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Biomedical subjects

K I Lie

Publications and source records attributed to K I Lie.

At least 199 records · Page 11Linked to original sources
PubMed1994

Myocardial protection during coronary angioplasty with autoperfusion and forced perfusion: an in vitro comparison.

During coronary angioplasty, perfusion distal to the inflated angioplasty balloon can be maintained with autoperfusion balloon catheters and coronary perfusion pumps. The blood flow rates through the autoperfusion balloon catheters and the flow rates achieved with a perfusion pump were compared in vitro with fresh human blood at 37 degrees C. In a specially designed system, blood flow rates through Stack autoperfusion balloon catheters were measured at 40, 60 and 80 mmHg continuous pressure. In another system, driving pressures were measured during perfusion with the pump, through a specially designed forced perfusion catheter at 20, 40 and 60 ml/min flow. The pressure applied in the autoperfusion experiments was converted into atmospheres (atm) to facilitate comparison with the driving pressures measured during pumping (1 mmHg = 1.316 x 10(-3) atm). Mean flow rates through the autoperfusion balloon catheters were: 46 ml/min at 0.05 atm, 66 ml/min at 0.09 atm and 75 ml/min at 0.1 atm. Mean pressures during pumping were: 1.8 atm at 20 ml/min, 3.5 atm at 40 ml/min, 5 atm at 60 ml/min. Due to the phasic nature of coronary blood flow, the flow through autoperfusion balloons is generally lower than the minimum required for adequate myocardial protection (= 60 ml/min). Thus, autoperfusion balloon catheters are simpler and cheaper devices than perfusion pumps, but generally they are not able to provide adequate myocardial protection.

Angioplasty, Balloon, Coronary↗
PubMed1993

Double-blind placebo-controlled study of ibopamine and digoxin in patients with mild to moderate heart failure: results of the Dutch Ibopamine Multicenter Trial (DIMT).

OBJECTIVES: This study was conducted to determine the efficacy and safety of long-term treatment with the orally active dopamine agonist ibopamine in patients with mild to moderate chronic congestive heart failure and to compare the results with those of treatment with digoxin and placebo. BACKGROUND: Ibopamine and digoxin are drugs that exert hemodynamic and neurohumoral effects. Because there is accumulating evidence that progression of disease in chronic heart failure is related not only to hemodynamic but also to neurohumoral factors, both drugs might be expected to have a favorable long-term effect. METHODS: We studied 161 patients with mild to moderate chronic heart failure (80% in New York Heart Association functional class II and 20% in class III), who were treated with ibopamine (n = 53), digoxin (n = 55) or placebo (n = 53) for 6 months. Background therapy consisted of furosemide (0 to 80 mg); all other drugs for heart failure were excluded. Clinical assessments were made at baseline and after 1, 3 and 6 months. RESULTS: Of the 161 patients, 128 (80%) completed the study. Compared with placebo, digoxin but not ibopamine significantly increased exercise time after 6 months (p = 0.008 by intention to treat analysis). Ibopamine was only effective in patients with relatively preserved left ventricular function, as it significantly increased exercise time in this subgroup (for patients with a left ventricular ejection fraction > 0.30; p = 0.018 vs. placebo). No patient receiving digoxin withdrew from the study because of progression of heart failure, compared with six patients receiving ibopamine and two receiving placebo. At 6 months, plasma norepinephrine was decreased with digoxin and ibopamine therapy (-106 and -13 pg/ml, respectively) but increased with placebo administration (+62 pg/ml) (both p < 0.05 vs. placebo). Plasma aldosterone was unaffected, but renin was decreased by both agents after 6 months (p < 0.05 vs. placebo). Total mortality and ambulatory arrhythmias were not significantly affected by the two drugs. CONCLUSIONS: Ibopamine and digoxin both inhibit neurohumoral activation in patients with mild to moderate chronic heart failure. However, the clinical effects of these drugs are different and appear to be related to the degree of left ventricular dysfunction.

Adolescent↗
PubMed1993

Changes in left and right atrial size after cardioversion of atrial fibrillation: role of mitral valve disease.

OBJECTIVES: The aim of this study was to examine the effect of cardioversion on left and right atrial volume in patients with chronic atrial fibrillation and to determine the influence of mitral valve disease on atrial size. BACKGROUND: Atrial enlargement is a common finding in atrial fibrillation and has been associated with an increased risk for embolic stroke. In addition, atrial enlargement may hamper long-term maintenance of sinus rhythm after cardioversion. METHODS: Forty-one patients with chronic atrial fibrillation (mean duration +/- SD, 45 +/- 62 months) underwent two-dimensional echocardiography before and 6 months after cardioversion to determine left and right atrial dimensions. Underlying heart disease was present in 26 patients: mitral valve disease in 12 (stenosis in 5, regurgitation in 5 and a combination in 2 patients) and other heart diseases in 14. Fifteen patients had lone atrial fibrillation. Patients with sustained sinus rhythm were compared with those who had a relapse of the arrhythmia 6 months after cardioversion. RESULTS: Six months after cardioversion, 28 patients still had sinus rhythm, whereas 13 patients had a relapse of the arrhythmia. In the 28 patients who had sinus rhythm after 6 months, left and right atrial volume decreased from a mean (+/- SD) 72.6 +/- 15.1 to 58.5 +/- 13.8 cm3 (-20%, p < 0.05) and from 68.7 +/- 14.6 to 58.6 +/- 11.6 cm3 (-14%, p < 0.05), respectively. Atrial dimensions also decreased significantly in the subgroup of patients with mitral valve disease. In contrast, no change in atrial size occurred in the 13 patients who had a relapse of atrial fibrillation. Left ventricular function did not change between the two echocardiographic studies, although New York Heart Association class improved in patients who had sinus rhythm after 6 months. CONCLUSIONS: Restoration of sinus rhythm reverts the process of left and right atrial enlargement in patients with chronic atrial fibrillation and mitral valve disease. Therefore, cardioversion may reduce the incidence of thromboembolic complications and prevent the arrhythmia from becoming refractory to medical therapy.

Aged↗
PubMed1993

[Carbon monoxide poisoning as a trigger for myocardial infarction].

A male aged 70 became unwell during work on the motor of his boat. He had an acute myocardial infarction, complicated by arrhythmias, which had probably been triggered by carbon monoxide intoxication. After treatment with, among other things, oxygen he recovered. Although the patient had experienced mild angina pectoris in the past, he had been symptom-free for years without medication. It is therefore suggested that the carbon monoxide intoxication played an important part in this case.

Aged↗
PubMed1993

Transneuronal viral labelling of rat heart left ventricle controlling pathways.

Retrograde transneuronal viral labelling and immunocytochemical methods were used for revealing neuronal networks controlling the left ventricle myocardium of the rat heart. After injections of 1 microliter pseudorabies virus solution (3 x 10(6) PFU ml-1) into the left ventricle, infected orthosympathetic preganglionic cells were found in the intermediolateral cell groups of the first 6 thoracic spinal segments. Preganglionic parasympathetic neurones were seen both in the nucleus ambiguus/retro-ambiguus area and the dorsal motor vagus nucleus. Large numbers of infected projecting interneurones were found in the rostral, caudal and medial parts of the ventral medulla oblongata, the Kölliker-Fuse nucleus and catecholaminergic cell group A5 and in the paraventricular hypothalamic nucleus.

Animals↗
PubMed1993

Effects of streptokinase during acute myocardial infarction on the signal-averaged electrocardiogram and on the frequency of late arrhythmias.

Although a number of studies have shown that the incidence of late potentials is lower after thrombolytic therapy, it is not known whether this is paralleled by fewer arrhythmic events during long-term follow-up. In patients with first acute myocardial infarction, filtered QRS duration was significantly shorter when treated with streptokinase (95 +/- 11 ms, n = 53) than when treated with conventional therapy (99 +/- 12 ms, n = 77, p < 0.05). The low-amplitude signal (D40) was shorter after thrombolysis (28 +/- 11 vs 33 +/- 12 ms, p < 0.02). Terminal root-mean-square voltage did not differ significantly (41 +/- 24 vs 35 +/- 23 microV). Irrespective of treatment, late potentials were predictive in the complete group (n = 171) for arrhythmic events during follow-up (13 +/- 6 months, range 6 to 24) (hazard ratio 7.7, p < 0.02, Cox proportional-hazards survival analysis), but treatment (streptokinase vs conventional) did not significantly affect outcome when added to the model. It is concluded that thrombolysis prevents the development of late potentials. However, this study does not confirm the hypothesis that prevention of late potentials leads to a decrease in arrhythmic events.

Adult↗
PubMed1993

Time course of hemodynamic changes and improvement of exercise tolerance after cardioversion of chronic atrial fibrillation unassociated with cardiac valve disease.

This study prospectively assessed the time course, magnitude and mechanism of the hemodynamic changes after restoration of sinus rhythm in patients with chronic atrial fibrillation (AF) unassociated with valvular disease. Severe cardiac dysfunction may occur after chronic supraventricular tachycardia in patients with and without underlying cardiac disease. Improvement may follow abolishment of the arrhythmia or adequate slowing of the ventricular rate. Eight patients were studied with a mean previous duration of AF of 10 +/- 9 months. Ejection fraction, exercise capacity and the atrial contribution to the left ventricular filling (only during sinus rhythm) were studied before cardioversion, after cardioversion and 1 week, 1 month and 6 months thereafter. A significant improvement in ejection fraction from 36 +/- 13 to 53 +/- 8% (p < 0.05) occurred at 1 month after cardioversion. Concomitantly, peak oxygen consumption had increased at 1 month, from 20.1 +/- 7 to 25.2 +/- 6 ml/min/kg (p < 0.05). Thereafter, no further improvement in hemodynamic parameters occurred. The atrial systole improved already at 1 week (from 3 +/- 5 to 16 +/- 11%, p < 0.05) and remained unchanged thereafter. Thus, restoration of sinus rhythm was associated with a delayed improvement in ejection fraction and maximal exercise capacity, preceded by an early restoration of atrial contractility and an acute slowing of the heart rate. The discrepancy in time course of restoration of atrial and ventricular function parameters suggests that an intrinsic left ventricular cardiomyopathy is present in patients with AF.

Aged↗
PubMed1993

Prevention of one-year vein-graft occlusion after aortocoronary-bypass surgery: a comparison of low-dose aspirin, low-dose aspirin plus dipyridamole, and oral anticoagulants. The CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands.

Aspirin, alone or in combination with dipyridamole, is known to prevent occlusion of aortocoronary vein grafts. The benefit of dipyridamole in addition to aspirin remains controversial, and the efficacy and safety of oral anticoagulants for prevention of vein-graft occlusion have not been established. We assessed one-year angiographic vein-graft patency after aortocoronary-bypass surgery in 948 patients assigned to receive aspirin, aspirin plus dipyridamole, or oral anticoagulants in a prospective, randomised trial. The design was double-blind and placebo-controlled for the aspirin groups, but open for oral anticoagulant treatment. Dipyridamole (5 mg/kg per 24 h intravenously for 28 h, followed by 200 mg twice daily) and oral anticoagulants (desired prothrombin time range 2.8-4.8 international normalised ratio) were started before surgery, and aspirin (50 mg per day) was started after surgery. Clinical outcome was assessed by the incidence of myocardial infarction, thrombosis, major bleeding, or death. Occlusion rate of distal anastomoses was 11% in the aspirin plus dipyridamole group versus 15% in the aspirin group (relative risk 0.76, 95% CI 0.54-1.05) and 13% in the oral anticoagulants group. Clinical events occurred in 20.3% of patients receiving aspirin plus dipyridamole compared with 13.9% of the aspirin group (relative risk 1.46, 95% CI 1.02-2.08) and 16.9% of the oral anticoagulants group. Our data provide no convincing evidence that addition of dipyridamole to 50 mg aspirin per day improves aortocoronary vein-graft patency. Moreover, there is evidence that the combination increases the overall clinical-event rate. Compared with aspirin, oral anticoagulants provided no benefit.

Acenocoumarol↗
PubMed1993

Recurrence of paroxysmal atrial fibrillation or flutter after successful cardioversion in patients with normal left ventricular function.

One hundred twenty-four consecutive patients (85%) with paroxysmal atrial fibrillation (AF) and 21 (15%) with atrial flutter (AFI) were studied immediately after pharmacologic or electrical cardioversion to sinus rhythm. Mean age was 59 +/- 13 years (range 23 to 79). Patients with reduced left ventricular function were excluded from the study. After restoration to sinus rhythm, the clinical course of all patients was followed for the first recurrence of paroxysmal AF or AFI irrespective of the therapeutic approach. Mean follow-up was 23 +/- 16 months. After 12 months of follow-up, 50% of all patients remained in sinus rhythm. Univariate analysis indicated that coronary artery disease (relative risk 1.9; 95% confidence interval 0.9-3.9), history of paroxysmal AF or AFI (2.3; 1.1-5.0), female sex (2.3; 1.1-4.6), pulmonary disease (3.9; 1.9-7.6) and valvular heart disease (4.4; 2.2-8.8) were associated with an increased risk for recurrent or frequent episodes of paroxysmal AF or AFI. No predictors were found to be associated with a decrease in length of the recurrence-free period after successful conversion to sinus rhythm. Multivariate analysis identified history of AF or AFI (odds ratio 2.5; 95% confidence interval 0.9-6.4), coronary artery disease (3.1; 1.1-8.2) and female sex (3.4; 1.3-8.9) as independent predictors for recurrent or frequent episodes of paroxysmal AF or AFI. The presence of these risk factors should be taken into account when prophylactic therapy with antiarrhythmic drugs is being considered in the treatment of paroxysmal AF or AFI.

Adult↗
PubMed1993

Early stent occlusion is not always caused by thrombosis.

Early occlusion of intracoronary stents has been exclusively attributed to thrombosis. Using intracoronary angioscopy, we have found 2 patients in whom this common and serious complication of coronary stenting was caused by obstructive intima dissection rather than thrombosis.

Aged↗
PubMed1993

Internal balloon tamponade: a non-surgical method for removal of accidentally placed sheaths from the subclavian artery.

One of the possible complications of subclavian vein puncture is accidental puncture of the subclavian artery. If this is not noted immediately after the puncture, insertion of a large bore sheath in the subclavian artery is likely to follow. We describe our experience with a new method that enables successful and safe removal of such sheaths without notable blood loss, in three patients.

Aged↗
PubMed1993

In vitro evaluation of blood flow through autoperfusion balloon catheters.

The effective flow rates with human blood through an autoperfusion catheter cannot be monitored in vivo and have not been experimentally determined in vitro. The manufacturers (Advanced Cardiovascular Systems [ACS], Temecula, CA) have suggested that "the flow rate" through the Stack over the wire and the RX-60 monorail catheter is 60 ml/min with a pressure gradient of 80 mmHg. We measured human blood flow rates in vitro through these catheters under different continuous pressure regimens (between 40 and 120 mmHg), with varying hematocrit levels (between 25% and 62%). Measured blood flows at a gradient of 80 mmHg were found to vary from 32 to 65 cc/min, with hematocrit levels of 62-25%. Minor variations in the circuitry, besides the viscosity of the medium, cause significant changes in observed flow rates (such as kinking of the catheter and blood sedimentation). In vitro determinations of blood flows cannot automatically be transferred to the in vivo condition, primarily because in vitro determinations do not account for the systolic intramural pressure increase (which may overcome the aortic pressure). If such a phenomenon is also considered, then the in vitro flow rates reported here should be multiplied by a factor of 0.40-0.60 to determine effective in vivo flow rates. Such information is relevant for the clinical operator of angioplasty, especially in the treatment of patients at high risk for undergoing percutaneous transluminal coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed1993

Exercise-induced ventricular tachycardia: a rare manifestation of digitalis toxicity.

Digitalis intoxication is one of the most common adverse drug reactions. Although some arrhythmias are seen more frequently than others, virtually any rhythm disturbance, including ventricular tachycardia, may occur. However, to our knowledge, exercise-induced ventricular tachycardia as a complication of digitalis therapy has never been described before. This case presents a patient with a digitalis-induced ventricular tachycardia occurring exclusively during exercise.

Digoxin↗