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Biomedical subjects

Jonathan Timperley

Publications and source records attributed to Jonathan Timperley.

16 recordsLinked to original sources

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↗

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↗

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↗

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↗

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↗

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↗

Can contrast dobutamine stress echocardiography be performed with standardized imaging settings for everybody?

OBJECTIVE: The objective was to assess a standardized imaging and contrast injection protocol for contrast-enhanced dobutamine stress echocardiography (DSE). METHODS: A total of 102 patients underwent DSE with tissue harmonic imaging and a standardized protocol with contrast power modulation. Contrast intensities in the left ventricular cavity and the myocardium were evaluated by a visual score and quantitative analysis. RESULTS: Of the contrast studies, 98% were diagnostic without modification of the settings. Excellent endocardial border definition was found in 93% of the segments with contrast versus 53% with tissue harmonic imaging (P < .05). The interobserver agreement in assessing segmental wall motion improved from 71.5% to 85.9%. There were no differences between the myocardial segments' video intensity in the four- and three-chamber views. In the two-chamber view video intensity was lower in the basal segments compared with the other segments. CONCLUSION: Power modulation contrast imaging can be applied with a completely standardized protocol for DSE in the majority of patients with excellent endocardial border definition.

Albumins↗

Quantitative analysis of myocardial perfusion in rats by contrast echocardiography.

BACKGROUND: The ability to assess myocardial perfusion in small animals is important, especially to investigate models of myocardial ischemia. Myocardial perfusion is usually assessed by postmortem techniques, eliminating the possibility of follow-up. We sought to evaluate whether contrast echocardiography was able to quantify myocardial perfusion in rats. METHODS: Twenty-four rats divided in 3 groups (sham-operated, and 8 and 21 days after left anterior descending coronary artery stenosis) underwent myocardial contrast echocardiography using intermittent triggered imaging. Peak plateau intensity and slope of refilling were compared with myocardial blood flow achieved with fluorescent microspheres. RESULTS: High-quality images were easily obtained for each experiment. Close correlation was found between myocardial contrast echocardiography and myocardial blood flow, especially for measurements of peak plateau intensity x slope of refilling relative to the control area (y = 1.15 x -0.14, r = 0.86). CONCLUSION: Quantification of myocardial perfusion in rats is feasible by myocardial contrast echocardiography using intermittent triggered imaging.

Animals↗

Echocardiographic assessment and percutaneous closure of multiple atrial septal defects.

Atrial septal defect closure is now routinely performed using a percutaneous approach under echocardiographic guidance. Centrally located, secundum defects are ideal for device closure but there is considerable morphological variation in size and location of the defects. A small proportion of atrial septal defects may have multiple fenestrations and these are often considered unsuitable for device closure. We report three cases of multiple atrial septal defects successfully closed with two Amplatzer septal occluders.

Adult↗

Quadricuspid aortic valves.

Quadricuspid aortic valves (QAV) are a rare but well recognized cause of significant aortic regurgitation. The first case was found reported in 1862. Since then there have been 110 reported cases of QAV and we report 4 more. Previously, these were diagnosed at the time of surgery or postmortem examination. With advances in echocardiography, including harmonic imaging, and also the advent of transesophageal echocardiography, more cases are being diagnosed prior to surgery. We describe four more cases, three diagnosed preoperatively and one at the time of surgery, and then review the previously reported cases. Of the 114 cases reported, 46 had the aortic valve replaced, most commonly in the 5th and 6th decade of life. Hurwitz and Roberts classified quadricuspid valves according to the size of the leaflets. It has previously been believed that QAVs with four equal sized leaflets were less likely to develop significant aortic regurgitation; however, on review of the available cases, this would not appear to be the case. The preoperative diagnosis of QAVs is important as they can be associated with abnormally placed coronary ostium. Of the 114 cases reported, there are 10 reports of abnormally placed ostia. There has been at least one reported case of death occurring because of obstruction of an abnormally placed right coronary ostium by a prosthetic aortic valve.

Adult↗