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UNASSIGNED: Endocardial fibroelastosis is characterized by proliferation of both elastic and collagenous fibers within the endocardium, causing diffuse or localized thickening. A four-and-a-half-month-old baby was admitted to a local hospital, with a history of seizures for one day. Baby developed features of heart failure and died within one week after admission. At the post-mortem examination, heart was found to be enlarged with dilated ventricles. The endocardium of left ventricle was markedly thickened with a whitish appearance. Histopathology showed a thick layer of collagenous fibrous tissue in the endocardium, which was confirmed by Masson trichrome stain. The cause of death was offered as dilated cardiomyopathy due to endocardial fibroelastosis. The underlying mechanisms of myocardial fibrosis remain unclear. It is hypothesized that genetic, infectious, inflammatory, and nutritional processes are involved in this condition. This case highlights the importance of gross specimen examination and special staining methods to support histopathology after postmortem examination, for ascertaining the cause of death.

A previous study reported primary macroreentrant atrial tachycardia (AT) in the left atrium (LA), including the epicardial circuit on a left atrial anterior wall (LAAW) scar, without any prior cardiac intervention (Miyazawa et al. in J Cardiovasc Electrophysiol 2019; 30: 263-264). However, determining the target for terminating macroreentrant ATs is challenging. The mapping revealed a centrifugal pattern but did not fully elucidate the AT circuit. The reentrant mechanism of these ATs was confirmed using entrainment pacing. The earliest excitation site (EES) was traditionally selected as the ablation site, typically located in healthy tissue. However, our two cases provide new insights into AT termination, including the epicardial bridge across the endocardial LAAW scar, using minimum ablation points, without the need to ablate the healthy EES.

Three cases of ventricular tachycardia ablation with pulsed-field ablation technology performed at 2 separate centers are reported, highlighting the advantages and disadvantages of this tool inside the ventricle: its dependence on proximity rather than contact makes it useful in sites with poor stability, while the speed of application and large scope of action provided by commercially available catheters could help with ablating large diseased areas of endocardium in a fast and hemodynamically well-tolerated fashion. However, lesion depth could be insufficient for guaranteeing efficacy in preventing ventricular tachycardias originating at an epicardial site, even in the right ventricle.

Contemporary reports showed that solid organ transplantation patients who contract SARS-CoV-2 infection have a high mortality rate. There are sparse data about recurrent cellular rejections and the immune response to the SARS-CoV-2 virus in patients after heart transplantation. Herein, we report a case of a 61-year-old male post-heart transplant patient who tested positive for COVID-19 and developed mild symptoms 4 months after transplantation. Thereafter, a series of endomyocardial biopsies showed histologic features of acute cellular rejection despite optimal immunosuppression, good cardiac functions, and hemodynamic stability. Demonstration of SARS-CoV-2 viral particles by electron microscopy in the endomyocardial biopsy confirmed the presence of the virus in the foci of the cellular rejection, pointing to a possible immunologic reaction to the virus. To our knowledge, there is limited information regarding the pathology of COVID-19 infection in immunocompromised heart transplant patients, and there are no well-established guidelines for treating such patients. Based on the demonstration of SARS-CoV-2 viral particles within the myocardium, we concluded that myocardial inflammation visible on endomyocardial biopsy might be attributed to the host\'s immune response to the virus, which mimics acute cellular rejection in newly heart transplanted patients. We report this case to increase awareness of such events post-transplantation and to add to knowledge regarding the management of patients with ongoing SARS-CoV-2 infection that proved to be challenging.

暂无摘要。

A 74-years-old man visited our hospital complaining chest discomfort, and he was diagnosed with variant angina. However, during close examination, a tumor with some small calcified nodules was accidentally pointed out in the right atrium. We carried out surgical removal to prevent embolism. A cystic tumor attached to the atrial septum was resected together with the atrial septum, and the defect was closed with a Dacron patch. The tumor size was 18×25×3 mm. Histologically, its wall was consisted of connective tissue, which was positive for CD34, negative for calretinin, and was diagnosed as an endocardial blood cyst. A core of the nodules in the cyst were calcified and they were phleboliths. Postoperative echocardiography detected no residual mass or atrial septal defect, and he was discharged uneventfully.

We present a case of a 66-year-old man who died on the scene in a traffic accident. He was a car driver involved in a head-on collision with a bus. Autopsy performed 4 days after death showed multiple head, torso, and limb injuries, including complete avulsion of the heart from the great vessels and avulsion of both lungs from the tracheobronchial tree due to rapid deceleration. Gross examination of the heart was remarkable for patchy hemorrhages beneath the endocardium involving the left side of the interventricular septum and papillary muscles. Histological examination identified streaky subendocardial hemorrhages and perivascular hemorrhages in the subendocardial myocardium. Since the death, in this case, was instantaneous, the most likely mechanism of subendocardial hemorrhages involved a precipitous decrease in left ventricle pressure, as it is improbable that the timeline of events allowed for a catecholamine surge to occur and take effect. Findings in this case also suggest that subendocardial hemorrhages are an indicator of intravital trauma and that the time required for them to develop is very short.

Outflow tract premature ventricular contractions sometimes demonstrate multiple exit sites in the right and left outflow tracts with preferential pathways. Here we present a case of outflow tract premature ventricular contractions, which were eliminated by ablation from the right ventricular outflow tract accompanied by additional ablation from the very distant endocardial left ventricular outflow tract. The findings during the ablation indicated there was a single origin with multiple exit sites rather than multiple origins for each QRS morphology. This case illustrates that the preferential pathways can demonstrate very distant multiple exit sites.

BACKGROUND: Left atrial dissection is an extremely rare complication of mitral valve replacement. Because of its severity, its prompt diagnosis and treatment is mandatory. The most effective treatment (i.e. surgical vs. non-surgical) for left atrial dissection has not been fully established yet.
METHODS: Herein, we have reported left atrial dissection after mitral valve replacement in a 68-year-old obese woman. After closing the thorax, transesophageal echocardiography (TEE) revealed an atrial mass of 3 cm × 2 cm, visualized as an oval hypoechoic appearance extending from the posterior annulus of the mitral valve to the posterior wall of the left atrium. Because hemodynamic conditions were stable, surgery was ruled out and conservative treatment with close observation was selected. On postoperative day 2, TEE revealed that the atrial mass had vanished and the broken piece of the endocardium merely remained fluttering in the atrium. On postoperative day 6, the appearance of the left atrium was normalized completely, leaving no traces of left atrial dissection. The patient recovered uneventfully. Serial TEE was a very effective imaging modality during the non-surgical treatment of left atrial dissection.
CONCLUSIONS: It is crucial to accurately define diagnosis and optimally consider therapeutic strategies for left atrial dissection based on the hemodynamic conditions of the patient and serial TEE follow-up examinations. In our case study, left atrial dissection was successfully treated with conservative treatment; therefore, we believe that TEE could be a feasible modality for the early diagnosis of this condition.