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Biomedical subjects

K I Lie

Publications and source records attributed to K I Lie.

At least 163 records · Page 9Linked to original sources
PubMed1994

Efficacy of metoprolol and diltiazem in treating silent myocardial ischemia.

Recent studies strongly support the prognostic importance of transient silent ischemia. Because patients with silent ischemia are at higher risk of a cardiac event, they are likely to benefit not only from control of symptoms, but also from treatment directed at prevention of ischemia. The efficacy of controlled-release metoprolol 200 mg once daily and diltiazem 60 mg 4 times daily was assessed in a randomized, double-blind, crossover study in 32 patients with proven coronary artery disease, predominantly asymptomatic myocardial ischemia, positive bicycle exercise test results, and > or = 5 minutes of asymptomatic ST-segment depression on a 24-hour screening ambulatory electrocardiogram (ECG). At the beginning and at the end of both 3-week treatment periods, an exercise test was performed and a 72-hour ambulatory ECG was recorded. Both active treatment periods were preceded by a 2-week placebo phase. Both treatments effectively reduced and postponed exercise-induced ST depression and reduced the total ischemic integral on the ambulatory ECG. Only metoprolol significantly reduced the mean number of ischemic episodes (54%, p = 0.0003, vs 31% for diltiazem, p = NS) and the mean duration of ischemia (51%, p = 0.012, vs 27% for diltiazem, p = NS) compared with baseline values. Metoprolol strongly blunted the morning and afternoon peak in the circadian distribution of ischemia, whereas diltiazem did not change the circadian distribution of ischemia at all.

Adult↗
PubMed1994

Autoperfusion balloon versus stent for acute or threatened closure during percutaneous transluminal coronary angioplasty.

Efficacy and major clinical end points were compared in 61 patients treated with a Stack autoperfusion balloon versus 36 patients who received a Palmaz-Schatz stent for acute or threatened closure during coronary angioplasty. The groups were comparable regarding baseline clinical characteristics. Procedural success was achieved in 43 patients (70%) treated with an autoperfusion balloon versus 34 patients (94%) who received a stent (p < 0.02). Emergency bypass surgery was performed in 13 patients (21%) with the autoperfusion balloon versus none of the patients with a stent (p < 0.001). In the stent group, 3 patients (8%) died (p < 0.05); 2 deaths were caused by thrombotic reclosure, and 1 patient died after unsuccessful stent delivery. Subacute reclosure during hospitalization occurred in none of the patients with autoperfusion versus 8 patients with the stent (22%) (p < 0.0002). Therefore, the number of patients with successful stent implantation at discharge decreased to 26 (72%). At 3-month follow-up in all patients with a successful intervention, reclosure or angiographic restenosis (> 50%) occurred in 13 patients with autoperfusion (30%) versus 3 patients with stents (12%) (p = NS). There was no difference in event-free survival during follow-up. Thus, both interventions were equally successful in the treatment of acute and threatened closure. More emergency surgery was performed in the autoperfusion balloon group, whereas a higher subacute reclosure rate was seen in the stent group. At 3-month follow-up, there were no significant differences regarding reclosure, restenosis, and event-free survival.

Aged↗
PubMed1994

Effects of low dose aspirin (50 mg/day), low dose aspirin plus dipyridamole, and oral anticoagulant agents after internal mammary artery bypass grafting: patency and clinical outcome at 1 year. CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands. Prevention of Coronary Artery Bypass Graft Occlusion by Aspirin, Dipyridamole and Acenocoumarol/Phenprocoumon Study.

OBJECTIVES: This study was performed to compare the efficacy and safety of aspirin, aspirin plus dipyridamole, and oral anticoagulant agents in the prevention of internal mammary artery graft occlusion. BACKGROUND: Antithrombotic drugs increase vein graft patency after coronary artery bypass surgery. Their benefit after internal mammary artery grafting has not been established. METHODS: Angiographic internal mammary artery graft patency at 1 year was assessed in 494 patients who received both internal mammary artery and vein grafts. These patients were a subgroup of a prospective, randomized vein graft patency study in 948 patients assigned to treatment with aspirin, aspirin plus dipyridamole, or oral anticoagulant agents. The design was double-blind for both aspirin groups and open for oral anticoagulant treatment. Dipyridamole (5 mg/kg body weight per 24 h intravenously, followed by 200 mg twice daily) and oral anticoagulant agents (prothrombin time target range 2.8 to 4.8 international normalized ratio) were started before operation, and low dose aspirin (50 mg/day) after operation. Clinical outcome was assessed by the incidence of myocardial infarction, thrombosis, major bleeding or death. RESULTS: Occlusion rates of distal anastomoses were 4.6% in the aspirin plus dipyridamole group and 6.8% in the oral anticoagulant group versus 5.3% in the aspirin group (p = NS). Overall clinical event rates were 23.3% and 13.3% in the aspirin plus dipyridamole group and the aspirin group, respectively (relative risk 1.75, 95% confidence interval 1.09 to 2.81, p = 0.025), and 17.1% in the oral anticoagulant group. CONCLUSIONS: Internal mammary artery graft patency at 1 year is not improved by aspirin plus dipyridamole or oral anticoagulant agents over that obtained with low dose aspirin alone. However, there is evidence that the overall clinical event rate increases if dipyridamole is added to aspirin.

Acenocoumarol↗
PubMed1994

Lipoprotein(a) levels in patients with myocardial infarction treated with anistreplase: no prediction of efficacy but inverse correlation with plasminogen activation in non-patency.

The aim of this study was to investigate whether failure of thrombolytic treatment might be due to inhibition of fibrinolysis by high lipoprotein(a) levels. Fifty-eight patients with acute myocardial infarction were treated intravenously within 4 h after onset of symptoms with anistreplase (30 units) and heparin (30,000 IU/24 h). Blood samples for measurement of coagulation parameters were taken before and 1.5 h after treatment. Coronary angiography was performed after 48 h. Levels of lipoprotein(a) were measured 6 months after discharge from hospital. The patency rate was 74% (43/58). Median lipoprotein(a) levels were not different between the patients with a patent and those with a non-patent vessel (10 and 8 mg/dl, respectively), however, in patients with a non-patent infarct-related vessel, a significant inverse correlation was found between the lipoprotein(a) level and the decrease of plasminogen in the first 1.5 h after treatment. It is concluded that high lipoprotein(a) levels, although not directly associated with a poor outcome of anistreplase therapy, might contribute to insufficient fibrinolysis in patients with a non-patent infarct-related vessel.

Adult↗
PubMed1994

Catheter sizes for quantitative coronary arteriography.

In quantitative coronary arteriography (QCA), the outer diameter of the contrast catheter is used almost exclusively as the calibration device. Since the true outer diameter of these catheters are smaller than the French sizes listed by the manufacturer, it has been advocated to measure the actual sizes with a precision micrometer. However, this represents a significant effort in the organizations of the QCA Angiographic Core Laboratories and of the participating cardiac catheterization laboratories. In the Dutch REGRESS trial on regression/progression of coronary artery disease, we have measured a total of 2,104 catheters from four different manufacturers. In 2,048 of the 2,104 catheters the variabilities in the measurements were 0.02-0.03 mm, which represents an error of only 1% of the average catheter sizes. In the remaining 56 catheter measurements, the variability was 0.04 mm. From these data we may conclude that from now on the stated mean values can be used for calibration purposes. This has important practical consequences for running clinical trials and QCA Core Laboratory operations.

Calibration↗
PubMed1994

Neurohumoral and hemodynamic effects of ibopamine in a rat model of chronic myocardial infarction and heart failure.

There is increasing evidence that both neurohumoral and hemodynamic factors play a role in disease progression in chronic heart failure (CHF). To examine the influence of the oral dopamine agonist ibopamine on these factors, we studied 20 rats with chronic myocardial infarction and CHF, and compared them with 20 normal rats. After 6 weeks, rats were randomly divided between control treatment (50%) or ibopamine (50%) for 3 weeks. At the end of the study, plasma and tissue neurohumoral parameters, as well as hemodynamics, were determined. In infarcted rats, the elevated plasma norepinephrine (PNE) levels were reduced by ibopamine (251 +/- 19 vs. 138 +/- 32 pg/ml; p < 0.05). Other plasma neurohormones measured (epinephrine, renin, aldosterone, and angiotensin converting enzyme [ACE]) were not significantly increased in rats with myocardial infarction and were not affected by ibopamine. Cardiac (tissue) ACE was increased in infarcted rats (12.1 +/- 1.9 U/l/min) and was significantly lowered by ibopamine (9.6 +/- 1.0 U/l/min; p < 0.05); renal ACE was unaffected. Blood pressure and heart rate were similar in the two groups and were not influenced by ibopamine treatment. In conclusion, in chronic myocardial infarction and CHF in rats, ibopamine reduces the elevated levels of PNE and cardiac ACE. Further research will be needed to determine whether this effect may lead to a favorable influence on disease progression in CHF.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Serial angioscopic and angiographic observations during the first hour after successful coronary angioplasty: a preamble to a multicenter trial addressing angioscopic markers for restenosis.

Percutaneous coronary angioscopy was used in 13 patients in a pilot study to assess the intracoronary changes that occur during the first hour after balloon angioplasty (PTCA). The dilated segment was studied with 4.5F angioscopes and with quantitative coronary angiography (QCA) immediately after PTCA and at 15-minute intervals for up to 1 hour after PTCA. Significant progression of intimal dissection and thrombus formation could be demonstrated with angioscopy. These dissections and thrombi remained undetected with angiography, which only showed haziness. Thus through its superior sensitivity to intimal damage and thrombus, coronary angioscopy can reveal important intravascular events that apparently occur even after successful PTCA. The relation of such angioscopic observations to restenosis will be addressed in a subsequent multicenter study.

Angioplasty, Balloon, Coronary↗
PubMed1994

Late potentials, QTc prolongation, and prediction of arrhythmic events after myocardial infarction.

In a series of 171 consecutive survivors of acute myocardial infarction, the predictive value of late potentials and QTc prolongation was prospectively assessed. QT intervals were measured in lead V2, corrected QT (QTc) was calculated using Bazett's equation (cut-off value 440 ms). Late potentials were considered to be present when all of the three signal-averaged electrocardiographic variables were abnormal (i.e. QRS > 114 ms, D40 > 38 ms, and V40 < 20 microV). Complete follow-up was obtained (mean 13 +/- 6 months, range 6-24 months). Six percent of the patients had an arrhythmic event (i.e. sustained ventricular tachycardia or sudden death). The relative risk of late potentials for arrhythmic events was 7.7 (P < 0.02). The relative risk of QTc > 440 ms was 1.1 (NS). In a multivariate analysis, the addition of QTc prolongation did not significantly improve the prognostic value of late potentials alone. It is concluded that late potentials are predictive of arrhythmic events after myocardial infarction, but the presence of concomitant QTc prolongation does not worsen the prognosis.

Action Potentials↗
PubMed1994

Angioscopic versus angiographic detection of intimal dissection and intracoronary thrombus.

OBJECTIVES: This study was undertaken to compare coronary angioscopy with angiography for the detection of intimal dissection and intracoronary thrombus. BACKGROUND: It has been demonstrated previously that coronary angioscopy provides more intravascular detail than cineangiography. Both imaging methods have to be compared directly to assess the additional diagnostic value of angioscopy. METHODS: The angiograms and videotapes of 52 patients who had undergone angioscopy were reviewed independently by two observers unaware of other findings. Classic angiographic definitions were used for dissection and thrombus. Angioscopic dissection was defined as visible cracks or fissures on the lumen surface or mobile protruding structures that are contiguous with the vessel wall. Angioscopic thrombus was defined as a red, white or mixed red and white intraluminal mass. RESULTS: Angiography and angioscopy were in agreement in 40.4% of cases in the absence of thrombus and in 11.5% in the presence of thrombus. No fewer than 25 (48.1%) angioscopically observed thrombi remained undetected at angiography. With angioscopy as the standard, although the specificity of angiography for thrombus was 100%, sensitivity was very low at 19%. Angioscopic dissection was present in 40 patients (76.9%) versus angiographic dissection in 15 patients (28.8%). With regard to dissection, there was no correlation between the two imaging methods (r phi = 0.15, p = 0.29). CONCLUSIONS: Coronary angiography underestimates the presence of intracoronary thrombus. Angioscopy and angiography are complementary techniques for detecting and grading intimal dissections.

Adult↗
PubMed1994

Efficacy of spinal cord stimulation as adjuvant therapy for intractable angina pectoris: a prospective, randomized clinical study. Working Group on Neurocardiology.

OBJECTIVES: In a prospective, randomized study with an 8-week follow-up period, we evaluated the efficacy of spinal cord stimulation on exercise capacity and quality of life in patients with intractable angina. BACKGROUND: Despite important achievements in therapy for ischemic heart disease, there remain patients with intractable symptoms of angina. In uncontrolled observations, several investigators have reported beneficial effects of spinal cord stimulation as an additional therapy for patients with angina pectoris. METHODS: Seventeen patients were randomly assigned to the treatment (implantation within 2 weeks, eight patients) or control (implantation after 8 weeks, nine patients) group. Assessment of exercise capacity was performed by treadmill exercise testing. Quality of life was evaluated by daily and social activity scores and recording sublingual glyceryl trinitrate intake and angina pectoris attacks in a diary. After the 8-week study period, the control group also received the spinal cord stimulation device, and all patients were followed up for 12 months. RESULTS: The treatment but not the control group demonstrated a significant increase in exercise duration (p < 0.02), rate-pressure product (p < 0.03) and time to angina (p < 0.04), with a decrease in ST segment depression (p < 0.05). This was associated with an increase in daily life (p < 0.008) and social activity (p < 0.005) scores and a reduction in glyceryl trinitrate intake (p < 0.004) and episodes of angina pectoris (p < 0.003). During the 1-year follow-up, improvement in all quality of life variables was linear for the entire group compared with baseline. The time to angina, exercise duration and ST segment depression showed a second-order trend. CONCLUSIONS: Spinal cord stimulation significantly improves exercise capacity and quality of life. On the basis of an increase in exercise capacity and rate-pressure product, the mechanism by which spinal cord stimulation acts may be related to improved oxygen supply to the heart combined with an analgesic effect.

Angina Pectoris↗
PubMed1994

Left ventricular dilatation and high-grade ventricular arrhythmias in the first year after myocardial infarction. CATS Investigators. Captopril and Thrombolysis Study.

Progressive left ventricular dilatation is an important determinant of prognosis after myocardial infarction. The association of this process with the occurrence of ventricular arrhythmias is less well established. Of 153 patients with a first anterior myocardial infarction treated with thrombolytic therapy, 34 (22%) had high-grade ventricular arrhythmias (Lown 4A and B) during Holter monitoring after 1 year. Patients with high-grade ventricular arrhythmias had a larger end-systolic volume (38 +/- 12 vs 25 +/- 11 mL/m2; P < .001) at hospital discharge and more left ventricular dilatation (10 +/- 18 vs 1 +/- 9 mL/m2; P = .011) during the follow-up period. Increased end-systolic volume at discharge and subsequent dilatation proved to be independent predictors of high-grade ventricular arrhythmias. Six patients died suddenly during the first 12 months after myocardial infarction. Four of these patients had an enlarged end-systolic volume (> 22 mL/m2) at discharge, and the three patients who died suddenly after 3 months showed a significant increase in end-systolic volume from discharge to 3 months compared to survivors (16 +/- 6 vs 2 +/- 9; P = .008). Left ventricular remodeling after myocardial infarction is an independent predictor of the occurrence of ventricular arrhythmias late after myocardial infarction.

Aged↗
PubMed1994

Analysis of vagal effects on ventricular rhythm in patients with atrial fibrillation.

1. Animal studies suggest that the heart-rate-lowering effect of vagal stimulation during atrial fibrillation is due to: (1) a direct depressant effect on atrioventricular node conductivity, (2) enhancement of concealed atrioventricular nodal conduction of atrial impulses through augmenting fibrillatory activity, thereby indirectly prolonging atrioventricular nodal refractoriness. The purpose of the present study was to analyse these effects in man. 2. Sixteen patients with chronic atrial fibrillation were studied. After administration of propranolol (0.2 mg/kg intravenously) baseline ventricular rhythm was recorded (500 R-R intervals). Recordings were repeated after methylatropine (0.02 mg/kg intravenously). The shortest R-R interval was taken to represent atrioventricular nodal refractoriness. The ratio of the longest to the shortest R-R interval and the coefficient of variation of R-R intervals were used as parameters of concealed conduction. 3. Methylatropine foremost shortened long R-R intervals: values for the mean, shortest and longest R-R intervals decreased from 834 to 685 ms (-18%) (P < 0.001), 573 to 498 ms (-13%) (P < 0.001) and 1228 to 924 ms (-25%) (P < 0.001), respectively. Accordingly, the ratio of the longest to the shortest R-R interval decreased: 2.12 to 1.89 (-11%) (P < 0.05). Also, the coefficient of variation decreased: 0.24 to 0.20 (-17%) (P < 0.05). 4. This study supports the contention that vagal stimulation lowers ventricular rate during atrial fibrillation both by exerting a direct effect on the atrioventricular node and by augmenting concealed conduction.

Adult↗
PubMed1994

Benefits and risks of antiarrhythmic drug therapy after DC electrical cardioversion of atrial fibrillation or flutter.

Electrical cardioversion is the method of choice to restore sinus rhythm in patients with chronic atrial fibrillation. After cardioversion, long-term maintenance of sinus rhythm is troublesome since many patients relapse. In addition, haemodynamic complications associated with recurrence and hazards of prophylactic antiarrhythmic drug therapy are among the problems threatening these patients. Several new antiarrhythmics have become available but their safety remains to be established. Advantages of prophylactic antiarrhythmic treatment must be carefully weighed against the hazards. As a consequence, non-pharmacological modalities like serial electrical cardioversions (no drugs) and His bundle ablation may become important treatment modalities. The present report summarizes current antiarrhythmic strategies, focusing primarily on feasibility of prophylactic treatment and on early and late proarrhythmia.

Anti-Arrhythmia Agents↗
PubMed1994

Long-term effect of cardioversion on peak oxygen consumption in chronic atrial fibrillation. A 2-year follow-up.

Restoration of sinus rhythm may improve functional capacity in atrial fibrillation in the short-term. Little is known, however, about its long-term effect on functional status. The aim of the present study was to evaluate the long-term effect of cardioversion on peak oxygen consumption (VO2) in patients with chronic atrial fibrillation. Patients with such a condition and due to undergo electrical cardioversion were eligible for the study. Patients underwent treadmill exercise testing with measurement of peak VO2 before cardioversion, and at 1 month and 2 years thereafter. Based on the rhythm present at those times after cardioversion, patients were categorized into three groups: those in sinus rhythm after 1 month and 2 years (Group I); those in sinus rhythm after 1 month, but with atrial fibrillation after 2 years (Group II); and those who were in atrial fibrillation both at 1 month and 2 years following cardioversion (Group III). Thirty-nine patients were included, and underlying heart disease was present in 24 of them (62%). In the comparison of the baseline characteristics of Group I (n = 17), Group II (n = 11), and Group III (n = 11), underlying heart disease was more frequent in Group I (88%, 45%, and 36%, respectively); otherwise they were similar. In Group I, peak VO2 showed an insignificant increase from 21.1 +/- 5.0 to 22.3 +/- 5.0 ml.min-1.kg-1 month after. cardioversion. After 2 years of sinus rhythm, peak VO2 showed a further increase to 23.8 +/- 5.0 ml.min-1.kg-1 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1994

Atrial flutter can be terminated by a class III antiarrhythmic drug but not by a class IC drug.

In atrial flutter, chemical conversion with class I drugs is often unsuccessful, whereas class III drugs seem more promising. The different electrophysiological effects of these drugs may explain this discrepancy. To date, only experimental data show the differential effects of these drugs on conversion rate and atrial flutter cycle length. This study evaluates the effects of the class IC antiarrhythmic drug flecainide, and of dofetilide, a new class III drug, on conversion rate and flutter cycle length in patients with atrial flutter. Flecainide (11 patients) was given as an intravenous bolus of 2 mg.kg-1 in 10 min and dofetilide (10 patients) as a maximum intravenous bolus of 8 micrograms.kg-1 in 15 min. Baseline characteristics were comparable between both groups. Only one patient treated with flecainide converted to sinus rhythm. This patient showed the largest flutter cycle length increase (280 to 420 ms). By contrast, seven of the 10 patients treated with dofetilide converted to sinus rhythm. Patients treated with flecainide showed a significantly larger increase in atrial flutter cycle length at the end of the infusion compared to the dofetilide-treated patients (from 226 +/- 28 to 317 +/- 52 ms vs from 221 +/- 26 to 239 +/- 39 ms, respectively). In conclusion, dofetilide is more effective than flecainide in the conversion of atrial flutter to sinus rhythm, despite the fact that flecainide produced a more prolonged flutter cycle length. Thus, action potential prolongation in the absence of conduction slowing seems more effective in terminating human atrial flutter than depression of the excitability.

Anti-Arrhythmia Agents↗