Nonatherosclerotic narrowing of the atrioventricular node artery and sudden death

A report of fifty cases with incidental diagnosis of anomalous origin of the right coronary artery from the left sinus of Valsalva

INTRODUCTION

Anomalous origin of the right coronary artery from the left sinus of Valsalva (R-ACAOS) is a relatively rare condition that can potentially lead to devastating outcomes. The current study aims to investigate the cardiac-related disorders among patients with incidental R-ACAOS diagnosis through computed tomography angiography (CTA).

METHODS

The current cross-sectional study has been conducted on 50 patients diagnosed with R-ACAOS who underwent CTA. Based on CTA, the patients' were categorized as R-ACAOS with interarterial course and non-interarterial course. The demographic and medical characteristics, any history of cardiac intervention and New York Heart Association (NYHA) Functional Classification at the time of diagnosis were recruited. Patients were revisited to assess cardiac-associated variables, including symptoms, the presence of heart failure and current NYHA function class.

RESULTS

The variables including the history of cardiac intervention (P-value<0.001), the presence of heart failure (P-value = 0.010) and NYHA function class at the time of diagnosis (P-value = 0.006) were remarkably higher among those with interarterial course of R-ACAOS; while, the other variables including chest pain at rest (P-value = 0.55) or on exertion (P-value = 0.12), current NYHA function class, current cardiac-associated symptoms except for dyspnea at rest (P-value = 0.012), mortality and coronary calium score did not differ (P-value>0.05). coronary interventions led to significantly improved NYHA function class (P-value<0.05).

CONCLUSION

Based on the findings of the current study, R-ACAOS with interarterial course leads to significantly higher rates of atherosclerotic-related symptoms and events compared with the other types of RCA anomalies. Moreover, coronary interventions led to significantly improved NYHA functional class regardless of R-ACAOS category.

Lesions of the Cardiac Conduction System and Sudden Death

ABSTRACT

When a young previously healthy person dies suddenly, occasionally, the scene is noncontributory and the autopsy and drug screen are negative. In such cases, additional studies, including genetic assessment and cardiac conduction system examination, should be performed. We performed a literature search and reviewed our own material to identify possible or definite conduction system anomalies that may cause death. We identified intrinsic conduction system disease including cystic tumor of the atrioventricular node, atrioventricular node (cystic tumor of the AV node), and fibromuscular dysplasia of the atrioventricular node artery to be likely causes of death. Extrinsic causes, in which a generalized disease affects the conduction system, include tumors, autoimmune disease, infiltrative disorders, and others, are a second category of diseases that can affect the conduction system and cause atrioventricular block and sudden death.

The anatomy of the atrioventricular nodal artery: A meta-analysis with implications for cardiothoracic surgery and ablation procedures

The objective of the present meta-analysis was to evaluate recent and applicable data regarding the location and variation of the atrioventricular nodal artery (AVNA) in relation to adjacent structures. In order to minimize postoperative risks and maintain physiological anastomosis for proper cardiac function, understanding such possible variations of vascularization of the AV node is of immense importance prior to cardiothoracic surgery as well as ablations. In order to perform this meta-analysis, a systematic search was conducted in which all articles regarding, or at least mentioning, the anatomy of the AVNA was searched. In general, the results were based on 3919 patients. AVNA was found to originate only from the RCA in 82.41% (95% CI: 79.46%-85.18%). The pooled prevalence of AVNA originating only from LCA was found to be 15.25% (95% CI: 12.71%-17.97%). The mean length of AVNA was found to be 22.64 mm (SE = 1.60). The mean maximal diameter of AVNA at its origin was found to be 1.40 mm (SE = 0.14). In conclusion, we believe that this is the most accurate and up-to-date study regarding the highly variable anatomy of the AVNA. The AVNA was found to originate most commonly from the RCA (82.41%). Furthermore, the AVNA was found to most commonly have no (52.46%) or only one branch (33.74%). It is hoped that the results of the present meta-analysis will be helpful for physicians performing cardiothoracic or ablation procedures.

Anatomical Study of the Atrioventricular Nodal Branch of the Heart

Background The atrioventricular (AV) node is a relay station for electrical signals passing between the atria and ventricles. The artery supplying the AV node is functionally important, and its anatomical topography is relevant during invasive procedures. Therefore, the aim of this study was to identify and understand the variations of the origin of the AV nodal branch (AVNb) and its variations. Materials and methods We dissected 31 adult human hearts to evaluate their AVNb and its variations. A classification scheme was used to detail the morphology found for each of these arteries. Results We identified five distinct origins of the AVNb: AVNb originating from the right coronary artery (RCA) proximal to the inferior interventricular branch (IVb) (type I, 3.2%), AVNb originating from the junction of the RCA and IVb (type II, 19.4%), AVNb originating from the RCA distal to the IVb (type III, 64.5%), AVNb originating from the IVb (type IV, 6.5%), and AVNb originating from the circumflex branch of the left coronary artery (LCA) (type V, 6.5%). Conclusions Our study provides data on the morphology and variations of the AVNb. Such information can assist in better diagnoses based on imaging, better guide invasive procedures, and provide the cardiac surgeon with an improved method of classifying the AVNb and its branches during procedures of the coronary arteries and their branches.

First international consensus on the diagnosis and management of fibromuscular dysplasia

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD) which was commissioned by the Working Group 'Hypertension and the Kidney' of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.

First International Consensus on the diagnosis and management of fibromuscular dysplasia

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD), which was commissioned by the working group ‘Hypertension and the Kidney’ of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.

Histologic spectrum of the cardiac conducting tissue in non-natural deaths under 30 years of age: an analysis of 43 cases with special implications for sudden cardiac death

In the past, histological findings of the cardiac conduction system or its adjacent structures, such as filiform fibers at the transition from bundle of His to bundle branches, connective tissue at the apex of the ventricular septum, or fibromuscular alterations of the arteries has been considered as a cause of death. However, the prevalence of such findings in a healthy population has been rarely analyzed systematically. In the present study, the morphology of the cardiac conduction system of 43 heart-healthy individuals who died of non-natural causes (ages 0 to 30 years) was investigated. In a high percentage of cases, connective tissue at the apex of the ventricular septum (97.7%), filiform fibers at the transition from bundle of His to the bundle branches (27.9%), and fibromuscular proliferations of the sinoatrial node artery (41.9%), and the AV-node artery (39.5%) could be detected. Based on our observations, these alterations should not be considered as a pathologic entity or as a cause of death.

Causes of sudden death in patients with obstructive sleep apnea

There are few autopsy studies of patients dying suddenly with obstructive sleep apnea (OSA). Twenty-five forensic autopsies of unexpected sudden death in individuals with OSA were reviewed. The causes of death were as follows: cardiomyopathy (n = 11); sudden unexpected death without morphologic findings (SUDNA, n = 6); and other cardiovascular diseases not related to OSA (n = 8). The cardiomyopathy group comprised five hearts with concentric left ventricular hypertrophy without dilatation and six with left ventricular diameter >4 cm (dilated cardiomyopathy). Four of six hearts in the SUDNA group showed right ventricular dilatation compared with seven of 11 showed cardiomyopathy and one of eight miscellaneous. The degree of obesity was greatest in the dilated cardiomyopathy group (10 of 11 obese) followed by the SUDNA group (four of six obese). The cardiac findings in patients dying suddenly and unexpectedly with OSA include nonspecific cardiomyopathy, other cardiac conditions, and hearts without a morphologic cause of death, which show frequent right ventricular dilatation as the only finding.

Histopathology of the Cardiac Conduction System in the Investigation of Sudden Unexpected Death

When a gross and microscopic autopsy, drug screen, and past medical history fail to yield a cause of death, the forensic pathologist may opt to study the cardiac conduction system. This paper describes the excision of the SA (sinoatrial) node and AV(atrioventricular) node-containing areas of the heart and the microscopic appearance of normal SA and AV nodes, His bundle and bundle branches. Conduction system findings that have been reported to be significant include fibromuscular hyperplasia (often mislabeled dysplasia) of the SA and AV nodes arteries, persistent fetal dispersion of the AV node and His bundle, accessory pathways, ganglionitis and neuritis near the SA node, fibrosis and fatty infiltration of the conducting tissue, AV node tumor, left-sided His bundle, and AV node fibrosis. In an otherwise normal autopsy, AV node tumors, severe fibromuscular hyperplasia of the AV node artery and AV node fibrosis are sufficient to cause death. Other findings, particularly Mahaim tracks, are competent causes of death if they correlate with premortem electrocardiographic findings. Conduction system examination, although a low-yield procedure, is a worthwhile endeavor. Care must be taken to not overestimate the significance of the findings.

Sudden adult death

In the investigation of sudden death in adults, channelopathies, such as long QT syndrome, have risen to the fore in the minds of forensic pathologists in recent years. Examples of these disorders are touched upon in this review as an absence of abnormal findings at postmortem examination is characteristic and the importance of considering the diagnosis lies in the heritable nature of these conditions. Typically, a diagnosis of a possible channelopathy is evoked as an explanation for a 'negative autopsy' in a case of apparent sudden natural death. However, the one potential adverse effect of this approach is that subtle causes of sudden death may be overlooked. The intention of this article is to review and discuss potential causes of sudden adult death (mostly natural) that should be considered before resorting to a diagnosis of possible channelopathy. Nonetheless, it becomes apparent that many of the potential causes of sudden death can have a genetic basis. Thus, it becomes an important consideration that there may be a genetic basis to sudden death that extends beyond the negative autopsy.

Cardiac valvular and vascular disease in Bull Terriers

The hearts of 27 Bull Terriers and 6 control dogs were evaluated. Heart murmurs were auscultated in 14 (52%) Bull Terriers. At necropsy, 25 Bull Terriers (93%) had myxomatous degeneration of the mitral valve or abnormalities of the left ventricular outflow tract. Small vessel arteriosclerosis in the myocardium and fibrosis of cardiac conduction tissue were common histologic findings in Bull Terriers with clinical cardiac disease. These lesions were also detected in dogs without clinical evidence of cardiac disease and only mild murmurs or structural valvular disease.

Ruptured cerebral aneurysm and acute coronary artery dissection in the setting of multivascular fibromuscular dysplasia: a case report

Fibromuscular dysplasia (FMD) is a segmental noninflammatory nonatherosclerotic vascular disease that has been described in almost every arterial bed, including the cerebral and coronary arteries. FMD of cerebral vessels has been associated with development of saccular aneurysms in the involved vessels. Acute dissection of coronary arteries is also a rare complication of FMD. Herein, we report the first case of both complications of FMD occurring in a single patient-a ruptured anterior communicating artery aneurysm and a right coronary artery dissection occurring in a 38-year-old woman. At autopsy, FMD was found in multiple vascular beds. Our findings reveal the potential for involvement of several vascular beds in patients with FMD, resulting in multiple vascular complications.

Sudden death in competitive athletes

Sudden death in athletes is an extremely rare event yet no less tragic for its infrequency. Up to 90% of these deaths are due to underlying cardiovascular diseases and therefore categorized as sudden cardiac death (SCD). The causes of SCD among athletes are strongly correlated with age. In young athletes (<35 years), the leading causes are congenital cardiac diseases, particularly hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and congenital coronary artery anomalies. By contrast, most of deaths in older athletes (<35 years) are due to coronary artery disease. This review focuses on the cardiac causes of SCD and provides a brief summary of the principal noncardiac causes. Current pre-participation screening strategies are also discussed, with particular emphasis on the Italian experience.

Sudden cardiac death in athletes: the Lausanne Recommendations

OBJECTIVES

This study reports on sudden cardiac death (SCD) in sport in the literature and aims at achieving a generally acceptable preparticipation screening protocol (PPSP) endorsed by the consensus meeting of the International Olympic Committee (IOC).

BACKGROUND

The sudden death of athletes under 35 years engaged in competitive sports is a well-known occurrence; the incidence is higher in athletes (approximately 2/100,000 per year) than in non-athletes (2.5 : 1), and the cause is cardiovascular in over 90%.

METHODS

A systematic review of the literature identified causes of SCD, sex, age, underlying cardiac disease and the type of sport and PPSP in use. Methods necessary to detect pre-existing cardiac abnormalities are discussed to formulate a PPSP for the Medical Commission of the IOC.

RESULTS

SCD occurred in 1101 (1966-2004) reported cases in athletes under 35 years, 50% had congenital anatomical heart disease and cardiomyopathies and 10% had early-onset atherosclerotic heart disease. Forty percent occurred in athletes under 18 years, 33% under 16 years; the female/male ratio was 1/9. SCD was reported in almost all sports; most frequently involved were soccer (30%), basketball (25%) and running (15%). The PPSP were of varying quality and content. The IOC consensus meeting accepted the proposed Lausanne Recommendations based on this research and expert opinions (http://multimedia.olympic.org/pdf/en_report_886.pdf).

CONCLUSION

SCD occurs more frequently in young athletes, even those under the age of 18 years, than expected and is predominantly caused by pre-existing congenital cardiac abnormalities. Premature atherosclerotic disease forms another important cause in these young adults. A generally acceptable PPSP has been achieved by the IOC's acceptance of the Lausanne Recommendations.

Causes of sudden death related to sexual activity: results of a medicolegal postmortem study from 2001 to 2005

Sexual activity (SA), combined with organic heart disease, may cause sudden death (SD). However, the causes of SD related to SA are not known well. The aim of this study was to assess the causes of SD related to SA. From August 2001 to November 2005, all autopsies (n=1,379) performed at Kyungpook National University were prospectively searched for SD cases related to SA. Fourteen cases (46+/-11 yr old, 9 males) of SD related to SA were found. All were heterosexual. The toxicologic study was negative in all. Ten cases were witnessed; during SA in 4 cases, just after SA in another 4 cases, 2 and 5 hr after in 1 each case. In 4 unwitnessed cases the victims were found dead less than 12 hr from the end of their SA. The partners were steady extramarital partners (n=8), prostitutes (n=2), marital partner (n=1) and unknown (n=3). The causes of the SD were as follows; coronary artery disease in 6, subarachnoid hemorrhage with ruptured berry aneurysm in 4, fibromuscular dysplasia of the atrioventricular nodal artery in 2, and unknown in 2. Coronary artery disease and subarachnoid hemorrhage with ruptured berry aneurysm were important as causes of SD related to SA.

Arteriosclerotic changes in the myocardium, lung, and kidney in dogs with chronic congestive heart failure and myxomatous mitral valve disease

BACKGROUND

The occurrence of small vessel arteriosclerosis in the myocardium, kidney, and lung in dogs with naturally occurring myxomatous mitral valve disease has not been previously investigated systematically.

METHODS

Twenty-one dogs with naturally occurring congestive heart failure and 21 age-matched, sex-matched, and weight-matched control dogs underwent extensive pathological and histopathological examination. Morphometry and scoring of tissue sections were used to measure arterial narrowing and fibrosis in the myocardium, kidney, and lung; and intimal thickness and plaque formation in the aorta and pulmonary artery.

RESULTS

Dogs with congestive heart failure had significantly more arterial narrowing in the left ventricle (P < .003), lung (P < .0001), and kidney (P < .02); intimal-medial thickening in the pulmonary artery (P = .04); and fibrosis in the left ventricle (P < .0001) than control dogs. However, they did not have more plaque formation or intimal-medial thickening in the aorta than controls. There was significantly more arterial narrowing in papillary muscles than in all other locations in dogs with congestive heart failure (P < .002). In control dogs, arterial changes were less pronounced and did not differ in different locations.

CONCLUSIONS

Dogs with naturally occurring myxomatous mitral valve disease have significantly more arterial changes in the myocardium, lung, and kidney, and significantly more fibrosis in the myocardium than control dogs. This could have important implications in the management of myxomatous mitral valve disease and raises interesting questions about the occurrence and importance of intramural small vessel disease in humans with primary mitral valve prolapse.

Relationship between cardiopulmonary resuscitation and injuries of the cardiac conduction system: Pathological features and pathogenesis of such injuries*

OBJECTIVE

The purpose of this study was to assess the incidence, features, and pathogenesis of microscopic injuries to the cardiac conduction system caused by cardiopulmonary resuscitation.

DESIGN

: Prospective study.

SETTING

Autopsy unit of the university.

PATIENTS

Victims who had been transferred to the emergency room due to cardiac arrest arising from nontraumatic cause plus age-matched control patients.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

The cardiac conduction system of 80 hearts without gross injury from patients who had received cardiopulmonary resuscitation due to nontraumatic causes was examined. Of these 80 patients, seven (9%) showed fresh injuries, including a lesion that had gone unreported in the previous literature. Localized hemorrhage without inflammatory reaction was evident in six of these patients. Three of the six patients showed hemorrhage in the sinoatrial node, whereas the other three patients showed hemorrhage in the atrioventricular conduction system. The remaining one patient showed localized dissection of the atrioventricular node artery with the appearance of red blood cells in the false lumen. There was no significant difference with regard to age, gender, cause of cardiopulmonary arrest, whether victim had received electrical shock treatment, whether victim had received anticoagulants, and the duration of cardiopulmonary resuscitation between the seven patients with fresh injuries and the other 73 patients. Fracture of the sternum or rib was found in only one of the seven patients but in 14 of the 73 patients. No pathologic lesions were found in the 30 control patients who did not receive cardiopulmonary resuscitation.

CONCLUSIONS

It can be presumed that injuries to the conduction system do occur in limited regions during cardiopulmonary resuscitation. Minute differences in the location of the cardiac silhouette or cardiac conduction system also need to be considered, rather than just the severity of force to the anterior chest, when determining the pathogenesis of these injuries.

Assessment of QT interval duration and dispersion in athlete's heart

An athlete's heart is characterized by morphological and functional changes occurring as a consequence of regular physical exercise. We sought to determine if these physiological changes lead to ventricular repolarization abnormalities in trained athletes. Forty-four trained athletes and 35 sex- and age-matched healthy sedentary controls were included in the study. A 12-lead surface electrocardiogram (ECG) was obtained from all participants. Maximum QT (QTmax) and minimum QT (QTmin) interval durations, QT dispersion (QTd) and corrected QT dispersion (QTcd) were calculated for each ECG record. Heart rate, systolic and diastolic blood pressure values were found to be identical in both groups. QTmax and QTmin interval durations were not statistically different between the athletic and control groups. Similarly, QTd and QTcd did not differ significantly between the two groups. No association was observed between an athlete's heart and ventricular heterogeneity compared with healthy sedentary controls, despite physiological and structural changes.

Multiple spontaneous coronary artery dissections in association with anomalous origin of right coronary and intramural coronary artery dysplasia

We present a case of sudden death due to spontaneous acute coronary artery dissection. In addition, there was a healing spontaneous coronary dissection, intramural coronary artery dysplasia, and an anomalous origin of the right coronary artery from the pulmonary trunk. The coincidence of multiple spontaneous coronary dissections, coronary arterial dysplasia, and anomalous origin of the right coronary artery is unique.

Intramyocardial arterial narrowing in dogs with subaortic stenosis

Earlier studies have described intramyocardial arterial narrowing based on hyperplasia and hypertrophy of the vessel wall in dogs with subaortic stenosis (SAS). In theory, such changes might increase the risk of sudden death, as they seem to do in heart disease in other species. This retrospective pathological study describes and quantifies intramyocardial arterial narrowing in 44 dogs with naturally occurring SAS and in eight control dogs. The majority of the dogs with SAS died suddenly (n=27); nine had died or been euthanased with signs of heart failure and eight were euthanased without clinical signs. Dogs with SAS had significantly narrower intramyocardial arteries (P<0.001) and more myocardial fibrosis (P<0.001) than control dogs. Male dogs and those with more severe hypertrophy had more vessel narrowing (P=0.02 and P=0.02, respectively), whereas dogs with dilated hearts had slightly less pronounced arterial thickening (P=0.01). Arterial narrowing was not related to age, but fibrosis increased with age (P=0.047). Dogs that died suddenly did not have a greater number of arterial changes than other dogs with SAS. This study suggests that most dogs with SAS have intramyocardial arterial narrowing and that the risk of dying suddenly is not significantly related to the overall degree of vessel obliteration.

Examination of the cardiac conduction system: forensic application in cases of sudden cardiac death

Forensic pathologists may occasionally encounter cases of apparent sudden cardiac death without gross cardiac abnormality. In some of these cases, evaluation of the cardiac conduction system may reveal pathologic lesions which may act as the substrates for ventricular tachyarrhythmias and sudden death. Sample case studies are used to illustrate the suggested criteria and techniques for examination, and commonly-encountered pathologic lesions and normal variants are discussed.

Sudden cardiac death in 15-35-year olds in Sweden during 1992-99

OBJECTIVES

To study the incidence, pathogenesis and symptoms preceding sudden cardiovascular death amongst 15-35-year olds without substance abuse in Sweden during 1992-99.

DESIGN

This was a register study of a national database of forensic medicine, Rattsbase. Clinical details were obtained from forensic, police and medical records and from interviews with family members.

SETTING

The whole nation of Sweden.

SUBJECTS

Individuals having suffered a sudden cardiac death.

RESULTS

We found 181 cases of sudden cardiovascular death in a nationwide database, Rattsbase, in 15-35-year olds, of which 132 (73%) were male and 49 (27%) were female, and a rather stable incidence of 0.93 per 100,000 per year. Preceding symptoms were seen in half of the cases. The most common forensic diagnoses were: no structural abnormality (21.0%), coronary atherosclerosis (17.7%), dilated cardiomyopathy (12.2%), hypertrophic cardiomyopathy (10.5%) and myocarditis (10.5%).

CONCLUSION

Sudden cardiovascular death was uncommon in the young, but the incidence was not decreasing. Postmortem diagnoses were often difficult to establish. There was a high frequency of structurally normal hearts. Because premortal cardiac-related symptoms are relatively common and treatment methods are developing, we should learn to recognize early symptoms of heart disease. To identify individuals at risk, further studies of preceding symptoms, life-style factors and electrocardiogram (ECG) changes are needed.

Sudden death resulting from lesions of the cardiac conduction system

Sudden unexpected deaths in young persons with noncontributory histories, autopsy results, and drug screen results are a common problem in forensic pathology. As part of the evaluation of such cases, the cardiac conduction system (CCS) should be studied. To determine the type and incidence of lethal CCS lesions, the authors reviewed their files of sudden unexpected cardiac deaths with particular attention to cases with causes of death in the conduction system. Cases of sudden cardiac death in patients aged < or=40 years during a 10-year period (Michigan) and a 4 year-period (Spain) were selected from the files. From this group, cases were identified in which the cause of death was a lethal change in the CCS. The portions of the heart containing the CCS were excised, and at least one hematoxylin and eosin slide and at least one trichrome or elastic trichrome slide per block were studied. In the two centers, 381 cases of sudden cardiac death were identified. The most common causes of sudden cardiac death were arteriosclerotic narrowing of the coronary arteries, cardiomyopathy, and myocarditis. In 82 cases, there was no identifiable cause of death even after complete gross and microscopic autopsy was performed, a medical history was obtained, and a drug screen was performed. In 11 cases, the CCS contained lesions that were considered lethal: narrowing of the atrioventricular node artery by fibromuscular hyperplasia (7 cases) and atrioventricular node tumors (4 cases). The 11 cases accounted for 2.9% of the 381 cases of sudden cardiac death and 11.8% of the indeterminable cases. It was concluded that examination of the CCS in deaths in which the gross and microscopic autopsy, history, and drug screen fail to provide a cause of death can yield a cause of death in a significant percentage of cases. If heart block was not documented during life and no explanatory lesions were found during routine cardiac examination, examination of the CCS can yield valuable information.

Sudden death related to small coronary artery disease

Two cases of sudden death of young people in apparently good health are reported. The only pathologic change found was a fibromuscular dysplasia of the artery supplying the conduction system of the heart with an important narrowing of the lumen and strong thickening of the arterial wall. The first case was of a 12-year-old girl who died suddenly while skiing; the second was of a 32-year-old man who died while talking to his wife. No other pathologic changes were found at autopsy, and the results of toxicologic analysis were negative. There was no individual or family history of cardiac diseases. These cases illustrate the importance of an analysis of the conduction system, including examination of the intramural coronary arteries supplying the conduction system.

Sudden unexpected death with dysplastic change in the atrioventricular node artery

We report an autopsy case of a 19-year-old male who died suddenly. Death happened while he was sleeping after drinking alcoholic beverages. His heart revealed concentric hypertrophy of the left ventricle without asymmetric septal hypertrophy or mitral regurgitation. Upon microscopic examination, the epicardial atrioventricular (AV) node artery revealed stenosis with intimal thickening before it entered the ventricular septum and acute ischemic change was observed beneath the conduction system in the upper ventricular septum. This finding suggests that death occurred after some preceding localized ischemic event within the ventricular septum. We therefore consider that the cause of death was fatal arrhythmia due to dysplastic change to the AV node artery.

Ischaemic heart disease in the dog: a review of 65 cases

Sixty-five dogs are reviewed with histopathologically confirmed intramural arteriosclerosis. Clinical data (clinical signs, electrocardiographic findings and ultrasound parameters) on these animals were collected from nine small animal clinics in Sweden: 16 dogs had died suddenly, with few or no previous clinical signs; 13 dogs died or were euthanased during or shortly after general anaesthesia or sedation; 30 dogs developed acute (14) or chronic (16) congestive heart failure; and six dogs died or were euthanased for causes unrelated to cardiac disease. Electrocardiography of 23 of the dogs revealed several types of arrhythmias, with atrial fibrillation and sinus tachycardia being most commonly detected. Ultrasonographic examinations of 24 dogs found a relatively high number (19) with decreased indices of contractility. Dogs that had died suddenly and in relation to general anaesthesia or sedation had a higher incidence (25 of 29) of purely arteriosclerotic changes in the myocardial vessels, whereas just over half the dogs with congestive heart failure (16 of 30) had other concomitant heart lesions (in most cases endocardiosis). The incidence of myocardial infarcts was high (51 of 65 cases). It is postulated that arteriosclerosis in the dog may be an important reason for sudden death and death during general anaesthesia. Coronary arterial disease should also be a consideration in the clinical evaluation of dilated cardiomyopathy and may contribute to the decreased myocardial contractility when it is present in dogs with mitral regurgitation.

Pathologic and electrocardiographic findings in sudden cardiac death in racehorses

Five racehorses in apparently normal condition succumbed to sudden cardiac death (SCD) during or shortly after intensive training exercise. Cardiopathologic examination was performed. In 1 of the 5 horses, the use of an electrocardiogram (ECG) recording taken continuously for 440 sec enabled us to analyze some of the arrhythmias in the terminal event of SCD. The ECG tracing exhibited the R-on-T phenomenon following a pair of ventricular premature contractions (VPCs). The phenomenon rapidly degenerated into ventricular fibrillation, which led to cardiac arrest. In all 5 horses cardiopathologic examination revealed the following lesions: (i) foci of myocardial fibrosis in the right atrium located close to the sinoatrial (SA) node, (ii) fibrotic and/or fibroplastic changes in the upper portion of the interventricular septum, including the atrioventricular (AV) conduction system, and (iii) arterio- and arteriolosclerosis of the SA and AV node vessels. Pathogenetically, the process by which the focal lesions of myocardial ischemia secondary to vascular sclerosis progressed into fibrosis and/or fibroplasia could play a major role in the genesis of arrhythmias. Presumably the fibrotic and/or fibroplastic changes in the area of the AV bundle and its bundle branches are closely related to the onset of fatal ventricular arrhythmias such as VPCs, deteriorating into ventricular fibrillation. SCD in training and racing Thoroughbred horses appears to be due to arrhythmia.

Intramural coronary artery dysplasia of the ventricular septum and sudden death

We report four cases of sudden unexpected death in three males and one female aged 12 to 31 years. Death occurred during exercise in three of four cases, and there was no history of sudden death or previous cardiac history in any patient. At autopsy, there was marked intramural coronary artery dysplasia of the ventricular septum, accompanied in three of the four cases by myocardial fibrosis. The arterial dysplasia was characterized by severe medial thickening with smooth muscle cell disorganization and marked luminal narrowing. There was no evidence of myofiber disarray or asymmetric septal hypertrophy to suggest hypertrophic cardiomyopathy. Other than an ostium secundum type atrial septal defect in one case, there were no associated cardiac or extracardiac lesions found at complete autopsy of these individuals. We conclude that small vessel disease of intramural coronary arteries of the ventricular septum may be an isolated finding leading to sudden cardiac death in young adults.

Complex causes of fatal myocardial infarction

It is too often deduced that myocardial infarction is due to coronary occlusion and that subsequent death needs no other explanation. But the great majority of myocardial infarctions are not fatal, whether treated or untreated. There is, of course, some relation to the size of the infarct and the presence or absence of complicating conditions such as diabetes mellitus or hypertension, but little attention has been directed at the myriad of other events and processes influencing the clinical course. Examples include the exact anatomic territory infarcted and whether it includes the sinus node or AV node or important neuroreceptors; whether many small arteries are occluded (especially downstream of narrowed main coronary branches); whether the heart is hypertrophied, dilated, infected, or infiltrated; and whether there may be intracardiac, extracardiac, or intracranial neuropathological conditions that could destabilize cardiac electrical activity. It is now known that apoptosis plays a major role in myocardial infarction or ischemia, but it also occurs within the heart completely independently of infarction. There is also the vexing dilemma that an effective coronary collateral circulation, which is determined primarily by transanastomotic pressure gradient, is made less effective by exactly those treatments that reestablish flow in an occluded coronary artery. Since thrombolysis and angioplasty are automatically considered urgent treatment for an occluded coronary artery, it is prudent to remember the complex causes that determine whether the patient lives or dies.

Fibromuscular dysplasia of small coronary arteries and fibrosis in the basilar ventricular septum in mitral valve prolapse

The mechanism of sudden cardiac death in patients with mitral valve prolapse is poorly understood. Twenty-four hearts from patients with mitral valve prolapse who suddenly died (mean age 34 +/- 8 years) and 16 trauma control hearts (mean age 30 +/- 7 years) were histologically studied. Dysplasia of the atrioventricular nodal artery was present in 18 of 24 hearts with mitral valve prolapse and four of 16 controls hearts (p = 0.003). The degree of luminal narrowing, as morphometrically measured, was significantly greater in hearts with mitral valve prolapse (p = 0.003). The degree of fibrosis in the base of the ventricular septum, as calculated by computerized morphometry, was greater in hearts with mitral valve prolapse (p = 0.0002) and independent of age, sex, and heart weight (p = 0.005). We conclude that arterial dysplasia in mitral valve prolapse may contribute to sudden cardiac death mediated by ventricular fibrosis.

Local delivery of antithrombotic drug prevents restenosis after balloon angioplasty in atherosclerotic rabbit artery

We investigated the ability of various antithrombotic drugs, delivered locally, to prevent restenosis after angioplasty in hypercholesterolemic rabbits. After dilating atherosclerotic iliac stenoses by balloon angioplasty, a low dose of heparin or a new antithrombotic drug, such as low molecular weight heparin (fragmin), argatroban, or batroxobin, was delivered locally using the balloon double-occlusion technique. In 1 group, high-dose heparin was administered intravenously. Animals that received no drugs served as a control group. After angioplasty, the stenotic segment was dilated and the mean percentage luminal stenosis fell from 89% to 9% in the group that received locally delivered heparin, from 88% to 7% in the group that received locally delivered argatroban, from 87% to 11% in the group that received locally delivered fragmin, from 88% to 15% in the group that received locally delivered batroxobin, from 82% to 18% in the group that received i.v. heparin (p < 0.0001 compared with before angioplasty in each case), and from 84% to 17% in the control group (p < 0.005 compared with before angioplasty). Twenty-eight days after angioplasty, the percentage luminal stenosis remained at 14% in the group that received locally delivered argatroban, 15% in the group that received locally delivered fragmin, and 28% in the group that received locally delivered batroxobin, whereas it increased to 45% in the group that received i.v. heparin, 30% in the group that received locally delivered heparin and 72% in the control group (p < 0.05 compared with after angioplasty in each case). Thus, local delivery low doses of new antithrombotic drugs prevents restenosis after angioplasty without affecting systemic coagulability; heparin, whether administered locally or intravenously, was less effective than the new drugs in preventing restenosis.

Sudden unexpected nontraumatic death in 54 young adults: a 30-year population-based study

The objective of this study was to evaluate the incidence and correlates of sudden unexpected nontraumatic death among young adults in a well-surveyed population. The incidence and pathogenesis of sudden unexpected nontraumatic death in a young adult population (aged 20 to 40 years old) have not been well defined. All residents 20 to 40 years old from Olmsted County, Minnesota, who had nontraumatic sudden death between 1960 and 1989 were included. Histologic and gross cardiac specimens were examined. The incidence of sudden death was estimated based on the ratio of number of observed events to relative census data for the Olmsted County population from the last 3 decades. Statistical comparisons between age decades were obtained with the chi-square test. Incidence trends were tested using Poisson regression. Of the 54 subjects, 19 were women (4.1/10(5) population annually) and 35 were men (8.7/10(5) population annually). An increase in incidence of sudden death was evident in men. Causes of death included coronary artery disease, noncardiovascular disease, suspected primary arrhythmia, vascular disease, myocarditis, hypertrophic cardiomyopathy, and unknown causes. Gross and histologic features suggestive of right ventricular dysplasia were found in 9 subjects (17%), but 6 of these 9 had other established causes of death. Of the 27 sudden deaths between 1980 and 1989, 9 (33%) had a history of cocaine abuse. A trend in increasing incidence of sudden death in young men is noted. A high prevalence of cocaine abuse was observed in young adults who died suddenly. Histologic features of right ventricular dysplasia were prevalent but were not necessarily the primary cause of death.