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Biomedical subjects

N Conway

Publications and source records attributed to N Conway.

At least 19 recordsLinked to original sources
PubMed1993

Emergency percutaneous transluminal coronary angioplasty for intractable ventricular arrhythmias associated with acute anterior myocardial infarction.

A previously fit marathon-running 54 year old man was admitted as an emergency having collapsed with chest pain caused by an acute transmural anterior myocardial infarction. He was initially resuscitated by his general practitioner then had recurrent episodes of ventricular flutter and fibrillation requiring continuing cardiopulmonary resuscitation and repeated defibrillation. During ambulance transfer and in the hospital emergency department he received appropriate intravenous antiarrhythmic drug treatment and a total of 63 transthoracic DC shocks, with good cardiac output between shocks. After his condition failed to stabilise in intensive care, an intra-aortic balloon pump was inserted and coronary angiography showed a proximal occlusion of the left anterior descending branch. Coronary angioplasty successfully re-opened the vessel with an excellent angiographic result. The intra-aortic balloon pump was withdrawn the following day and he was well enough to be discharged 7 days later. At 4 weeks he performed a satisfactory maximal exercise test and remains in New York Heart Association functional class I.

Angioplasty, Balloon, Coronary↗
PubMed1993

Late functional results after surgical closure of acquired ventricular septal defect.

To assess the longer term outlook for patients who have undergone surgery for acquired (postinfarction) ventricular septal defect, we interviewed and studied 60 survivors from a single regional cardiac center between 3 and 144 months after the operation. Including the patients who died within 1 month of the operation, the 5-, 10-, and 14-year survivals (with standard errors) were 69% (65% to 74%), 50% (44% to 57%), and 37% (27% to 46%). Eighty-two percent of patients were in New York Heart Association class I or II. Ten patients (17%) had a persisting but not hemodynamically significant ventricular septal defect. Mean left ventricular ejection fraction was reduced at 0.39 (standard deviation 0.15), but this did not correlate with either New York Heart Association class or exercise tolerance. Twenty-eight patients (47%) had asymptomatic arrhythmias (17 with ventricular premature beats). Angina and other medical problems were not prevalent.

Aged↗
PubMed1991

Postoperative myocardial damage in patients with coronary artery disease undergoing major non cardiac surgery.

A prospective study was carried out in a group of 50 patients with coronary artery disease, presenting for major non-cardiac surgery, to investigate the timing and incidence of further perioperative myocardial damage. A standardised anaesthetic was used. A standard 12-lead ECG was taken immediately before surgery and at 24, 48, and 72 hr after the start of anaesthesia. Blood samples were taken immediately preoperatively and at 6, 24, 48, and 72 hr after anaesthesia for total CK and CK-MB assay. Thirty-three patients (66%) showed ECG evidence suggestive of further infarction, and of these, two (4%) died in the immediate perioperative period. The first ECG change occurred in 27/31 (87%) by 24 hr, in 3/31 (10%) by 48 hr, and 1/31 (3%) by 72 hr. Twenty-nine patients (58%) including the two deaths showed CK-MB enzyme changes. The first elevation in CK-MB was nil at 6 hr and 72 hr, with 23/27 (85%) at 24 hr, and 4/27 (15%) at 48 hr. In 22/50 (44%) ECG and enzymes were correlative. Goldman and Cooperman risk indices were calculated for each patient. The Cooperman risk index was superior to the Goldman scale in the correlation of observed with predicted myocardial morbidity. Patients with ECG changes only before surgery were just as liable to further myocardial damage as those patients with ECG changes and a documented history of a previous infarct and/or symptoms. Myocardial damage is maximal in the first 24 hr after surgery, and may not be adequately predicted by current risk indices.

Adult↗
PubMed1991

Early postoperative myocardial morbidity in patients with coronary artery disease undergoing major non-cardiac surgery: correlation with perioperative ischaemia.

As a part of a study assessing early postoperative myocardial morbidity in 50 patients with active coronary artery disease undergoing major non-cardiac surgery, the ECG was monitored continuously for 24 hr after the onset of anaesthesia, using a frequency modulated (FM) Holter monitor. Concurrent automated blood pressure and pulse were measured non-invasively at three-minute intervals during anaesthesia and subsequently at five-minute intervals. Thirty patients were monitored with two-site ECG recordings, from modified V1 and V5 (Group A). Twenty patients had seventeen-site ECG monitoring, multiplexing a four by four array of precordial electrodes onto one channel of the frequency modulated recorder (Group B). Tapes were analyzed for noise, supraventricular and ventricular dysrythmias, runs of tachy- and bradycardia, and ST segment changes. These data were correlated with serial standard 12-lead ECGs and CK-MB assay in the 72 hr after surgery. Seven tapes from Group A could not be analyzed. Change (greater than 1 mm) on ST monitoring from both Groups A (14/23), B (14/20), correlated with serial 12-lead ECG and/or CK-MB changes. The majority of first ST change 19/28 (70%) occurred after anaesthesia. In 14/28 (50%) ST change occurred during episodes of tachycardia and elevated blood pressure (greater than 20% above baseline). Nine patients (9/23) in Group A had no ST change; however, six had serial 12-lead ECG and/or CK-MB changes. Six patients (6/20) in Group B had no ST changes, and none of these patients had any change of serial 12-lead ECGs or CK-MB assay. No patient complained of chest pain during the Holter monitoring period. Continual monitoring of heart rate and blood pressure and accurate ST monitoring are essential to detect and treat perioperative myocardial ischemia. A multiple-lead precordial system is substantially more sensitive than traditional two-lead ECG holter monitoring in detecting myocardial ischaemia.

Arrhythmias, Cardiac↗
PubMed1990

Doppler color flow mapping in the diagnosis of ventricular septal rupture and acute mitral regurgitation after myocardial infarction.

Fifty consecutive patients with a newly acquired systolic murmur and severe cardiac decompensation following a recent myocardial infarction (27 with an anterior and 23 with an inferior infarct) were studied by a combination of two-dimensional echocardiography, spectral Doppler and Doppler color flow mapping. The initial ultrasound study defined a ventricular septal rupture in 43 patients and severe isolated mitral regurgitation in 7 patients (5 with papillary muscle rupture and 2 with severe papillary muscle dysfunction). All 50 patients had subsequent confirmation of the diagnosis by either cardiac catheterization or surgical inspection, or both. Two-dimensional echocardiography alone directly visualized a septal defect in only 17 (40%) of the 43 patients with ventricular septal rupture. In all 43 patients the mitral valve appeared normal on imaging. In six of the seven patients with isolated mitral regurgitation, two-dimensional echocardiography correctly demonstrated the structural abnormality of the mitral valve (five with flail anterior leaflet and one with posterior leaflet prolapse). The addition of Doppler color flow mapping greatly improved the diagnostic information in both patient groups. In all 43 patients with ventricular septal rupture, Doppler color flow mapping demonstrated both an area of turbulent transseptal flow and a diagnostic systolic flow disturbance within the right ventricle. In the seven patients with isolated papillary muscle rupture or dysfunction, Doppler color flow mapping not only demonstrated the presence of mitral regurgitation in all cases, but also identified the specific mitral leaflet abnormality by defining the direction of the regurgitant jet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Surgical treatment for infarct-related ventricular septal defects. Improved early results combined with analysis of late functional status.

A total of 101 patients (mean age 64.9 years) underwent surgical correction of postinfarction ventricular septal defect at this institution over a 15-year period (1973 to 1988). The overall early mortality rate was 20.8%, although the most recent experience with 36 patients (January 1987 to October 1988) has seen this decline to 11.1%. Factors found to influence early death significantly, when analyzed univariately, were as follows: (1) site of infarction (anterior 12.1%, inferior 32.6%, p = 0.02); (2) time interval between infarction and operation (less than 1 week 34.1%, greater than 1 week 10.5%, p = 0.008); (3) cardiogenic shock (present 38.1%, absent 8.5%, p = 0.001). Nonsignificant variables included preoperative renal function, age, and concomitant coronary artery bypass, although older age (greater than 65 years) became significant when examined in a multivariate fashion. Of the 80 hospital survivors, eight were subsequently found to have a recurrent or residual defect necessitating reoperation, with survival in seven. Late follow-up is 99% complete and reveals an actuarial survival rate for 100 patients of 71.1% at 5 years (95% confidence interval 60.6 to 80.0), and 40.0% at 10 years (95% confidence interval 21.7 to 58.4). A significant recent change in policy of not using coronary angiography in patients with a ventricular septal defect caused by anterior wall infarction has not resulted in any increase in either the early mortality or in the late prevalence of angina. The functional status of 38 surviving patients has been analyzed by a graded treadmill exercise protocol, whereas left ventricular functional assessment was by nuclear scan with additional information on mitral valve function by echocardiogram. Color Doppler flow mapping has been used to determine the presence of a residual defect. Most late survivors have limited exercise tolerance related to both cardiac and noncardiac factors. Left ventricular function is moderately impaired (mean ejection fraction = 0.39). However, many patients are elderly and have adapted to their residual symptoms without significant changes in life-style.

Age Factors↗
PubMed1989

Diagnosis of ventricular septal rupture after myocardial infarction: value of colour flow mapping.

Twenty patients with ventricular septal rupture after myocardial infarction were investigated by cross sectional echocardiography with integrated pulsed and continuous wave Doppler and colour flow mapping. Confirmatory cardiac catheterisation was performed in 12 patients. Eighteen patients had surgical repair with inspection of the defect. Six patients in whom recurrent ventricular septal rupture developed were also investigated by Doppler echocardiography and colour flow mapping. Cross sectional echocardiography correctly predicted the infarct territory in all cases but visualised the septal rupture in only seven (35%). Pulsed and continuous wave Doppler detected a disturbance of right ventricular systolic flow that was diagnostic of a ventricular septal rupture in 19 (95%), but this only accurately predicted the site in 14 (70%). Colour flow mapping studies showed a mosaic jet traversing the interventricular septum in all 20 cases, and this accurately predicted the site of rupture. In addition colour flow mapping defined three sites of ventricular septal rupture: apical, posterior, and anterior trabecular. Five of the six patients with recurrent rupture were correctly diagnosed by pulsed and continuous wave Doppler and all six were diagnosed by colour flow mapping. Cross sectional echocardiography with colour flow mapping is a highly sensitive and rapid technique for the assessment of postinfarction ventricular septal rupture before and after operation. It was more informative about the site of the rupture than pulsed and continuous wave Doppler echocardiography.

Aged↗
PubMed1988

The surgical treatment of restrictive cardiomyopathy in pseudoxanthoma elasticum.

A patient with pseudoxanthoma elasticum presented in pulmonary oedema with restrictive left ventricular cardiomyopathy caused by calcified endocardial bands that were confirmed on echocardiography and at catheterisation. The bands were resected as far as possible and the involved mitral valve was replaced by a heterograft. A year later calcification of the heterograft forced its replacement by a St Jude prosthesis. Relief of symptoms has been good in the medium term.

Adult↗
PubMed1985

Left ventricular aneurysm. The Wessex experience.

One hundred patients with left ventricular aneurysms were operated on between February 1973 and January 1983. The principal indications for operation were left ventricular failure in 58, angina in 23, both in 17, with arrhythmia and systemic emboli accounting for one case each. Eighty five had had anterior infarction causing 82 anteroapical and three lateral aneurysms, while the remainder had had inferior infarcts resulting in 14 inferior aneurysms and one lateral aneurysm. Coronary angiography detected a single coronary lesion in 46%. Three patients had aneurysmal plication and the remainder had aneurysmectomy. Eleven mitral valve replacements were performed. Forty patients underwent coronary artery bypass grafting with a mean number of grafts per patients of 1.4. The early mortality was 7% with no early deaths since 1978. The actuarial five year survival was 68%, and 82% of survivors are in New York Heart Association class I or II (mean follow up three years). Left ventricular aneurysmectomy may be performed with a low operative mortality and good long term results.

Coronary Artery Bypass↗
PubMed1983

Cardiac surgery in Wessex.

The results of 3000 consecutive operations using cardio-pulmonary bypass show that the overall early mortality was 6.1%, dropping from 8.9% in the first 1000 to 4.4% in the third 1000. Operations for valve disease have been the most common, the early mortality for aortic valve replacement being 3.1% and for mitral valve replacement 2.9%. Combined aortic and mitral valve replacement had an early mortality of 4.4%. The number of patients undergoing isolated coronary artery bypass grafting has increased from 59 in the first 1000 to 292 in the third 1000 operations, with an overall early mortality of 1.3%. Six hundred and ninety seven patients underwent surgery for congenital heart disease with an overall early mortality of 10.9% (7.5% in the last 2000 cases). The patients have been followed up from one to 8.5 years. A high proportion have returned to work and enjoy a normal life. At the time of review, 87% of the 3000 patients were alive. Long waiting times for outpatient and inpatient care indicate underprovision of facilities relative to regional demand.

Adolescent↗
PubMed1983

Valve surgery in patients over the age of sixty-five.

Two hundred one patients over the age of 65 underwent valvular heart surgery with a hospital mortality of 5.5% and a late mortality of 18.4%. One hundred forty-one patients underwent isolated valve replacement (90 AVR, 51 MVR) with a hospital mortality of 1.5% (AVR 1%, MVR 2%). Multiple procedures carried a significantly higher hospital mortality (16%). Analysis of hospital and late deaths does not suggest that age alone should be accepted as a decisive factor in selection for surgery. There is a significantly higher late mortality in those who have had MVR (30%) compared with those having had AVR (14.6%). The importance of associated coronary artery disease as a risk factor has not been defined, but there is some evidence to suggest it is more important in this respect when found in association with mitral valve rather than aortic valve disease. An improved quality of life postoperatively was evident in the majority of survivors.

Age Factors↗
PubMed1983

Acquired ventricular septal defect.

The past 9 years' experience with ventricular septal rupture complicating myocardial infarction has been reviewed. Thirty-six patients were treated surgically, with 10 early deaths (28%) and one late death, for an 8 year actuarial survival rate of 63%. The mortality was highest for those defects which followed inferior infarction, 38% compared with 13% following anterior infarction. The infarction-operation interval also greatly influenced mortality; under 2 weeks, 43%; over 2 weeks, 18%. Concomitant coronary artery bypass grafts (13 patients) or left ventricular aneurysmectomy (14 patients) did not carry an increased mortality. Of 17 patients who presented with cardiogenic shock, eight died (47%). The intra-aortic balloon pump (IABP) was used in 16 patients (44%) and helped greatly in the management of the critically ill. With an estimated 17 acquired septal defects occurring each year in persons under 65 years of age in Wessex, awareness of this complication and of the favorable outcome of operation is essential among those who treat the aftereffects of myocardial infarction.

Aged↗
PubMed1982

Myocardial imaging with dipyridamole: comparison of the sensitivity and specificity of 201Tl versus MUGA.

Myocardial imaging was performed at rest and after dipyridamole infusion using 201Tl and 99Tcm - gated blood pool studies (MUGA). Of 38 patients studied, 21 had coronary artery disease (CAD) and 17 were normal. With 201Tl imaging, 19 of 21 patients with CAD (sensitivity 88%) showed perfusion defects during dipyridamole. Of 17 normals 6 (specificity 65%) showed clear perfusion defects during dipyridamole. With MUGA, 2 of 15 patients with CAD (sensitivity 13%) developed abnormal wall motion during dipyridamole; both patients developed ST depression greater than 1 mm. Of 10 normals none developed abnormal wall motion. Twenty six of 38 patients developed angina during dipyridamole, which was reversed by aminophylline in 24 of 26. We suggest that dipyridamole infusion is effective for 201Tl-perfusion imaging, and easily performed, but is not suitable for MUGA studies where ischaemia is the required endpoint.

Aminophylline↗
PubMed1981

Pulmonary perfusion imaging applied to prediction of pulmonary vascular pressures in mitral and aortic valve disease.

Radionuclide lung perfusion imaging was performed on 27 patients with valvular disease of the left heart. The ratio of upper to total counts for the lungs, determined by computer, was correlated against pulmonary vascular mean pressures. A close correlation (r = 0.91) was obtained against pulmonary wedge pressure. After corrective cardiac surgery upper/total ratios fell towards normal in four patients in whom pulmonary vascular pressures were measured and the correlation persisted. This simple non-invasive index can be used to follow changes in pulmonary venous hypertension.

Adult↗
PubMed1981

left ventricular segmental wall motion-a comparison between equilibrium radionuclide angiography and contrast angiography.

The qualitative assessement of left ventricular wall motion using a four-point scale has been compared between left ventricular contrast angiography and equilibrium radionuclide angiography in the 30 degrees right anterior oblique projection. Analysis was carried out for five segments of the left ventricle. Four modes of analysis of equilibrium radionuclide angiography were compared and the reproducibility assessed. Overall accuracy of equilibrium radionuclide angiography compared to contrast angiography was greater than 82% to within one degree of motion. One method using a cine display, averaged 97%. We suggest that equilibrium radionuclide angiography using the cine display is the non-invasive investigation of choice in the screening of patients with suspected regional wall motion abnormalities.

Adult↗