Diuretics are crucial in the treatment of infantile heart failure, particularly in cases of left-to-right shunt heart disease. Their use should be guided by an understanding of renal structure, the functions of nephrons, renal corpuscles, and tubules, as well as the mechanisms of renin secretion from the juxtaglomerular apparatus, the renin-angiotensin-aldosterone system, the counter-current system, renal nerves, the macula densa, and tubuloglomerular feedback. Although evidence from large clinical trials exists for most heart failure medications, there is a lack of sufficient clinical trial data specifically for diuretics. Additionally, higher doses of diuretics in chronic heart failure have been associated with a worse prognosis. The effectiveness of diuretics in patients with heart failure who exhibit diuretic resistance is still unclear. This review discusses the structure and function of the kidney, outlines the types of diuretics, their mechanisms of action, and side effects, and emphasizes the importance of recognizing diuretic resistance in chronic heart failure.

Early neonatal open-heart surgery for total anomalous pulmonary venous return (TAPVR) often results in unfavorable outcomes. However, recent reports suggest that placing a ductus venosus stent in low-birth-weight infants with infracardiac type TAPVR could lead to better outcomes by avoiding the need for early neonatal open-heart surgery. Because stent stenosis caused by intimal thickening frequently occurs after stenting, an objective method to evaluate restenosis needs to be developed. This study presents a case with infracardiac type TAPVR, born at 34 weeks of gestation with a body weight of 1,556 g, who underwent ductus venosus stenting on day 7 of life. The stent was repeatedly expanded when needed after evaluating the narrowing within the stent, which included measuring the highest pulse Doppler velocity of the hepatic vein over a period of time. After weight gain, the patient successfully underwent TAPVR repair. This study shows that sequential measurements of the pulse Doppler velocity of the hepatic vein can be used to effectively evaluate stent stenosis.

A ductus arteriosus aneurysm (DAA) involves cystic or tubular dilatation of the persistent ductus arteriosus and can lead to life-threatening complications, including aneurysm rupture, thromboembolism, and infection. We report the case of a 56-year-old man who underwent percutaneous DAA closure. The patient was diagnosed with DAA following computed tomography (CT) scans after an abnormal finding on a routine chest radiography examination. CT imaging revealed an aneurysm with a maximum diameter of 39 mm, an aortic side diameter of 5.6 mm, and a pulmonary side diameter of 2.2 mm. The patient did not have any symptoms, such as dysphagia and hoarseness. Although surgical correction and stent graft implantation were considered, a minimally invasive percutaneous approach was chosen. A guidewire was introduced from the aortic side and retrieved with a snare catheter from the pulmonary artery (PA) side, creating a wire-loop. A delivery sheath was inserted from the PA side, and the aortic side of the DAA (measuring 5.6 mm) was percutaneously closed using a 12 mm/10 mm Amplatzer™ Duct Occluder (ADO). Follow-up CT conducted three months later confirmed near-complete thrombosis of the aneurysm. This case demonstrates that percutaneous closure of large DAAs in adults using devices such as the ADO is a safe, effective, and minimally invasive treatment option.

Transthoracic echocardiography (TTE) is essential for detecting macrovascular lesions such as aortic dilatation, aortic regurgitation, and mitral valve deviation in Marfan syndrome. However, visualizing the aortic valve can be challenging due to scoliosis or other thoracic abnormalities. We report a case involving a 15-year-old female patient with severe postoperative aortic valve stenosis that was undiagnosed by TTE prior to her emergency admission. She had undergone aortic root replacement via the Bentall procedure using a bioprosthetic valve at the age of 11. Although she was followed up with TTE in the outpatient department, her scoliosis complicated the imaging process. The patient presented to the emergency department with a respiratory disorder of one-week duration and subsequently underwent emergency reoperation for severe aortic stenosis caused by calcification of the bioprosthetic valve. In patients with Marfan syndrome, scoliosis may result in poor TTE imaging results, making additional evaluations with magnetic resonance imaging, computed tomography, or transesophageal echocardiography necessary. Moreover, patients with Marfan syndrome require close follow-up because elastin-derived proteins may contribute to the calcification of the bioprosthetic valve, resulting in early valve dysfunction.

Acute pericarditis is commonly caused by viral infections. However, cardiac tamponade associated with viral pericarditis is a rare condition. This paper reports the case of a 12-year-old boy with a history of intracardiac repair for a ventricular septal defect at 11 months of age. Five days prior to admission, he presented with symptoms of gastroenteritis followed by seizures, which necessitated emergency transport to the hospital. He was in hypotensive shock, and echocardiography revealed significant pericardial effusion with right ventricular collapse. The central venous pressure (CVP) was elevated to 24 mmHg. The patient was diagnosed with low cardiac output syndrome due to cardiac tamponade, and pericardial drainage was performed. The blood pressure recovered promptly, and the CVP decreased to 13 mmHg. Loxoprofen and diuretics were initiated, and no reaccumulation of pericardial effusion was observed. The patient was discharged on the 14th day of hospitalization. Serological tests revealed that the Coxsackievirus A2 (CoxA2) antibody titer was 1:32 at admission, and increased to 1:128 three weeks later (a fourfold increase), confirming the diagnosis of acute CoxA2 pericarditis. To our knowledge, this is the first case report of acute CoxA2 pericarditis.

Postnatal pulmonary circulation depends on the ductus in neonates with pulmonary atresia with an intact ventricular septum (PAIVS), requiring intravenous administration of prostaglandin. However, life-threatening events, such as necrotizing enterocolitis, can occur due to pulmonary overcirculation through the ductus. To address this issue, prostaglandin therapy may be discontinued or hypoxic inhalation treatment may be attempted. This paper reports the case of a 2.2-kg male infant with PAIVS who underwent successful staged surgery. The patient exhibited heart failure due to pulmonary overcirculation soon after birth despite the discontinuation of prostaglandin therapy and the initiation of hypoxic gas treatment. At the age of 3 days, he underwent bilateral pulmonary arterial banding to regulate the pulmonary blood flow, resulting in stable hemodynamics. Subsequently, we performed transcatheter pulmonary valvuloplasty and surgical right ventricular outflow plasty at 21 and 55 days of age, respectively. Bilateral pulmonary arterial banding could serve as an alternative bridge therapy to definitive corrective surgery to achieve stable hemodynamics during the neonatal period.