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Biomedical subjects

K I Lie

Publications and source records attributed to K I Lie.

At least 109 records · Page 6Linked to original sources
PubMed1996

Limited value of stress electrocardiographic changes in predicting late 201Tl reversibility: do all patients need reinjection?

The aim of this study was to assess the relationship between the exercise electrocardiogram (ECG) and late thallium-201 (201Tl) reversibility in a series of 72 consecutive patients with undiagnosed chest pain and an initial persistent perfusion defect on conventional stress/4-h redistribution imaging. We wished to establish the diagnostic accuracy of the exercise ECG in predicting the outcome of late 201Tl reversibility. All 72 patients, of whom 44 (61%) had had a previous myocardial infarction (MI), underwent quantitative planar 201Tl stress-redistribution imaging followed by resting 201Tl imaging 1-4 days later. Fifty (69%) patients showed exercise ECG changes during conventional stress-redistribution imaging, of whom 30 (42%) had a history of previous MI and 20 (28%) had suspected coronary artery disease (CAD). The overall diagnostic accuracy of the exercise ECG in predicting 201Tl reversibility was 83% (60/72 patients): 75% (21/28 patients) in patients with suspected CAD and 87% (39/44 patients) in patients with previous MI. Only the patients with a previous MI and a negative exercise ECG showed 100% accuracy (n = 14). We conclude that reinjection of 201Tl might be withheld in patients with a previous MI and a negative exercise ECG. For patients with previous MI and a positive exercise ECG, and for patients with suspected coronary artery disease regardless of the result of their exercise ECG, reinjection of 201Tl should be strongly considered if the redistribution images are abnormal, because of the suboptimal diagnostic accuracy of the exercise ECG in these patients.

Adult↗
PubMed1996

Electrophysiological, rate dependent, and autonomic effects of the class III antiarrhythmic almokalant after myocardial infarction in the pig.

Ventricular arrhythmias remain a major problem, in particular in patients with left ventricular dysfunction or heart failure. In this group of patients, Class I drugs were shown to be ineffective, and they even increased mortality during chronic treatment. New antiarrhythmic agents should preferably not only have pure antiarrhythmic effects, but should also be free from adverse autonomic properties. In the present study, the electrophysiological, rate dependent and autonomic effects of intravenously administered almokalant, a new Class III antiarrhythmic drug, were investigated in nine pigs surviving a myocardial infarction. The ventricular effective refractory period (VERP) increased after almokalant (loading dose: 0.05 mumol.kg-1.min-1, continuous infusion: 0.0025 mumol.kg-1.min-1) from 292 +/- 25 to 308 +/- 13 ms (pacing cycle length [PCL] 500 ms + 1 extrasystole [ES]), from 249 +/- 19 to 261 +/- 16 ms (PCL 400 ms +1ES), and from 209 +/- 18 to 219 +/- 18 ms (PCL 300 ms +1ES). The VERPs increased most after three ES at PCL 400 ms: from 167 +/- 27 to 186 +/- 29 ms (P < 0.05) and at PCL 300 ms: from 150 +/- 29 to 174 +/- 27 ms (P < 0.05). The ventricular monophasic action potential durations (MAPD) were similarly prolonged and the ratio VERP/MAPD did not change. Prolongation of MAPD after almokalant remained present at short pacing cycle lengths. Before almokalant infusion, sustained monomorphic ventricular tachycardia (VT) was inducible in two pigs, and nonsustained VT in a third animal. After almokalant, only one pig remained inducible. Two weeks after myocardial infarction, heart rate variability and baroreflex sensitivity were reduced. Furthermore, subsequent electrophysiological testing transiently reduced these parameters of autonomic activity. During almokalant however, no changes in autonomic functions were observed after programmed stimulation. Heart rate variability decreased after myocardial infarction from 6.3 +/- 2.5 ms to 5.4 +/- 4.2 ms (P = NS). After programmed stimulation, it further decreased to 2.8 +/- 2.0 ms (P = 0.028). Almokalant infusion prevented autonomic deterioration: 3.3 +/- 2.2 ms before stimulation and 3.3 +/- 1.3 after stimulation (P = NS). In postinfarct pigs, almokalant prolongs VERP and MAPD at shorter pacing cycle lengths. The results indicate absence of reverse rate dependence and of adverse autonomic changes.

Action Potentials↗
PubMed1996

Beta adrenergic blockade in the treatment of sustained ventricular tachycardia or ventricular fibrillation.

The value of beta-blockers as antiarrhythmic drugs in patients with sustained VT or VF has received only little attention. This article summarizes the current state of knowledge regarding the identification of patients with sustained VT or VF with the highest benefit of beta-blockade. The antiarrhythmic mechanisms of beta-blockade and its efficacy as single or adjuvant therapy in patients with sustained VT or VF are reviewed. Current insights into the effects of beta-blockade in patients suffering from VT, in particular in the setting of heart failure, are discussed and future directions are considered.

Adrenergic beta-Antagonists↗
PubMed1996

Effects of lacidipine on peak oxygen consumption, neurohormones and invasive haemodynamics in patients with mild to moderate chronic heart failure.

OBJECTIVE: To evaluate the efficacy and safety of the second generation dihydropyridine calcium channel blocker lacidipine in patients with heart failure. DESIGN: Placebo controlled, parallel group, double blind study over 8 weeks. SETTING: General community hospital in Breda, The Netherlands. PATIENTS: A random sample was studied of 25 outpatients with symptoms of mild to moderate heart failure, despite treatment with diuretics, digoxin, and angiotensin converting enzyme inhibitors. Their mean age was 65 years, with mean left ventricular ejection fraction of 0.24 and a peak oxygen consumption of 14.4 ml/min/kg. Two patients dropped out on lacidipine, one patient on placebo. INTERVENTION: Treatment with lacidipine 4 mg once daily or placebo for eight weeks. MAIN OUTCOME MEASURE: Cardiopulmonary exercise testing, invasive haemodynamics, and plasma neurohormones. RESULTS: Treatment with lacidipine 4 mg once daily, as compared to placebo treatment, significantly improved peak oxygen consumption (P < 0.02), cardiac index (P < 0.01), and stroke volume (P < 0.03) paralleled by a decrease in systemic vascular resistance (P < 0.03) and arteriovenous oxygen content difference (P < 0.01). Plasma noradrenaline, plasma renin activity, and aldosterone values did not differ between lacidipine and placebo. CONCLUSIONS: This second generation dihydropyridine may be of value as an adjunct to standard treatment in congestive heart failure patients.

Aged↗
PubMed1996

Increased myocardial [123I]-metaiodobenzylguanidine uptake after enalapril treatment in patients with chronic heart failure.

OBJECTIVE: To assess non-invasively the effect of enalapril on cardiac sympathetic neuronal uptake function in patients with congestive heart failure, by using [123I]-metaiodobenzylguanidine (MIBG), which is a noradrenaline analogue. Cardiac MIBG uptake was visualised by single photon emission tomography (SPET). In addition, plasma noradrenaline concentration, indicating systemic sympathetic activity, was measured to see whether it was related to cardiac MIBG uptake. DESIGN: Consecutive patients were treated with enalapril and served as their own controls. SETTING: Cardiac unit of a tertiary care centre. PATIENTS: 23 Patients with chronic, mild to moderate, stable congestive heart failure, and a left ventricular ejection fraction less than 40%. Heart failure was caused by ischaemic heart disease or was idiopathic. INTERVENTIONS: Cardiac MIBG SPET was performed and plasma noradrenaline concentration was measured before and after 6 weeks treatment with enalapril. MAIN OUTCOME MEASURES: Cardiac uptake of MIBG was measured by using the left ventricular cavity and a venous blood sample as a reference. RESULTS: Cardiac uptake of MIBG increased significantly after enalapril treatment, indicating improved cardiac neuronal uptake function. Plasma noradrenaline concentration did not decrease significantly. Cardiac MIBG uptake was not related to plasma noradrenaline concentration. CONCLUSIONS: Cardiac MIBG SPET can be used to assess changes in cardiac sympathetic neuronal uptake function caused by pharmacological intervention. Enalapril seemed to improve cardiac sympathetic neuronal uptake function but did not significantly affect plasma noradrenaline concentrations in a group of patients with predominantly moderate heart failure. These results accord with the hypothesis that restoration of cardiac neuronal uptake of noradrenaline is one of the beneficial effects of enalapril in such patients.

3-Iodobenzylguanidine↗
PubMed1996

Effects of permanent dual chamber pacing on myocardial perfusion in symptomatic hypertrophic cardiomyopathy.

OBJECTIVE: Angina and the presence of myocardial ischaemia are common in hypertrophic cardiomyopathy. Dual chamber pacing results in clinical improvement in these patients. This study evaluates the effects of permanent dual chamber pacing on absolute regional myocardial perfusion and perfusion reserve. SETTING: University hospital. PATIENTS AND DESIGN: Six patients with hypertrophic cardiomyopathy and severe symptoms of angina received a dual chamber pacemaker. Absolute myocardial regional perfusion and perfusion reserve (dipyridamole 0.56 mg/kg) were measured by dynamic positron emission tomography with 13N-ammonia both during sinus rhythm and 3 months after pacemaker insertion. Results were compared with those from 28 healthy volunteers. RESULTS: Pacing resulted in a reduction of anginal complaints and a reduction in intraventricular pressure gradient from 65 (SD 30) mm Hg to 19 (10) mm Hg. During sinus rhythm, baseline perfusion was higher in patients with hypertrophic cardiomyopathy than controls (184 (31) v 106 (26) ml/min/100 g, P < 0.01), and perfusion reserve was lower (1.6 (0.4) v 2.8 (1.0), P < 0.05). During pacing myocardial perfusion decreased to 130 (27) ml/min/100 g (P < 0.05), with variable responses in terms of perfusion reserve. Pacing caused a redistribution of myocardial stress perfusion and perfusion reserve. The coefficient of regional variation of myocardial stress perfusion decreased from 19.7 (7.0)% to 14.6 (3.9)% during pacing (12.9 (3.8)% in controls, P < 0.01). The coefficient of regional variation of perfusion reserve decreased from 16.7 (6.6)% to 11.4 (2.6)% during pacing (9.8 (4.1)% in controls, P < 0.01). CONCLUSIONS: Pacing caused a decrease of resting left ventricular myocardial blood flow and blood flow during pharmacologically induced coronary vasodilatation. Although global perfusion reserve remained unchanged, myocardial perfusion reserve became more homogeneously distributed.

Adult↗
PubMed1996

Evidence for a synergistic effect of calcium channel blockers with lipid-lowering therapy in retarding progression of coronary atherosclerosis in symptomatic patients with normal to moderately raised cholesterol levels. The REGRESS Study Group.

To date, lipid-lowering therapy appears to be the most effective medical intervention to retard progression of coronary atherosclerosis. In spite of promising experimental results, clinical trials completed so far have failed to demonstrate that calcium channel blockers (CCBs) alone influence the evolution of established coronary atherosclerosis. To assess whether the two therapies may have an additive or synergistic beneficial effect on human atherosclerosis, we reviewed in this regard the data of the angiographic Regression Growth Evaluation Statin Study (REGRESS) trial. REGRESS was designed to determine the effect of lipid-lowering therapy with pravastatin in symptomatic patients with normal to moderately raised cholesterol levels. Angiographically, with respect to the minimum obstruction diameter, in the pravastatin group, patients had on average 0.05 mm (95% confidence interval [CI]: 0.01-0.09) less progression if cotreated with CCBs compared with no CCB treatment, whereas in the placebo (no pravastatin) group, no effect of CCB treatment was observed (interaction test for differential effect of CCB treatment in patients with pravastatin compared with patients receiving placebo: P=.0016). With respect to the mean segment diameter, similar although not significant (P=.33) results were found. With respect to new lesion formation, in the pravastatin group, there were 50% (CI: 25-83) fewer patients with new angiographic lesions if cotreated with CCBs compared with no CCB cotreatment, whereas in the placebo (no pravastatin) group, no significant effect of CCB treatment was observed (interaction test: P=.0026). No beneficial effects of CCB treatment on clinical events were observed. Although the REGRESS trial was not designed to evaluate combination therapy, the results suggest strongly that addition of CCBs to 3-hydroxy-3-methyl-glutaryl-coenzyme reductase inhibitor therapy (pravastatin) acts synergistically in retarding the progression of established coronary atherosclerosis.

Aged↗
PubMed1996

Aprotinin in aortocoronary bypass surgery: increased risk of vein-graft occlusion and myocardial infarction? Supportive evidence from a retrospective study.

To assess the thrombotic risk of aprotinin in aortocoronary bypass surgery, we retrospectively analyzed the results of a trial, originally designed to compare the effects of one-year treatment with various antithrombotic drugs in the prevention of vein-graft occlusion. Graft patency at one year was assessed by angiography. Myocardial infarction, thromboembolism, major bleeding, and death were clinical endpoints. Of 948 randomized patients, 42 received aprotinin, all enrolled by one of the participating centres. Occlusion rates of distal anastomoses were 20.5% in the aprotinin group and 12.7% in the non-aprotinin group (p = 0.091). The proportions of patients with occluded grafts were 44.1% versus 26.3% (p = 0.029). Perioperative myocardial infarction occurred in 14.3% and 7.0%, respectively (p = 0.12). Mean postoperative blood loss was 451 ml in the aprotinin group compared with 1039 ml in the non-aprotinin group (p < 0.0001). Mean transfusion requirements were 1.1 U versus 2.1 U of red blood cells (p = 0.004). Aprotinin decreases blood loss and transfusion requirement. Our data suggest that this benefit may be associated with a reduction of graft patency and an increased risk of myocardial infarction.

Aprotinin↗
PubMed1996

Angiographic left ventricular wall motion score to predict arrhythmia recurrence in patients with sustained ventricular tachycardia or fibrillation.

METHODS: Sixty-nine patients with sustained ventricular tachyarrhythmias were followed up to evaluate the predictive value of functional capacity (i.e., New York Heart Association class and peak oxygen consumption) and resting left ventricular function (i.e. radionuclide left ventricular ejection fraction, angiographic left ventricular wall motion score and echocardiographic dimensions) with respect to arrhythmia recurrence. RESULTS: During a mean follow-up of 19 months 18 patients (26%) had an arrhythmia recurrence. Parameters of functional capacity and echocardiographic dimensions were not related to arrhythmia recurrence. Left ventricular ejection fraction and wall motion score were worse in patients with a recurrence compared with the arrhythmia-free patients: 30 +/- 16% versus 40 +/- 19% (mean +/- SD, P = 0.035) and 25 +/- 7 versus 20 +/- 7 (P = 0.01), respectively. Multivariately the most powerful parameter was left ventricular wall motion score (odds ratio 1.12, 95% Cl 1.02-1.23). CONCLUSIONS: Arrhythmia recurrence in ventricular tachyarrhythmia patients relates to resting left ventricular function and not to functional capacity. Since angiographic left ventricular wall motion score is prognostically more important than ejection fraction this parameter should be considered for risk stratification in these patients.

Aged↗
PubMed1996

Cardiac sympathetic neuronal function in left ventricular volume and pressure overload.

OBJECTIVES: In heart failure cardiac sympathetic neuronal function and activity appear to be altered. Although these changes are widely accepted, controversy exists concerning the neurohormonal changes occurring in pressure and volume overloaded hearts. The present study in rabbits was performed to assess the effects of mechanical overload on cardiac sympathetic neuronal function and beta-adrenoceptor density, in relation to left ventricular function. METHODS: In nine rabbits the aortic valve was perforated to induce left ventricular volume overload. Pressure overload was induced by suprarenal banding of the aorta abdominalis (group 1). Five animals were sham operated (group 2). Subanalysis of group 1 was performed for non-failing (n = 5) and failing (n = 4) hearts. Heart failure was defined as any reduction in left ventricular fractional shortening 2 weeks after the second operation compared to baseline. RESULTS: In animals with cardiac overload, left ventricular weight was higher compared with the control animals, 7.99 +/- 1.13 vs. 6.16 +/- 0.86 g (P < 0.02). Left ventricular end diastolic diameter increased from 1.35 +/- 0.16 to 1.57 +/- 0.15 cm (P < 0.005) after surgically induced overload. Left ventricular end systolic diameter and fractional shortening did not change significantly. Myocardial noradrenaline (NA) concentration and beta-adrenoceptor density were significantly lower in group 1 than in group 2, 1005 +/- 393 vs. 1643 +/- 109 ng/g (P < 0.02) and 167 +/- 36 vs. 224 +/- 36 fmol/mg protein (P < 0.03), respectively. Myocardial [123I]-MIBG uptake did not significantly differ between group 1 and 2, 2.1 +/- 0.58 vs. 1.8 +/- 0.44 (%ID/g x kg). A significant positive correlation between myocardial NA concentration and beta-adrenoceptor density was found (r = 0.66, P < 0.02). Myocardial NA concentration was inversely related to left ventricular weight (r =-0.75, P < 0.003). CONCLUSION: The present data indicate that in a condition of cardiac volume and pressure overload, sympathetic activity is enhanced as shown by myocardial noradrenaline depletion and beta-adrenoceptor downregulation. In contrast, no cardiac neuronal dysfunction is observed, even in the stage of early heart failure.

3-Iodobenzylguanidine↗
PubMed1996

Comparison of myocardial uptake of fluorine-18-fluorodeoxyglucose imaged with PET and SPECT in dyssynergic myocardium.

UNLABELLED: PET with 18F-fluorodeoxyglucose (FDG) can detect viable myocardium and predict functional recovery after revascularization. The use of PET for clinical routine, however, is limited. Recently, imaging FDG with SPECT was proposed. The aim of this study was to compare the diagnostic value of FDG-PET and FDG-SPECT in the detection of viable myocardium in segments with abnormal wall motion. METHODS: Twenty patients with previous myocardial infarction were studied. All underwent FDG-PET and FDG-SPECT during hyperinsulinemic glucose clamping. Regional perfusion was assessed with 13N-ammonia PET and early resting 201TI- SPECT. Regional wall motion was assessed with two-dimensional echocardiography. The agreement between FDG/13N-ammonia PET and FDG/201TISPECT to detect viability in dyssynergic myocardium was 76%. On a patient basis, PET and SPECT yielded comparable results in 17 of 20 patients. In a subgroup of patients with LVEF < or = 35% (n = 12), all PET and SPECT viability data were identical. CONCLUSION: This study shows a good correlation between the detection of viability in dyssynergic myocardium with FDG/13N-ammonia PET and FDG/201TI SPECT, both on a segmental and patient basis.

Ammonia↗
PubMed1996

Acceptance and side effects of ambulatory blood pressure monitoring: evaluation of a new technology.

Ambulatory blood pressure (BP) monitoring is probably becoming a clinically useful procedure for the evaluation of hypertensive patients. Previous reports have shown that the devices are safe and serious side effects are rare. Discomfort and inconveniences associated with its use are more frequent. In this study, patient acceptance of ambulatory blood pressure monitoring (ABPM) was compared with acceptance of other diagnostic procedures and their side effects were assessed. Patients were asked to fill in a form and 129 of 166 patients responded. The acceptance was measured with a visual analogue scale which ranged from 'very annoying' on the left to 'not annoying at all' on the right. All forms were collected anonymously. Mean distance (cm) of the visual likert scale was 8.6 to 9.4 for the diagnostic procedures frequently used in routine patient care. Ambulatory BP measurement (ABPM) scored 6.1 cm. Reported side effects (in 27% of patients) were: plan (9%), skin irritation (8%), noisy device (8%), inconvenience with work (3%), haematoma (2%) and other (4%). Reports from the patients on sleep quality were: 23% normal, 61% minor disturbance, 14% had sleep, and 2% did not sleep at all. It can be concluded that ambulatory BP monitoring was the diagnostic procedure with the lowest patient acceptance. Side effects of this new technology were reported by 27% of patients. However, risks are relatively minor. Sleep disturbances were very frequent and was a serious problem for 16% of patients.

Blood Pressure Monitoring, Ambulatory↗
PubMed1995

Evaluation of importance of central effects of atenolol and metoprolol measured by heart rate variability during mental performance tasks, physical exercise, and daily life in stable postinfarct patients.

BACKGROUND: Physical exercise and mental work cause alterations in cardiac autonomic control. beta-Blockers protect the heart against stress, and this effect may be in part centrally mediated. In this context, the lipophilicity of the drug would be clinically relevant. METHODS AND RESULTS: Thirty postinfarct patients were randomized to receive 100 mg atenolol or 200 mg metoprolol CR in a double-blind, crossover manner, each for a 6-week period. Heart rate (HR) variability was used to study autonomic effects during mental and physical stress and to study circadian variations. Mean 24-hour HR decreased from 77 +/- 7 to 60 +/- 6 beats per minute after atenolol and to 62 +/- 6 beats per minute after metoprolol (P = .046). At baseline, mental performance tasks did not affect HR, but decreased HR variability (SDNN index from 51 +/- 26 to 30 +/- 13 milliseconds [ms], P < .001; high-frequency power from 130 +/- 143 to 110 +/- 125 ms2, P = .046; and low-frequency power from 538 +/- 447 to 290 +/- 275 ms2, P < .001). Both beta-blockers decreased HR during mental performance tasks (P < .001) and increased SDNN index and high-frequency power. Before treatment, bicycle exercise decreased HR variability; root-mean-square of successive difference decreased from 21 +/- 8 to 15 +/- 10 ms (P = .004). beta-Blockade could not prevent this decrease. No differences between atenolol and metoprolol were observed for absolute high- and low-frequency power or after adjustment for HR. Vagal blockade with methylatropine during chronic beta-blocker treatment nearly abolished all components of spectral power. HR was found to be the parameter most strongly affected by beta-blockade but not by an influence on vagal tone. No differences were found between atenolol and metoprolol. CONCLUSIONS: In stable postinfarct patients, chronic treatment with metoprolol and atenolol attenuates the reduction in HR variability induced by mental performance tasks, but the effects during exercise are limited. beta-Blockers do not appear to increase vagal tone in this stable patient group. The point of action in these patients is mainly a reduction in HR, probably due to a reduction in stress-induced sympathetic activation. Clinically significant differences between atenolol and metoprolol were absent, indicating that the degree of lipophilicity does not distinguish among the beta-blockers what their salutary effects are on HR variability during the specific challenges used.

Activities of Daily Living↗
PubMed1995

Left ventricular beat-to-beat performance in atrial fibrillation: contribution of Frank-Starling mechanism after short rather than long RR intervals.

OBJECTIVES: This study sought to evaluate control mechanism of the varying left ventricular performance in atrial fibrillation. BACKGROUND: Atrial fibrillation is characterized by a randomly irregular ventricular response, resulting in continuous variation in left ventricular beat-to-beat mechanical behavior and hemodynamic variables. METHODS: Fourteen patients with chronic nonvalvular atrial fibrillation were studied, using a nonimaging computerized nuclear probe linked to a personal computer. Left ventricular ejection fraction, end-diastolic and end-systolic volume counts, stroke volume counts and filling time were calculated on a beat-to-beat basis during 500 consecutive RR intervals. Multiple regression analysis was used to assess how ejection fraction was predicted by these variables. RESULTS: The preceding RR interval and end-diastolic volume showed a positive relation, and prepreceding interval and end-systolic volume an inverse relation, with ejection fraction (all p < 0.001). Sensitivity analysis suggested that the preceding interval and the end-diastolic volume were equally important in predicting ejection fraction. There was a relatively strong interaction between the preceding interval and end-diastolic volume, indicating that the influence of the end-diastolic volume on ejection fraction was diminished after long intervals. A second interaction showed that the effect of end-diastolic volume on ejection fraction was attenuated after short prepreceding cycles. CONCLUSIONS: Cycle length-dependent contractile mechanisms, including postextrasystolic potentiation and mechanical restitution, determine the varying left ventricular systolic performance during atrial fibrillation over the entire range of intervals. Beat-to-beat changes in preload, consistent with the Frank-Starling mechanism, also play a role, but their influence is diminished after long preceding and short prepreceding intervals.

Aged↗
PubMed1995

Usefulness of heart rate variability in predicting drug efficacy (metoprolol vs diltiazem) in patients with stable angina pectoris.

We investigated whether analysis of heart rate (HR) variability may be used to predict the efficacy of drug treatment of myocardial ischemia. In a double-blind, crossover study, 28 patients with stable angina pectoris, proven coronary artery disease, and myocardial ischemia during Holter monitoring received metoprolol controlled-release 200 mg once daily and diltiazem 60 mg 4 times daily. After a placebo run-in phase and after each treatment period, 72-hour Holter recordings were obtained for HR variability and ST-segment analysis. At baseline, the total duration of myocardial ischemia was 11.4 +/- 13.9 minutes (mean +/- SD per 24 hours), and the total number of episodes was 2.2 +/- 2.3. Metoprolol significantly reduced the total duration of ischemia by -8.7 minutes (95% CI -14.5 to -2.8) and the total number of episodes by -1.9 (-2.9 to -0.8) in patients with a low SD of normal-to-normal intervals at baseline (SDNN), using the median value of 50 ms as a cut-off value. In contrast, significant treatment effects were not observed in patients with a high SDNN at baseline. Similar results were obtained using baseline total power or low-frequency power, but not when using baseline heart rate. Diltiazem reduced the total duration of ischemia by -4.9 minutes (-9.7 to -0.1), but not the number of episodes. Moreover, in contrast to metoprolol, efficacy of diltiazem was not related to baseline HR variability. In conclusion, patients with reduced HR variability at baseline responded to treatment with metoprolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗