Cardiac magnetic resonance, transthoracic and transoesophageal echocardiography: a comparison of in vivo assessment of ventricular function in rats.

In vivo assessment of ventricular function in rodents has largely been restricted to transthoracic echocardiography (TTE). However 1.5 T cardiac magnetic resonance (CMR) and transoesophageal echocardiography (TOE) have emerged as possible alternatives. Yet, to date, no study has systematically assessed these three imaging modalities in determining ejection fraction (EF) in rats. Twenty rats underwent imaging four weeks after surgically-induced myocardial infarction. CMR was performed on a 1.5 T scanner, TTE was conducted using a 9.2 MHz transducer and TOE was performed with a 10 MHz intracardiac echo catheter. Correlation between the three techniques for EF determination and analysis reproducibility was assessed. Moderate-strong correlation was observed between the three modalities; the greatest between CMR and TOE (intraclass correlation coefficient (ICC) = 0.89), followed by TOE and TTE (ICC = 0.70) and CMR and TTE (ICC = 0.63). Intra- and inter-observer variations were excellent with CMR (ICC = 0.99 and 0.98 respectively), very good with TTE (0.90 and 0.89) and TOE (0.87 and 0.84). Each modality is a viable option for evaluating ventricular function in rats, however the high image quality and excellent reproducibility of CMR offers distinct advantages even at 1.5 T with conventional coils and software.

Multivessel coronary artery spasm.

Coronary spasm is increasingly recognised as an important aetiological mechanism causing myocardial ischaemia. Occasionally cases present with evidence of ST segment elevation myocardial infarction, usually secondary to spasm confined to a solitary coronary artery. We present the rare and life-threatening case of severe coronary spasm afflicting all three major epicardial arteries simultaneously. It describes the difficult emergency scenario and ongoing management dilemmas encountered by physicians confronted with multivessel coronary spasm. Moreover we discuss the malignant prognosis associated with this ailment and describe the potential insights provided by cardiac magnetic resonance imaging that might identify those at greatest risk after the index event.

Gross echocardiographic underestimation of mitral valve calcification--a near fatal experience.

Acute severe mitral regurgitation is a feared complication following percutaneous balloon mitral valvuloplasty (PBMV) for the treatment of severe mitral stenosis, contributing to the 1% peri-procedural mortality rate of this procedure. Whilst there is an extensive experience with the use of the Wilkins echocardiographic score to assess patient suitability and predict long-term clinical outcomes following PBMV, catastrophic severe acute mitral regurgitation, such as that described in our patient, is a remarkably rare occurrence following PBMV in patients with favourable Wilkins echocardiographic criteria. We highlight a case of the gross underestimation of the degree of valvular calcification using trans-oesophageal echocardiography, when compared to the findings at surgery, which contributed to our patients' life-threatening mitral regurgitation following the first balloon inflation. We advocate further research into the utility of multi-detector computed tomography (MDCT) imaging for the adjunctive pre-procedural assessment of the degree mitral calcification in order to further minimise the risk of peri-procedural complications associated with PBMV. This would be particularly suitable in the elderly population who normally have greater degrees of valvular calcification that may be underestimated with echocardiography alone.

Giant saphenous vein graft pseudoaneurysm rupture presenting with cardiac tamponade.

Saphenous vein graft aneurysms are a rare but potentially fatal complication following coronary artery bypass graft (CABG) surgery, with a wide variation in clinical presentations ranging from recurrent atypical chest pain to sudden cardiac death. Although uncommon, the diagnosis should be considered in all patients presenting with a hilar or mediastinal mass following CABG, as timely treatment may avert potentially fatal aneurysm rupture and death. We report a rare case of a giant vein graft pseudoaneurysm rupture causing cardiac tamponade.

Hypereosinophilic syndrome associated with multiple coronary aneurysms.

Aneurysmal coronary artery disease occurring in the absence of stenotic atherosclerotic plaques is extremely rare and the pathophysiology of focal aneurysm formation is poorly understood. Whilst clinical-histological correlates exist linking spontaneous coronary artery dissection and perivascular eosinophilic infiltration in otherwise healthy individuals, the occurrence of aneurysms exclusively affecting the coronary tree in the setting of hypereosinophilic syndrome has not been previously reported. We describe the case of a 72-year-old woman presenting with cardiac chest pain in the context of recently diagnosed idiopathic hypereosinophilic syndrome with subsequent coronary angiography revealing multiple coronary aneurysms but only minor coronary atherosclerosis and no evidence of systemic arterial aneurysm formation. A brief review of the management strategies of patients with ectatic coronary artery disease is presented.

Takotsubo cardiomyopathy following lightning strike.

Lightning strike is the most common environmental cause of sudden cardiac death, but may also be associated with a myriad of injuries to various organ systems. Direct myocardial injury may be manifest as electrocardiographic alterations or elevation in cardiac-specific isoenzymes; however, significant electrical cardiac trauma appears uncommon. A case is presented of severe acute cardiomyopathy in a "Takotsubo" distribution causing cardiogenic shock following lightning strike in a previously healthy 37-year-old woman. Although rarely identified in this context, Takotsubo cardiomyopathy (also known as "transient left ventricular apical ballooning syndrome") is characterised by transient cardiac dysfunction, electrocardiographic changes that may mimic acute myocardial infarction and minimal release of cardiac-specific enzymes in the absence of obstructive coronary artery disease. The condition is associated with a substantial female bias (up to 90% of cases) in reported series, and despite occasionally dramatic presentations recovery of left ventricular function is almost universal over days to weeks. In rare instances, however, the syndrome has been associated with more catastrophic complications such as papillary muscle or cardiac free wall rupture, necessitating emergency surgical intervention to preserve life. In clinical practice, non-lethal lightning strike-induced cardiac injury is frequently associated with small elevations of cardiac isoenzymes without overt clinical sequelae; however, the incidence of silent myocardial mechanical dysfunction remains unknown. Cases such as the one presented highlight the potential for serious, albeit usually transient, cardiac sequelae from lightning strike injury and remind us that our mothers' advice to remain indoors during thunderstorms is probably worth heeding.

Serial magnetic resonance imaging correlates with neurological outcome in an experimental model of spinal cord ischemia.

BACKGROUND: Paraplegia complicating surgical thoracoabdominal aneurysm (TAA) repair remains an unpredictable and poorly understood phenomenon. The ability to identify patients at increased risk of delayed paraplegia before the process becomes irreversible could allow early interventions to attenuate this risk. METHODS: In a rabbit model of infra-renal spinal cord ischemia, serial T2 weighted (T2W) magnetic resonance (MR) imaging was performed 2- and 8 h after the ischemic insult with changes correlated with clinical outcome. Using the axial T2W images, signal intensity measurements of the lateral horns of the spinal cord were acquired, both above (that is, thoracolumbar cord) and below (that is, lumbar cord) the renal arteries. This ratio (lumbar/thoracolumbar cord signal intensity) was evaluated and compared between groups. RESULTS: No changes were seen in the signal intensity of rabbits that remained neurologically intact. Rabbits with delayed paralysis showed a significant (P<0.01) decrease in signal intensity ratio at 2 h (1.13+/-0.03), while a significant (P<0.01) increase was noted in those rabbits with immediate persistent paralysis (1.43+/-0.04). There was a significant (P<0.01) increase in the signal intensity ratios at 2 h in the delayed paralysis group (1.55+/-0.14), with a further significant (P<0.01) increase at 8 h in the immediate persistent paralysis group (1.76+/-0.07). CONCLUSIONS: Findings on MR imaging can differentiate clinical outcomes in this experimental model of spinal cord ischemia. While further studies are required, MR could be useful in predicting which patients are at risk for delayed paraplegia after TAA repair.

Coronary aneurysms and ankylosing spondylitis: what stenting option is truly optimal?

Vascular inflammation, particularly aortitis, is a known rare manifestation of ankylosing spondylitis. This condition has not been reported to date in the coronary circulation. We present the first documented case of a coronary aneurysm in a patient with ankylosing spondylitis. This association may limit treatment options in such patients, as newer drug-eluting stents may potentiate degeneration in established aneurysmal coronary arteries.