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Biomedical subjects

Andrew R J Mitchell

Publications and source records attributed to Andrew R J Mitchell.

At least 19 recordsLinked to original sources
PubMed2008

Ventricular septal rupture following abciximab infusion.

Ventricular septal rupture is a rare complication of myocardial infarction. Despite a significant reduction in its incidence with reperfusion therapy, thrombolysis has been implicated in the pathogenesis of septal rupture. There is little information regarding the impact of glycoprotein IIb-IIIa receptor blockers on ventricular septal rupture. We report a case of rupture of the ventricular septum occurring after treatment with the glycoprotein IIb-IIIa receptor blocker abciximab, in the absence of thrombolysis.

Abciximab↗
PubMed2008

Percutaneous closure of an iatrogenic atrial septal defect.

We report the successful percutaneous closure of an iatrogenic atrial septal defect in a 71-year-old woman. The patient had undergone mitral valve replacement and coronary artery bypass grafting, followed by redo surgery to repair a para-valvular mitral leak. Post-operatively she remained significantly limited by dyspnoea. Repeat transoesophageal echocardiography documented a large iatrogenic atrial septal defect. The patient underwent percutaneous, trans-femoral closure of the defect using the Helex septal occluder (W.L. Gore, Newark, Delaware, USA) with dramatic clinical improvement.

Aged↗
PubMed2006

Cardiac changes in systemic amyloidosis: visualisation by magnetic resonance imaging.

Cardiac involvement is a significant cause of morbidity and mortality in patients with amyloidosis. A 73-year old Caucasian woman was admitted to a hospital with increasing dyspnoea. Examination revealed a large left-sided pleural effusion, gross peripheral oedema and a pan-systolic murmur. The electrocardiogram showed low voltage QRS complexes with lateral T wave inversion. Recent angiography had demonstrated normal coronaries. Echocardiography revealed left ventricular hypertrophy and an ejection fraction of 43%. There was a restrictive filling pattern with elevated left-sided filling pressures, left atrial enlargement and mild mitral regurgitation. The right heart was normal with normal filling pressures. The patient was referred for cardiovascular magnetic resonance imaging for investigation of restrictive cardiomyopathy. This case provides a striking demonstration of the characteristic features of cardiac amyloidosis by cardiovascular magnetic resonance imaging - impaired biventricular systolic function, thickened atrioventricular valves, bi-atrial enlargement, increased atrial septal thickness and left ventricular mass, pleural and pericardial effusions, and the most impressive finding of widespread subendocardial hyperenhancement of both ventricles, as well as the inter-atrial and inter-ventricular septa, representing infiltration with amyloid protein. Cardiac involvement with systemic amyloidosis was suspected and confirmed on biopsy. Cardiovascular magnetic resonance imaging should be considered early in the diagnostic work-up of suspected cardiac amyloidosis.

Aged↗
PubMed2006

Intracardiac echocardiography to guide myocardial biopsy of a primary cardiac tumour.

A 61-year-old man presented with recurrent ventricular tachycardia (left bundle branch block morphology, superior axis). Magnetic resonance imaging (Fig. 1) and contrast-enhanced transthoracic echocardiography (Fig. 2) demonstrated an ill-defined mass in the right heart along the free wall of the right atrium, involving the tricuspid valve and extending into the right ventricle. Extensive investigation showed no evidence of extra-cardiac involvement and a tissue diagnosis was recommended. Accordingly, we elected to proceed to myocardial biopsy and, to facilitate accurate tissue localisation, we performed the procedure under guidance with intracardiac echocardiography.

Biopsy↗
PubMed2006

Percutaneous closure of an atrial septal defect in a patient with congenitally corrected transposition.

Congenitally corrected transposition of the great arteries can be associated with other congenital cardiac abnormalities. The development of percutaneous closure devices potentially offers the opportunity to close related cardiac defects without exposing patients to the increased risks of cardiac surgery. This case report describes the successful closure of an atrial septal defect in a patient with congenitally corrected transposition of the great arteries using an Amplatzer septal occluder.

Abnormalities, Multiple↗
PubMed2006

Pacemaker implantation in a patient with paroxysmal atrial fibrillation and left pneumonectomy.

Paroxysmal atrial fibrillation is a common occurrence in patients following thoracic surgery and in some patients remains refractory to medical therapy. New pacemaker devices are available with atrial preventative and termination pacing algorithms designed to reduce arrhythmia recurrences. This report describes the implantation of such a device in a patient following pneumonectomy and the subsequent effect on atrial arrhythmia burden.

Atrial Fibrillation↗
PubMed2006

DC cardioversion of persistent atrial fibrillation: a comparison of two protocols.

BACKGROUND: Current guidelines for transthoracic direct-current cardioversion (DCCV) of atrial fibrillation (AF) recommend a step-up energy protocol. The aim of this study was to compare such a protocol with a protocol involving a high initial energy shock, anteroposterior paddle position and reversal of shock polarity, on cardioversion efficacy, total energy delivery, use of sedation and patient tolerability. METHODS: 261 patients (mean age 71+/-10 years, 62% male) referred for elective DCCV of persistent AF were enrolled. Patients were randomised to either protocol A: (1) 200 J anteroapical, (2) 360 J anteroapical, (3) 360 J anteroposterior; or protocol B: (1) 360 J anteroapical, (2) 360 J anteroposterior, and (3) 360 J posteroanterior. All procedures were performed under sedation with intravenous diazepam. RESULTS: Protocol B improved shock success rates (protocol A first shock success rate=42%, protocol B=68%, p<0.001; protocol A second shock success rate=72%, protocol B 86%, p=0.006; protocol A third shock success rate=83%, protocol B=92%, p=0.03) and required fewer shocks to achieve sinus rhythm (1.3+/-0.6) compared with protocol A (1.6+/-0.7, p<0.001). There were no differences in cumulative energy used (protocol A 473+/-286 J, protocol B 436+/-273 J, p=0.24) or sedation requirements (protocol A diazepam 22.1+/-9.0 mg, protocol B 21.7+/-8.9 mg, p=0.75). Both protocols were equally well tolerated by patients. CONCLUSION: High initial energy increased success rates and decreased the number of shocks but resulted in similar cumulative energy delivery, sedation use and patient tolerability compared with a conventional step-up protocol.

Aged↗
PubMed2006

Pharmacological management of no reflow during percutaneous coronary intervention.

Angiographic no reflow is a recognized phenomenon during percutaneous coronary intervention (PCI). It usually follows successful lesion dilation and, by definition, it represents a reduction in epicardial coronary blood flow in the absence of identifiable dissection, obstruction or distal vessel cut off (indicative of distal embolisation). No reflow appears to be more commonly associated with PCI for acute myocardial infarction and PCI for saphenous vein graft occlusions. While the exact mechanism of no reflow is unknown, theoretical causes include local humoral and microembolic effects leading to microcirculatory dysfunction. As the process is multifactorial, various therapeutic strategies are required in different situations. The present day pharmacological management involves the use of vasodilators including nitrates, verapamil, papaverine, adenosine, nicardipine and sodium nitroprusside, but interestingly a vasoconstrictor like epinephrine may also have a role. Glycoprotein IIb/IIIa platelet receptors antagonist have shown a powerful de-thrombotic effect, and the intracoronary administration appears to be particularly promising. We review the pathogenesis of a reduced epicardial flow during PCI and focus on those drugs that have been studied for the treatment of no reflow. Although no double blind, randomized trial has been conducted to assess any of these agents, or to determine the appropriate dosage, we try to identify some useful conclusions from the published evidence.

Angioplasty, Balloon, Coronary↗
PubMed2005

Flecainide overdose--support using an intra-aortic balloon pump.

BACKGROUND: Flecainide is an antiarrhythmic agent which is being used increasingly for the management of super-ventricular arrhythmias. Overdose with flecainide is frequently fatal with mortality reported as high as 22% due to arrhythmias, myocardial depression and conduction defects leading to electro-mechanical dissociation and asytole. Supportive measures are often required during the case and previously have included inotropes, extracorporeal membrane oxygenation and cardiopulmonary bypass. CASE PRESENTATION: A 47 year old lady presented to the emergency department with a four hour history of severe central chest pain. Her ECG showed atrial fibrillation and broad QRS complexes with a sine wave appearance. She had a past history of paroxysmal atrial fibrillation and significant psychiatric history. Following thrombolysis for a presumed myocardial infarction she developed cardiogenic shock with severely impaired left ventricular function. An intra-aortic balloon pump was inserted and coronary angiography demonstrated normal coronary arteries. With inotropic support she improved over 48 hours, with both her QRS duration and left ventricular function returning to normal. Biochemical testing following her discharge demonstrated significantly elevated levels of flecainide. CONCLUSION: The use of an intra-aortic balloon pump is a useful supportive measure during the acute phase of flecainide overdose associated with severe myocardial depression.

Journal Article↗
PubMed2005

Safety of contrast dobutamine stress echocardiography: a single center experience.

BACKGROUND: Contrast is increasingly being used during dobutamine stress echocardiography. However, there are few data regarding the safety of this combination. METHODS: We retrospectively analyzed 751 consecutive stress echocardiograms, 332 without contrast and 419 with contrast (299 with Sonouve, 120 with Optison). Reported side effects and physiologic data were then compared. RESULTS: There were no fatalities. The incidence of side effects was similar in the 3 groups. The Optison group had a lower diastolic blood pressure compared with the noncontrast group ( P < .05) at rest, and the Sonovue group had a higher peak heart rate compared with the noncontrast group ( P < .001). Patients receiving Optison had more premature atrial contractions ( P < .05) but there was no difference in the incidence of ventricular tachycardia, supraventricular tachycardia, or vagally mediated episodes. CONCLUSION: The use of contrast during dobutamine stress echocardiography was not associated with an increased risk of side effects.

Aged↗
PubMed2005

Left ventricular pseudoaneurysm and rupture after limited myocardial infarction.

A 50-year-old man had a large lateral left ventricular wall pseudoaneurysm with rupture after a limited myocardial infarction. This was diagnosed by the combination of flow in and out of the aneurysm and pulsatile flow in the pericardial cavity using color flow and continuous wave Doppler ultrasound. This report describes the case management, the use of echocardiography in this setting, and the implications of pseudoaneurysm formation.

Aneurysm, False↗
PubMed2005

What is the role of balloon dilatation for severe aortic stenosis during pregnancy?

BACKGROUND AND AIM OF THE STUDY: Severe aortic stenosis in pregnancy creates several challenges for the physician. In recent years, balloon valvuloplasty has become more widely used, though the indications for its use in this setting are unclear. A review of the available evidence is presented, and a suggested management strategy illustrated. METHODS AND RESULTS: Available literature on the subject was reviewed via Medline search and reference lists from the identified articles. Particular attention was paid to prediction of risk, management options and outcome. The data suggest the importance of early symptoms in determining management, as there is a high risk of complications if left untreated. This group should be considered for valvuloplasty, whereas asymptomatic patients are at low risk, and can be managed expectantly. This is illustrated with two contrasting cases from the authors' practice: the symptomatic patient underwent aortic balloon valvuloplasty as a palliative procedure, using transesophageal and minimal fluoroscopic guidance, with good medium-term results. Both patients required aortic valve replacement in the medium to long-term. CONCLUSION: The use of aortic balloon valvuloplasty in pregnancy is useful as a palliative procedure, allowing deferral of valve replacement until after birth. Echocardiographic features alone are not enough to decide on management, and symptoms play a vital role in determining risk. The use of transesophageal echocardiography during the procedure significantly reduces fluoroscopy time.

Adult↗
PubMed2004

Intravascular ultrasound to guide the management of intracoronary thrombus: a case report.

Percutaneous coronary intervention can be associated with distal embolization of thrombotic material causing myocardial necrosis and infarction. We discuss the role of intravascular imaging to guide the use of a distal protection device by describing the outcome of a young woman presenting with non-ST elevation myocardial infarction. Coronary angiography demonstrated an isolated minor stenosis in the proximal left anterior descending coronary artery with slight haziness beyond the lesion. Intravascular ultrasound confirmed an extensive thrombus overlying a bulky atherosclerotic plaque. A distal filter wire was therefore successfully used to reduce the risk of distal embolization. The use of intravascular ultrasound in patients presenting with acute coronary syndrome may reveal large thrombi that are difficult to image using conventional angiographic techniques. Intravascular ultrasound can therefore be used as a tool to select lesions requiring distal protection.

Adult↗