Acute coronary syndrome with non-obstructive coronary arteries (ACS-NOCA) in patients with hypertrophic cardiomyopathy

Influence of cardiac biomarkers on predicting significant coronary artery disease in hypertrophic cardiomyopathy patients

BACKGROUND

In this study, our aim was to investigate the role of cardiac biomarkers in predicting the presence of significant coronary artery disease in hypertrophic cardiomyopathy (HCM) patients.

METHODS

The study population was composed of hypertrophic cardiomyopathy patients who underwent coronary angiography at a single center between June 2021 and March 2023, and whose cardiac biomarkers were evaluated before the procedure. HCM patients were screened retrospectively. Significant CAD was defined as > 50% stenosis of the left main coronary artery or > 70% stenosis in a major coronary vessel. Demographic, echocardiographic and cardiac biomarker values were compared between the two groups.

RESULTS

A total of 123 patients were evaluated. Significant CAD was detected in 39 (31.7%) patients. Patients with significant CAD had higher CK-MB values than those without CAD [2.8 (2.1-4.0) vs. 3.4 (2.8-4.6), p = 0.036], and a higher level of high-sensitivity troponin T (hs-TnT) than those without CAD (24 vs. 17.8, p = 0.022). the NT-proBNP/hs-TnT ratio was found to be significantly lower in patients with CAD than in those with CAD (31.4 vs. 21.4, p = 0.019). In multivariate anaylsis, NT-proBNP/hs-TnT was determined as an independent predictor for significant CAD. In ROC analysis, NT-proBNP/hs-TnT ratio lower than the cut-off value of 30.7 could detect the presence of significant CAD with 76.9% sensitivity and 53.6% specificity (AUC: 0.632, 95% CI: 0.528-0.736, p = 0.019).

CONCLUSION

To sum up, we suggest that cardiac biomarkers were valuable and simple parameters in terms of significant CAD in HCM patients.

Misdiagnosed myocarditis in arrhythmogenic cardiomyopathy induced by a homozygous variant of DSG2: a case report

Background

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiomyopathy that is rarely diagnosed in infants or young children. However, some significant homozygous or compound heterozygous variants contribute to more severe clinical manifestations. In addition, inflammation of the myocardium and ventricular arrhythmia might lead to misdiagnosis with myocarditis. Here, we describe an 8-year-old patient who had been misdiagnosed with myocarditis. Timely genetic sequencing helped to identify this case as ACM induced by a homozygous variant of DSG2.

Case presentation

The proband of this case was an 8-year-old boy who initially presented with chest pain with an increased level of cardiac Troponin I. In addition, the electrocardiogram revealed multiple premature ventricular beats. Cardiac magnetic resonance revealed myocardial edema in the lateral ventricular wall and apex, indicating localized injuries of the myocardium. The patient was primarily suspected to have acute coronary syndrome or viral myocarditis. Whole-exome sequencing confirmed that the proband had a homozygous variation, c.1592T > G, of the DSG2 gene. This mutation site was regulated by DNA modification, which induced amino acid sequence changes, protein structure effects, and splice site changes. According to MutationTaster and PolyPhen-2 analyses, the variant was considered a disease-causing mutation. Next, we used SWISS-MODEL to illustrate the mutation site of p.F531C. The ensemble variance of p.F531C indicated the free energy changes after the amino acid change.

Conclusion

In summary, we reported a rare pediatric case initially presenting as myocarditis that transitioned into ACM during follow-up. A homozygous genetic variant of DSG2 was inherited in the proband. This study expanded the clinical feature spectrum of DSG2-associated ACM at an early age. Additionally, the presentation of this case emphasized the difference between homozygous and heterozygous variants of desmosomal genes in disease progression. Genetic sequencing screening could be helpful in distinguishing unexplained myocarditis in children.

A Left Atrial Myxoma Masquerading As Acute Coronary Syndrome

Acute coronary syndrome is caused by a rupture of atherosclerotic plaque with superimposed thrombus formation. Non-ST-segment elevation acute coronary syndrome (NSTE-ACS) occurs when occlusion of the epicardial coronary artery by a thrombus causes partial thickness myocardial ischemia and an ischemic cascade downstream. Cardiac masses are known to produce symptoms predominantly by local obstruction or systemic embolism. Coronary artery tumor embolism causing acute coronary syndrome is a rare presentation of cardiac mass. We report NSTE-ACS as the initial presentation of the left atrial myxoma in a 62-year-old woman. She presented to the emergency department with acute onset severe anginal chest pain, diaphoresis, and dizziness. Her serial electrocardiograms (ECGs) were normal, and serial troponins were elevated, consistent with non-ST-segment elevation acute coronary syndrome. Cardiac catheterization revealed insignificant coronary artery disease, and transthoracic and transesophageal echocardiograms showed a left atrial mass attached to the interatrial septum consistent with myxoma. The patient underwent surgical excision, and histopathology was consistent with myxoma. Her symptoms subsided after surgery. Primary cardiac tumors are very uncommon and can present with myriad symptoms, from tumor embolism, local cardiac effects, to constitutional symptoms. Although embolism to other organs has been reported, left atrial myxoma presenting as an acute coronary syndrome is very uncommon.