The US opioid crisis has rapidly escalated over the past 4 decades, with a shifting profile of available substances contributing to rising fatalities. Leading this crisis is illicitly manufactured fentanyl, now increasingly adulterated with xylazine, a veterinary sedative not approved for human use. Despite a greater awareness in recent years regarding the vital role of naloxone in preventing fatal cases of overdose, xylazine has been associated with a sharp increase in overdose-related deaths due to its potent central nervous system effects. Recent data suggest a significant spread of xylazine, underscoring the importance of strategies to counteract fentanyl and implement aggressive supportive care for xylazine-fentanyl toxicity. This combination, often undetectable by standard drug tests, presents challenges in diagnosis and treatment of overdoses. These challenges have become relevant among young adults, a demographic particularly affected, underscoring the need for harm reduction measures and further research into the shifting patterns of fentanyl-related intoxication across the United States.

Pericardial cysts (PCs) are rare, benign congenital abnormalities that are encountered as mediastinal lesions. Despite their rarity, they remain clinically important due to their potential to mimic other mediastinal or cardiac pathologies and their capacity, in select cases, to cause significant complications. PCs are typically identified incidentally on imaging studies such as chest x-ray or transthoracic echocardiography, as most patients remain asymptomatic throughout their lives. When symptoms do occur, they are often nonspecific and related to compression of adjacent structures. Serious complications—including infection, rupture, and, rarely, cardiac tamponade—have been reported, underscoring the importance of accurate diagnosis and appropriate follow-up. Definitive characterization of PCs is best achieved using advanced imaging modalities such as cardiac computed tomography or cardiac magnetic resonance imaging, which help differentiate PCs from other mediastinal masses. While many PCs remain stable or even regress spontaneously, intervention may be warranted for symptomatic patients, enlarging cysts, or when the diagnosis remains uncertain. Therapeutic options include percutaneous aspiration, which carries a risk of recurrence, and surgical resection, which offers definitive treatment with excellent outcomes. This review provides a comprehensive overview of the etiology, clinical manifestations, diagnostic evaluation, differential diagnosis, complications, and management strategies for PCs.

Cystic fibrosis (CF) has undergone a remarkable transformation from a fatal childhood disease to a chronic adult condition, with a median predicted survival now exceeding 50 years following the introduction of highly effective CFTR modulator therapy (HEMT). This demographic shift has unmasked cardiovascular complications that were previously unrecognized due to premature mortality. In a multinational propensity-matched cohort, CF conferred a 65% higher risk of major adverse cardiac events (MACEs), including myocardial infarction, heart failure, and atrial fibrillation, versus matched controls (Frost et al., HR 1.65). In a separate Canadian population-based cohort, cardiovascular disease occurred at 2.9 times the rate of the general population and at least 20 years earlier (Arya et al., RR 2.9). Cardiac involvement extends beyond the traditional paradigm of cor pulmonale. CFTR is expressed in cardiomyocytes, vascular endothelium, and smooth muscle, where its dysfunction disrupts ion homeostasis, impairs nitric oxide-dependent vasodilation, and promotes oxidative stress. Clinically, these mechanisms manifest as biventricular dysfunction detectable by strain echocardiography and cardiac MRI even when ejection fraction is preserved, diffuse myocardial fibrosis, endothelial dysfunction and accelerated arterial stiffness from childhood, increased arrhythmia susceptibility, and, in a single-center cohort, an unexpectedly high prevalence of pericardial calcification (18%) on chest CT that awaits independent replication. Paradoxically, while HEMT has dramatically improved pulmonary outcomes, it introduces new cardiovascular considerations including hypertension, dyslipidemia, and obesity, and cross-sectional data in modulator-treated cohorts show persistent cardiac abnormalities, though whether these predate treatment or would differ without it is unknown. This review synthesizes the genetic, molecular, and clinical dimensions of cardiovascular disease in CF; distinguishes direct CFTR-mediated cardiac effects from indirect consequences of chronic lung disease; examines vascular, electrophysiological, valvular, and pericardial manifestations; and discusses management implications including CFTR modulator therapy, exercise, nutritional paradigm shifts, and transplantation considerations.

Acute coronary syndrome (ACS) remains a leading cause of emergency department presentations, yet triage based on the ST-elevation myocardial infarction (STEMI)/non-ST-elevation myocardial infarction (NSTEMI) paradigm misses approximately 25-34% of acute coronary occlusion myocardial infarction (OMI). Early artificial intelligence-electrocardiography (AI-ECG) models showed retrospective promise for detecting ischemic ECG patterns but lacked prospective validation. This review synthesizes emerging multicenter registry, prospective cohort, and pathway trial evidence for AI-ECG in ACS triage, including the Queen of Hearts registry, ROMIAE, and DIFOCCULT-3 studies. It is essential to distinguish two separate clinical tasks: (1) detecting OMI for emergent catheterization laboratory activation, and (2) ruling out acute myocardial infarction (MI), which requires serial high-sensitivity troponin and cannot be achieved by ECG alone. Contemporary findings suggest AI-ECG significantly improves OMI detection sensitivity (92% vs. 71% for standard care) and reduces false-positive catheterization laboratory activations by up to 91% among biomarker-negative patients. For acute MI rule-out, AI-ECG shows promise as an adjunct to troponin-based strategies, with a negative predictive value of approximately 99% when combined with high-sensitivity troponin and clinical risk scores. We propose a 'Second Opinion' framework in which AI augments physician judgment as a clinical decision support tool. Key implementation challenges include algorithmic bias, alert fatigue, documentation, and the risk of widening the digital divide. AI-ECG represents a shift toward a physiologically driven OMI vs. non-occlusive myocardial infarction (NOMI) diagnostic framework.