Children with long QT syndrome (LQTS) live with the risk of sudden death, activity restrictions, and the need for daily medications. We sought to evaluate the quality of life (QOL), self-perception, and behavior of patients with LQTS as perceived by both patients and their parents and identify predictors of lower QOL. QOL (Pediatric QOL Inventory [PedsQL] and Pediatric Cardiac Quality of Life Inventory [PCQLI]), self-perception, and behavioral inventories were completed by patients with LQTS and their parents. Comparison of PedsQL scores was made to published data for healthy children using t tests, and PCQLI scores were compared with those of patients with differing complexity of congenital heart disease. Mixed modeling was used for multivariable analysis. Sixty-one patients with LQTS were evaluated (age 13.6 ± 3.0 years; male 49%). Compared with healthy children, the PedsQL Total, Psychosocial, and Physical Health Summary scores were significantly lower for patients with LQTS and parent proxy reports (p ≤0.001). In general, PCQLI scores of patients with LQTS and parents were similar to those of patients with tetralogy of Fallot (p ≥0.2), lower than those of patients with bicuspid aortic valve (p ≤0.02), and higher than those of patients with single ventricle (p ≤0.03). Lower patient and parent PCQLI scores were associated with internalizing problems. For parents, the presence of a cardiac device and medication side effects were additionally associated with lower PCQLI scores. In conclusion, patients with LQTS and their parents report lower QOL than normal children secondary to physical and psychosocial factors. Increasing focus on the psychological well-being of these patients is needed in an effort to improve their QOL.
Long QT syndrome (LQTS) is a genetic disorder affecting myocardial repolarization and predisposes patients to ventricular arrhythmias. Therapy for LQTS generally includes β blockers and potentially restriction from competitive athletics. For patients with refractory symptoms on medical therapy, an implantable cardioverter-defibrillator (ICD) may be indicated. A diagnosis of LQTS potentially places various psychosocial stressors on the patient and family. Patients must take medications and may be restricted from activities that they enjoy and from which they derive positive self-esteem. All these stressors may impact quality of life (QOL), self-perception, and behavior. Few studies have investigated the psychosocial impact of the diagnosis of LQTS. Limited evaluations have documented significant levels of distress, fear, and uncertainty in parents of children with LQTS. In previous work in pediatric patients with various forms of electrophysiologic disease, patients with LQTS were noted to have lower QOL scores than patients with complete congenital heart block and similar scores to those with supraventricular tachycardia and ventricular tachycardia. In addition, the presence of an ICD has been shown to be associated with a lower QOL, similar to that of patients with severe congenital heart disease (CHD). The purpose of this study was to evaluate the QOL, self-perception, and behavior of patients with LQTS as perceived by both patients and their parents and to identify predictors of QOL and self-perception in patients with LQTS.
Methods
This is a corollary study of the cross-sectional Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study including patients with LQTS and their parent proxy from 2 participating centers. The study was approved by the institutional review boards at both centers. As part of the PCQLI Testing Study, patients and their parent proxy reporters (hereafter referred to as parents) independently completed disease-specific QOL (PCQLI), generic QOL (Pediatric QOL Inventory [PedsQL]), self-perception (Self-Perception Profile for Children and Adolescents [SPPC/A]), and behavioral (Achenbach) inventories. Before participation, consent was obtained from the parent and assent from the patient. Data were obtained from the PCQLI Testing Study data set on the assembled LQTS cohort.
Study subjects were participants in the PCQLI Testing Study, which is a multicenter, multinational study assessing the psychometric properties of the PCQLI. Patients in the PCQLI Testing Study were (1) 8 to 18 years of age; (2) had known congenital or acquired heart disease; and (3) did not have any other significant co-morbid medical conditions. Patients and parents in the Testing Study were English speaking and completed the questionnaires before a “routine” follow-up visit in the cardiology outpatient clinic. Patients included in this corollary study were patients who participated in the PCQLI Testing Study at The Children’s Hospital of Philadelphia and Cincinnati Children’s Hospital Medical Center and had a clinical diagnosis of LQTS. A diagnosis of LQTS was based on the judgment of an attending pediatric electrophysiologist through assessment of QTc duration, T-wave morphology, family history and patient symptoms, and genetic status, when available. Patients were excluded if they had a significant co-morbid condition (e.g., depression, reactive airway disease, or diabetes).
For this study, outcome variables included generic QOL (PedsQL Total, Physical Health Summary, and Psychosocial Health Summary Scores), disease-specific QOL (PCQLI Total, Disease Impact, and Psychosocial Impact scores), and patient’s self-perception (Global Self-Worth and Discrepancy Scores). The generic PedsQL, a well-established reliable and valid measure of pediatric QOL for children 8 to 18 years of age, was used to compare patients with LQTS to healthy controls. The disease-specific PCQLI, a well-established reliable and valid measure of QOL in the pediatric cardiac population for children 8 to 18 years of age, was used to compare patients with LQTS with other CHD groups and was used as the outcome variable for multivariable modeling. The SPPC/A, a reliable and valid measure of self-perception in children 8 to 18 years of age, was used to measure patient self-esteem. The Global Self-Worth measure is a global judgment of his/her self-worth. The SPPC/A Discrepancy Score was used to assess the difference between functional domains that the child deems as important and their competency within that functional domain.
Given that patient behavioral and emotional functioning, as assessed by the patients and their parent, has been shown to be associated with patient- and parent-reported QOL in the pediatric cardiovascular population, this study used the Achenbach Assessment Instruments: Youth Self-Report (YSR) and Child Behavior Checklist (CBCL) Internalizing (anxiety, depression, and somatic complaints) and Externalizing scores (aggression, attention problems, and delinquent behavior). Potential clinical predictors of worse QOL were collected separately from the PCQLI Testing Study through chart review and included family history of sudden cardiac death, a genetic diagnosis, history of syncope, history of pacemaker/ICD implantation, whether a patient is taking a β blocker, whether there are symptoms associated with β blocker, time since diagnosis, and QTc. (QTc intervals were calculated from electrocardiograms.)
Demographic covariates available from the PCQLI Testing Study that were used for this study included current age, gender, race (dichotomized as white/nonwhite), whether primary caregiver had a college degree, parental marital status, and family income above the national median of $50,000.
In this study, the QOL of the assembled LQTS cohort was compared with healthy controls derived from previously published normative PedsQL data. In addition, the LQTS cohort was compared with 3 CHD control groups chosen based on the severity of disease to allow for comparison to mild (isolated bicuspid aortic valve [BAV] with no aortic stenosis or insufficiency), moderate (tetralogy of Fallot [TOF]), and severe CHD (patients with single ventricle who had undergone Fontan palliation) lesions. In the previous PCQLI Testing Study, significant differences in QOL scores were seen between patients with mild CHD who did not require surgical intervention, patients with surgically repaired biventricular physiology, and patients with single ventricle physiology. Because the PCQLI is a disease-specific cardiac QOL measure, no comparison to a heart-healthy population was possible.
Summary statistics for continuous variables are expressed as means and SDs. Dichotomous variables are expressed as percentages. Outcome data were examined for distributional characteristics. To examine the level of agreement between patient- and parent-reported behavioral (Achenbach) and QOL (PCQLI) scores, Bland-Altman plots and Pearson’s correlation coefficient were calculated. Correlations were interpreted as ≤0.20 low; 0.21 to 0.40 fair; 0.41 to 0.60 moderate; 0.61 to 0.80 good; and ≥0.81 excellent agreement.
Means, SDs, and sample sizes for healthy controls on the PedsQL, the Achenbach measures, and the Harter SPPC/A Global Self-Worth were pulled from previously published data containing normative scores. The LQTS sample was compared with healthy controls using Student t tests and chi-square tests. p Values <0.05 were considered statistically significant. In addition, comparisons of PCQLI Total score were made among patients with LQTS and the CHD groups: BAV, TOF, and single ventricle. Analysis of variance and a Bonferroni adjustment for multiple comparisons were used for these comparisons (with 3 separate comparison groups, a p value <0.02 was considered statistically significant).
Univariate analysis of behavioral, clinical, and demographic predictors of QOL was performed using Pearson’s correlation coefficient for continuous variables and point biserial correlations for dichotomous variables. Variables in the univariate analysis with a p value <0.1 on the outcome variables were included in multivariable modeling. All potential predictors were checked for multicollinearity.
With multiple family members in the data set, there was the potential for biased results because of correlations between family members, thus mixed-effect modeling was used for this analysis. A backward elimination process based on an alpha <0.05 was used to remove nonsignificant variables from the final model. The outcome variables for this analysis were PCQLI Total, Disease Impact, and Psychosocial Impact scores, and the SPPC/A Global Self-Worth and Discrepancy scores. Standardized estimates (β) were used to show the effect sizes and R 2 amount of variance explained for each model. All data were analyzed in SAS 9.3, Cary, North Carolina.
Results
A total of 69 patients were identified in the PCQLI data registry, who had a clinical diagnosis of LQTS and were followed at The Children’s Hospital of Philadelphia and Cincinnati Children’s Hospital Medical Center. Eight patients were excluded from analysis because of the presence of a significant co-morbid medical condition. Data on the sample characteristics can be found in Table 1 . Sixty-one patient–parent dyads were analyzed from 45 unique families. Twenty-seven patients (44%) had a family history of sudden cardiac death. Twenty-seven patients (44%) were the first in their family to be diagnosed with LQTS. All patients were taking β blockade at the time of study. Additionally, 1 patient was taking a calcium channel blocker and 2 patients were taking antidepressant medications.
| Parent Characteristics | |
|---|---|
| Age, (years, mean [SD]) | 45 (+/-7) |
| Female | 39 (87%) |
| White | 41 (91%) |
| College Graduate | 27 (60%) |
| Married | 32 (71%) |
| Above Median Household Income | 36 (80%) |
| Family History of LQTS | 17 (37%) |
| Quality of Life | |
| PedsQL Total Score, mean (SD) | 76 (+/-16) |
| PedsQL Physical Summary Score, mean (SD) | 80 (+/-17) |
| PedsQL Socio-Emotional Summary Score, mean (SD) | 74 (+/-18) |
| PCQLI Total Score, mean (SD) | 73 (+/-14) |
| PCQLI Disease Impact Score, mean (SD) | 36 (+/-7) |
| PCQLI Psychosocial Impact Score, mean (SD) | 37 (+/-8) |
| Behavioral and Emotional Functioning | |
| CBCL Internalizing Problems (T-score), mean (SD) | 53 (+/-11) |
| CBCL Externalizing Problems (T-score), mean (SD) | 48 (+/-11) |
| Patient Characteristics | |
|---|---|
| Total Number of Patients | 61 |
| Current Age (years mean [SD]) | 14 (+/-3) |
| Age at Diagnosis, in years, mean (SD) | 9 (+/-4) |
| Time Since Diagnosis, in years, mean (SD) | 4 (+/-3) |
| Female | 34 (56%) |
| White | 55 (90%) |
| Genetic Confirmation | 18 (30%) |
| Syncope | 18 (30%) |
| Has a Device | 8 (13%) |
| QTc ms, median (range) | 483 (416-600) |
| Beta Blocker Therapy | 61 (100%) |
| Atenolol | 12 (20%) |
| Nadolol | 49 (80%) |
| Symptoms on Beta Blocker | 6 (10%) |
| Number of Medications, median (range) | 1 (1-7) |
| Number of Catheterizations, median (range) | 0 (0-3) |
| Number of MD visits, median (range) | 4 (0-15) |
| Number of Cardiac Hospitalization, median (range) | 1 (1-20) |
| Time Since Last Hospitalization, in years median (range) | 2 (0-18) |
| Quality of Life | |
| PedsQL Total Score, mean (SD) | 77 (+/-16) |
| PedsQL Physical Summary Score, mean (SD) | 81 (+/-17) |
| PedsQL Socio-Emotional Summary Score, mean (SD) | 75 (+/-17) |
| PCQLI Total Score, mean (SD) | 74 (+/-15) |
| PCQLI Disease Impact Score, mean (SD) | 36 (+/-7) |
| PCQLI Psychosocial Impact Score, mean (SD) | 38 (+/-9) |
| Behavioral and Emotional Functioning | |
| YSR Internalizing Problems (T-score), mean (SD) | 54 (+/-11) |
| YSR Externalizing Problems (T-score), mean (SD) | 51 (+/-9) |
There was low to moderate agreement between patients and their parents on PCQLI Total, Disease Impact, and Psychosocial Impact scores. There was fair agreement between patients and their parents on the CBCL Internalizing and Externalizing Problems scales. Bland-Altman plots and reported correlation coefficients show the strongest patient–parent agreement on PCQLI Psychosocial Impact subscale scores and the lowest agreement on PCQLI Disease Impact subscale scores ( Supplementary Figure 1 ).
Mean scores for the Internalizing and Externalizing Problems scales for the CBCL and YSR are not statistically different than normative standards (50 ± 10). However, on the Internalizing Problems scale, almost 1/3 of patients with LQTS on the YSR and 25% of parents on the CBCL reported elevated scores ≥60 (at risk population 1 SD above the normative mean of 50). Both results were significant compared to the 16% expected for the normal population (YSR: p <0.01; CBCL: p = 0.04).
Patients with LQTS reported lower PedsQL Total, Physical Health Summary, and Psychosocial Health Summary scores compared with healthy children (p ≤0.001; Figure 1 ). Similarly, parents reported lower PedsQL Total, Physical Health Summary, and Psychosocial Health Summary scores for their children with LQTS compared with healthy children (p ≤0.001). The mean Global Self-Worth score for the patients with LQTS was 3.3 ± 0.56, which was not statistically different from reported normative data in the SPPC/A validation study.
Patients with LQTS had statistically lower Total and Disease Impact PCQLI scores compared with patients with BAV (p = 0.007 and p = 0.002), had similar PCQLI Total and Disease Impact scores compared with patients with TOF (p = 1.0 and p = 1.0), and had higher PCQLI Total and Disease Impact scores compared with Fontan patients with single ventricle (p <0.001 for both; Figure 2 ). Patients with LQTS had statistically higher PCQLI Psychosocial Impact subscale scores compared with patients with single ventricle (p = 0.004) but had similar Psychosocial Impact subscale scores compared with patients with BAV (p = 0.08) and TOF (p = 1.0).
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