Sudden cardiac death in the young: A consensus statement on recommended practices for cardiac examination by pathologists from the Society for Cardiovascular Pathology.

Sudden cardiac death is, by definition, an unexpected, untimely death caused by a cardiac condition in a person with known or unknown heart disease. This major international public health problem accounts for approximately 15-20% of all deaths. Typically more common in older adults with acquired heart disease, SCD also can occur in the young where the cause is more likely to be a genetically transmitted process. As these inherited disease processes can affect multiple family members, it is critical that these deaths are appropriately and thoroughly investigated. Across the United States, SCD cases in those less than 40 years of age will often fall under medical examiner/coroner jurisdiction resulting in scene investigation, review of available medical records and a complete autopsy including toxicological and histological studies. To date, there have not been consistent or uniform guidelines for cardiac examination in these cases. In addition, many medical examiner/coroner offices are understaffed and/or underfunded, both of which may hamper specialized examinations or studies (e.g., molecular testing). Use of such guidelines by pathologists in cases of SCD in decedents aged 1-39 years of age could result in life-saving medical intervention for other family members. These recommendations also may provide support for underfunded offices to argue for the significance of this specialized testing. As cardiac examinations in the setting of SCD in the young fall under ME/C jurisdiction, this consensus paper has been developed with members of the Society of Cardiovascular Pathology working with cardiovascular pathology-trained, practicing forensic pathologists.

Iatrogenic aortic dissection of the descending aorta after percutaneous coronary intervention.

Aortic dissection is a rare and potentially fatal complication of coronary angiography. We report a case of a woman in her late 80s who underwent a left femoral approach coronary angiogram for evaluation of a transcatheter aortic valve replacement (TAVR). Following the procedure, she had a cardiac arrest and was found to have a descending aortic dissection on transoesophageal echocardiogram. Autopsy showed an acute intimal tear of the descending aorta, most likely related to catheter manipulation. Patients undergoing evaluation for TAVR, who tend to be elderly with concomitant atherosclerosis, are at risk for complications following cardiac catheterisation including aortic dissection.

Acute Myocardial Infarction-Like Events in Related Patients With a Desmoplakin-Associated Arrhythmogenic Cardiomyopathy.

Patients with familial arrhythmogenic cardiomyopathy typically present with ventricular arrhythmias or progressive heart failure. This paper characterizes a rare presentation of an underlying genetic cardiomyopathy with clinical manifestations mimicking an acute myocardial infarction in 2 siblings, each with the same mutation in the desmoplakin (DSP) gene. (Level of Difficulty: Advanced.).

Sudden Unexpected Death Due to Myocarditis in Young People, Including Athletes.

Sudden deaths in young active people and athletes are distinctly uncommon and frequently related to highly visible cardiovascular conditions including hypertrophic cardiomyopathy and congenital coronary anomalies. Myocarditis is also a cause of sudden death in the young, but frequently under-recognized clinically, and therefore deserving of the present analysis. Two large registries were interrogated for cases of myocarditis, and clinical, demographic, and pathologic findings were assessed. Of 97 cases of myocarditis identified, ages were 19.3 ± 6.2 years, 76% male, and 58 were physically active at or near the time of death. Almost one-half of the 97 cases (47%) had a viral prodrome or symptoms (i.e., syncope, malaise, chest pain or palpitations). Nine were evaluated by cardiologists, but in none was a diagnosis of myocarditis established before death. The inflammatory cellular infiltrate was predominantly lymphocytic (67%), was most frequently multifocal (59%) and involved the conduction system (including atrioventricular node), 38%. In conclusion, myocarditis is an important but under-recognized cause of sudden death in young people including competitive athletes. Clinical diagnosis is difficult because symptoms are nonspecific and often ignored, requiring high index of suspicion for diagnosis. Our data support the ACC/AHA consensus guidelines recommending removal of individuals with myocarditis from competitive sports during recovery. Selective examination of conduction systems showed a number of cases with involvement of myocarditis, suggesting a novel mechanism for sudden death.

Hypertrophic Cardiomyopathy and Sudden Death Initially Identified at Autopsy.

Hypertrophic cardiomyopathy (HC) is associated with a well-recognized risk for unexpected sudden death (SD). Most such reported patients have been referred to dedicated centers and/or expert cardiologists for risk stratification, with the number of SDs decreasing sharply due to penetration of the implantable cardioverter-defibrillator (ICDs) into HC practice. However, the clinical circumstances, and morphologic features of HC patients who incur SD without the opportunity to be considered for preventive intervention with ICDs are largely undefined. Using the long-standing unique Jesse Edwards Registry (St. Paul, Minnesota), we studied 86 selected heart specimens from young HC patients who died suddenly and unexpectedly without prior clinical evaluation, ages 31 ± 16 years. The patients were predominantly male (87%) with only modest phenotypic expression and maximum LV wall thickening of only 18 ± 4 mm. SD events occurred predominantly with sedentary/mild activities (66%) often in bed or asleep (32%), but also during physical activity (22%) including with organized competitive sports. This largely unappreciated sub-population of patients with HC (and SD) is characterized by mild-to-moderate degree of LV hypertrophy, representing a clinical challenge which is particularly relevant in the current ICD era for HC, with the potential for SD prevention.

Clinical and pathologic findings of aortic dissection at autopsy: Review of 336 cases over nearly 6 decades.

BACKGROUND: We aimed to characterize the clinical and pathologic findings of aortic dissection (AD) over a nearly 60-year period. METHODS: The Jesse E. Edwards Registry of Cardiovascular Disease database was queried for cardiac specimens from autopsies with AD as a diagnosis and compared 2 cohorts: early (1956-1992) and current (1993-2015). RESULTS: From 1956 to 2015, 338 cases (166 early, 170 current) with AD were included (mean age: 60; 62% male). The AD was 86% type A and 14% type B. Sixty-two percent of cases were under medical care at time of death (61% early, 62% current, P = not significant). Of those under medical care, 63% were not diagnosed prior to death (64% early, 62% current, P = not significant). Risks for dissection did not differ between time intervals and include left ventricular hypertrophy, suggestive of hypertension (84%), prior cardiovascular surgery (38%), bicuspid valve (14%), and connective tissue disease (9%). An intimal tear was identified in the ascending aorta in the majority (68%), followed by descending (14%), root (9.5%), and arch (7%). Aortic rupture occurred in 58%, most frequently in the ascending aorta (41%). CONCLUSIONS: In a large cardiovascular registry, >60% of cases of AD were not detected clinically and first identified at autopsy. Although diagnostic techniques have significantly improved over the time interval, the percentage of AD discovered at autopsy did not differ from the early to the current era. The most prevalent risk factors for dissection including hypertension and prior cardiovascular surgery remain similar in both time periods. AD death is related to rupture of the aorta in the majority of cases.

Autosomal-dominant biventricular arrhythmogenic cardiomyopathy in a large family with a novel in-frame DSP nonsense mutation.

A novel autosomal-dominant in-frame deletion resulting in a nonsense mutation in the desmoplakin (DSP) gene was identified in association with biventricular arrhythmogenic cardiomyopathy across three generations of a large Caucasian family. Mutations that disrupt the function and structure of desmosomal proteins, including desmoplakin, have been extensively linked to familial arrhythmogenic right ventricular cardiomyopathy (ARVC). Analysis of data from 51 individuals demonstrated the previously undescribed variant p.Cys81Stop (c.243_251delCTTGATGCG) in DSP segregates with a pathogenic phenotype exhibiting variable penetrance and expressivity. The mutation's pathogenicity was first established due to two sudden cardiac deaths (SCDs), each with a biventricular cardiomyopathy identified on autopsy. Of the individuals who underwent genetic screening, 27 of 51 were heterozygous for the DSP mutation (29 total with two obligate carriers). Six of these were subsequently diagnosed with arrhythmogenic cardiomyopathy. An additional nine family members have a conduction disorder and/or myocardial structural changes characteristic of an evolving condition. Previous reports from both human patients and mouse studies proposed DSP mutations with a premature stop codon impart mild to no clinical symptoms. Loss of expression from the abnormal allele via the nonsense-mediated mRNA decay pathway has been implicated to explain these findings. We identified an autosomal-dominant DSP nonsense mutation in a large family that led to SCD and phenotypic expression of arrhythmogenic cardiomyopathy involving both ventricles. This evidence demonstrates the pathogenic significance of this type of desmosomal mutation and provides insight into potential clinical manifestations.

Histologic Examination of the Heart in the Forensic Autopsy.

Histologic examination of the myocardium, valves, and cardiac blood vessels is often as important as the gross examination. The diagnostic features and categories of heart disease are many and varied, possibly more than any other organ. We present a review of the histologic features of forensically important heart disease.

Uhl's anomaly: perspective of fetal echocardiography and histopathological correlation.

We report a case of Uhl's anomaly imaged at 19 weeks of gestation by fetal echocardiography with pathological confirmation by anatomical gross heart specimen and tissue histology. Uhl's anomaly of the right ventricle is a rare cardiac disorder with isolated right ventricular enlargement with almost complete absence of the right ventricular myocardium.

Patho-Histological Findings of Annular Rupture Related to Left Ventricular Outflow Tract (LVOT) Calcification Following Transcatheter Aortic Valve Replacement (TAVR).

Peri-aortic hematoma has been recently described as a potentially life-threatening complication following transcatheter aortic valve replacement (TAVR). Patient- and procedure-related factors exist that predispose to peri-aortic hematoma formation, which can progress to myocardial rupture at the aortic root-myocardial junction. While conservative therapy with blood pressure control is the expectant management following peri-aortic hematoma formation, myocardial rupture can occur at the site of the aortic annulus. Hence, interventionists and echocardiologists must be prepared for emergent intervention to salvage the patient once the complication is recognized. The present report highlights the patho-histological findings related to left ventricular outflow tract calcification following TAVR.

Comparison of the Frequency of Sudden Cardiovascular Deaths in Young Competitive Athletes Versus Nonathletes: Should We Really Screen Only Athletes?

The issue of sudden death in young athletes and consideration for the most practical and optimal strategy to identify those genetic and/or congenital heart diseases responsible for these tragic events continues to be debated. However, proponents of broad-based and mandatory national preparticipation screening, including with 12-lead electrocardiograms have confined the focus to a relatively small segment of the youthful population who choose to engage in competitive athletic programs at the high school, college, and elite-professional level. Therefore, lost in this discussion of preparticipation screening of athletes is that the larger population of young people not involved in competitive sports (and, therefore, a priori are excluded from systematic screening) who nevertheless may die suddenly of the same cardiovascular diseases as athletes. To substantiate this hypothesis, we accessed the forensic Hennepin County, Minnesota registry in which cardiovascular sudden deaths were 8-fold more common in nonathletes (n = 24) than athletes (n = 3) and threefold more frequent in terms of incidence. The most common diseases responsible for sudden death were hypertrophic cardiomyopathy (n = 6) and arrhythmogenic right ventricular cardiomyopathy (n = 4). These data raise ethical considerations inherent in limiting systematic screening for unsuspected genetic and/or congenital heart disease to competitive athletes.

Expression of cathepsin K and tartrate-resistant acid phosphatase is not confined to osteoclasts but is a general feature of multinucleated giant cells: systematic analysis.

OBJECTIVE: Cathepsin K and tartrate-resistant acid phosphatase (TRAP) are two proteins expressed in osteoclastic giant cells. Recently we showed that lesional multinucleated giant cells (MNGs) in pulmonary granulomatosis with polyangiitis expressed these proteins. We aimed to clarify whether the expression of these two proteins has any specificity or is a general feature of MNGs associated with multiple types of granulomatous inflammation. METHODS: In total, 7 Crohn's disease (CD), 5 GCA, 5 giant cell myocarditis (GCM), 11 sarcoidosis and 6 tuberculosis cases were examined for expression of cathepsin K and TRAP using immunohistochemistry (IHC). Protein expression was semi-quantitatively classified as none, weak, moderate or strong. In addition, tissue TRAP activity was examined using an enzymatic reaction. RESULTS: The expression of cathepsin K was robust in >95% of MNGs of all examined disease groups, whereas TRAP expression varied; CD, GCA and tuberculosis showed strong TRAP expression. TRAP expression in sarcoidosis and GCM was weaker (CD vs GCM, P = 0.04; CD vs sarcoidosis, P = 0.06). Compared with IHC, TRAP detection using an enzymatic colour reaction had limited sensitivity. CONCLUSION: Expression of TRAP and cathepsin K is a general feature of MNGs and their expression might be related to histopathological pattern.

Sudden death due to spontaneous acute dissection of the left subclavian artery with rupture during postpartum period: a case report.

Subclavian artery dissection is usually associated with coexisting aortic disease. Isolated and spontaneous acute subclavian artery dissection is uncommon and rarely reported. In addition, no case of left subclavian artery dissection during pregnancy and early puerperium has been described. We report the autopsy case of a 24-year-old female who died suddenly 3 days after delivery due to a spontaneous left subclavian artery dissection with rupture.

Altered desmosomal proteins in granulomatous myocarditis and potential pathogenic links to arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Immunoreactive signal for the desmosomal protein plakoglobin (γ-catenin) is reduced at cardiac intercalated disks in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), a highly arrhythmogenic condition caused by mutations in genes encoding desmosomal proteins. Previously, we observed a false-positive case in which plakoglobin signal was reduced in a patient initially believed to have ARVC but who actually had cardiac sarcoidosis. Sarcoidosis can masquerade clinically as ARVC but has not been previously associated with altered desmosomal proteins. METHODS AND RESULTS: We observed marked reduction in immunoreactive signal for plakoglobin at cardiac myocyte junctions in patients with sarcoidosis and giant cell myocarditis, both highly arrhythmogenic forms of myocarditis associated with granulomatous inflammation. In contrast, plakoglobin signal was not depressed in lymphocytic (nongranulomatous) myocarditis. To determine whether cytokines might promote dislocation of plakoglobin from desmosomes, we incubated cultures of neonatal rat ventricular myocytes with selected inflammatory mediators. Brief exposure to low concentrations of interleukin (IL)-17, tumor necrosis factor-α (TNF-α), and IL-6 (cytokines implicated in granulomatous myocarditis) caused translocation of plakoglobin from cell-cell junctions to intracellular sites, whereas other potent cytokines implicated in nongranulomatous myocarditis had no effect, even at much higher concentrations. We also observed myocardial expression of IL-17 and TNF-α and elevated levels of serum inflammatory mediators, including IL-6R, IL-8, monocyte chemoattractant protein 1, and macrophage inflammatory protein 1ß, in patients with ARVC (all P<0.0001 compared with controls). CONCLUSIONS: The results suggest novel disease mechanisms involving desmosomal proteins in granulomatous myocarditis and implicate cytokines, perhaps derived in part from the myocardium, in disruption of desmosomal proteins and arrhythmogenesis in ARVC.

Pathology of the aortic arch in hypoplastic left heart syndrome: surgical implications.

Aortic arch reconstruction plays an important role in the success of the Norwood procedure (NP) for hypoplastic left heart syndrome (HLHS). This study investigated the cardiac specimens to determine the etiology of distal aortic arch obstruction after the NP for HLHS and to locate coarctation of the aorta in HLHS untreated by surgery. This study examined 17 cardiac specimens: 9 that had NP and 8 not treated by surgery. The findings after NP showed frequent failure to resect the coarctation segment completely and failure to extend the augmentation patch into the descending aorta. Five (62.5%) of the eight hearts not treated by surgery had significant periductal coarctation of the aorta. After NP for nine patients, three (33%) had residual coarctation of the aorta. To minimize the risk of recurrent or persistent aortic arch obstruction after NP and to improve the long- and short-term outcome, the ductal tissue and the coarctation segment encircling the aortic lumen should be resected. The distal wall incision should be extended at least 5 mm beyond the distal aspect of the ductal tissue. These steps could avoid major aortic arch obstruction, promote growth of the native aortic tissue, and avoid ventricular dysfunction.

Clear cells in the atrioventricular valves of infants with severe human mucopolysaccharidosis (Hurler syndrome) are activated valvular interstitial cells.

BACKGROUND: Severe mucopolysaccharidosis type I (Hurler syndrome) is an autosomal recessive lysosomal storage disease of childhood that results in accumulation of glycosaminoglycans within cardiac valves and consequent valve dysfunction. Valve thickening in mucopolysaccharidosis type I (Hurler syndrome) is due, in part, to the presence of glycosaminoglycan-laden cells (the so-called "clear" or "Hurler" cells) within the valve that remain largely unstudied with respect to identity, origin, and function. We hypothesized that the "clear" or "Hurler" cells within the atrioventricular valves from individuals with untreated mucopolysaccharidosis type I are activated valvular interstitial cells. METHODS: We performed routine and immunohistochemical staining on atrioventricular valves from two infants with untreated severe mucopolysaccharidosis type I (Hurler syndrome) and compared them to atrioventricular valve tissue from two age-matched and gender-matched normal infants. RESULTS: Despite the marked differences in their histological appearances, mucopolysaccharidosis type I valve cells have an immunohistochemical fingerprint identical to that of normal infant valvular interstitial cells. Both mucopolysaccharidosis type I valvular interstitial cells and normal infant valvular interstitial cells have the phenotype of activated myofibroblasts, as evidenced by positive staining for vimentin, smooth muscle actin, and metalloproteinase-9. However, the number of mucopolysaccharidosis type I valvular interstitial cells is significantly increased when compared to that of normal cells (P<.0031). Both mucopolysaccharidosis type I (Hurler syndrome) cells and normal valvular interstitial cells express CD34(+), a hematopoietic and capillary endothelial progenitor cell marker, suggesting a common response to activation. CONCLUSIONS: We conclude that "clear" or "Hurler" cells are valvular interstitial cells with the immunohistochemical phenotype of activated myofibroblasts and may be engaged, albeit ineffectively, in valve repair.

Beware of the B(e)all valve: mistaken valve identity, 30-year survival, and valve replacement.

Effective management of patients after the implantation of mechanical cardiac valves includes correct recognition of each valve and its related complications. Herein, we present the case of a patient who had undergone implantation of a floating-disc Beall-Surgitool mitral valve in 1976 and developed multiple valve-related complications. Over 30 years and in multiple medical centers, the device was mistakenly assumed to be a "ball" valve. The correct identification of the prosthesis led to the recognition of valvular failure, and the patient underwent its replacement with an On-X bileaflet carbon valve. Pathologic and microscopic examination of the explanted Beall valve showed massive pannus formation that extended over the sewing cuff on the atrial and ventricular side, preventing complete disc closure; disrupted fabric coating of the sewing ring, with exposure of the underlying metal; and a marked inflammatory reaction. We report one of the longest intervals on record between the implantation and replacement of a Beall-Surgitool valve.

Sudden death with circumferential subepicardial fibrofatty replacement: left-sided arrhythmogenic ventricular cardiomyopathy.

We report 5 cases of sudden cardiac death, with similar cardiac findings. All 5 cases had circumferential left ventricular subepicardial fibrofatty replacement of the myocardium, similar to the histologic features of arrhythmogenic right ventricular cardiomyopathy (ARVC). In these cases, the findings were predominantly in the left ventricle with minimal or no involvement of the right ventricle. Four of the 5 cases had siblings with either sudden death or cardiac symptoms. This report highlights 5 cases of sudden death in the young with histologic findings similar to ARVC, with predominant left ventricular involvement and questions whether the cases represent a larger spectrum of the cardiomyopathy known as ARVC, which perhaps should be more correctly termed as "arrhythmogenic cardiomyopathy" or represent a separate, potentially inheritable cardiomyopathic entity. We report these cases to familiarize forensic pathologists with this uncommon and potentially inheritable condition.

Myocardial bridging, a frequent component of the hypertrophic cardiomyopathy phenotype, lacks systematic association with sudden cardiac death.

AIMS: The clinical significance attributable to myocardial bridging of left anterior descending coronary artery in hypertrophic cardiomyopathy (HCM) remains controversial. METHODS AND RESULTS: Prevalence and depth of coronary artery bridges (CBs) were assessed in 255 hearts, including 115 with HCM (median age 29, range 5-90; 75% male), and 140 controls. Coronary artery bridges were more common in HCM (47/115; 41%) than in patients who died of a variety of non-HCM-related causes (21/100; 21%; P = 0.002), or in patients with congenital aortic stenosis and left ventricular (LV) hypertrophy (5/40; 12%; P = 0.001). Among the HCM hearts, CBs were present in 33 of 77 patients (43%) with sudden death, in 10 of 27 (37%) with heart failure death (or heart transplantation), and in 4 of 11 (36%) with other modes of death (P = 0.826). Deeply embedded CBs (> or =2 mm) occurred with similar frequency in HCM patients with sudden (21 of 77; 27%) or heart failure death (5 of 27; 13%; P = 0.191). In sudden death patients, the presence of CB was unrelated to gender (33% in women and 45% in men, P = 0.406) and age (41% <18 years vs. 44% > or =18 years; P = 0.827). CONCLUSION: In this morphological analysis of more than 250 hearts, CBs are a frequent component of phenotypically expressed HCM, and more common than in other disorders with or without LV hypertrophy. Although no systematic association with HCM-related sudden death is evident, our findings do not exclude the possibility that CB could contribute to increased risk in some individual patients, potentially impacting management decision-making on a case-by-case basis.