ABSTRACT
The diagnosis of unstable angina (troponine undetectable) is often difficult in the absence of electrocardiographic changes after suggestive chest pains. The object of this study was to analyse the kinetics of Brain Natiuretic Peptide (BNP) during acute coronary syndromes (ACS) without ST elevation. Plasma BNP was measured every 6 hours for 48 hours in 65 patients admitted for suspicion of ACS without ST elevation and without clinical, radiological or echocardiographic signs of left ventricular dysfunction. The results of BNP measurements were masked until the final diagnosis was established on the usual investigations (ECG changes, troponine I values, myocardial scintigraphy, coronary angiography). These investigations identified 3 groups of patients: non-Q wave infarction (group A: 19 patients), unstable angina (group B: 21 patients) and non-coronary chest pain (group C: 25 patients). The peak BNP was significantly higher in groups A (210 +/- 172 pg/ml) and B (152 +/- 159 pg/ml) than in group C (16 +/- 14 pg/ml). However, the BNP was normal or only slightly increased (< 50 pg/ml) in 25% of cases of ACS. Analysis of the kinetics of BNP was much more discriminating: early increase after the pain, peak between the 14th and 24th hours (19th hour on average), followed by a progressive decrease. The kinetics were identical in Groups A and B, contrasting with the flat profile of the curve in group C. A change of > 20 pg/ml in BNP was a better criterion of ACS with a diagnostic accuracy > 90% than increased troponine (group A) or undetectable troponine (group B). The authors conclude that BNP kinetics is a new and reliable diagnostic marker of unstable angina when the usual criteria of ACS are not present (notably a normal ECG and undetectable troponine).
Subject(s)
Angina, Unstable/diagnosis , Natriuretic Peptide, Brain/blood , Aged , Biomarkers/blood , Chest Pain/etiology , Coronary Disease/classification , Coronary Disease/diagnosis , Female , Humans , Kinetics , Male , Middle Aged , Reference Values , Reproducibility of Results , Time FactorsABSTRACT
The extended use of interventional surgery of revascularisation has modified the prognosis and the evolution of ischaemic heart diseases. However, both coronary artery bypass graft and percutaneous transluminal coronary angioplasty failed to make the symptomatic or subclinical ischaemic manifestations of chronic coronary insufficiency disappear. The interest of using betablockers as a first-line therapy was widely demonstrated. However, their combination with another efficient molecule is often necessary. The aim of this trial has been to appreciate the efficiency of the association of a betablocker with either trimetazidine or with isosorbide monoitrate. Hundred and eighty five patients retaining a positive effort test despite 100 mg of atenolol, received in addition, either 60 mg of trimetazidine (93 cases) of 60 mg of isosorbide mononitrate (92 cases) for a two-month period and are then re-evaluated at the end of this period. The ischaemic threshold is delayed in a significant way in both groups (p < 0.0001; trimetazidine +7%, isosorbide mononitrate +10.7%). Twenty-three percent of the exercise tests under trimetzidine and 19% under isosorbide mononitrate become negative after two months of the therapeutic combination. The clinical improvement is even clearer with the disappearance of the angina crisis during the week before the second exercise test in 63% of the cases under trimetazidine and 54% of the cases under isosorbide mononitrate, among the patients who had kept it under atenolol at the inclusion. In conclusion, the combination of a second efficient molecule, trimetazidine or isosorbide mononitrate, brings a functional and objective improvement to patients with insufficient chronic coronary disease not totally controlled using a betablocker, even with high dosage. One should notice two important advantages in favour of the trimetazidine: one is practical due to a better tolerance (lack of cephalalgia), the other is conceptual (use of the complementary metabolic approach of cellular oxygenation rather than the haemodynamic approach of nitrate compounds which are already in concurrency with all other anti-ischaemic molecules).
Subject(s)
Adrenergic beta-Antagonists/therapeutic use , Atenolol/therapeutic use , Coronary Artery Disease/drug therapy , Isosorbide Dinitrate/analogs & derivatives , Isosorbide Dinitrate/therapeutic use , Trimetazidine/therapeutic use , Vasodilator Agents/therapeutic use , Aged , Drug Therapy, Combination , Exercise Test , Hospitals, General , Humans , Middle Aged , Treatment OutcomeABSTRACT
The generalisation of the use of transthoracic echocardiography in the investigation of pulmonary embolism leads to the diagnosis of mobile right heart thrombus in about 5% of cases. A review of the literature shows that this association is mainly observed in clinically severe pulmonary embolism. The presence of a mobile right heart thrombus is associated with a poor prognosis and emergency treatment is based on thrombolytic therapy or surgical embolectomy. In minimal or infraclinical pulmonary embolism, the finding of a mobile right heart thrombus is rare and there is no consensus about its treatment. The authors report the case of a 61 year old man admitted to hospital for bilateral deep vein thrombosis with no symptoms of pulmonary embolism in whom investigations revealed a mobile right heart thrombus with minimal pulmonary embolism. The outcome was favourable with progressive resolution of the right heart thrombus with oral anticoagulation after three weeks of heparin therapy.
Subject(s)
Coronary Thrombosis/complications , Pulmonary Embolism/etiology , Anticoagulants/therapeutic use , Coronary Thrombosis/pathology , Heparin/therapeutic use , Humans , Male , Middle Aged , Prognosis , Pulmonary Embolism/pathology , Severity of Illness Index , Treatment Outcome , Venous Thrombosis/complicationsABSTRACT
The authors report the first case of cardiac sarcoidosis involving only the interatrial septum and the atrioventricular node in a 30 year old man with known lymph node sarcoidosis. The diagnosis was suspected after the finding of an apparently innocent 1st degree atrioventricular block and confirmed by transoesophageal echocardiography and by IMATRON computerised tomography. Isolated atrial involvement of sarcoidosis is rare in the absence of any left ventricular disease. This explains the negative findings at transthoracic echocardiography and radio-isotopic investigations usually recommended for diagnosing cardiac sarcoidosis.
Subject(s)
Cardiomyopathies/diagnosis , Sarcoidosis/diagnosis , Adult , Cardiomyopathies/diagnostic imaging , Diagnosis, Differential , Echocardiography, Transesophageal , Electrocardiography , Heart Atria/diagnostic imaging , Humans , Lymphatic Diseases/diagnosis , Male , Radionuclide Imaging , Sarcoidosis/diagnostic imaging , Tomography, X-Ray ComputedABSTRACT
The technique of acoustic quantification (AQ), because of its automatic detection of the contours, enables left ventricular volumes to be calculated in real time using the technique of disk summation. The objective of the study was to evaluate the reliability of cardiac output (CO) measurements obtained with AQ based on left ventricle volumes in patients with severe congestive heart failure. Seventeen patients, mean age 68 +/- 11 years, NYHA stage IV, in sinus rhythm and without significant valve regurgitation were enrolled prospectively. CO, measured simultaneously by 2-dimensional echocardiography (2DE), pulsed Doppler echocardiography (DOP) and AQ, was compared to the thermodilution technique (TD) data. CO, measured by AQ, was highly correlated with TD (r = 0.875; p < 0.001) with a small bias (-0.05 l/min). DOP and 2DE were also well correlated with TD (r = 0.835 and r = 0.701, respectively). Concerning ventricular volume measurement, AQ was well correlated with 2DE (for telediastolic, r = 0.892, and telesystolic volumes, r = 0.874). However, telesystolic (bias, +36.6 +/- 35 ml) and telediastolic volumes (bias, +35.6 +/- 35 ml) were overestimated. We conclude that AQ is a reliable technique, able to estimate CO precisely in patients with severe congestive heart failure. On the other hand, both telesystolic and telediastolic volumes were overestimated.
Subject(s)
Cardiac Output , Heart Failure/diagnostic imaging , Heart Failure/physiopathology , Ventricular Function, Left/physiology , Aged , Diastole , Echocardiography , Echocardiography, Doppler , Female , Heart Rate , Humans , Male , Middle Aged , Reproducibility of ResultsABSTRACT
The analysis of segmental wall motion using two-dimensional (2-D) echocardiography is subjective with high interobserver variability. Color kinesis is a new technique providing a color-encoded map of endocardial motion. We evaluated the accuracy of color kinesis and 2-D for assessment of regional asynergy compared with left ventricular angiography as a reference method. Fifteen patients admitted for myocardial infarction were studied by echocardiography the day before left ventricular angiography. The left ventricle was divided into seven segments. Each segment was classified by two independent observers as normal or abnormal in 2-D and color kinesis. Accuracy of color kinesis and 2-D was evaluated and compared to left ventricular angiography. Color kinesis is significantly superior to 2-D for all seven segments (mean 0.80/0.68, P = 0.05), except for the septum (0.67/0.60, P = NS). Interobserver variability studied by chi-square statistic is lower with color kinesis (0.70) than with 2-D (0.57). We conclude that these data suggest that color kinesis is a useful method for assessing systolic wall motion in all segments, except the septum and for improving the accuracy of segmental ventricular function and interobserver variability.
Subject(s)
Angiography/methods , Echocardiography, Doppler, Color/methods , Myocardial Infarction/diagnostic imaging , Ventricular Dysfunction, Left/diagnostic imaging , Adult , Aged , Humans , Image Interpretation, Computer-Assisted , Kinesis , Male , Middle Aged , Myocardial Contraction/physiology , Observer Variation , Prospective Studies , Reproducibility of Results , Sensitivity and Specificity , Ventricular Function, Left/physiologyABSTRACT
An open randomized hospital study conducted in 169 centers in France compared the blood pressure response to the first 36 h of treatment with perindopril (PER), 2 mg once daily, with that to captopril (CAP), 6.25 mg t.i.d., in 725 patients (mean age, 70 years; men, 67%) with echocardiographic left ventricular systolic dysfunction (fractional shortening, < or = 28%) due to ischemia (56.7%) or hypertension (34.5%) and a systolic blood pressure (SBP) > or = 120 mm Hg. Each dose of CAP induced a sharp and rapid decrease in blood pressure (maximum, 1.5-2 h); with PER, the decrease was gradual (maximum, 6 h) and variation was less marked. However, at 36 h, the decrease in blood pressure versus baseline was similar on both treatments. Over the 36-h period, there were 22 (3%) dropouts due to marked orthostatic hypotension (SBP, <90 mm Hg), and they were fewer with PER than with CAP: 16 cases in the CAP group versus six in the PER group (p = 0.036). At 36 h, heart rate was lower with CAP than with PER: 75.2 versus 77.5 beats/min, respectively (p = 0.039). As initial therapy for stabilized left ventricular systolic dysfunction, the first dose of PER (2 mg) induced a significantly smaller decrease in blood pressure than the first dose of CAP (6.25 mg); dropouts due to orthostatic hypotension were also significantly fewer with PER than with CAP.
Subject(s)
Angiotensin-Converting Enzyme Inhibitors/pharmacology , Blood Pressure/drug effects , Captopril/pharmacology , Heart Failure/drug therapy , Indoles/pharmacology , Ventricular Dysfunction, Left/drug therapy , Aged , Echocardiography , Female , Humans , Hypertension/complications , Hypotension, Orthostatic/chemically induced , Male , Myocardial Ischemia/complications , Patient Dropouts , Perindopril , Time Factors , Ventricular Dysfunction, Left/etiologyABSTRACT
The object of this study was to assess the value of CK in the evaluation of left ventricular wall motion. Fifteen coronary patients aged 56 +/- 12 years were included: 8 patients were examined after acute myocardial infarction and 7 after unstable angina with a history of myocardial information. The left ventricle was divided into 7 segments after a modified Heger model, excluding the basal septal and basal lateral segments not seen on angiography. The left ventricular wall motion was assessed in two-dimensional echocardiography (2DE) and colour kinesis (CK) by two observers and compared with the results of left ventriculography, considered the reference method. Over all the 105 segments studied (7 segments for each of the 15 patients), CK was significantly better than 2DE (80% of segments correctly evaluated by CK vs 68% by 2DE, p < 0.05). Colour kinesis significantly improved the study of all segments except the interventricular septum (67% vs 60%, p = NS). The inter-observer variability in 2DE and CK evaluated over 135 segments (9 per patient) by the kappa was improved by colour kinesis (0.57 in 2DE, 0.7 in CK). The authors conclude that CK enables evaluation of left ventricular wall motion with greater precision and less inter-observer variability.
Subject(s)
Coronary Disease/physiopathology , Kinesics , Ventricular Dysfunction, Left/physiopathology , Ventricular Function, Left/physiology , Aged , Coronary Disease/diagnostic imaging , Echocardiography/methods , Female , Humans , Male , Middle Aged , Ultrasonography, Doppler, ColorABSTRACT
The authors report the case of a 34 year old woman, admitted to hospital because of myocardial infarction two months after delivery of her fifth child. The infarction was caused by spontaneous dissection of the left main coronary and left anterior descending arteries. Twenty-three months later, the patient was well with medical therapy. This case is an example of spontaneous post-partum coronary dissection which is the commonest cause of infarction occurring in that period. The physiopathology of this complication is not fully understood. The prognosis is poor, lethal in two thirds of cases. However, it must be emphasised that coronary dissection may regress spontaneously. Patients were previously referred systematically for surgery, but now it is usually reserved for cases with persistent myocardial ischaemia despite medical therapy. Angioplasty may be preferred despite the risks and may be successful in some cases.
Subject(s)
Aortic Dissection/complications , Coronary Aneurysm/complications , Myocardial Infarction/etiology , Puerperal Disorders/complications , Adult , Aortic Dissection/pathology , Angioplasty, Balloon, Coronary , Coronary Aneurysm/pathology , Coronary Vessels/pathology , Female , Humans , Myocardial Infarction/drug therapy , Prognosis , Remission, Spontaneous , Treatment OutcomeSubject(s)
Cardiotonic Agents/therapeutic use , Digitoxin/therapeutic use , Digoxin/therapeutic use , Aged , Cardiotonic Agents/pharmacology , Child , Digitoxin/metabolism , Digitoxin/pharmacology , Digoxin/metabolism , Digoxin/pharmacology , Female , Humans , Pregnancy , Pregnancy Complications, Cardiovascular/drug therapyABSTRACT
AIMS: Although linsidomine shares common properties with nitrovasodilators, it releases nitric oxide directly without catalytic involvement by thiols. We conducted a prospective, randomized, multicentre, parallel group, single-blind study to compare the efficacy of intravenous administration of linsidomine with that of isosorbide dinitrate in unstable angina. METHODS AND RESULTS: Between November 1990 and July 1992, 568 patients with suspected unstable angina (class IIIB of the Braunwald classification) received a continuous infusion of either linsidomine (1 mg.h-1 on average) or isosorbide dinitrate (2.5 mg.h-1 on average) for 72 h. All patients received concomitant aspirin and intravenous heparin, 81% beta-blockers and 38% calcium antagonists. Holter monitoring was performed in all patients and analysed blindly. Only 25% of the patients had at least one episode of chest pain during the study (24.6% vs 25.8% in the linsidomine and isosorbide dinitrate groups, P = 0.74), of which 12% were associated with ECG changes. Holter criteria yielded similar results in both groups: 33% of patients presented episodes of myocardial ischaemia (32.6% vs 33.9% in the linsidomine and isosorbide dinitrate groups, P = 0.74), while 45% showed episodes of ventricular arrhythmia (43.5% vs 46.5% in the linsidomine and isosorbide dinitrate groups, P = 0.48). The incidence of serious clinical events at 72 h (death, myocardial infarction or myocardial revascularization) was 6.5% (5% vs 8% in the linsidomine and isosorbide dinitrate groups, P = 0.17). CONCLUSION: Intravenous linsidomine is at least as efficacious as isosorbide dinitrate in the stabilization of patients with severe unstable angina.
Subject(s)
Angina, Unstable/drug therapy , Isosorbide Dinitrate/therapeutic use , Molsidomine/analogs & derivatives , Vasodilator Agents/therapeutic use , Aged , Confidence Intervals , Electrocardiography, Ambulatory , Female , France , Humans , Male , Middle Aged , Molsidomine/therapeutic use , Nitric Oxide , Prospective Studies , Single-Blind Method , Statistics, Nonparametric , Treatment OutcomeABSTRACT
Spontaneous, long lasting reduction of chronic permanent atrial fibrillation, usually complicating rheumatic valvular heart disease, has rarely been described in the literature. Its mechanism is unclear. In practice, the question is to determine whether the electrical activation coincides with restoration of a mechanical atrial contraction. The authors report the case of a woman with mixed rheumatic aortic and mitral valve disease (essentially mitral stenosis), in whom reversion to sinus rhythm was observed after 9 years of atrial fibrillation and which was long lasting (at least 9 months), and, above all, accompanied by atrial contraction documented for the first time to the best of the authors' knowledge, by Doppler echocardiography.
Subject(s)
Mitral Valve Stenosis/complications , Atrial Fibrillation/diagnostic imaging , Atrial Fibrillation/etiology , Atrial Fibrillation/physiopathology , Chronic Disease , Echocardiography, Doppler , Electrocardiography , Female , Heart Valve Prosthesis , Humans , Middle Aged , Mitral Valve Stenosis/surgery , Remission, Spontaneous , Time FactorsABSTRACT
The authors report a case of Kearns-Sayre syndrome, a rare mitochondrial myopathy, diagnosed in a 19 year old man. Distal conduction defects are constant findings and are a dominant factor in the prognosis of this condition. Their early appearance and rapid progression pose the problem of prophylactic cardiac pacing despite the young age. In the case report, pacing was decided at the age of 23 in the absence of symptoms but with bifascicular block (right bundle branch block and left anterior hemiblock), without electrophysiological investigation. During follow-up, left bundle branch block was observed 3 years later and permanent complete atrioventricular block occurred 7 years after pacemaker implantation.
Subject(s)
Cardiac Pacing, Artificial , Heart Block/etiology , Kearns-Sayre Syndrome/complications , Adult , Electrocardiography , Follow-Up Studies , Heart Block/therapy , Humans , Kearns-Sayre Syndrome/diagnosis , Kearns-Sayre Syndrome/genetics , Male , Prognosis , Treatment OutcomeABSTRACT
The authors report the case of a 31 year old woman at 30 weeks' gestation who developed a non-Q wave postero-lateral myocardial infarction during treatment with salbutamol. There were no complications and delivery took place at term normally. Coronary angiography was performed 3 months post-partum and was normal: the Methergin test was negative. Myocardial ischaemia occurring during treatment with a beta-2 mimetic in pregnancy is rare and hardly ever progresses to myocardial infarction. The usual mechanism of ischaemia is an imbalance of myocardial oxygen demand and supply. Myocardial oxygen consumption is naturally increased during pregnancy and excess intracellular calcium secondary to the beta-1 stimulation occurring with the use of beta-2 mimetic drugs further aggravates matters. This hypothesis raises the question of the value of calcium inhibitors in these forms of myocardial ischaemia.
Subject(s)
Albuterol/adverse effects , Myocardial Infarction/chemically induced , Pregnancy Complications, Cardiovascular/chemically induced , Sympathomimetics/adverse effects , Abortion, Threatened/drug therapy , Adult , Coronary Angiography , Electrocardiography , Female , Humans , Myocardial Infarction/drug therapy , Myocardial Infarction/physiopathology , Pregnancy , Pregnancy Trimester, ThirdABSTRACT
Cardiac transplantation remains the standard treatment for severe cardiomyopathy resistant to medical therapy. However, new techniques may help to put this off. Two patients with dilated cardiomyopathy were treated surgically since October 1996, one aged 48 and the other 52. They were in NYHA Class IV and one was dependent on inotropic drugs. Both had relative or absolute contra-indications to transplantation. The left ventricular end diastolic dimensions were over 70 mm with mild mitral regurgitation and fractional shortening of less than 12%. Coronary angiography was normal. They were operated in October 1996 and January 1997. The procedure consisted of correction of mitral regurgitation (annuloplasty) and of reduction of left ventricular volume by a triangular resection from the apese to the base of the heart. At histological examination, the resected myocardium measured 11 to 13 cm long and 5 to 7 cm at its base. The two patients were discharged from hospital after 45 and 30 days. There were no clinical signs of cardiac failure. Follow-up investigations showed a marked decrease in ventricular volumes, the end diastolic dimensions changing from 70 to 52 mm in the first, and from 76 to 54 mm in the second patient. The corresponding values of fractional shortening increased from 11 to 20% and from 6 to 17%. Left ventricular volumes decreased from 328 mL (end diastole) and 259 mL (end systole) to 140 mL and 74 mL in the first case, and from 300 mL (end diastole) and 280 mL (end systole) to 122 mL and 83 mL respectively in the second case. The ejection fraction increased from 20 to 40% and from 10 to 32%. These preliminary results show that the theoretical advantages of this surgical technique correspond to a practical reality. Larger series of patients are required to determine the optimal indications.
Subject(s)
Cardiac Surgical Procedures/methods , Cardiomyopathy, Dilated/surgery , Heart Ventricles/surgery , Cardiomyopathy, Dilated/pathology , Heart Valve Prosthesis Implantation , Heart Ventricles/pathology , Hemodynamics , Humans , Male , Middle Aged , Mitral Valve Insufficiency/surgery , Treatment Outcome , Ventricular Function, LeftABSTRACT
The authors report two cases of spontaneous paroxysmal atrial fibrillation closely followed by syncopal ventricular tachycardia resulting in cardiac arrest requiring defibrillation. Both patients, men aged 62 and 64 years, had a past history of myocardial infarction without arrhythmias; atrial fibrillation occurred during severe myocardial ischaemia; coronary arteriography showed tight stenoses of the left main coronary artery with normal left ventricular function. Ventricular tachycardia (or fibrillation) during spontaneous paroxysmal atrial fibrillation is a rare occurrence. This sequence of events has been described in patients with accessory conduction pathways or in hypertrophic cardiomyopathy. It is an exceptionally rare complication of ischemic heart disease with only a very few previously reported cases. Myocardial ischaemia is probably the cause of the arrhythmia in together with irregularity of the ventricular contractions responsible for long cycle-short cycle sequences which are particularly arrhythmogenic and changes in sympathetic tone.
Subject(s)
Atrial Fibrillation/complications , Myocardial Infarction/complications , Syncope/etiology , Tachycardia, Ventricular/etiology , Atrial Fibrillation/diagnosis , Atrial Fibrillation/physiopathology , Autonomic Nervous System/physiopathology , Coronary Angiography , Electrocardiography , Heart Arrest/etiology , Heart Arrest/therapy , Humans , Male , Middle Aged , Syncope/diagnosis , Syncope/physiopathology , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/physiopathologyABSTRACT
Coronary by-pass surgery and percutaneous transluminal angioplasty (PTCA) have changed the prognosis and life quality of patients with stable angina. Medical treatment and myocardial revascularisation are both useful and most often complementary. Coronary by-pass surgery is indicated in the treatment of coronary left main disease and three-vessel disease with poor left ventricular function. PTCA is the best choice in patient with one-vessel disease resulting in myocardial ischaemia. Discussion remains open in other cases mainly in stenosis of proximal left anterior descending artery. Often the ultimate choice results from the limits of each technique: sapheneous by-pass occlusion or coronary artery restenosis after PTCA. New techniques and devices in revascularization are expected to improve prognosis:use of arterial by-pass grafts, gene transfer, local drug delivery.
Subject(s)
Angina Pectoris/therapy , Angioplasty, Balloon , Clinical Trials as Topic , Coronary Artery Bypass , Humans , Myocardial RevascularizationABSTRACT
The umbilical arteries play an important role in the foetal circulation. These vessels, which have no sympathetic tone, are a valuable model for the study of a direct pharmacological effect on vascular smooth muscle. The aims of this study were to determine if the potassium-channel reopener, nicorandil, could relax the smooth muscle of the human umbilical artery, if glibenclamide, an inhibitor of ATP-dependant potassium channels, can influence the action of nicorandil and, finally, to evaluate the role of the vascular endothelium. Rings of human umbilical artery 3 mm wide were placed in glycosated, oxygenated (95% O2, 5% CO2) Krebs-Henseleit solution, at 37 degrees C, pH 7.4 for isometric myography. The rings were contracted with 10(-5) M 5-hydroxytryptamine (5-HT). After stabilisation, a dose-effect graph of nicorandil (10(-9) to 3 x 10(-4) M) was constructed. In another series of experiments, the rings were incubated with NG nitro-L-arginine (NLA) at 10(-4) M, an inhibitor of NO-synthase, for 15 minutes and then contracted with 5-HT (10(-5) M) and relaxed with nicorandil at the same dosage. In yet another series of experiments, glibenclamide (10(-4) M) was added to the bath 15 minutes before contraction with 5-HT (10(-5) M). The vessel was then relaxed by incremental doses of nicorandil from 10(-9) to 3 x 10(-4) M. During this study, no significant difference was observed with respect to the contractions to 5-HT; moreover, the maximal relaxations obtained by nicorandil before and after glibenclamide were no significant. On the other hand, only the relaxations obtained after incubation with NLA were significant (p < 0.005). Furthermore, the pD2 did not differ significantly between the different groups of vascular rings. The authors conclude that nicorandil is a powerful dilatator of human umbilical artery. Glibenclamide has an inhibitory effect on nicorandil but only at low concentrations and in a non-competitive manner. The endothelium seems to modulate the vascular tone because relaxation is greater in the presence of an inhibitor of NO-synthase: in this type of vessel, the presence of the endothelium predisposes to the liberation of contractile factors.