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Biomedical subjects

D Hackett

Publications and source records attributed to D Hackett.

At least 55 records · Page 3Linked to original sources
PubMed1988

Coronary constriction in acute myocardial infarction: role of nitrates.

We have investigated the coronary vasodilator responses to nitrates in the early stages of acute myocardial infarction before, during and after the administration of thrombolytic therapy. Before thrombolysis, intracoronary doses (2-4 mg) of isosorbide dinitrate failed to induce recanalisation of the totally occluded infarct related artery. Episodes of coronary reopening and reocclusion associated with ST-segment resolution and re-elevation were frequently observed both spontaneously before and during thrombolytic therapy. In 50-86% of patients, intracoronary isosorbide dinitrate promptly re-established full coronary patency immediately after acute reocclusion or whenever coronary occlusion was incomplete, both before and during thrombolysis. After thrombolysis further intracoronary isosorbide dinitrate dilated the infarct related stenoses but not uninvolved adjacent normal coronary branches. Coronary thrombosis and constriction frequently interact during the early phases of acute myocardial infarction. The combination of high local concentrations of nitrates with thrombolytic agents promotes stable coronary recanalization and may be beneficial in patients with acute myocardial infarction.

Coronary Vessels↗
PubMed1988

Pre-existing coronary stenoses in patients with first myocardial infarction are not necessarily severe.

The sudden, often unheralded, onset of symptoms in acute myocardial infarction suggests that pre-existing coronary stenoses susceptible to acute thrombosis in the infarct-related artery may not necessarily have been severe. We investigated the severity of residual coronary stenoses after successful thrombolytic recanalization and the relationship to previous symptoms, collateral vessels and the extent of coronary artery disease in 60 consecutive patients at the time of presentation of their first acute myocardial infarction by performing quantitative coronary arteriography before, during and after intracoronary thrombolytic therapy. Recanalization was achieved in 48 (80%) patients with a residual stenosis of 58.1 +/- 10.8% (mean +/- ISD; range 33-82%) obstruction diameter and a minimum lumen calibre of 1.10 +/- 0.3 mm (range 0.39-1.95 mm). A residual stenosis of less than 60% obstruction diameter was present in 28 (47%) patients. When residual stenoses were mild, no acute collateral filling of the occluded artery was observed. After thrombolysis, residual infarct-related coronary stenoses in patients with their first acute myocardial infarction are not necessarily severely obstructive. This raises the problem of identifying which non-obstructive coronary stenoses are likely to occlude suddenly and why they do so.

Adult↗
PubMed1987

Intermittent coronary occlusion in acute myocardial infarction. Value of combined thrombolytic and vasodilator therapy.

We performed continuous electrocardiographic ST-segment monitoring and serial coronary arteriography in 45 consecutive patients presenting in the early stages of acute myocardial infarction. During cardiac catheterization, 28 episodes of arteriographically confirmed coronary reopening and subsequent reocclusion were observed in 16 patients before (3 episodes) and during (25 episodes) continuous intracoronary infusion of streptokinase. In addition, ST-segment monitoring demonstrated 12 episodes of spontaneous transient return of the ST segment to the base line in eight patients between the time of admission and the performance of coronary arteriography. During arteriographically documented reocclusion, intracoronary isosorbide dinitrate (2 mg) reestablished the patency of the coronary artery within one to two minutes in 14 of 28 episodes that occurred in 11 of 16 patients. After streptokinase infusion, intracoronary administration of isosorbide dinitrate was followed by dilatation of the infarct-related stenosis from a mean value (+/- SD) of 1.12 +/- 0.3 mm (58.1 +/- 12.1 percent) to 1.33 +/- 0.4 mm (51.6 +/- 12.9 percent; P = 0.004). Spontaneous intermittent coronary recanalization and reocclusion resulting from a variable combination of thrombosis and vasoconstriction are frequent during the early phase of acute myocardial infarction. We propose that the combination of intracoronary streptokinase and isosorbide dinitrate may increase the rate of stable coronary recanalization.

Adult↗
PubMed1987

Usefulness of Holter monitoring to improve the sensitivity of exercise testing in determining the degree of myocardial revascularization after coronary artery bypass grafting for stable angina pectoris.

To assess whether Holter monitoring improves the sensitivity of exercise testing in identifying incomplete myocardial revascularization, both tests were performed in 45 patients from 3 to 5 months after elective coronary artery bypass grafting (CABG) for stable angina pectoris. Coronary angiography revealed incomplete revascularization in 26 patients. Six of these 26 had 52 episodes of ST-segment depression during Holter monitoring and myocardial ischemia during exercise testing. Their exercise capacity was significantly lower than that of 10 other patients in whom the results of exercise testing only were positive (heart rate at 0.1 mV ST-segment depression 112 +/- 9 vs 123 +/- 15 beats/min, p less than 0.001). In the other 10 patients with incomplete myocardial revascularization the results of both investigations were negative. The graft patency rate was lower in patients with a positive response to exercise testing than in those with a negative response (52% vs 71%, p less than 0.005). Myocardial revascularization was angiographically complete in 19 patients. In 18 of these 19 patients the findings of both investigations were negative; in 1 patient Holter monitoring revealed episodes of ST-segment elevation suggestive of variant angina. Thus, after CABG for stable angina pectoris the results of Holter monitoring do not improve the sensitivity of exercise testing in identifying patients with angiographically incomplete myocardial revascularization because findings are positive only in patients with low exercise capacity. Both tests fail to show evidence of myocardial ischemia in most patients with angiographically complete myocardial revascularization.

Aged↗
PubMed1987

Coronary artery infusion of neuropeptide Y in patients with angina pectoris.

Neuropeptide Y was infused into a coronary artery of 6 patients with typical angina but no significant coronary stenosis. 3 patients had transient myocardial ischaemia, shown by typical pain and electrocardiographic change, at doses of 0.2 pmol/kg per min in 2 patients and 1.0 pmol/kg per min in 1 patient. The arteriographic appearances suggested constriction of small vessels rather than constriction of epicardial coronary arteries. The ischaemia was completely reversed by intracoronary administration of isosorbide dinitrate with no adverse sequelae. This is the first demonstration of myocardial ischaemia in man induced by a peptide neurotransmitter.

Adult↗
PubMed1987

Ten-year clinical evaluation of isolated mitral valve and double-valve replacement with the Starr-Edwards prostheses.

From 1974 through 1983, 689 hospital survivors of Starr-Edwards (SE) valve replacement were identified; 279 (40.4%) patients with complete follow-up had an isolated mitral valve (SE model 6120 or 6400) replacement: 60.6% of these patients were women, 33.4% were in sinus rhythm, 32.3% had predominantly mitral stenosis, and 23.6% had predominantly regurgitation. Forty-six (6.7%) patients had mitral and aortic valve (SE model 1260 or 2400) replacement, 60.9% were women, and 13% were in sinus rhythm. To determine the long-term outcome of these SE valve prostheses, 325 (97.8%) patients were observed for up to 10 years. Total 10-year mortality was 40 patients (2.54% patients/yr) in the mitral group, of which 26 deaths (9.3%) were cardiac in origin; 8 deaths (2.8%) were directly valve related. Eight patients died (3.47% patients/yr) in the double-valve group, of which 5 deaths (10.8%) had a cardiac cause; 2 deaths (4.3%) were directly valve related. Primary valve failure was never proved. Actuarial estimates of survival at 10 years were 82 +/- 2.6% for the mitral valve group and 81 +/- 6% for the double-valve group. Actuarial estimates of freedom from valve-related morbidity were 87 +/- 2% for the mitral valve group and 59 +/- 7% for the double-valve group. Actuarial estimates of freedom from thromboembolism were 93 +/- 2% for the mitral valve group and 70 +/- 7% for the double-valve group. This prosthesis-based assessment has shown satisfactory long-term performance characteristics of the SE mitral models 6120 and 6400 without any recorded episodes of mechanical valve dysfunctions.

Actuarial Analysis↗
PubMed1987

Ten year clinical evaluation of Starr-Edwards 2400 and 1260 aortic valve prostheses.

The long term performance characteristics of the 2400 and 1260 series of Starr-Edwards aortic prostheses were investigated by a follow up study of clinical outcome of 327 patients discharged from hospital with isolated aortic valve replacement. Follow up lasted for up to 10 years and was based on 1616 patient-years. The 2400 series cloth covered tracked valve was implanted in 182 patients from 1974 to 1980 and the 1260 series bare strut silastic ball valve was inserted in 145 patients from 1979 to 1983. Total 10 year mortality and valve related morbidity were low and no cases of mechanical valve failure were recorded. There were no significant actuarial differences in mortality or valve related morbidity between the 2400 and 1260 valves. Starr-Edwards models 2400 and 1260 aortic valve prostheses showed excellent durability without any mechanical failures over a 10 year period. The long term outcome of isolated aortic valve replacement with these models is associated with a low frequency of valve related complications.

Adolescent↗
PubMed1987

Induction of coronary artery spasm by a direct local action of ergonovine.

To investigate whether ergonovine acts directly on coronary arteries or via remote neurohumoral reflexes, we administered small titrated increments of intracoronary ergonovine up to a maximum cumulative dose of 50 micrograms to 15 patients. In six patients with variant angina (group 1), ischemic electrocardiographic ST changes, angina, and localized coronary spasm (local coronary diameter reduction of 87.8 +/- 18.9% [mean +/- SD]) followed after 6 to 50 micrograms (mean 20.7) cumulative intracoronary ergonovine. In nine patients with atypical chest pain, normal baseline coronary arteriograms, and no evidence of variant angina (group 2), there was no ischemic ST segment change or localized coronary spasm after 6 to 50 micrograms (mean 31.6) intracoronary ergonovine. Coronary diameter of proximal vessels of patients in group 2 was reduced by 16.2 +/- 6.5% and did not differ from the response of nonspastic vessels of comparable size of group 1 (20.5 +/- 13.8%; p = .7). There was no significant difference in the median effective dose values in the dose-response curves of the spastic and nonspastic segments between groups 1 and 2. Ergonovine causes coronary spasm by a direct local effect, which seems to be caused by localized arterial hyperreactivity rather than supersensitivity. Intracoronary delivery may be safer than intravenous administration because negligible drug recirculation may prevent perpetuation of spasm and selective coronary administration can avoid branches with critical stenoses.

Coronary Vasospasm↗
PubMed1986

Transient myocardial ischemia during daily life in patients with syndrome X.

Nineteen patients with syndrome X (typical exertional angina, positive exercise test response [at least 0.1 mV of ST-segment depression], no evidence of coronary spasm and angiographically normal coronary arteries) underwent continuous 48-hour electrocardiographic (ECG) monitoring during unrestricted daily life. Fifty-eight ischemic episodes of at least 0.1 mV of ST-segment depression were observed in the same ECG leads that showed ST depression during stress testing: 28 (48%) were accompanied by anginal pain and 30 (52%) were asymptomatic. No significant differences were found between painful and silent ST-segment depression with regard to the number of episodes, their temporal distribution, magnitude, duration or heart rate (HR) at onset of ST-segment depression. In the minute preceding ischemic ST shifts, HR did not change in 33% of episodes or increased by less than 10 beats/min in 28%. HR at onset of ST depression was significantly lower during ambulatory ECG monitoring than during exercise testing (98 +/- 18 vs 117 +/- 18 beats/min, p less than 0.01). During ambulatory monitoring, 85 episodes of sinus tachycardia (exceeding by 10 to 80 beats/min the HR that triggered ischemia during exercise testing) occurred in the absence of angina or ST-segment shifts. The results of this study suggest that in patients with syndrome X, myocardial ischemia frequently develops during daily life; silent ischemia is an important component of this syndrome; and increased oxygen demand in the presence of impaired coronary vasodilatory capacity is not the only cause of myocardial ischemia. Active mechanisms that transiently reduce coronary flow may act and explain occurrence of angina at rest and with minimal exertion.

Adult↗
PubMed1986

Left atrial myxoma: new perspectives in the diagnosis of murmur free cases.

No cardiological signs or symptoms were seen in three patients with left atrial myxomas. The diagnosis was established by cross sectional echocardiography. In two patients this investigation was performed to exclude a cardiac source of systemic emboli. The third patient had constitutional signs only. All three had raised erythrocyte sedimentation rates and C reactive protein concentrations. In two patients the myxomas were successfully excised; the third patient who had presented with massive peripheral and central embolisation died during emergency operation. Cross sectional echocardiography is the technique of choice for detecting atrial myxomas and the absence of the cardiological signs should not preclude referral for diagnostic echocardiography.

Adult↗
PubMed1986

Pulmonary hypertension in systemic lupus erythematosus: a report of three cases.

Three women with systemic lupus erythematosus (SLE) who developed pulmonary hypertension as a terminal feature of their illness, are reported. One patient with quiescent SLE had marked sicca syndrome when pulmonary hypertension developed. Two of the 3 patients possessed the "lupus anticoagulant" and antibodies to cardiolipin. All 3 patients had positive rheumatoid factor in their sera.

Adult↗
PubMed1986

Acute myopericarditis in influenza A infection.

Heart disease is a recognised complication of influenza. We report a unique case in which myopericarditis and collapse due to acute influenza A infection was associated with pericardial effusion and tamponade. In addition, the patient had myositis and pleurisy. Emergency pericardiocentesis and inotropic drugs were needed but recovery was complete.

Female↗
PubMed1985

Rheumatoid arthritis and pulmonary hypertension. A report of three cases.

Three women with well established rheumatoid arthritis (RA) who developed pulmonary hypertension during the course of their disease are reported. In one patient there was mild pulmonary fibrosis but this appeared unrelated to the severity of the pulmonary hypertension. Another patient had increased platelet stickiness which may have contributed to this complication, whereas in the third patient, no contributing factors were apparent. The pulmonary complications of RA and their relationship to the development of pulmonary hypertension are discussed.

Adult↗
PubMed1985

Ten year follow up of models 1260 and 2400 Starr-Edwards isolated aortic valve replacement.

In our experience the structural durability of the S-E models 1260 and 2400 aortic prostheses is excellent, with no episodes of mechanical valve failure recorded over a 10 year period. Long term performance characteristics compare favourably with other published series and other prostheses, with a specifically low incidence of thromboembolism recorded. Such data will provide a useful comparison against newer prostheses in the search for the ideal cardiac valve substitute.

Adolescent↗
PubMed1985

Myocardial depression and nephrotic syndrome in Streptococcus sanguis endocarditis.

Nephrotic syndrome is a most unusual complication of infective endocarditis. We report a case of Streptococcus sanguis endocarditis of the tricuspid valve in a patient with a small congenital ventricular septal defect who developed this complication. Severe myocardial depression also occurred and the clinical behaviour and subsequent recovery of this closely paralleled that of the nephrotic syndrome. These unusual associations, their possible interactions and pathogeneses are discussed.

Adult↗