Life-Threatening Ventricular Arrhythmias: Current Role of Imaging in Diagnosis and Risk Assessment

Sudden cardiac arrest continues to be a major cause of death from cardiovascular disease but our ability to predict patients at the highest risk of developing lethal ventricular arrhythmias remains limited. Left ventricular ejection fraction is inversely related to the risk of sudden death but has a low sensitivity and specificity for the population at risk. Nevertheless, it continues to be the main variable considered in identifying patients most likely to benefit from implantable defibrillators to prevent sudden death. Imaging myocardial sympathetic innervation with PET and SPECT as well as imaging characteristics of myocardial infarcts using gadolinium-enhanced cardiac magnetic resonance are emerging as imaging modalities that may further refine patient selection beyond ejection fraction. This review will primarily focus on employing advanced imaging approaches to identify patients with left ventricular dysfunction that are most likely to develop lethal arrhythmias and benefit from inserting a primary prevention implantable cardiac defibrillator. While not yet tested in prospective studies, we will review risk prediction models incorporating quantitative imaging and biomarkers that have been developed that appear promising to identify those at highest risk of sudden death.     

Exercise-related sudden death due to an unusual coronary artery anomaly

Coronary artery anomalies are, after hypertrophic cardiomyopathy, the second most common cause of exercise-related sudden cardiac death in young American athletes. These anomalies have been associated with myocardial ischemia, arrhythmia, and sudden death during exercise. A 14-yr-old male with no previous abnormal medical history collapsed during soccer practice and was successfully resuscitated without defibrillation. An extensive cardiac workup did not reveal any abnormalities. Two weeks later, he experienced a cardiac arrest while running and could not be resuscitated. Autopsy demonstrated an acute angle take-off of the left main coronary artery and a transverse slit-like opening with a fibrous cushion, which created a kink near its origin. This case report illustrates the difficulty in diagnosing coronary artery anomalies in general, and acute angle take-off and ostial ridges in particular.     

Sudden cardiac arrest in children and young athletes: the importance of a detailed personal and family history in the pre-participation evaluation

Healthcare providers have become more aware of and concerned about paediatric sudden cardiac arrest. The diseases predisposing a patient to sudden cardiac arrest are all infrequently encountered. However, a detailed and comprehensive patient and family history may reveal warning signs and symptoms that identify a patient at higher risk for sudden cardiac arrest. Since many of these diseases are genetic, extensive family evaluation may uncover a previously undetected cardiac disease process and as well direct the development of a complete family evaluation and treatment plan. Published data document that in many cases preceding warning symptoms and signs are present, but may be misinterpreted or disregarded by medical staff. Attention to the details of patient history, family history and physical exam is critical to the success of any detection strategy, which can and should be widely applied.     

Criminal gunshot wound and iatrogenic tension pneumothorax detected by post-mortem computed tomography

Post-mortem imaging at autopsy is gradually increasing in popularity among forensic practitioners. The objective of the present paper was to demonstrate that it is essential to survey the cadaver using computed tomography (CT) before autopsy. This case report presents an iatrogenic tension pneumothorax caused by left subclavian vein puncture undertaken during treatment for a gunshot-related wound. The victim, a 64-year-old woman, was shot by her husband at home, and transferred to the hospital emergency unit. Before surgical procedures were carried out, left subclavian vein puncture was performed; however, during the operation, the victim experienced sudden cardiac arrest. Subsequent intensive resuscitation was unsuccessful. The clinical cause of death was recorded as traumatic shock caused by the gunshot injury. However, before the legal autopsy took place, CT clarified the existence of tension pneumothorax not on the same side as the gunshot wound, but on the side of the iatrogenic subclavian vein puncture. Because of this information gained prior to legal dissection, a typical dissection procedure for tension pneumothorax could be performed. Post-mortem imaging prior to regular dissection is essential as an adjunct diagnostic tool.     

Sudden death due to rupture of major aortopulmonary collateral arteries in a patient with tetralogy of Fallot and pulmonary atresia

We report a case of fatal mediastinal hemorrhage in a 20-year-old man caused by rupture of the major aortopulmonary collateral arteries (MAPCAs). The patient had an unoperated tetralogy of Fallot with pulmonary atresia. Plain chest radiograph and computed tomography showed a large hematoma in the upper mediastinum. Previous cardiac angiography, performed 6 years previously, demonstrated markedly tortuous vascular structures arising from the inferior aspect of the aortic arch. In this case, the mediastinal hemorrhage was thought to be due to rupture of the MAPCAs. If a patient presents with sudden cardiac arrest and mediastinal dilatation, and unoperated congenital heart disease is suggested by a plain chest film, the radiologist should consider the possibility, although rare, of mediastinal hemorrhage resulting from rupture of the MAPCAs.     

Direct puncture of the proximally occluded internal carotid artery for treatment of carotid cavernous fistulas

Three patients with symptomatic carotid cavernous fistulas (CCFs) characterized by complete occlusion of the proximal internal carotid artery were treated by percutaneous puncture and embolization. Two patients had CCFs associated with traumatic dissections of the internal carotid artery and were treated initially with trapping procedures. Both patients had persistent symptoms related to the CCF and underwent additional surgical procedures (ophthalmic artery ligation and intraoperative embolization) without improvement. The third patient had traumatic occlusion of the internal carotid artery. After direct percutaneous puncture of the carotid artery above the occlusion, a catheter was advanced into the petrous internal carotid artery. Balloons (one case) or coil emboli (two cases) were placed into the cavernous sinus to produce CCF closure. There were no complications from this procedure. Direct puncture of the carotid artery is an alternative treatment for patients lacking safe access for CCF embolization.     

Unexpected sudden death resulting from anomalous origin of the right coronary artery from the left sinus of Valsalva: a case report involving identical twins

An anomalous origin of the coronary arteries had been implicated as a cause of sudden cardiac death in a case involving a 16-year-old student who suddenly collapsed while running track at school. An autopsy revealed that the right coronary artery arose from the aorta in the left sinus of Valsalva. In order to determine whether the same anomaly was inherent in his brother--an identical twin--a complete cardiac medical examination was conducted. Multi-detector-row computed tomography (MDCT) coronary angiography showed no anomaly at the sinus of Valsalva, which indicates that the anomaly, in this case, was not hereditary. This case exemplifies instances where forensic medicine may intervene to prevent sudden deaths in surviving family members.     

An unusual complication of carotid stenting: spontaneous rectus sheath hematoma and its endovascular management

Carotid stenting has recently emerged as a potential alternative to surgical treatment. We report a case of a spontaneous rectus sheath hematoma in a patient who underwent anticoagulation therapy following carotid stenting. Computed tomography findings were consistent with active bleeding within the hematoma, and this was confirmed with selective angiography via right deep circumflex iliac artery injection. Transcatheter embolization of the right deep circumflex iliac artery with n-butyl 2-cyanoacrylate was successfully performed. To the best of our knowledge, spontaneous anterior abdominal wall hemorrhaging following carotid stenting has not been previously reported in the English language literature.     

Lethal myocardial infarction subsequent to compression of the left anterior descending coronary artery induced by traumatic hematoma

Summary Post-traumatic myocardial infarction is a well-known although rare complication of blunt chest traumas. In cases of proximally located damage to the coronary arteries, modern vascular surgery such as bypass operations may be lifesaving. In this paper we describe a case, where a healthy 35-year-old man developed a lethal myocardial infarction 8 days after a chest trauma caused by a moped. The ECG obtained 4 h after the accident showed extensive transmural ischemia of the anterior wall. At autopsy a hematoma originating from a side branch was found to compress the left anterior descending coronary artery immediately distal to its origin from the main stem. This finding suggests that bypass surgery could have saved the life of this young man. Patients with evidence of myocardial ischemia following chest traumas should be transferred to a cardiac center as early as possible.      

Sudden death due to rupture of the right internal carotid artery in neurofibromatosis type 1: A case report

Vascular involvement is a well-recognized manifestation of neurofibromatosis type 1 (NF1) which has the potential to be fatal when disrupted. We here present a case of sudden death due to the fatal arterial rupture resulted from infiltration of the neurofibromas. A 42-year-old man who suffered from NF1 presented a 1-h history of sudden onset of pain in his right cervical region. His condition worsened and became unconscious on his way to the emergency room. Despite resuscitation efforts, he died 30 min later without regaining consciousness. Autopsy examination showed that a neurofibroma located around the right internal carotid artery, confirmed immunohistochemically with S-100, vimentin and CD34. Furthermore, proliferation of spindle cells positive for S-100 was seen in the wall of right internal carotid artery, which was disrupted and resulted in a hemorrhage. These findings suggest that the artery was disrupted by neurofibromas in the vascular wall, which led to fragility of the vessel. On the basis of these findings, we concluded that the cause of death was asphyxia resulting from airway obstruction compressed by the hematoma due to the arterial rupture. As the locality of the neurofibroma and hemorrhage were closed to the carotid baroreflex, we considered another possible mechanism of his sudden death, which could be cardiac inhibition induced by vagal stimulation. We hope this case will increase recognition of NF-1 vasculopathy when encountering any sudden death in NF1 patients.     

Subdural hematoma in the setting of internal carotid artery occlusion: CT studies

A 72-year-old woman with previously symptomatic internal carotid artery occlusion subsequently presented with an acute hemispheric deficit. The patient was initially diagnosed as having an ischemic infarction but eventually was shown to have a subacute subdural hematoma with delay in surgical evacuation and a major permanent deficit. We speculate that internal carotid artery occlusion may predispose the patient to greater morbidity from subdural hematoma. Patchy hemispheric infarction may reflect greater vulnerability to extrinsic hemispheric compression in the setting of carotid occlusion. This case illustrates the necessity for vigorous pursuit of the diagnosis of subdural hematoma in patients presumed to have transient ischemic attacks or acute cerebral infarction.     

Major cerebral hypoperfusion on an internal carotid loop during an otologic surgery: A case report

An aberrant course of the internal carotid artery, such as a carotid loop or kinking, is a rare type of malformation. These malformations are typically asymptomatic, their occurrence is unpredictable, and they can exacerbate clinical disorders such as heart failure. We report the case of a seven-year-old child who died consecutively to cardiac arrest during otologic surgery for a cholesteatoma. After rapid and effective cardiorespiratory resuscitation, the child was transferred to a paediatric intensive care unit. In the following days, pronounced cerebral hypoperfusion led to the death of the child. The autopsy revealed a right carotid loop and a left carotid kink that presumably led to the cerebral hypoperfusion.     

Internal mammary artery injury following subclavian vein catheterization

Inappropriate puncture of the internal mammary artery caused by subclavian vein puncture is a rare but potentially lethal complication. We report a case of 45-year-old woman with internal mammary artery injury following subclavian vein catheterization successfully treated by transcatheter arterial embolization using coils.     

Occlusion of arteriovenous malformations of the cavernous sinus via the superior ophthalmic vein

The treatment of five patients with dural arteriovenous malformations (AVMs) of the cavernous sinus via the superior ophthalmic vein (SOV) is reported. The procedure was performed by transcutaneous puncture of the SOV under the guidance of real-time digital subtraction angiography. Complete resolution of the ocular symptoms was achieved in all cases. Angiograms after embolization showed complete obliteration of the malformation in four cases and partial obliteration in one. This method can cure dural AVMs of the cavernous sinus, with preservation of blood flow in the internal carotid artery. It is particularly indicated when the SOV is enlarged and when (1) dural AVMs of the cavernous sinus are fed by small branches of the internal carotid artery or direct carotid cavernous fistulas with small tears; (2) dural AVMs of the cavernous sinus are fed by multiple branches from both the internal and external carotid arteries, one or both sides; or (3) dural AVMs of the cavernous sinus or direct carotid cavernous fistulas recur after trapping of the internal carotid artery. Transcutaneous puncture and catheterization of the SOV was performed safely with the aid of digital subtraction angiography. The SOV approach was able to treat the fistula with preservation of the internal carotid artery.     

Percutaneous transmyocardial intracardiac retroperfusion shunts: technical feasibility in a canine model

PURPOSE: To test the technical feasibility of creating a left ventricle to coronary sinus shunt using endovascular techniques. MATERIALS AND METHODS: By means of a right jugular vein approach, a needle puncture was made from the coronary sinus to the left ventricle in 10 dogs. The tracts were balloon dilated and lined with 6-mm Wallstents. Shunt patencies, immediate and 4-hours later, were fluoroscopically assessed by contrast material injection into the left ventricle. Blood pressure, pulse, oxygen saturation, and cardiac rhythm were monitored. The dogs were then euthanized. Thoracic cavities and hearts were dissected and inspected. RESULTS: Technical success and immediate shunt patency were 100%. No cardiac dysrhythmias, electrocardiographic changes, or reduction in voltage potential were seen. Eight (80%) of the shunts were patent at 4 hours, one (10%) had thrombosed, and one dog died. Nine (90%) dogs had no pericardial hematoma and one (10%) had minimal pericardial blood from needle passes into the pericardial sac. The coronary sinuses were intact and no injuries to the valve leaflets or chordae tendineae were seen. The puncture sites were from the coronary sinus, 1-2 mm (mean, 1.3) from its auricular orifice, into the left ventricle, just below the inferior margin of the posterior leaflet of the mitral valve. One dog died at 3 hours with no preceding electrocardiographic evidence of impending demise. Autopsy showed no pericardial hematoma and the heart findings were no different from the other nine dogs. CONCLUSIONS: Creation of a left ventricle to coronary sinus shunt with use of endovascular techniques is technically feasible. Study of a transmyocardial intracardiac coronary retroperfusion shunt to deliver oxygenated blood to the ischemic myocardium is warranted.     

Rupture of intracranial aneurysm during carotid angiography

Summary The reports of rupture of an aneurysm during carotid angiography are very few but the actual incidence is doubtless higher than recorded. The case presented is documented with the demonstration of a large middle cerebral artery aneurysm with an intratemporal hematoma, and, in sequence, the rupture of the aneurysm during the height of the injection and the subsequent extensive leakage of the contrast medium. The factors which which can lead to rupture of an aneurysm during the angiographic procedure are discussed.     

A forensic autopsy case: Sudden unexpected death due to cardiac inflammatory myofibroblastic tumor

We report an autopsy case of a 25-year-old man with no medical history who died suddenly in an Internet cafe. He was found in cardiorespiratory arrest and did not respond to cardiopulmonary resuscitation. Traumatic lesions were not observed on his body. An autopsy was performed to investigate the cause of death. Upon examination, we discovered a heart tumor that infiltrated from the outside wall to the outflow tract of the left ventricle. Left ventricular outflow tract obstruction due to a cardiac tumor was considered the mechanism of death. Histological examination identified an inflammatory myofibroblastic tumor (IMT). The final diagnosis was death secondary to circulatory failure due to a cardiac IMT. Additionally, a cardiac tumor was diagnosed using post-mortem computed tomography. Only few cases of sudden unexpected death due to cardiac IMT have been reported; we report this case along with a review of the literature.     

Direct percutaneous puncture of a cervical internal carotid artery aneurysm for coil placement after previous incomplete stent-assisted endovascular treatment

Direct percutaneous puncture for coil placement has been described for visceral aneurysms, but the procedure has not been previously reported for aneurysms of the head and neck. We report a case in which stent-assisted endovascular treatment was successfully combined with direct puncture for additional coil placement to treat a symptomatic giant aneurysm of the cervical internal carotid artery.     

Sudden cardiac arrest during computed tomography examination: clinical findings and "dense abdominal veins" on computed tomography

We report imaging findings in five patients who had sudden cardiac arrest during contrast-enhanced computed tomography (CT). We observed strikingly dense abdominal veins, variable degrees of arterial enhancement, and poor abdominal visceral enhancement. Comparison with a control group of 30 patients revealed a statistically significant increase in mean enhancement of the abdominal veins (including the inferior vena cava, bilateral renal veins, and major tributaries of the hepatic vein) (Kruskal-Wallis test, P< 0.05). These patients lacked any clear cause of cardiac arrest, and the arrest may have been related to an adverse reaction to contrast medium. Despite resuscitation, two patients died and three convalesced. In summary, sudden cardiac arrest is characterized by "dense abdominal veins" on CT in the absence of the cardiac pump function. This effect was presumably the result of forced reflux and stagnation of contrast medium in the abdominal veins without any dilution with the circulating blood, leading to a markedly dense appearance of these venous structures.     

Long QT syndrome KCNH2 mutation with sequential fetal and maternal sudden death

We report a case of a woman who experienced intrauterine fetal death at full term pregnancy, and then died suddenly soon after learning about the death of her fetus. At autopsy, previously undiagnosed neurofibromatosis and an adrenal gland pheochromocytoma were discovered in the mother. Genetic screening also revealed a novel KCNH2mutation in both fetus and mother indicating type 2 congenital long-QT syndrome (LQTS). A catecholamine surge was suspected as the precipitating event of fetal cardiac arrhythmia and sudden fetal death, while the addition of emotional stress provoked a lethal cardiac event in the mother. This case illustrates the potential for lethal interactions between two occult diseases (pheochromocytoma, LQTS).