Drug overdoses requiring temporary cardiac pacing; a study of six cases treated at Altnagelvin Hospital, Londonderry

Drug overdoses in general are increasing and overdoses of cardiac medications are also increasing; some are associated with a high mortality. Temporary cardiac pacing has a valuable role in cases of hypotension related to dysrhythmia, or when it is necessary to provide overdrive pacing. However, despite technically successful and uncomplicated pacemaker insertion and restoration of cardiac electrical activity, patients developing bradyarrhythmia and hypotension after an overdose are in a high risk group.

Abnormal left ventricular early diastolic filling during dobutamine stress Doppler echocardiography is a sensitive indicator of significant coronary artery disease

OBJECTIVES

This study was designed to assess changes in Doppler indexes of left ventricular ejection and filling in response to high dose (40 micrograms/kg body weight per min) dobutamine stress and their utility in detection of coronary artery disease compared with that of new wall motion abnormalities.

METHODS

Ten patients with a low likelihood of coronary artery disease served as a control group, and 23 patients with documented single-vessel coronary artery disease underwent baseline and peak dobutamine echocardiographic and Doppler studies.

RESULTS

In both groups dobutamine induced similar increases in heart rate and systolic blood pressure. During the test, 14 patients had new wall motion abnormalities, 13 had angina, and 7 had electrocardiographic ST segment changes. No markers of ischemia occurred in the control subjects. Dobutamine induced qualitatively similar changes from baseline to peak dobutamine stress in control subjects and patients in peak aortic velocity (46% vs. 42%, p = NS), average aortic acceleration (61% vs. 43%, p = 0.03) and systolic time-velocity integral (7% vs. 2%, p = NS). Dobutamine caused marked increases in control subjects and decreases in patients in peak early filling velocity (E) (33% vs. -22%, p < 0.0001) and average E acceleration (76% vs. -28%, p < 0.0001). The response of Doppler early filling indexes to dobutamine stress was abnormal in all patients. There was no overlap in the percent change from baseline to peak dobutamine stress between control subjects and patients for E and E acceleration.

CONCLUSIONS

During dobutamine stress testing, an abnormal response of Doppler indexes of left ventricular early filling is a more sensitive marker of significant single-vessel coronary disease than are new wall motion abnormalities, and it is far superior to the response of Doppler ejection variables as a predictor of coronary artery disease.

Prognostic value of dipyridamole sestamibi single-photon emission computed tomography and dipyridamole stress echocardiography for new cardiac events after an uncomplicated myocardial infarction

A high-dose dipyridamole stress test (0.84 mg/kg in 6 minutes) with simultaneous sestamibi single-photon emission computed tomographic (SPECT) and echocardiographic imaging was performed in 89 patients before hospital discharge after an uncomplicated myocardial infarction. The aim of this study was to determine the prognostic value of these tests for new cardiac events and to compare the relative values of SPECT and echocardiography in a postinfarction dipyridamole stress test. Two years after infarction, nine patients (10%) had died, five patients (6%) had suffered a nonfatal reinfarction, and 14 patients (16%) had been readmitted to the hospital for a revascularization procedure. Cardiac death had occurred in 5 (10%) of 48 patients with a positive SPECT versus 4 (10%) of 41 with a negative SPECT (difference not significant) and in 6 (19%) of 31 with a positive echocardiogram versus 3 (5%) of 56 with a negative echocardiogram (p = 0.05). Cardiac death or reinfarction had occurred in 8 (17%) of 48 patients with a positive SPECT versus 6 (15%) of 41 with a negative SPECT (difference not significant) and in 6 (19%) of 31 with a positive echocardiogram versus 8 (14%) of 56 with a negative echocardiogram (difference not significant). Thus the predictive value of the dipyridamole stress test for new cardiac events after an uncomplicated myocardial infarction was limited, irrespective of the method used to detect ischemia. Reversible perfusion defects were identified more frequently than new wall motion abnormalities but did not predict late events. A positive dipyridamole echocardiogram was associated with a higher late mortality rate but did not predict other cardiac events.

[Stress echocardiography: 4 years of experience at the Thoraxcenter]

In this article, we report the experience on stress echocardiography at the Thoraxcenter of Erasmus University of Rotterdam in the years 1990-1994. Different types of stress have been used in conjunction with ultrasound techniques. The results have been compared with other non-invasive methods (exercise ECG testing, myocardial perfusion scintigraphy with single photon emission computed tomography) and with coronary arteriography. Both the diagnostic and prognostic value of stress echocardiography have been assessed in different clinical situations, as in patients with chest pain and suspected or proven coronary artery disease, patients referred for percutaneous transluminal coronary angioplasty, patients referred for major non cardiac vascular surgery. After this period of validation, stress echocardiography has now a definite role in the clinical decision making for the evaluation of myocardial ischemia. The assessment of viable myocardium, especially in patients with advanced left ventricular dysfunction, is one of the major topic currently under investigation. Practical aspects of the interpretation of the tests, costs and organization of the stress echo laboratory, indications and newest research applications are also discussed.

Time delays to lytic therapy and outcome in 100 consecutive patients with a history suggestive of acute myocardial infarction in an area with access to a mobile coronary care unit

Time delays to fibrinolytic treatment and outcome were assessed in 100 consecutive patients, with suggestive symptoms and electrocardiographic changes of acute myocardial infarction, admitted to the coronary care unit of this hospital. All patients admitted from out-of-hospital had access to a mobile coronary care unit. Initially, 40 patients called a general practitioner, 30 called the '999' operator, 12 called the mobile coronary care unit, 10 reported directly to the Accident and Emergency Department, seven were in-hospital and one spoke to the general practitioner's receptionist. Subsequently, 59 patients were attended by the mobile coronary care unit, 34 were admitted via the Accident and Emergency Department and seven had symptoms in-hospital. Thrombolytic therapy was initiated in 45/59 (76%) patients by the mobile coronary care unit staff and in 29/34 (85%) patients in the Accident and Emergency Department by cardiac staff. The remaining 26 patients received thrombolytic treatment in the hospital coronary care unit or cardiac department. The mean (+/- SEM) time from symptom onset to the initiation of thrombolytic therapy was 127 (+/- 11 min) for those patients treated by the mobile coronary care unit staff and for those treated in the Accident and Emergency Department was 187 (+/- 13 min) (P = 0.005). Multiple regression analysis showed significant reductions in total time delay if patients received thrombolytic therapy by the mobile coronary care unit staff out-of-hospital, when chest pain began in-hospital, or if patients had a previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atropine increases the accuracy of dobutamine stress echocardiography in patients taking beta-blockers

Dobutamine-atropine stress echocardiography is used for the non-invasive diagnosis of coronary artery disease, but stress test results may be influenced by beta-blockers. The aim of this study was to assess if the addition of atropine can compensate for the presence of beta-blockers in dobutamine stress echocardiography. Twenty-six patients referred for evaluation of chest pain were studied twice, on and off metoprolol 100 mg b.i.d. (in random order sequence) with a wash-out period of at least 48 h. Dobutamine stress echocardiography was performed using up to 40 micrograms.kg-1.min-1, followed, if necessary, by the addition of atropine to achieve 85% of the age-predicted maximal heart rate, unless symptoms or markers of ischaemia appeared. Atropine was given to patients on beta-blockers more often [(22/26) vs (6/26)] than to those off beta-blockers (P < 0.001). Heart rate at every stage of the test was lower on beta-blockers. Chest pain occurred in patients on beta-blockers significantly less than in those off beta-blockers (8% vs 46%), and the addition of atropine made no significant difference (31% vs 46%). During dobutamine stress, new wall motion abnormalities occurred in three patients on beta-blockers (12%); this number increased to 15 after the addition of atropine (57%). New or worsened wall motion abnormalities occurred in 12 patients (46%) off beta-blockers with dobutamine alone and in 14 patients after adding atropine (53%).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of 100 mg of double-bolus alteplase in achieving complete perfusion in the treatment of acute myocardial infarction

OBJECTIVES

The purpose of this study was to assess the efficacy of 150 mg of aspirin plus 100 mg of alteplase, administered as two intravenous bolus injections of 50 mg each given 30 min apart, and followed by intravenous heparin, on infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3).

BACKGROUND

Previous workers have shown in animals that reducing the duration of an infusion of recombinant tissue-type plasminogen activator increases the initial rate of thrombolysis, resulting in high early infarct-related coronary artery patency rates. The logical progression of this idea is bolus administration.

METHODS

Consecutive patients presenting up to 6 h from the onset of symptoms were recruited for the study. Angiography was performed at 60 and 90 min after the first bolus and between 19 to 48 h after study entry. Patients were followed up for 1 month.

RESULTS

At 60 min, angiography revealed infarct-related coronary artery patency of TIMI flow grade 3 in 55 (86%) of 64 patients (95% confidence interval [CI] 75% to 93%) and TIMI flow grade 2 or 3 in 58 (91%) of 64 patients (95% CI 81% to 97%). At 90 min, infarct-related artery patency of TIMI flow grade 3 was achieved in 74 (88%) of 84 patients (95% CI 79% to 94%) and TIMI flow grade 2 or 3 in 78 (93%) of 84 patients (95% CI 85% to 97%). Two patients (2.4%) had early angiographic reocclusion whereas 10 (11.9%) had late reinfarction. Bleeding episodes were mostly minor, and there was no cerebrovascular bleeding. Five patients (6.0%) died within 1 month of the acute myocardial infarction.

CONCLUSIONS

In 84 patients with acute myocardial infarction, administration of 100 mg of double-bolus (2 x 50 mg) alteplase, aspirin and heparin is associated with remarkably high early infarct-related coronary artery patency rates (TIMI flow grade 3) of 86% and 88%, respectively, at 60 and 90 min.

Double-blind randomized trial of alteplase versus placebo in patients with chest pain at rest

Patients who have chest pain occurring at rest are at a significant risk of myocardial infarction and or sudden death. Most trials enter patients with anginal rest pain after an initial screening period. Thus, the clinical efficacy of early thrombolytic treatment for patients with rest pain remains unproven. Eighty patients with chest pain at rest and with ECG changes of ST depression of at least 1 mm in any ECG lead, were randomized to alteplase 100 mg infused over 3 h, or placebo. Concomitantly, all patients received intravenous heparin and 300 mg of aspirin daily (unless contra-indicated). Seventy-four patients had coronary angiography (the majority within 72 h of admission) of which 73 were assessable. The patency of the ischaemia-related vessel was not significantly greater in the alteplase treated group (81% vs 78%, P = 0.82). The culprit lesion morphology tended to be more concentric in the alteplase treated group (84% vs 56%, P = 0.06) although alteplase treatment was not associated with a significant reduction in the severity of the culprit lesion stenosis. Intra-coronary thrombi were detected in 7% of patients (3% placebo, 11% alteplase, P = 0.35). The mean left ventricular ejection fraction or the alteplase-treated group was 49 +/- 3% and for the placebo-treated patients 56 +/- 3% (P = 0.05). There was no difference in the total in-hospital cardiac event rate i.e. cardiac death, myocardial infarction and coronary revascularization between patients receiving alteplase (10%, 63%, and 38%) and those receiving placebo (8%, 65%, and 30%) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Dobutamine stress--Doppler echocardiography before and after coronary angioplasty

To determine if dobutamine-induced myocardial ischaemia causes abnormalities in Doppler parameters of left ventricular ejection and filling and to assess early effects of successful coronary angioplasty (PTCA) on these parameters, dobutamine stress echocardiography and Doppler studies were performed once in 11 normal volunteers and twice in 17 patients (within 1 day pre- and post-PTCA). Dobutamine induced wall motion abnormalities, ST changes and angina in 11, five and five patients, respectively, before and three, two and one patients, respectively, after PTCA. Doppler indices of both systolic and diastolic function were comparable at rest, before and after PTCA. Dobutamine induced similar increases in peak aortic velocity and average acceleration in healthy individuals (39% and 53%) and in patients with one-vessel disease both before (38% and 39%) and after PTCA (39% and 40%). In the three patients with multivessel disease, peak aortic velocity showed a blunted response (-0.3%) before PTCA but increased by 17% after PTCA, while acceleration decreased both before (12%) and after PTCA (14%). There were significant differences (P < 0.0001) between healthy individuals and pre-PTCA patients in the effect of dobutamine on peak early (E) filling velocity (+34% vs -19%), E-acceleration (+35% vs -26%), peak early to atrial filling velocity ratio (E/A) (-0.7% vs -37%) and diastolic time velocity integral (TVI) (+34% vs -22%). After PTCA, the response of Doppler diastolic indices improved during dobutamine, as shown by the increase in E and E-acceleration (+8%, +24%), respectively) and by the decline in the reduction of E/A and TVI (-17% and -10%, respectively). Thus, the response of Doppler diastolic parameters to dobutamine stress is a sensitive indicator of significant coronary disease and is superior to changes in ejection indices. Successful PTCA resulted in an improved diastolic filling response to dobutamine stress.

Simultaneous dobutamine stress echocardiography and technetium-99m isonitrile single-photon emission computed tomography in patients with suspected coronary artery disease

OBJECTIVES

The purpose of this study was to determine the relative value of dobutamine stress echocardiography and technetium-99m isonitrile single-photon emission computed tomography (mibi SPECT) in the detection of myocardial ischemia.

BACKGROUND

Stress-induced new wall motion abnormalities and transient perfusion defects are both used for the diagnosis of myocardial ischemia.

METHODS

One hundred five consecutive patients with either proved or suspected coronary artery disease, who were referred for perfusion scintigraphy, were studied by a combination of the two techniques. Both echocardiographic and mibi SPECT images were visually analyzed. Three patients were excluded from the final analysis because of unsatisfactory examinations: two with noninterpretable stress echocardiograms and one with noninterpretable mibi SPECT images. The response to stress was concordantly classified by both techniques in 68% of patients (kappa = 0.51).

RESULTS

Dobutamine stress echocardiography revealed the presence of ischemia in 38 and mibi SPECT in 45 patients (overall agreement = 74%, kappa = 0.46). The agreement was higher in patients without previous myocardial infarction (84%, kappa = 0.62). When regional analysis was performed, concordance of stress echocardiography and mibi SPECT occurred in 84% of the 306 regions (kappa = 0.45). Regional agreement was also slightly higher in patients without previous infarction (88%, kappa = 0.50). In 21 patients without previous myocardial infarction who underwent coronary angiography, the overall sensitivity of dobutamine stress echocardiography and mibi SPECT for the diagnosis of coronary artery disease (diameter stenosis > 50%) was 75% and 83%, respectively, with a specificity of 89% (eight of nine patients) for both tests.

CONCLUSIONS

Dobutamine stress echocardiography represents a reasonable alternative to dobutamine mibi SPECT for the functional assessment of patients with suspected myocardial ischemia and without previous myocardial infarction.

Pharmacological stress echocardiography in the diagnosis of coronary artery disease and myocardial ischaemia: a comparison between dobutamine and dipyridamole

The objective of this study was to relate regional wall motion abnormalities assessed by dobutamine and dipyridamole stress echocardiography to quantitative measurements of coronary artery stenoses in consecutive patients referred for coronary angiography, and to compare haemodynamic effects of and complications related to the two agents. Patients underwent stress echoes on separate days in random sequence and had coronary angiography within 3 days of stress echocardiography. Echocardiograms were assessed by two investigators unaware of the patients' coronary anatomy. Coronary angiograms were also assessed quantitatively using the computer-assisted Cardiovascular Angiography Analysis System. There were 46 consecutive patients referred for coronary angiography; 28 were using beta-antagonists. Main outcome measures were sensitivity and specificity for dobutamine and dipyridamole stress echocardiography for detection of coronary artery disease (wall motion abnormalities at rest or stress) and myocardial ischaemia (stress induced new wall motion abnormalities). Sensitivity for the detection of myocardial ischaemia was found to be 57% for dobutamine and 64% for dipyridamole. Specificities were 78% and 89% respectively. Sensitivities for detection of coronary artery disease (lesion > or = 50% diameter stenosis) was 79% for dobutamine and 82% for dipyridamole; specificities were 78% and 89% respectively. These differences between the two agents are not significant. There were no severe side effects with either agent. Mean heart rate rose significantly with both tests but was higher with dobutamine; mean systolic blood pressure rose with dobutamine and fell with dipyridamole. It was concluded that dobutamine and dipyridamole stress echocardiography have similar sensitivities and specificities for detection of myocardial ischaemia and coronary artery disease although the haemodynamic effects of the two agents are different. Both are free from serious complications.

Enhanced sensitivity for detection of coronary artery disease by addition of atropine to dobutamine stress echocardiography

Patients undergoing dobutamine stress echocardiography often take beta antagonists which limit heart rate response and sensitivity in the test for detection of coronary artery disease. The aim of this study was to assess the effect of the addition of atropine to dobutamine stress echocardiography on clinical, electrocardiographic and echocardiographic outcomes. Dobutamine stress echocardiography was performed starting at and increasing every 3 minutes with 10 micrograms/kg/min to a maximum of 40 micrograms/kg/min (stage 4), which was continued for 6 minutes. In patients not achieving 85% predicted maximal exercise heart rate and in whom the test was not judged positive on echocardiographic or electrocardiographic criteria, atropine (0.25 mg intravenously, repeated up to a maximum of 1 mg if necessary) was added and dobutamine continued for up to a further 5 minutes, or until an adequate heart rate was achieved or the test was stopped because of chest pain or electrocardiographic changes. Of 80 consecutive patients undergoing dobutamine stress echocardiography within 2 weeks of coronary angiography, 49 required atropine (group A) and 31 required only dobutamine (group B). After dobutamine alone, heart rate (mean +/- SD) was higher in group B than in group A: 129 +/- 20 vs 90 +/- 18 beats/min, p less than 0.0001; but after the addition of atropine, heart rate in group A increased to 120 +/- 20 beats/min. Overall sensitivity for the detection of coronary disease was 70%, 95% confidence interval (CI) 55 to 83%; after the addition of atropine, sensitivity for group A was 65%, 95% CI 45 to 81%; in group B, sensitivity was 81%, 95% CI 54 to 96%.(ABSTRACT TRUNCATED AT 250 WORDS)

Dobutamine stress echocardiography before and after coronary angioplasty

Myocardial function was assessed by stress echocardiography in 28 patients before and after successful elective coronary angioplasty. Dobutamine stress echocardiography was performed using up to 40 micrograms/kg/min, followed by the addition of atropine in 20 patients to achieve 85% of the predicted maximal exercise heart rate. The initial studies were performed 1 day before and the second ones within 3 days (mean 1.3) after angioplasty. Peak heart rates and systolic blood pressures were the same for the 2 studies. The frequency of dobutamine-induced new wall motion abnormalities decreased from 20 (71%) before to 4 (14%) after angioplasty (p less than 0.0001). Before angioplasty, wall motion score index (an indicator of left ventricular wall motion, an increase in which indicates impaired wall motion due to myocardial ischemia) increased from 1.06 at rest to 1.23 at peak stress (p less than 10(-6)), but there was no significant increase in this index in the study after angioplasty. Before angioplasty, 14 patients (50%) developed chest pain during the stress test compared with 6 (21%) after angioplasty (p = 0.05), and before angioplasty, the stress test was stopped before the target heart rate was achieved, because of symptoms, ST-segment change or severe new wall motion abnormality in 14 patients compared with 7 after angioplasty (p = 0.09). Thus, early after angioplasty there is a reduction in myocardial ischemia as assessed by dobutamine stress echocardiography.

Recurrent ventricular arrhythmias complicating myocardial infarction in the presence of phaeochromocytoma

After an acute myocardial infarction a 49 year old man developed late recurrent severe ventricular arrhythmias coincident with transient hypertensive episodes. A phaeochromocytoma was diagnosed on the basis of the urinary concentration of catecholamines and computerised tomography of the adrenal glands. After stabilisation of his cardiac rhythm and blood pressure with alpha and beta adrenergic blockade and anti-arrhythmic treatment the right adrenal gland, which contained the tumour, was successfully resected. The diagnosis of a phaeochromocytoma should be considered when recurrent ventricular arrhythmias are associated with intermittent hypertension after myocardial infarction.

Dobutamine stress echocardiography: its role in the diagnosis of coronary artery disease

We have assessed the usefulness of dobutamine infusion for the diagnosis of coronary artery disease by using two-dimensional echocardiography and 12-lead electrocardiogram. Dobutamine was infused at incremental doses (up to a maximum of 40 micrograms kg-1 min-1) in 52 patients with chest pain; all the patients underwent coronary angiography; significant coronary artery disease was quantitatively defined as greater than or equal to 50% diameter stenosis. Thirty-six patients were on betablockers. The test was considered positive when new regional wall motion abnormalities appeared during dobutamine infusion. No significant side effects occurred in any patient during the test. Transient wall motion abnormalities were detected in 20 of 37 patients with coronary artery disease (sensitivity = 54%); ischaemic ST segment changes were present on ECG in nine patients (sensitivity = 24%). Dobutamine stress echocardiography was negative in 12 of 15 patients with coronary artery diameter stenosis less than 50% (specificity = 80%). Exercise electrocardiography (ECG) was performed in 35 of these 52 patients. Maximum heart rate and systolic blood pressure were significantly higher during exercise than during dobutamine stress test (127 +/- 23 vs 99 +/- 24 beats min-1, P less than 0.0001; 179 +/- 25 vs 152 +/- 30 mmHg, P less than 0.0001). The exercise ECG test was positive in 12 of the 26 patients with significant coronary artery disease (sensitivity = 46%), and dobutamine stress echocardiography in 16 (sensitivity = 62%). Dobutamine stress echocardiography test is a safe and feasible diagnostic test for the noninvasive diagnosis of coronary artery disease and can be performed in patients unable to exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombolytic therapy within one hour of the onset of acute myocardial infarction

Between 1986 and 1988, 239 consecutive patients with acute myocardial infarction received thrombolytic therapy up to 285 minutes after onset of symptoms; in 39 (17 with anterior infarction, 21 inferior, one lateral infarction) recombinant tissue plasminogen activator or anistreplase was administered a mean of 51 minutes (range 20-60 minutes) after the onset of symptoms. The patency rates (26 of 30; 87 per cent), rapid ST segment resolution (36 of 38; 95 per cent) and QRS score of less than or equal to 3 (28 of 38; 74 per cent) were statistically significantly higher for those seen and treated in the first hour in comparison with those seen and treated later. For those treated within the first hour mean peak creatine kinase was 1264 U/l for those with TIMI grade 2 or 3 (partial or complete perfusion) compared with 3005 U/l for those with TIMI grade 0 or 1 (no perfusion or penetration without perfusion) (p = 0.02): mean peak creatine kinase-MB for those with TIMI grade 2 or 3 perfusion was 115 U/l compared with 312 U/l for those with TIMI grade 0 or 1 (p = 0.01). Four of the 39 patients developed ventricular fibrillation following thrombolytic therapy, three within 24 hours of infarction and one following reinfarction on day 15. There were no significant bleeding complications. One patient died. Thrombolytic therapy within 1 hour of the onset of symptoms led to a very high angiographic patency rate, rapid ST segment resolution with preservation of left ventricular function. This therapy is without significant complications.

One-year follow-up after recombinant tissue plasminogen activator administered to patients with acute myocardial infarction

Of 106 patients seen within 4 h of chest pain with 107 episodes of acute myocardial infarction, nine died before or during hospitalization mainly from cardiogenic shock, and four died during the next year, three were sudden deaths. The 93 survivors were reviewed at a mean of 53 (range 49-70) weeks after infarction. Of these 93, 18 had had attempted angioplasty (successful in 12) and 15 had had coronary artery bypass grafting (including one patient who had coronary artery bypass grafting performed after unsuccessful angioplasty). The remaining 61 patients continued on medical therapy only. During the one-year follow-up two patients suffered reinfarction and a further 22 had one or more cardiac admissions, mostly for chest pain. At review, 22 patients had angina (16 New York Heart Association Grade I or II) and five dyspnoea (all NYHA Grade II). Forty-three patients were taking oral nitrates, 53 were receiving calcium antagonists, 54 were using betablocking agents and 73 used anti-platelet agents. However, many of these patients continued on anti-anginal therapy prophylactically after their myocardial infarction, without continuing chest pain. Thus after recombinant tissue plasminogen activator therapy and following hospital discharge the mortality rate for patients with acute myocardial infarction was four out of 97 (4.1%) and reinfarction rate among survivors was two out of 93 (2.2%). Although the incidence of cardiac symptoms was low this may be partly due to the high incidence of angioplasty and coronary artery grafting, together with the use of anti-anginal agents.

Anistreplase in early acute myocardial infarction and the one-year follow-up

Of consecutive patients seen with first myocardial infarction (88 of whom were treated out-of-hospital by mobile coronary care staff), 139 received 30 units of intravenous anistreplase at a mean of 101 minutes (range 35-180) from onset of symptoms. Thrombolysis in myocardial infarction patency grade 2 or 3 was found in 76/91 (83.5%) patients. At 3-4 months after hospital discharge, the mean global left ventricular ejection fraction and mean infarct-related regional third ejection fraction declined with increasing delay to anistreplase. For the first, second and third hour administrations, global ejection fraction was 54%, 50% and 45% (P = 0.002) and for regional third ejection fractions 49%, 43% and 41% (P = 0.02) respectively. Of the patients, 130 were reviewed at approximately 1 year: reinfarction had occurred in 9, 6 had undergone coronary angioplasty and 1 had coronary arterial bypass grafting performed since discharge. Mean global left ventricular ejection fraction was 52% and mean infarct-related regional third ejection fraction was 51%. Thus, intravenous anistreplase induces high rates of arterial patency. Global and regional third ejection fractions decline with increasing delay in the time of administration of anistreplase. Mortality and morbidity is low in the first year.

A randomized dose-ranging study of rt-PA in acute myocardial infarction. Effects on coronary patency and fibrinolytic parameters

This study was designed to examine the relationships between dose of Wellcome two-chain recombinant tissue type-plasminogen activator (BW rt-PA) and coronary patency and fibrinolytic parameters in acute myocardial infarction (AMI). In an open randomized study, patients with AMI (determined by ECG) and symptoms of less than 4 h duration without contraindications for fibrinolytic therapy were treated with rt-PA in nominal doses of 20 (7.7 MU), 50 (14.8-29.6 MU) or 100 mg (29.6-48.2 MU) administered over 90 min followed by intravenous heparin. Coronary patency was determined by coronary arteriography of the infarct-related artery and haematological parameters (fibrinogen, plasminogen, alpha 2-antiplasmin and fibrin(ogen) degradation products) measured at 90 min. Coronary patency increased in a dose-related manner to 53% (95% C.I. 37-69%) in the 100 mg/90 min group. Logistic regression demonstrated a relationship between dose (in MU kg-1) and coronary patency. Fibrinogen at 90 m was reduced to 74 (61.5-86.4%) of the pooled plasma standard in the nominal 100 mg group. Patients with a higher predose fibrinogen had higher reductions of fibrinogen. Serious bleeding occurred in three (3%) patients, and no intracranial bleeds were reported. BW rt-PA produces dose-related patency of the coronary arteries with moderate, dose-related reduction in fibrinogen.

A double blind placebo controlled study of early and late administration of recombinant tissue plasminogen activator in acute myocardial infarction

Within four hours of the onset of acute myocardial infarction 57 consecutive patients were randomised blindly to infusion of 150 mg recombinant tissue plasminogen activator (rt-PA) (group 1) over five hours or placebo (group 2) when they were first seen outside hospital or in the accident and emergency department. When they were admitted to the coronary care unit patients in group 1 also had placebo infused and those in group 2 were treated with rt-PA as well as placebo. Treatment with rt-PA started at a mean of 119 minutes (range 38-235) after the onset of pain in group 1 and 187 minutes (range 80-285) after the onset of pain in group. In 19 (79%) of 24 in group 1 and 16 of 25 (64%) in group 2 cardiac catheterisation 10-14 days after infarction showed thrombolysis in myocardial infarction grades 2 or 3. There was mean percentage shortening of the infarct related segments (Leighton method) of 16% in group 1 and 10.3% in group 2. For patients with anterior infarction mean percentage shortening was 20.5% in group 1 and 12.2% in group 2. Although there was no significant difference in global ejection fraction as assessed by contrast ventriculography or radionuclide ventriculography the infarct related regional third ejection fraction (a measure of the function of the territory of the affected coronary artery) was significantly improved by early treatment (41% group 1 and 28% group 2). Assessment of infarct size by the QRS scoring method of Palmeri showed QRS score less than or equal to 15/25 patients in group 1 and 8/27 in group 2. Nine patients developed 11 episodes of ventricular fibrillation; all patients in whom ventricular fibrillation developed during treatment with rt-PA were successfully resuscitated. There was no clinically significant bleeding. In seven (12%) patients clinical and electrocardiographic criteria suggested reocclusion. Five patients died from cardiac causes. Prehospital administration of rt-PA was feasible and significantly reduced the delay before thrombolysis was started. Earlier treatment improved myocardial function in the the infarct area and reduced the infarct size.

A randomised dose ranging study of recombinant tissue plasminogen activator in acute myocardial infarction

To assess the thrombolytic efficacy and the effect on the systemic fibrinolytic system of recombinant tissue plasminogen activator doses of 20 mg, 50 mg, and 100 mg were compared in a randomised study. Tissue plasminogen activator was infused intravenously over 90 minutes in 50 consecutive patients with acute myocardial infarction of four hours' duration or less; on average the infusion was started 135 minutes (range 20 to 240) after the onset of pain. The affected artery was patent at the end of the 90 minute infusion in 14/17 (82%) of those who received 100 mg, 12/17 (71%) of those who received 50 mg, and 8/16 (50%) of those who received 20 mg. Regardless of dose, reperfusion rates were significantly better for patients treated within two hours of the onset of symptoms (81%) than for those treated in the third and fourth hours (54%). At the end of the infusion serum fibrinogen concentrations fell to 86% of the preinfusion value after 20 mg, 75% after 50 mg, and 63% after 100 mg, and similar dose dependent changes occurred in plasminogen, (alpha 2 anti-plasmin, and fibrinogen and fibrin degradation products. The mean infarct related regional third ejection fraction was 46% for patients with grade 2 or 3 reperfusion and 35% for those with grade 0 or 1. Ventricular fibrillation occurred in six (12%) patients during the infusion of tissue plasminogen activator, but no late ventricular fibrillation occurred. Bleeding was minimal, reocclusion occurred in three patients, and four patients died from cardiac causes. Recombinant tissue plasminogen activator is an effective thrombolytic agent which produces better reperfusion rates after a 50 or 100 mg dose than after a 20 mg dose. The effect on the systemic fibrinolytic system is dose dependent. Successful reperfusion results in improvement of left ventricular function.

Diabetic ketoacidosis in a district general hospital, 1981-1986

The outcome of therapy of poorly controlled insulin-requiring cases of diabetes mellitus needing admission to a district general hospital from 1981 to 1986 was examined. There were 156 admissions to the hospital, 17 of these classified as severe diabetic ketoacidosis (serum standard bicarbonate less than 14 mmol/l). A 'low dose' insulin regimen was used in each case of severe ketoacidosis. No patient who was admitted died within a six-month period. These figures emphasise the value of a policy of direct hospital admission for poorly controlled diabetics and suggest that early diagnosis in general practice is vital to allow the application of relatively simple and standard hospital treatment.

The assessment of the beta-adrenoceptor blocking activity and cardioselectivity of Koe 3290 in normal subjects

1. The beta-adrenoceptor antagonist activity, cardioselectivity and antilipolytic properties of Koe 3290 were investigated in healthy subjects. 2. Koe 3290 12.5, 25, 50 and 100 mg, atenolol 25, 50 and 100 mg and placebo were given in double-blind randomised order to eight subjects. All doses of both Koe 3290 and atenolol reduced supine, standing and exercise heart rate (P less than 0.02). From 2 to 8 h after administration the exercise heart rate after Koe 3290 100 mg was similar to that for atenolol 50 mg. 3. The cardioselectivity of Koe 3290 and atenolol was compared. Koe 3290 50, 100 and 150 mg, atenolol 50 and 100 mg and placebo were given to six subjects in a double-blind random order. Isoprenaline dose-response curves were constructed for cardiovascular parameters and finger tremor. 4. For doses which were equipotent at the beta 1-adrenoceptor (Koe 3290 100 mg and atenolol 50 mg) atenolol caused less attenuation of heart rate, diastolic blood pressure, forearm blood flow and finger tremor (P less than 0.02). 5. There was no difference in the isoprenaline-induced changes in serum free fatty acids, blood glucose, plasma lactate or potassium after Koe 3290 and atenolol. Koe 3290 attenuated the rise in serum insulin more than atenolol (P less than 0.02). 6. Koe 3290 is an effective beta-adrenoceptor blocking drug in man. It is not as cardioselective as atenolol and does not possess specific antilipolytic properties.

Cardiogenic shock due to papillary muscle rupture in acute myocardial infarction

We report a case of papillary muscle rupture complicating acute myocardial infarction which resulted in acute cardiogenic shock. The patient underwent urgent replacement of the mitral valve and made an uncomplicated recovery.

Effects of ICI 141,292 on exercise tachycardia and isoprenaline-induced beta-adrenoceptor responses in man

The beta-adrenoceptor blocking properties and cardioselectivity of ICI 141, 292 were investigated in healthy male subjects. Seven subjects received in random order oral doses of ICI 141,292 20, 50, 100, 200 and 400 mg, atenolol 50 and 100 mg and placebo. ICI 14 292 had no effect on supine heart rate which was reduced by atenolol 100 mg. ICI 141,292 50, 100 and 200 mg had no effect on standing heart rate which was reduced by 400 mg at 2 h. Both doses of atenolol caused greater reductions. The maximum percent reduction of an exercise tachycardia after ICI 141,292 200 mg (23.9 +/- 3.7%) and 400 mg (24.3 +/- 5.2%) were similar to atenolol 50 mg (27.3 +/- 4.7%) but less than atenolol 100 mg (30.8 +/- 2.9%) (P less than 0.02). Six subjects received in random order single oral doses of ICI 141,292 100, 200 and 400 mg, atenolol 50 mg, propranolol 40 mg and placebo. Following each dose each subject received graded infusions of isoprenaline sulphate until heart rate increased by 40 beats min-1. Dose-response curves were constructed for the changes in heart rate, finger tremor, blood pressure and forearm blood flow produced by each infusion. At the 4 micrograms min-1 dose of isoprenaline, ICI 141,292 200 mg caused more attenuation than atenolol 50 mg but less than propranolol 40 mg in the changes of heart rate, diastolic blood pressure and finger tremor (P less than 0.02). ICI 141,292 400 mg caused more attenuation of the changes of all parameters than atenolol 50 mg but less attenuation of the changes in diastolic blood pressure and finger tremor than propranolol 40 mg (P less than 0.02). These results indicate that ICI 141,292 is a cardioselective beta-adrenoceptor antagonist with partial agonist activity.