QT interval dispersion in North Indian children with Kawasaki disease without overt coronary artery abnormalities

Assessment of Endothelial Dysfunction in Acute and Convalescent Phases of Kawasaki Disease Using Automated Edge Detection Software: A Preliminary Study From North India

OBJECTIVE

The aim of this study was to assess endothelial dysfunction in acute and convalescent phases of Kawasaki disease (KD) using automated edge detection software.

METHODS

This was a case-control study to assess the flow-mediated dilatation (FMD) of brachial artery (BA) in patients with KD during acute phase and at least 3 months after diagnosis. A 10-MHz multifrequency linear array probe attached to a high-resolution ultrasound machine (PHILIPS Medical System-IU22) was used to acquire the images. Automated edge detection software was used to assess BA diameter.

RESULTS

A total of 16 children with KD and 16 healthy children were enrolled in the study. Mean ± SD maximum BA diameter was found to be significantly low during the acute stage of KD (2.56 ± 0.36 mm) as compared with the convalescence phase (2.93 mm ± 0.31) and in healthy controls (2.95 mm ± 0.56). The mean ± SD percentage change in the FMD was found to be significantly low in the acute phase of KD (12.32 ± 6.2) as compared with the convalescence phase of KD (17.99 ± 8.13) and healthy controls (26.88 ± 12.76). The mean ± SD percentage change in the FMD was also found to be significantly low in the convalescence phase of KD as compared with healthy controls.

CONCLUSIONS

The FMD of the BA is significantly reduced in patients during the acute and convalescence phase of KD as compared with normal healthy children. The endothelial dysfunction was present even in patients who had no obvious coronary artery abnormalities during the acute stage.

Increased QT Interval Dispersion is Associated with Coronary Artery Involvement in Children with Kawasaki Disease

Objectives

Coronary artery (CA) involvement is the most well known complication of Kawasaki disease (KD). Previous studies have suggested that QT dispersion has a predictive value in diagnosing cardiac ischemia, ventricular arrhythmia, and sudden cardiac death. However, limited data exits regarding the application of QT dispersion in KD. Therefore, we sought to determine whether there is a relationship between QT dispersion and CA involvement in patients with KD.

Methods

We performed a cross-sectional study of all consecutive patients with KD who were followed-up at the Pediatric Rheumatology Department (Pediatrics Center of Excellence affiliated to Tehran University of Medical Sciences, Tehran, Iran) from September 2013 to November 2015. Patients who met the criteria for KD, based on the American Heart Association guideline, were enrolled in the study. We collected data regarding patients' demographics, clinical manifestations, laboratory, and echocardiographic findings.

Results

A total of 70 KD patients were identified, including 43 males (61.4%) and 27 females (38.6%). The median age of patients was 21.0 (11.0-48.0) months. We found statistically significant differences between age, gender, and platelet count among patients with and without CA involvement (p < 0.050). Median corrected QT dispersion in patients with CA involvement calculated from 12 leads in the acute phase was significantly higher compared to the non-CA involvement group (108.0 (89.5-138.5) ms vs. 63.0 (54.0-74.5) ms, respectively (p < 0.001)).

Conclusions

Prolonged QT dispersion (corrected or non-corrected) during the acute and convalescence phases in patients with KD is associated with coronary involvement.

Cardiovascular Involvement in Kawasaki Disease Is Much More Than Mere Coronary Arteritis

Kawasaki disease (KD) is now a common cause of acquired heart disease in children. Coronary artery involvement is the most serious complication in children with KD. Several non-coronary complications have now been identified in this condition but these are often overlooked. Myocarditis is an integral component of KD and may be more common than coronary artery abnormalities. Pericardial involvement and valvular abnormalities have also been observed in patients with KD. KD shock syndrome is now being increasingly recognized and may be difficult to differentiate clinically from toxic shock syndrome. Endothelial dysfunction has been reported both during acute stage and also on follow-up. This may be a potentially modifiable cardiovascular risk factor.

IL-1-dependent electrophysiological changes and cardiac neural remodeling in a mouse model of Kawasaki disease vasculitis

Kawasaki disease (KD) is the leading cause of acquired heart disease in children. In addition to coronary artery abnormalities, aneurysms and myocarditis, acute KD is also associated with echocardiogram (ECG) abnormalities in 40-80% of patients. Here, we show that these ECG changes are recapitulated in the Lactobacillus casei cell wall extract (LCWE)-induced KD vasculitis mouse model. LCWE-injected mice developed elevated heart rate and decreased R wave amplitude, with significant differences in prolonged ventricular repolarization. LCWE-injected mice developed cardiac ganglion inflammation, that may affect the impulse-conducting system in the myocardium. Furthermore, serum nerve growth factor (NGF) was significantly elevated in LCWE-injected mice, similar to children with KD vasculitis, associated with increased neural remodeling of the myocardium. ECG abnormalities were prevented by blocking interleukin (IL)-1 signaling with anakinra, and the increase in serum NGF and cardiac neural remodeling were similarly blocked in Il1r1^-/- mice and in wild-type mice treated with anakinra. Thus, similar to clinical KD, the LCWE-induced KD vasculitis mouse model also exhibits electrophysiological abnormalities and cardiac neuronal remodeling, and these changes can be prevented by blocking IL-1 signaling. These data support the acceleration of anti-IL-1 therapy trials to benefit KD patients.

Electrocardiographic Analysis of Repolarization Changes in South Indian Children with Kawasaki Disease after the Acute Phase of Illness

Background

Cardiac involvement in children with Kawasaki disease (KD) may present with repolarization abnormalities which are associated with increased risk of ventricular arrhythmias and sudden cardiac events.

Methods

Twenty children with history of KD without cardiac involvement in the acute phase were recruited along with age and sex-matched controls. Twelve-lead ECG was obtained from both groups using CARDIART 610T ECG system at 25 mm/sec and 50 mm/sec paper speed. ECG was repeated in 19 children in the study group after 9 ± 2 months. Measurements (QT dispersion (QTd), T-wave peak to end (Tp-Te) interval, and Tp-Te/QT ratio) were made using standard digital calipers. Statistical analysis was performed with student t-test and analysis of variance (ANOVA) using SSPS version 17.0.

Results

The mean value of QTd in the first ECG in cases was significantly high: 43.15 ± 14.13 versus 29.47 ± 8.637 in the controls (p = 0.001). The follow-up ECG in 19 cases showed a mean value of 46.26 ± 16.25 versus 43.89 + −14.53 at baseline (p = 0.440). QTd was increased in the follow-up ECG but was not statistically significant. There was no statistical significance seen in the Tp-Te interval and Tp-Te/Qt ratio as observed in Lead II and Lead V5.

Conclusion

Significant increase in the QTd in children with KD indicates repolarization changes in the myocardium even in the absence of clinical carditis. The persistence of this change on follow-up could indicate a possible increased risk for ventricular arrhythmia and warrants long term assessment of the cardiovascular status.

Mid-term Risk for Subclinical Atherosclerosis and Chronic Myocarditis in Children with Kawasaki Disease and Transient Coronary Abnormalities

There is evidence for premature atherosclerosis and systemic arterial stiffening during follow-up of children with Kawasaki disease (KD) and coronary artery abnormalities (CAA). Moreover, patients with KD may also have subclinical myocardial involvement and inhomogeneous ventricular repolarization. The inhomogeneous ventricular repolarization manifests as increased QT dispersion on electrocardiography. There is a paucity of studies in endothelial dysfunction and QT dispersion in children with KD and transient CAA. Twenty children with KD and transient CAA were studied at least 1 year after resolution of CAA. Mean follow-up period between KD onset and enrolment in the study was 53.7 months. Twenty age and sex-matched controls were enrolled. High-resolution B-mode ultrasonography was used to analyze brachial artery dilatation in response to reactive hyperemia (cases and controls) and sublingual nitroglycerine (cases only). Carotid artery intima-media thickness (cIMT) and stiffness index were calculated. The difference between maximum and minimum QTc intervals on 12 lead electrocardiogram was calculated as QTc dispersion (QTcd). No statistically significant difference was noted in percent flow-mediated dilatation of brachial arteries in response to reactive hyperemia between cases (13.31 ± 10.41%) and controls (12.86 ± 7.09%). Sublingual nitroglycerine-mediated dilatation in children with KD was 14.88 ± 12.03%. Mean cIMT was similar in cases (0.036 ± 0.015 cm) and controls (0.035 ± 0.076 cm; p = 0.791). No statistically significant difference between groups was observed in mean QTcd values (0.057 ± 0.018 s vs. 0.059 ± 0.015 s in controls, p = 0.785). No evidence of significant endothelial dysfunction or increased QT dispersion in patients with KD and transient coronary artery abnormalities was found in our cohort when studied at a mean follow-up of 53.7 months. This is reassuring, and indicates that risk of subclinical atherosclerosis and myocarditis in a subset of children with KD and transient coronary artery abnormalities is not significant.

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association

BACKGROUND

Kawasaki disease is an acute vasculitis of childhood that leads to coronary artery aneurysms in ≈25% of untreated cases. It has been reported worldwide and is the leading cause of acquired heart disease in children in developed countries.

METHODS AND RESULTS

To revise the previous American Heart Association guidelines, a multidisciplinary writing group of experts was convened to review and appraise available evidence and practice-based opinion, as well as to provide updated recommendations for diagnosis, treatment of the acute illness, and long-term management. Although the cause remains unknown, discussion sections highlight new insights into the epidemiology, genetics, pathogenesis, pathology, natural history, and long-term outcomes. Prompt diagnosis is essential, and an updated algorithm defines supplemental information to be used to assist the diagnosis when classic clinical criteria are incomplete. Although intravenous immune globulin is the mainstay of initial treatment, the role for additional primary therapy in selected patients is discussed. Approximately 10% to 20% of patients do not respond to initial intravenous immune globulin, and recommendations for additional therapies are provided. Careful initial management of evolving coronary artery abnormalities is essential, necessitating an increased frequency of assessments and escalation of thromboprophylaxis. Risk stratification for long-term management is based primarily on maximal coronary artery luminal dimensions, normalized as Z scores, and is calibrated to both past and current involvement. Patients with aneurysms require life-long and uninterrupted cardiology follow-up.

CONCLUSIONS

These recommendations provide updated and best evidence-based guidance to healthcare providers who diagnose and manage Kawasaki disease, but clinical decision making should be individualized to specific patient circumstances.

Prognostic Significance of QT Interval Dispersion in the Response to Intravenous Immunoglobulin Therapy in Kawasaki Disease

BACKGROUND

Kawasaki disease (KD) is classified as a systemic vasculitis syndrome and QT interval dispersion (QTD) has been associated with cardiac involvement and disease activity in patients with cardiovasculitis. We examined whether baseline QTD could predict a response to intravenous immunoglobulin (IVIG) in KD.Methods and Results:QTD was recorded in 86 patients with KD before IVIG, who were separated into IVIG responders (R group; n=62) and nonresponders (N group; n=24). The association between baseline QTD and response to IVIG was investigated, and the predictive response value was compared with conventional risk scores from Gunma and Kurume universities. Baseline-corrected QTDs with Bazett's (QTbcD) and Fridericia's (QTfcD) formulae were significantly increased in the N group (R group vs. N group: 31.6 [28.3, 44.0] ms vs. 66.6 [50.5, 76.3] ms and 27.4 [25.2, 39.1] ms vs. 55.2 [42.4, 66.3] ms, respectively, both P<0.001). Multiple logistic regression analysis revealed QTfcD as an independent predictor of a response to IVIG after adjustment for conventional scores (odds ratio: 1.133, 95% confidence interval: 1.061-1.210, P<0.001). Moreover, QTfcD provided incremental predictive value for IVIG nonresponders over Gunma score (increment in global χ²=25.46, P<0.001).

CONCLUSIONS

QTD was significantly associated with a response to IVIG in KD patients and may represent a useful identifier of IVIG nonresponders with high risk of coronary aneurysm.

Kawasaki disease for dermatologists

Kawasaki disease (KD) is a systemic vasculitis that mostly affects children below the age of 5. The vasculitis involves arteries of medium size, especially the coronaries. Various etiologies have been proposed including association with micro-organisms, bacterial superantigens, and genetic factors, however, the exact cause remains unknown. There is no specific laboratory test for KD. Diagnosis is clinical and depends upon the presence of fever for ≥5 days and 4 or more of five principal features, viz. polymorphous exanthem, extremity changes, mucosal changes involving the lips and oral cavity, bilateral bulbar conjunctival injection, and unilateral cervical lymphadenopathy. The term "incomplete KD" refers to the presence of fever and less than four principal clinical features. Recognition of this group of patients is important because it is usually seen in infants and risk of coronary abnormalities is increased probably because of delays in diagnosis. However, what appears to be "incomplete" at a given point of time may not actually be so because some of the features may have already subsided and others may evolve over time. Hence, a detailed dermatological examination is warranted in all cases, especially in incomplete KD, to ensure timely diagnosis. Although KD is a self-limiting disease in most patients, coronary artery abnormalities (CAAs) including coronary dilatations and aneurysms may develop in up to 25% of untreated patients. CAAs are the most common cause of morbidity and mortality in patients with KD. Treatment is aimed at reducing inflammation and consists of intravenous immunoglobulin (IVIG) along with aspirin. Despite treatment, some patients may still develop CAAs, and hence, long-term follow up is of utmost importance.

Ventricular repolarization markers for predicting malignant arrhythmias in clinical practice

Malignant cardiac arrhythmias which result in sudden cardiac death may be present in individuals apparently healthy or be associated with other medical conditions. The way to predict their appearance represents a challenge for the medical community due to the tragic outcomes in most cases. In the last two decades some ventricular repolarization (VR) markers have been found to be useful to predict malignant cardiac arrhythmias in several clinical conditions. The corrected QT, QT dispersion, Tpeak-Tend, Tpeak-Tend dispersion and Tp-e/QT have been studied and implemented in clinical practice for this purpose. These markers are obtained from 12 lead surface electrocardiogram. In this review we discuss how these markers have demonstrated to be effective to predict malignant arrhythmias in medical conditions such as long and short QT syndromes, Brugada syndrome, early repolarization syndrome, acute myocardial ischemia, heart failure, hypertension, diabetes mellitus, obesity and highly trained athletes. Also the main pathophysiological mechanisms that explain the arrhythmogenic predisposition in these diseases and the basis for the VR markers are discussed. However, the same results have not been found in all conditions. Further studies are needed to reach a global consensus in order to incorporate these VR parameters in risk stratification of these patients.

Aortic stiffness studies in children with Kawasaki disease: preliminary results from a follow-up study from North India

Kawasaki disease (KD) is an acute medium vessel vasculitis seen in children. Coronary artery abnormalities are the most notable long-term complications. Intravenous immunoglobulin therapy has led to significant reduction in incidence of coronary aneurysms. However, higher risk of cardiovascular disease has been noted even in those children who have never been reported to develop coronary artery aneurysms during the subacute phase. Noninvasive estimation of this cardiovascular risk is useful in initiating timely preventive strategies. Arterial stiffness has been shown to be an independent predictor of cardiovascular events in general population. This study was aimed at measuring abdominal aorta stiffness in a cohort of children with KD from North India. Thirty children diagnosed to have KD at least 5 years prior to enrollment were evaluated by echocardiography for cardiac and abdominal aorta studies. Electrocardiographs were done in all patients for QT dispersion. There was a noticeable trend toward lower aortic strain, higher pressure strain elastic modulus and normalized pressure strain elastic modulus in children in the study group, though this difference did not reach statistical significance. Mean corrected QT dispersion was significantly higher in cases compared with controls. On cardiac evaluation, none of the subjects had any residual coronary artery involvement. A trend toward lower distensibility and higher stiffness of abdominal aorta was seen in cases compared with controls, though it was not found to be statistically significant. This could be a predictor of premature atherosclerosis in long term. Significantly higher QT dispersion was seen in cases compared with controls. More multicentric studies with larger sample size and longer follow-up periods are needed to clarify this issue.

QT Dispersion and T Wave Peak-to-end Interval Dispersion in Children with Kawasaki Disease

BACKGROUND

The main complication of Kawasaki disease is the Coronary Artery (CA) involvement and long term follow up of patients depends on the severity of coronary arterial aneurysms, ischemia, and thrombosis. Early diagnosis of these complications can lead to a more desirable outcome for patients. Myocardial ischemia can prolong QT dispersion and increase the risk of cardiac arrhythmias as well as sudden cardiac arrests. Also, T wave peak-to-end (Tp-Te) interval dispersion, which provides a valuable index of transmural dispersion of repolarization, can trigger the arrhythmia.

MATERIALS AND METHODS

We evaluated the non-corrected QT interval dispersion (QTD) and the corrected QT (QTc) dispersion and measured Tp-Te interval dispersion in 49 Iranian children (28 males and 21 females) with the diagnosis of Kawasaki disease (KD) in the acute phase and 49 age-matched controls in a prospective study from 2009 to 2012. Student's t-test and Pearson correlation were used to analyze the data. All the statistical analyses were performed through the SPSS 16. Besides, P<0.05 was considered as statistically significant.

RESULTS

Patients with KD had significantly longer QTc dispersion (0.099±0.055 s versus. 0.040±0.018 s; P<0.001), non-corrected QT dispersion (0.075±0.046 versus 0.042±0.019; P<0.001), and Tp-Te dispersion (0.047±0.054 versus 0.022±0.011; P=0.015). The patients with elevation in white blood cell count (above 15000) had a statistically significant increased in QTD (P=0.011). No significant correlation was found between coronary involvement and repolarization indexes.

CONCLUSIONS

In conclusion, the QT interval (corrected or non-corrected) and the Tp-Te dispersion significantly increased in the patients with KD which shows repolarization changes during the acute phase of KD. However, there is no correlation between the QT interval and the coronary involvement.

Prolongation of heart rate-corrected QT interval is a predictor of cardiac autonomic dysfunction in patients with systemic lupus erythematosus

Heart rate-corrected QT interval duration (QTc) has been shown to be related to cardiac autonomic dysfunction in patients with diabetes mellitus, although this association has not been previously described in patients with systemic lupus erythematosus (SLE). We retrospectively reviewed the medical records of 91 SLE patients and 144 non-SLE connective tissue disease patients visiting our clinic from November 2010 to April 2011. We compared ambulatory heart rate identified by pulse measured by automated machine in an outpatient waiting area versus resting heart rate identified on prior screening electrocardiogram. Heart rate differences were analyzed in relation to QTc interval and other characteristics. Ambulatory and resting heart rate differences were larger among SLE patients with QTc prolongation (QTc > 430 ms) than those without QTc prolongation (mean difference, 15.9 vs. 9.6, p = 0.001). In multivariate analysis, differences in heart rate were associated with QTc prolongation (OR 1.10, 95 % CI 1.01-1.21; p = 0.038), independent of age, duration of disease, immunosuppressant use, hydroxychloroquine use, diabetes mellitus, cardiac abnormality, anti-Ro/SS-A antibody positivity, or resting heart rate. Cardiac autonomic dysfunction is a common manifestation of SLE and may be related to QTc prolongation.

Value of amino-terminal pro B-natriuretic peptide in diagnosing Kawasaki disease

BACKGROUND

The aim of the present study was to investigate the diagnostic value of the N-terminal B-type natriuretic peptide (NT-proBNP) in acute Kawasaki disease (KD) given that the clinical criteria and the current basic laboratory tests lack the necessary specificity for accurate diagnosis.

METHODS

Basic biological tests and serum NT-proBNP levels obtained from acute KD patients were compared to that of febrile controls. NT-proBNP was considered abnormal based on the following definitions: above a cut-off determined on receiver operator characteristic (ROC) analysis, above the upper limit for age, or above 2 SD calculated from healthy children. Analyses were also performed for KD cases with complete or incomplete criteria combined and separately.

RESULTS

There were 81 patients and 49 controls aged 3.60 ± 2.77 versus 4.25 ± 3.88 years (P= 0.69). ROC analysis yielded significant area under the curve for NT-proBNP. The sensitivity, specificity, positive and negative predictive values were 70.4-88.9%, 69.4-91.8%, 82.8-93.4%, and 65.2-79.1%. The odds ratios based on NT-proBNP definitions varied between 18.13 (95% confidence interval [CI]: 7.21-45.57), 20.82 (95%CI: 8.18-53.0), and 26.71 (95%CI: 8.64-82.57; P < 0.001). Results were reproducible for cases with complete or incomplete criteria separately.

CONCLUSION

NT-proBNP is a reliable marker for the diagnosis of KD. Prospective clinical studies with emphasis on NT-proBNP in a diagnostic algorithm are needed.

Ventricular repolarisation during exercise challenge occurring late after Kawasaki disease

Exercise testing can highlight repolarisation abnormalities in adults with coronary artery disease. Late after Kawasaki disease (KD), increased QT dispersion (QTd) has been reported on resting ECG in children, but there are no reported studies of QTd during exercise. Our objective was to determine the pattern of QTd response to exercise testing in children late after KD. Twenty-five KD patients without coronary complications, 28 with coronary dilation, and 18 with severe complications were compared with 28 controls. KD patients were 11.6 ± 3.0 years old versus 12.8 ± 2.9 for controls [p = not significant (NS)], and these patients were studied 7.5 ± 3.4 years after the onset of the disease. QT was measured from the onset of QRS to the apex (QTa) and the end (QTe) of T wave. Resting QTd was significantly increased in KD subjects (p < 0.05). The proportion of abnormal QTd was evenly distributed across the three KD groups (29-36%; p = NS). QTd response to exercise was significantly altered in KD, irrespective of resting QTd or coronary sequelae. Abnormal resting- and exercise-induced repolarisation are detectible after KD irrespective of the severity of coronary sequelae.