KUIS WS PEDI_EP PRETEST

In pediatric patients with CHD and heart failure, why is ivabradine preferable over increasing beta-blocker dose in certain cases?

• It suppresses supraventricular arrhythmias

• It increases preload and stroke volume

• It reduces heart rate without negative inotropy

• It blocks beta-2 receptor–mediated vasodilation

Which of the following explains the poor responsiveness to exogenous catecholamines in neonates with advanced HF?

• Downregulation of myocardial beta-1 receptors

• Upregulation of PDE-3 enzymes

• Elevated intracellular calcium stores

• Predominant expression of alpha-adrenergic receptors

Which of the following pharmacokinetic characteristics of milrinone is most relevant in adjusting its dosing in neonates with renal insufficiency?

• Hepatic clearance via CYP3A4

• High plasma protein binding

• Renal excretion with a short half-life

• Low first-pass metabolism

Which metabolic limitation in the immature myocardium contributes most to reduced inotropic reserve during neonatal HF?

• High density of functional mitochondria

• Predominant reliance on fatty acid oxidation

• Inability to upregulate beta-oxidation during stress

• Deficient glycogenolysis and immature glycolytic pathways

A 2-week-old infant with large VSD presents with severe tachypnea, hepatomegaly, and failure to thrive. Despite maximum furosemide and ACEi, symptoms persist. What is the most appropriate next step?

• Increase ACE inhibitor dose beyond pediatric range

• Refer for surgical closure of VSD

• Add carvedilol immediately

• Switch to ARB

In a patient with dilated cardiomyopathy and EF <25%, which of the following mechanisms explains the superiority of milrinone over dobutamine for long-term support?

• Greater beta-1 receptor selectivity

• Increased myocardial oxygen demand

• Vasodilatory effect independent of adrenergic receptor saturation

• Direct positive chronotropic effect

In neonates with decompensated heart failure due to duct-dependent systemic circulation (e.g., critical coarctation), what is the most pathophysiologically sound reason to avoid rapid diuresis?

• Diuretics increase afterload and worsen perfusion

• Rapid preload reduction impairs ductal flow and systemic perfusion

• Diuretics blunt beta-receptor sensitivity in neonates

• Sodium depletion triggers closure of the ductus arteriosus

Which of the following combinations of biomarkers and echocardiographic parameters best predicts poor prognosis in a pediatric patient with advanced HF awaiting transplant?

• Elevated BNP + EPSS <5 mm

• Normal BNP + TAPSE >17 mm

• Elevated NT-proBNP + EPSS >10 mm

• Low BNP + EF >50%

A 2-month-old infant with post-op TOF repair develops low cardiac output syndrome despite adequate filling pressures and inotropy. Milrinone is initiated. What intracellular mechanism best explains its lusitropic action in this context?

• Inhibition of calcium reuptake via SERCA2a

• Reduced phosphorylation of phospholamban

• Increased cAMP-mediated SERCA2a activity enhancing calcium reuptake into SR

• cGMP-mediated activation of nitric oxide synthase in cardiomyocytes

Which of the following genetic/molecular mechanisms underlies beta-blocker resistance in pediatric dilated cardiomyopathy with high catecholamine state?

• Increased phosphorylation of beta-adrenergic receptor by GRK2, leading to receptor desensitization

• Downregulation of GRK2 (G-protein coupled receptor kinase 2)

• Overexpression of beta-1 receptor subtypes

• Upregulation of adenylate cyclase activity