performed on tissue from the RA and left atrium (LA) from autopsy specimens of Fontan hearts (n = 47). The findings were compared to those from control samples from young patients with normal atrial hemodynamics (n = 15). Most Fontan specimens were from young patients who died after a relatively short duration of Fontan physiology. The tissues were analyzed for wall thickness, fibrosis content, and fibrosis pattern. The mean wall thickness for the RA (3.0 +/- 1.0 mm) and LA (2.3 +/- 0.6 mm) in the Fontan hearts was significantly greater than that in the control hearts (RA, 1.8 +/- 0.4 mm; LA, 1.8 +/- 0.5 mm; p <0.001 and p = 0.024, respectively). The predictors for thickening of the RA included (1) older age at Fontan surgery, (2) older age at death, and (3) longer duration of Fontan circulation. The Fontan hearts and control hearts exhibited nearly identical fibrosis patterns in the RA and LA. Neither wall thickness nor fibrosis varied with the underlying heart defect or style of Fontan connection. In conclusion, atrial remodeling after Fontan surgery for univentricular heart physiology involves increased wall thickness in both the RA and LA. Interstitial fibrosis was also observed in the Fontan atria; however, because a similar pattern was present in the control tissue, this likely represented normal fibroelastic atrial structure, rather than a specific response to Fontan hemodynamics. The degree of wall thickening observed in the Fontan atria was not so excessive as to preclude transmural lesions during catheter or surgical ablation of reentrant arrhythmias.

Duration and dispersion of the P wave after the Senning operation

We studied the duration and dispersion of the P wave in patients after a Senning operation, assessing its value in detecting the risk of atrial tachycardias.We measured the duration and dispersion of the wave in surface 12 lead electrocardiograms obtained from 18 patients with sinus rhythm, having a mean age of 12.8 years, with 13 being males and 5 females, who had undergone a Senning operation, comparing the values obtained in 35 age and gender-matched healthy people. The patients had undergone repair at a mean age of 13.4 months, and had a mean duration of follow-up of 12.8 years after the procedure. We also made 24 hour Holter recordings.The maximal duration of the P wave, at a mean of 129.3 milliseconds, and dispersion with a mean of 78 milliseconds, were both significantly increased in the patients compared with their controls, the mean values for the normal subjects being 103.7 and 54 milliseconds. Supraventricular tachycardia was detected in 1 of 3 patients with dispersion greater than 100 milliseconds, and in 2 of 15 patients (13%) with dispersion less than 100 milliseconds as measured from the Holter recordings (p > 0.05).Thus, the maximum duration and dispersion of the P wave were increased in patients after a Senning operation, but we were unable to establish any relationship between these measurements and atrial tachycardias as observed using Holter monitoring.

Prediction of the atrial flutter circuit location from the surface electrocardiogram

Identification of atypical atrial flutter (AFL) (non-cavo-tricuspid isthmus-dependent) prior to the electrophysiology laboratory is potentially useful because it allows appropriate procedural planning and enables discussion of the likely success rates and risks of the procedure with the patient. Typical counterclockwise AFL has a stereotypic appearance, the electrocardiogram (ECG) is predictive of the diagnosis in the majority of cases, and ablation procedures are associated with a high degree of safety and success. Atypical right atrial and left AFLs have a highly variable flutter wave morphology and may appear atypical, resemble typical flutter or appear to be focal in origin. Targeting these complex and often multiple re-entrant circuits is aided by expertise and use of electroanatomic mapping systems. This review will address whether there are clues from the 12-lead ECG which assist in the localization of AFL circuits.

The relationship between the left atrial volume and the maximum P-wave and P-wave dispersion in patients with congestive heart failure

PURPOSE

A maximum P-wave duration (Pmax) of > or = 110 msec and a P-wave dispersion (PWD) > or = 40 msec are accepted indicators of a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse, respectively. The left atrial (LA) volume has been reported to be strongly associated with a systolic and diastolic dysfunction and is considered to be an index of atrial remodeling. We aimed to investigate the relationship between LA volume and Pmax or PWD in patients with congestive heart failure (CHF).

PATIENTS AND METHODS

Sixty-one patients with CHF were enrolled in this study. The study population was classified into four groups: two groups were divided according to the Pmax (> or = 110 msec or < 110 ms), and the other two groups were formed based on the PWD (> or = 40 msec or < 40 msec). The left atrial volume index (LAVi) was measured by three-dimensional (3-D) transthoracic echocardiography. The Pmax and PWD were measured from a 12-lead electrocardiogram.

RESULTS

There were significant differences in the ejection fraction (EF), diastolic function, and LAVi between patients with a Pmax > or = 110 ms or a PWD > or = 40 ms and those with a Pmax < 110 ms or a PWD < 40 ms. The LAVi was independently associated with a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse. The LAVi can be used to identify patients with a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse with reasonably good accuracy.

CONCLUSION

We concluded that a disturbance in interatrial conduction and an inhomogeneous propagation of the sinus impulse in patients with CHF is associated with an increase in the LA volume and a deleterious systolic and diastolic dysfunction.

High prevalence of widened P waves among pediatric patients in 2 separate hospitals

INTRODUCTION

In adults, P waves of 110 milliseconds or longer are often associated with significant disease. In the pediatric population, however, cutoffs for P-wave durations are naturally lower but could vary physiologically with age because of increasing heart mass. We appraised if age-proportionate increase in P-wave duration does indeed occur in both hospitalized infants and children and also investigated the prevalence of widened P-wave durations using currently accepted "normal" cutoffs (</=70 milliseconds for infants and </=90 milliseconds for children).

METHODS

We consecutively obtained 12-lead electrocardiograms of infants and children aged up to 16 years (range, 0.1-16 years; mean +/- SD, 10.1 +/- 5.2 years; male, 46.9%) who presented through the emergency department for nonacute, noncardiac conditions at the Nassau University Medical Center (NUMC), East Meadow, NY, and Saint Vincent Hospital (SVH), Worcester, MA, from January to May 2006. Electrocardiograms were then evaluated for the greatest P-wave duration in every lead to the nearest 10 milliseconds using a calibrated magnifying graticule on a blinded, single read.

RESULTS

The study sample consisted of 96 nonacute pediatric patients: infants and children from NUMC (age, 0.1-16 years; mean +/- SD, 9.1 +/- 5.4 years; male, 46.6%) and children from SVH (age, 6-16 years; mean +/- SD, 13.1 +/- 2.5 years; male, 47.8%). Prolonged P waves longer than 70 milliseconds were present in 3 (23%) of the 13 NUMC infants, whereas prolonged P waves longer than 90 milliseconds were observed in 16 (27%) of the 60 NUMC children and 7 (30%) of the 23 SVH children. Linear regression analysis revealed that age was the sole predictor of increasing P-wave durations on any lead [age = -15.33 + 0.30 (P-wave duration [milliseconds]); r(2) = 0.44]. Moreover, there was a significant increase in P-wave duration for patients aged 10 years or older, where a notable step-up in such measurements was observed.

CONCLUSION

P-wave duration is significantly associated with age among hospitalized children as well as infants, where particular increase occurs at 10 years of age or older. General pediatricians and, more importantly, pediatric cardiologists, need to be more vigilant in using appropriate age-based P-wave cutoffs when assessing interatrial conduction in this population.

Optimal timing of the Fontan conversion: change in the P-wave characteristics precedes the onset of atrial tachyarrhythmias in patients with atriopulmonary connection

OBJECTIVES

Atrial tachyarrhythmia is a common complication late after the atriopulmonary connection Fontan procedure. The P-wave duration and dispersion have been regarded as useful markers for its prediction. The purpose of this study was to analyze change in the P-wave characteristics over time after the atriopulmonary connection Fontan procedure, with a special emphasis on the timing of the Fontan conversion.

METHODS

We reviewed clinical and electrocardiographic data in 18 patients with classic tricuspid atresia who underwent the atriopulmonary connection Fontan procedure. Their median age at operation was 4.1 years (range, 1.1-22 years), and the median follow-up period was 18.1 years (range, 10-25 years). We measured the P-wave duration, dispersion, and axis from consecutive 12-lead electrocardiograms in each patient.

RESULTS

There was a significant increase in the maximum P-wave duration as well as the P-wave dispersion over time. Transient ectopic atrial rhythm was observed in 16 patients during follow-up. Atrial tachyarrhythmia developed subsequent to transient ectopic atrial rhythm in 8 patients. Ten patients underwent the conversion. Atrial tachyarrhythmia recurred in 2 patients who had sustained arrhythmia (6.0 and 8.0 years) before the conversion. In contrast, the other 8 patients with transient ectopic atrial rhythm alone or nonsustained atrial tachyarrhythmia have been free from arrhythmia after the conversion.

CONCLUSIONS

Patients commonly and increasingly had prolonged P-wave duration, larger P-wave dispersion, and ectopic atrial rhythm, along with an atrial tachyarrhythmia propensity, late after the atriopulmonary connection Fontan procedure. These P-wave characteristics were informative when considering the Fontan conversion before a sustained atrial tachyarrhythmia ensued.

Preserved regional atrial contractile function following extra-atrial rather than intra-atrial type Fontan operation

OBJECTIVE

To determine the univentricular and atrial function in patients following Fontan operation using tissue Doppler echocardiography (TDE).

SETTING

Hospital-based outpatient clinic and inpatient unit.

PATIENTS

Thirty-six patients (mean age 13 ys [2-34 ys]) after Fontan procedure and 30 healthy individuals matched for age and heart rate.

MAIN OUTCOME MEASURES

Pulsed wave Doppler derived Tei index was determined for global univentricular function. Tissue-Doppler derived strain rate and strain were measured for regional ventricular function. Different planimetric approaches were used to evaluate the global atrial function. Strain rate was measured for regional atrial contractile function.

RESULTS

The Tei index, reflecting global univentricular function, was significantly higher in Fontan patients than in the control group (p<0.001). The regional ventricular contractile function, which was determined by TDE derived strain and strain rate, was significantly lower in Fontan patients than in healthy controls (p<0.001). The global atrial function evaluated planimetrically, and the regional atrial function assessed using the TDE strain rate, were significantly lower in Fontan patients than in normal controls (p<0.001, p<0.001, respectively). A comparison of different types of Fontan operations with extra-atrial or intra-atrial baffle showed a better regional left atrial wall strain rate in patients with extra-atrial baffle than with intra-atrial baffle.

CONCLUSION

Patients who have undergone the Fontan procedure may present with altered ventricular and atrial performance independent of whether the extra-atrial or intraatrial type Fontan operation was performed. However, the regional atrial contractile function seems to be better preserved following the extra-atrial type Fontan operation.

Pulmonary and caval blood flow patterns in patients with intracardiac and extracardiac Fontan: a magnetic resonance study

AIMS

We compared in vivo blood flow and pulsatility after different types of Fontan operation using magnetic resonance imaging.

MATERIAL AND METHODS

A total of 37 consecutive patients (mean age 19+/-7.9 years, 7.3+/-3.2 years after Fontan operation), 7 with atriopulmonary anastomosis (APC), 18 with intra-atrial lateral tunnel (LTFO) and 12 with extracardiac Fontan (ECFO) were studied using magnetic resonance phase-contrast velocity mapping. Blood flow (volume flow) in the superior vena cava (SVC), inferior vena cava (IVC) and both pulmonary arteries were measured and a pulsatility index was calculated for each vessel.

RESULTS

For all modifications, the blood flow distribution between the SVC and IVC was normal (1:2). Patients with APC had a normal pulsatility, a dilated right atrium, partial backward flow in the IVC and physiological blood flow distribution between the pulmonary arteries. LTFO and ECFO patients had no retrograde flow in the IVC, equal blood flow distribution between the pulmonary arteries and very low or absent pulsatility.

CONCLUSIONS

MRI allows hemodynamic quantification and characterization of various types of Fontan modifications and may be a valuable tool to predict Fontan failure. Despite showing normal pulsatility, patients with APC have right atrial dilatation and partial backward flow in the IVC, demonstrating suboptimal Fontan circulation. LTFO and ECFO both produce unidirectional antegrade flow in the IVC but pulsatility is very low or absent, which may promote poor pulmonary artery growth and increase of pulmonary vascular resistance contributing to late Fontan failure.

Acute Hemodynamic Effects of Pacing in Patients With Fontan Physiology

OBJECTIVES

The purpose of this research was to assess the hemodynamic response to atrial, ventricular, and dual-chamber pacing in patients with Fontan physiology.

BACKGROUND

Bradycardia, due to sinus node dysfunction or atrioventricular (AV) block, with need for pacing, is common after the Fontan operation. The optimal pacing mode for Fontan patients is unknown, but is critical, as hemodynamic aberrancies may cause severe clinical deterioration. We hypothesized that AV synchrony is vital for maximizing Fontan hemodynamics.

METHODS

A cross-over trial was conducted with 21 patients (age 2 to 18 years, median 4 years; male patients = 13) in the intensive care unit after a Fontan operation. Hemodynamic parameters, including mean left atrial pressure (LAP, in mm Hg), mean pulmonary artery pressure (PAP, in mm Hg), mean arterial blood pressure (MAP, in mm Hg), and indexed cardiac output via Fick (Qs, in l/min/m2) were measured with atrial, ventricular, and dual-chamber pacing. Measurements were made after pacing for 10 min in each mode, and a 10-min rest was given between each pacing maneuver.

RESULTS

Asynchronous ventricular (VOO) pacing resulted in significantly worse hemodynamics when compared to dual-chamber (DOO) and atrial (AOO) pacing with a higher LAP (9.4 VOO; 6.8 DOO; 5.4 AOO) and PAP (15.2 VOO; 13.5 DOO; 12.7 AOO) and lower Qs (3.0 VOO; 3.5 DOO; 3.9 AOO) and MAP (60.1 VOO; 66.5 DOO; 67.2 AOO).

CONCLUSIONS

Asynchronous ventricular pacing, after the Fontan procedure, has acute, adverse hemodynamic consequences (elevated LAP and PAP and decreased Qs and MAP).