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Biomedical subjects

M J Monaghan

Publications and source records attributed to M J Monaghan.

52 records · Page 3Linked to original sources
PubMed1988

Balloon dilatation of the aortic valve for inoperable aortic stenosis.

The place of balloon dilatation of the aortic valve in the treatment of calcific aortic stenosis is controversial. Thirty two patients (mean age 76) in whom valve replacement was contraindicated were followed up for three to 24 months (mean 8); 25 were in functional class III or IV according to the New York Heart Association's classification. Major complications of the procedure occurred in four patients. Echocardiography and Doppler studies were performed before operation and before discharge in 28 patients, and the area of the valve was measured again six to 50 (mean 23) weeks after operation in 11 patients. The peak to peak aortic pressure gradient fell from a mean of 65 (SD 24) to 46 (20) mm Hg, but the area of the aortic valve, measured by Doppler echocardiography, in 18 patients showed a modest but significant increase, from 0.61 (0.16) to 0.74 (0.23) cm2. One month after dilatation, 29 patients were alive, of whom 17 had improved symptoms. Only two had lasting clinical benefit. Sixteen patients died, 12 of a cardiac cause. The estimated one year survival rate was 49%. Six patients underwent or required valve replacement because of persisting symptoms. In view of its limited long term efficacy balloon dilatation of the aortic valve should be used only for patients with severe symptoms whose life expectancy is limited by other disease or who are considered to be unsuitable for valve replacement. It may have a role in improving the condition of patients who present with cardiogenic shock or pulmonary oedema before valve replacement is undertaken.

Aged↗
PubMed1988

Digital subtraction contrast echocardiography: a new method for the evaluation of regional myocardial perfusion.

The potential of contrast enhanced digital subtraction echocardiography to demonstrate and quantitate myocardial perfusion was evaluated in 36 patients undergoing routine coronary arteriography or angioplasty. In 24 technically successful studies, multiple cross sectional echocardiographic images, obtained before and after intracoronary (sonicated contrast) injection, were stored by high speed, real time data transfer to an on line minicomputer. Subsequent digital subtraction processing of the stored image data provided composite images in which the distribution of myocardial perfusion was easily seen. Quantitative analysis of peak enhanced myocardial grey level and washout half time successfully differentiated between myocardial segments in which angiography had suggested normal, reduced, and grossly impaired or absent perfusion. The results suggest that this new method of digital image capture and quantitative processing has substantial advantages over previous off line qualitative techniques. It is likely to be of considerable value for routine coronary arteriography, angioplasty, and coronary thrombolysis.

Adult↗
PubMed1987

Chronic cardiac toxicity after inhalation of 1,1,1-trichloroethane.

Two patients showed evidence of chronic cardiac toxicity after repeated exposure to 1,1,1-trichloroethane. In both cases there was circumstantial evidence of a deterioration after routine anaesthetic use of the related compound halothane. An adolescent boy who sniffed trichloroethane presented with multiple ventricular arrhythmias during tonsillectomy. Follow up showed mild chronic left ventricular impairment. A 54 year old man had repeated industrial exposure to trichloroethane and deteriorated from mild stable cardiac failure to end stage cardiac failure after halothane anaesthesia for herniorrhaphy. Chronic cardiac toxicity is a previously unreported feature of this type of solvent exposure. Related compounds such as halothane may have a toxic interaction after exposure to trichloroethane.

Adolescent↗
PubMed1987

Doppler echocardiographic appearance of cusp tears in tissue valve prosthesis.

Characteristic Doppler echocardiographic abnormalities were noted in five patients with a failing tissue prosthesis shown to have severe regurgitation and no evidence of obstruction. The audio signal was musical in quality and the regurgitant flow pattern was bidirectional and striated. There were 4 to 6 striations in the mitral and 18 in the aortic regurgitant jets per 100 cm/s length of signal. Pulsed Doppler ultrasound localized the jet to the valve in all cases although angiography failed to localize it in one of four cases. At surgery each valve had a tear in or partial disintegration of one cusp whereas the other two cusps were intact, mobile and of normal thickness. The Doppler appearance is thought to be caused by fluttering of the disrupted cusp leading to the shedding of families of vortices in both a retrograde and an orthograde direction. It is suggested that this is likely to be a useful sign for the diagnosis of cusp tears.

Adult↗
PubMed1984

Potential value of oral beta 2-adrenoceptor agonists in congestive heart failure: a haemodynamic and metabolic study.

This study was designed to investigate and compare the haemodynamic and metabolic responses to pirbuterol and salbutamol in patients with congestive heart failure and coronary artery disease. Attention was directed towards the effects these beta 2-adrenoceptor agonists have on left ventricular systolic function, systemic and coronary haemodynamics and myocardial substrate metabolism. Sixteen patients were randomly allocated to treatment with either pirbuterol 20 mg or salbutamol 6 mg. Since no statistically significant differences between the responses to these drugs were observed, combined data for both agents are presented. Ninety minutes after the drug intervention cardiac index increased from 2.2 +/- 0.1 to 2.9 +/- 0.2 1/min per m2 (P less than 0.001) in association with marked reductions in systemic vascular resistance (from 22 +/- 1 to 15 +/- 1 units, P less than 0.001) and increments in left ventricular dp/dtmax (from 1074 +/- 85 to 1422 +/- 133 mm Hg/sec, P less than 0.05). Modest reductions in left ventricular end-diastolic pressure (from 21 +/- 1 to 15 +/- 1 mm Hg, P less than 0.01) were observed. Heart rate increased from 82 +/- 5 to 91 +/- 4 beats/min (P less than 0.01) but the small fall in mean arterial pressure (from 86 +/- 3 to 78 +/- 3 mm Hg) was not significant. Drug-induced coronary vasodilatation reduced coronary coronary vascular resistance from 0.65 +/- 0.06 to 0.47 +/- 0.04 units (P less than 0.01) and led to a marked increase in coronary sinus blood flow (from 124 +/- 9 to 155 +/- 9 ml/min, P less than 0.05). Arterial levels of free fatty acids increased from 0.78 +/- 0.13 to 1.05 +/- 0.18 mmol/l (P less than 0.05) resulting in the preferential utilization of this substrate as a myocardial energy source. Despite the substantial haemodynamic improvement, however, no significant increase in myocardial oxygen uptake or lactate production was observed. Thus, in patients with coronary artery disease and congestive heart failure pirbuterol and salbutamol improve left ventricular function by a combination of afterload reduction and positive inotropism such that no appreciable deterioration in myocardial energetics occurs.

Adult↗
PubMed1984

Acute haemodynamic and metabolic effects of felodipine in congestive heart failure.

Felodipine is a new calcium antagonist with a high degree of vascular selectivity. To examine its potential value as an afterload reducing agent in congestive heart failure 11 patients were studied. Substantial increments in cardiac index were associated with a fall in systemic vascular resistance. Left ventricular end diastolic pressure was also significantly reduced. Although left ventricular maximum dP/dt remained unchanged, maximum dP/dt/P increased. Left ventricular unloading was reflected by a reduction in cavity dimensions and a shift in the relation between end systolic pressure and dimension downwards and to the left. The myocardial oxygen supply to demand ratio was also improved: coronary sinus flow increased significantly despite a decline in myocardial oxygen consumption. These beneficial haemodynamic and metabolic effects suggest that felodipine may extend the clinical application of calcium antagonists to include the treatment of congestive heart failure.

Adult↗
PubMed1983

Diagnosis of acute aortic dissection by M-mode and cross-sectional echocardiography: a five-year experience.

During a five-year period, 26 cases of acute thoracic aortic dissection were studied by M-mode and cross-sectional echocardiography prior to cardiac catheterization and aortography. The diagnosis could be made non-invasively in 20 patients. Important information concerning the extent of the dissection, and the presence or absence of aortic regurgitation or a pericardial effusion could be obtained. Negative examinations were largely confined to cases where the distal thoracic aorta alone was involved. In a further 30 cases admitted to the coronary care unit during this period in which echocardiography was performed to rule out aortic dissection, two false-positive examinations led to aortography which demonstrated aortic dilatation and aortic regurgitation only. In the remaining 28 cases, echocardiographic examination was negative and none of these patients subsequently evidenced aortic dissection. Echocardiography using both M-mode and cross-sectional techniques is a rapid and highly effective method of making an early diagnosis of thoracic aortic dissection. Cross-sectional echocardiography is complementary to the M-mode technique, enhancing diagnostic accuracy by improving structural recognition in a condition where the normal anatomy is often severely distorted.

Acute Disease↗
PubMedDate not supplied

Sonovue improves endocardial border detection and variability in assessing wall motion score and ejection fraction during stress echocardiography.

BACKGROUND: Stress echocardiography is useful for assessing patients with coronary artery disease unable to undergo formal exercise testing. Considerable skill is required to avoid large intra- and inter-observer variability due to poor endocardial definition. Intravenous ultrasound contrast agents are now available which may improve this variability. AIM: To study intravenous Sonovue in assessing wall motion score and ejection fraction (EF) during stress echocardiography. METHODS: Thirty-eight patients undergoing arbutamine stress echocardiography for known or suspected coronary artery disease were studied. Echocardiographic analysis of wall motion score index, endocardial border detection (EBD) and EF was performed at rest and at peak stress before and after intravenous injection of Sonovue, by experienced and inexperienced observers. RESULTS: All three observers noted an improvement in endocardial border definition following Sonovue (p=<0.001). At baseline, there was a significant difference in wall motion score index between experienced and inexperienced observers at rest (p=0.01) and at peak stress (p=0.001). Following Sonovue administration this was no longer significant (p=0.07, p=0.114). Intra-observer variability of end diastolic, end systolic volumes (ESV) and EF improved following contrast (p<0.05) at rest and during stress. CONCLUSION: Sonovue significantly improved EBD and reduced intra-observer variability of EF at rest and during peak arbutamine infusion.

Echocardiography, Stress↗
PubMedDate not supplied

The value of transthoracic echocardiography during percutaneous balloon mitral valvuloplasty.

Percutaneous balloon mitral valvuloplasty is a standard alternative to surgery in a selected group of patients with symptomatic dominant rheumatic mitral stenosis. With careful transthoracic and transesophageal echocardiographic selection of patients, there is a low complication and high success rate. Echocardiography has also been established as extremely useful in the long-term follow-up of patients. We present four cases that highlight our view that transthoracic echocardiography should be performed during the procedure, after each balloon inflation, and before and after the intervention. In our experience transthoracic echocardiography during balloon mitral valvuloplasty is invaluable in assessing commissural separation, increasing mitral valve area, new mitral regurgitation, and occasional unexpected anatomic sequelae of balloon inflation.

Adult↗
PubMedDate not supplied

Left atrial spontaneous echo contrast assessed by TEE in patients with either native mitral valve disease or mitral valve replacement.

The incidence of spontaneous echo contrast in the left atrium, the factors with which it is associated, and its clinical significance were studied in 128 patients with native mitral valve disease or mitral valve replacement. All patients underwent both transesophageal and transthoracic echocardiography. Spontaneous echo contrast was visualized in 42 patients (33%) during transesophageal and in none during transthoracic echocardiography. Patients with spontaneous echo contrast had a significantly larger left atrial diameter (6.1 [1.1] cm vs 4.9 [0.9] cm, p < 0.001) and a greater incidence of both atrial fibrillation (54% vs 4%, p < 0.001) and left atrial thrombi (60% vs 28%, p < 0.01) compared with patients without spontaneous echo contrast. Multivariant analysis confirmed that these factors were independently associated with spontaneous echo contrast (left atrial size, p < 0.001; atrial fibrillation, p < 0.001; left atrial thrombus, p < 0.01). Patients with pure mitral regurgitation did not have any spontaneous echo contrast and anticoagulation did not influence its incidence. Spontaneous echo contrast was the only factor that was associated with a previous history of systemic embolization (history of systemic emboli in 28.6% of patients with spontaneous echo contrast vs 13.9% without spontaneous echo contrast, p < 0.05). In conclusion, spontaneous echo contrast is a common finding in the left atrium of patients with mitral valve disease or mitral valve replacement and represents a marker of increased thromboembolic risk in these patients.

Adult↗
PubMedDate not supplied

Aortoatrial fistulae diagnosed by transthoracic and transesophageal echocardiography: advantages of the transesophageal approach.

Aortoatrial fistulae are uncommon, providing a difficult diagnostic challenge both in the clinical diagnosis and in the choice of an imaging modality that fully delineates the abnormal anatomy and flow patterns. This report describes four cases of aortoatrial fistula resulting from three different underlying causes. The fistula communicated with the right atrium in three cases and the left atrium in one. We also describe the diagnostic information obtained during both transthoracic and transesophageal echocardiography and stress that full detail of the abnormal anatomy and shunting could be obtained only with the transesophageal approach, with its improved image quality of the aortic root. No extra information, other than the coronary anatomy, was obtained during aortography in the two patients who underwent cardiac catheterization. Transesophageal echocardiography should, therefore, be the investigation of choice in patients in whom there is a suspicion of aortoatrial shunting after clinical examination and routine transthoracic studies, and it may avoid the need for invasive investigation in these potentially hemodynamically unstable patients.

Adult↗
PubMedDate not supplied

Transesophageal echocardiography in the detection and surgical management of a papillary fibroelastoma of the mitral valve causing partial mitral valve obstruction.

Primary mitral valve tumors are rare. We describe the transesophageal appearances of a papillary fibroelastoma (Lambl's giant excrescence) of the anterior mitral valve leaflet causing partial mitral valve obstruction. Transesophageal echocardiography proved particularly useful in identifying the limited attachment of the tumor to the anterior mitral valve leaflet and excluding its attachment to the interatrial septum. These features helped to exclude the possibility of the tumor being a left atrial myxoma, the primary differential diagnosis of the lesion. Transesophageal echocardiography enabled the planned surgical option to be mitral valve repair and also allowed intraoperative monitoring to assess the results of the surgical repair.

Aged↗