Resistant Kawasaki has been associated with the aggressive development of large coronary aneurysms, despite prompt treatment. In this paper, we present an infant who presented with resistant Kawasaki. Although initially he seemed to defervesce after the initial administration of intravenous immunoglobulin, he developed a new onset of fever, requiring a repeat dose of immunoglobulin. Coronary aneurysms developed rapidly, necessitating a second dose of immunoglobulins and second-line treatments such as anakinra and infliximab. High titers of COVID-19 antibodies have been a confounding factor in the management of that child, as the alternative diagnosis of multisystem inflammatory syndrome in children (MIS-C) was considered. Finally, the clinical and laboratory values were more in keeping with MIS-C.

We present the electrocardiogram (ECG) of an elderly woman with Mobitz II atrioventricular (AV) block, left bundle branch block (LBBB), and ventricular ectopic activity. At first glance, the ECG may give the misleading impression of Wenckebach periodicity and raise the suspicion of intermittent left anterior fascicular block (LAFB) and left posterior fascicular block (LPFB), suggesting an apparent alternating conduction block in the main divisions of the LBB. This intriguing appearance prompted us to present the case.

L-Carnitine (LC) is integral to energy production and fatty acid metabolism, facilitating the transport of long-chain fatty acids into mitochondria for β-oxidation. It modulates metabolic pathways, including pyruvate dehydrogenase activity, proteolysis, and protein synthesis, while also having anti-inflammatory and antioxidant characteristics. LC can be commonly applied to win the battle against HIV and cancer cachexia. Also, it can be recruited with the aim of improving physical and cognitive functions in athletes and the elderly. Despite these benefits, long-term LC administration has been associated to cardiovascular risks due its conversion to trimethylamine-N-oxide (TMAO) by the gut microbiota. Elevated TMAO levels are linked to atherosclerosis, oxidative stress, and an increased risk of cardiovascular disease, diabetes, and chronic kidney disease. Managing TMAO levels using dietary treatments and gut microbiota-targeting techniques, such as probiotics, may reduce these risks. This comprehensive review presents the state-of-the-art information on LC’s dual role, emphasizing the balance between its therapeutic potential and the risks of prolonged supplementation. It aims to guide clinicians and researchers in optimizing LC’s benefits while addressing its long term cardiovascular safety concerns.