Reversible second degree atrioventricular block after a severe sickle cell crisis

Nuclear Imaging in Pediatric Cardiology: Principles and Applications

Nuclear imaging plays a unique role within diagnostic imaging since it focuses on cellular and molecular processes. Using different radiotracers and detection techniques such as the single photon emission scintigraphy or the positron emission tomography, specific parameters can be assessed: myocardial perfusion and viability, pulmonary perfusion, ventricular function, flow and shunt quantification, and detection of inflammatory processes. In pediatric and congenital cardiology, nuclear imaging can add complementary information compared to other imaging modalities such as echocardiography or magnetic resonance imaging. In this state-of-the-art paper, we appraise the different techniques in pediatric nuclear imaging, evaluate their advantages and disadvantages, and discuss the current clinical applications.

[Acute atrio-ventricular block in sickle cell anemia]

BACKGROUND

Even though sickle cell disease has a high prevalence amongst the black race and despite its well known potential of micro infarction, there have been only a few reports regarding the acute myocardial damage during vaso-occlusive crisis. The risk of atrio ventricular block during these crises has never been described in a large survey.

PATIENTS AND RESULTS

Ten patients (six men and four women, mean age 39 years old) were hospitalized for an acute atrio ventricular block. The patients were all African or Caribbean natives. Three patients were found with a heterozygous phenotype for hemoglobin S (sickle trait) and seven were found with a homozygous phenotype. The most common symptoms were asthenia (10 cases), shortness of breath (8 cases) and acute coronary syndrome (1 case) (syncope was not reported). Four patients had a second degree atrio ventricular block and six patients had third degree block. The treatment involved bed rest, intravenous hydration, and pain relief with opiates. All the cases of atrio ventricular block were only transitory and none of the patients underwent a pacemaker implantation.

CONCLUSION

This report is the largest survey regarding transitory acute atrio ventricular block in patients with sickle cell disease. A local ischemic event affecting the AV node and Hiss bundle area can explain the conduction abnormalities. Sickle cell disease must be ruled out in black patients with an AV block.

Prolonged QT interval in pediatric sickle cell disease

We recently cared for a patient with sickle cell disease (SCD) who presented with cardiac arrest and was found to have a prolonged corrected QT interval (QTc). This prompted us to perform a retrospective review of all electrocardiograms performed in patients with SCD during the last two years. Among 142 patients with ECG results, we identified 12 patients (8 males and 4 females), who had one or more documented measurements of prolonged QTc intervals. The relatively high prevalence of borderline or moderately prolonged QTc intervals in our patient population warrants further investigation.

Psychological aspects of hematologic diseases

This article focused on two hematologic diseases that have received significant attention in the pediatric literature: sickle cell anemia and hemophilia. As the data indicate, these illnesses present lifelong challenges to individuals afflicted. With advances in medical interventions, many children with these hematologic diseases are living longer and with fewer serious complications. Intervention efforts only recently have begun to consider issues related to quality of life and increased psychological adjustment, including active coping strategies by children and their parents and necessary social support for all family members. Theoretical models [54] have highlighted the multiple factors that play a role in illness adjustment and the complex interactions of these factors. Individual, family, and community characteristics are impacted by and, in turn, impact on illness-related characteristics. The notion that illness severity is predictive of psychological adjustment has been discarded in favor of a model that recognizes multiple influences and multiple outcomes. Child coping, parent coping, social support, adaptive functioning, treatment compliance, and illness severity are being considered to better understand and influence overall psychological functioning. The field of pediatric psychology has made tremendous advances in improving knowledge of illness and its impact on development. Even with these advances, however, there remains much to be discovered. To date, pediatric psychology research has focused primarily on individual illness categories, making comparisons across illness types difficult. By considering different illnesses within the same study, characteristics that are crucial to improved adjustment and common across illnesses can be identified. As we continue to work for cures for these debilitating illnesses, our goal remains to improve quality of life for children.