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Biomedical subjects

M A Stefadouros

Publications and source records attributed to M A Stefadouros.

At least 19 recordsLinked to original sources
PubMed2005

Long term clinical and echocardiographic results of mitral balloon valvotomy in children and adolescents.

AIMS: To assess the safety, efficacy, and long term results of mitral balloon valvotomy (MBV) for rheumatic mitral stenosis in children and adolescents in comparison to adults. METHODS: The results of 468 patients with mitral stenosis who underwent successful MBV and were followed up for 0.5-13 years were analysed. Patients were divided according to age at the time of MBV into group 1 consisting of 84 patients < or = 20 years of age (children and adolescents) and group 2 that included 384 patients, age > 20 (adults). RESULTS: Patients in group 1 had a lower mitral echo score (mean (SD) 7.5 (1.3) v 8 (1.1), p < 0.001), smaller Doppler mitral valve area (MVA) (0.84 (0.17) v 0.92 (0.18) cm2, p < 0.001), and higher Doppler mitral valve gradient (15.0 (5.3) v 12.7 (4.5) mm Hg, p < 0.001) than group 2. Immediately after MBV group 1 had larger MVA, whether measured by Doppler (2.0 (0.30) v 1.96 (0.28) cm2, p < 0.05) or by catheter (2.0 (0.59) v 1.8 (0.52) cm2, p < 0.001), and similar complication rates, compared to group 2. After a mean follow up of 5 (3.5) years there was no significant difference between groups 1 and 2 in the incidence of restenosis (14.3% v 16.1%, NS). Event-free survival rates at 5, 10, and 12.5 years were 93%, 79%, and 79% for group 1 and 94%, 90%, and 84% for group 2 (p = 0.18). CONCLUSIONS: MBV is safe and effective in children and adolescents with rheumatic mitral stenosis. It provides better immediate results than in adults and excellent long term results that are comparable to those seen in adults.

Adolescent↗
PubMed1999

Long-term effects of balloon angioplasty on systemic hypertension in adolescent and adult patients with coarctation of the aorta.

AIMS: To define the long-term effect of balloon angioplasty of aortic coarctation on hypertension, in adolescent and adult patients. METHODS: Balloon angioplasty of discrete, native aortic coarctation was performed on 50 patients (34 male) aged 23+/-8 (mean+/-standard deviation) years. In 42 of these patients cardiac catheterization and angiography were repeated 1 year later, and on the basis of sphygmomanometric blood pressure determination at that time, they were divided into 31 patients (group A) with normalized blood pressure and 11 patients (group B) who still needed antihypertensive medication. Both groups were followed annually thereafter for 12-123 (66+/-37) months. RESULTS: Coarctation gradient values before, immediately after and 1 year after angioplasty were 69+/-24 mmHg, 12+/-8 mmHg (P<0.001) and 7+/-6 mmHg. The corresponding systolic blood pressure values were 165+/-17 mmHg, 128+/-12 mmHg (P<0.001) and 115+/-10 mmHg (P<0.001) in group A; 182+/-21 mmHg, 141+/-24 mmHg (P<0.001) and 134+/-18 mmHg (P<0.001) in group B. Echocardiographic left ventricular mass index before angioplasty and at follow-up was 130+/-31 g x m-2 and 105+/-23 g x m-2 in group A; 157+/-38 g x m-2 and 132+/-35 g x m-2 in group B (P<0.001 for both comparisons). CONCLUSION: Normalization of blood pressure without medication occurred in 74% of patients after angioplasty for aortic coarctation, with subsequent long-term regression of left ventricular hypertrophy. In comparison to reported surgical results, balloon angioplasty should be considered as first line treatment for native, discrete aortic coarctation in adolescent and adult patients.

Adolescent↗
PubMed1999

The long-term effect of successful mitral balloon valvotomy on left atrial size.

BACKGROUND AND AIM OF THE STUDY: The study aim was to determine the extent of regression of left atrial (LA) enlargement following mitral balloon valvotomy (MBV) for mitral stenosis. METHODS: Data obtained from 205 patients before, and at a mean of 31.0 +/- 21.1 months (range: 6 to 86.3 months) after successful MBV were analyzed retrospectively. RESULTS: The invasively determined mitral valve area increased from 0.81 +/- 0.27 cm2 at baseline to 1.73 +/- 0.54 cm2 immediately after valvotomy (p <0.0001), and the mean mitral gradient fell from 15.6 +/- 5.3 to 5.4 +/- 2.5 mmHg (p <0.0001). Similar changes were noted in Doppler-determined mitral valve area (0.89 +/- 0.16 to 1.97 +/- 0.29 cm2; p <0.0001) and gradient (12.6 +/- 5.3 to 4.9 +/- 1.7 mmHg; p <0.0001). In comparison with baseline, significant (p <0.0001) reductions were noted at follow up in the echocardiographic anteroposterior (48.7 +/- 6.9 to 42.4 +/- 6.6 mm), superior-inferior (68.5 +/-8.1 to 59.6 +/- 8.2 mm) and medial-lateral LA dimension (51.2 +/- 6.7 to 44.1 +/- 7.7 mm) and calculated LA volume (91.6 +/- 29.1 to 60.7 +/- 23.8 cm3) Patients in atrial fibrillation had larger LA dimensions, but substantially smaller absolute and relative reduction in LA size at follow up than patients in sinus rhythm. Among patients with prevalvotomy LA enlargement, normalization of LA dimension at follow up was seen in 29.2% of patients in sinus rhythm, but in none of the 32 with atrial fibrillation. CONCLUSIONS: Successful MBV results in significant long-term reduction in LA size in most patients, but normalization of LA size is unusual.

Adolescent↗
PubMed1993

A new system of visual presentation of analysis of test performance: the "double-ring" diagram.

Substitution of graphic representation for extensive lists of numerical statistical data is highly desirable by both editors and readers of medical journals, faced with an exploding abundance of contemporary medical literature. A novel graphic tool, the "double-ring diagram", is described herein which permits visual representation of information regarding certain statistical variables used to describe the performance of a test or physical sign in the diagnosis of a disease. The diagram is relatively easy to construct on the basis of a number of primary data such as the prevalence and the true positive, true negative, false positive and false negative test results. These values are reflected in the diagram along with the values of other statistical variables derived from them, such as the sensitivity, specificity, predictive values for positive and negative test result, and accuracy. This diagram may be useful in visualizing a test's performance and facilitating visual comparison of performance of two or more tests.

Audiovisual Aids↗
PubMed1993

The role of anticoagulation in the development of pericardial effusion and late tamponade after cardiac surgery.

This study aimed at elucidating the role of anticoagulation in the genesis of late pericardial effusion and tamponade after cardiac surgery. Using serial 2-D echocardiography, 141 patients undergoing surgery for coronary artery bypass (56), valvular (69) or congenital (16) [corrected] heart disease were studied postoperatively. Group 1 (74 patients) received full anticoagulation (warfarin 73; heparin 1) and group 2 (67 patients) received either antithrombotic agents (aspirin plus dipyridamole), or no treatment. Fifty percent (70/141) of patients developed effusion. There was no significant difference between the two groups in the incidence of either effusion in general (43/74; 58% vs 27/67; 40%, respectively) or small or medium sized effusion. However, a large effusion was significantly more common in group 1 than in group 2 (32% vs 4%, P < 0.005). Twelve patients (12/141; 8.5%) developed late tamponade, 7 to 33 (15 +/- 7.3 mean +/- SD) days after surgery. All had a large effusion demonstrated by echo, drained by pericardiocentesis, and none died. All 12 patients with tamponade belonged to group 1 (P < 0.001). Excess anticoagulation was detected at least once in 41 of the 74 group 1 patients (55%). When compared to properly anticoagulated patients, excessively anticoagulated patients had a similar overall incidence of effusion and a similar incidence of small or moderate effusion, but a higher incidence of large effusion (18% vs 44%, [corrected] P < 0.05) and tamponade (3% vs 27%, P < 0.025). We conclude that, unlike small or medium-sized effusions, large pericardial effusions and tamponade are more likely to occur among anticoagulated patients, especially if they are excessively anticoagulated.

Adult↗
PubMed1987

Cardiovascular effects of ritodrine tocolysis: a new noninvasive method to measure pulmonary capillary pressure during pregnancy.

The cardiovascular effects of ritodrine tocolytic therapy were assessed by noninvasive simultaneous recordings of indirect carotid pulse, electrocardiogram (ECG), phonocardiogram, and M-mode echocardiogram in 12 patients in preterm labor. The study was performed before and during infusion, and afterward when the patient was on oral drug therapy. Ritodrine therapy increased heart rate, left ventricular fractional shortening, pre-ejection period/left ventricular ejection time ratio, and cardiac index. A progressive rise in pulmonary capillary pressure was observed in all patients, exceeding 18 mmHg (the threshold for the development of pulmonary congestion) in six patients. Systolic arterial pressure, left ventricular end-diastolic dimension, and plasma protein oncotic pressure remained unchanged during therapy. Ritodrine therapy resulted in a significant drop in diastolic blood pressure and peripheral vascular resistance. This noninvasive means of measuring cardiovascular parameters, including pulmonary capillary pressure, may be useful in monitoring patients who develop significant cardiovascular side effects during tocolytic therapy.

Echocardiography↗
PubMed1984

Potentially lethal arrhythmias and their management in hypertrophic cardiomyopathy.

The prevalence of potentially lethal arrhythmias (PLA) in groups of patients with hypertrophic cardiomyopathy has been assessed, but the rate at which they develop (their incidence) during long-term follow-up has not been reported. Therefore, conduction system disease (CSD) (sick sinus syndrome and His-ventricular disease), ventricular couplets and ventricular tachycardia (VT) detected by routine electrocardiograms, periodic 24-hour Holter monitoring and periodic exercise stress testing were studied in 50 patients treated with large doses of beta-adrenergic blocking drugs who were followed for 2 to 14 years (mean 5.9). Sixteen PLAs detected at the beginning of observation were excluded from actuarial analysis for new PLAs . Twenty-one patients had 24 new PLAs (7 with CSD, 1 patient with sustained supraventricular tachycardia, 6 with ventricular couplets and 10 with VT); only 43% of these PLAs were heralded by new symptoms. In 6 patients, the arrhythmia caused symptoms and was identified by a routine electrocardiogram. The 3 patients with His-ventricular disease presented with syncope and required electrophysiologic confirmation of this diagnosis. In only 1 patient was a PLA (ventricular couplets) detected only by exercise testing. All other ventricular arrhythmias were detected by Holter monitoring. The incidence of CSD in 47 patients free of this condition at entry was 5% at 5 years and 33% at 10 years. The incidence of ventricular couplets or VT in 39 patients free of these at entry was 26% at 5 years and 75% at 10 years, and the incidence of VT only was 18% at 5 years and 40% at 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Value of ventricular premature complex (VPC) morphology in the diagnosis of hypertrophic cardiomyopathy.

Experimental and clinical studies have established the value of ventricular premature complexes (VPC) with a QR pattern in the diagnosis of occult antecedent myocardial infarction. However, the clinical significance of a QR pattern VPC in patients with hypertrophic cardiomyopathy has not been previously evaluated. In order to study this, we examined the ECGs and 24-hour Holter monitor records of 45 consecutive patients with hypertrophic cardiomyopathy and 106 consecutive patients with various other diseases. A QR pattern VPC in the precordial leads with a Q greater than or equal to 40 ms and a Q/R ratio greater than or equal to 0.20 had a specificity of 97%, a sensitivity of 29% and a predictive value of 80% in the diagnosis of hypertrophic cardiomyopathy. We conclude that a QR pattern VPC may be of value in the eclectic diagnosis of hypertrophic cardiomyopathy and that it is not specific for antecedent myocardial infarction as previously reported.

Cardiomyopathy, Hypertrophic↗
PubMed1983

Long-term medical management of hypertrophic cardiomyopathy: usefulness of propranolol.

Chronic therapy with propranolol has been shown to reduce the incidence of sudden death in patients with hypertrophic cardiomyopathy (HCM). However, the long-term effect of beta blockade on exercise capacity has not been studied adequately. Therefore, 32 patients with HCM (21 men), mean age of 47 years (range = 14 to 80 years), were evaluated for dyspnea and chest pain and underwent stress testing (ST) prior to therapy. At entry, ST was contraindicated in four patients, because of heart failure (three patients) and sustained supraventricular tachycardia (one patient). The remaining patients completed 4.9 +/- 3.2 min (mean +/- S.D.) of the Bruce protocol with a functional aerobic capacity (FAC) of 51 +/- 28%. All were placed on propranolol, unless a beta blocker with other characteristics was indicated. Dosage was adjusted to achieve a standing heart rate of 60 beats/min unless adverse effects occurred. At last follow-up, 25 patients were receiving 501 +/- 147 mg propranolol/day while the remainder received nadolol or metoprolol. On the most recent ST, patients exercised 6.6 +/- 3.1 min (38% increase), while mean FAC increased by 24% (both P less than 0.05). The FAC improved by more than 15% in 21, by less than 15% in five, was unchanged in five and was worse in only one, a noncompliant patient. The 21 patients with an FAC increment much greater than 15% exercised longer at entry than the remaining 11 (6.6 +/- 3.3 vs 3.9 +/- 2.8 minutes, P less than 0.05). The mean peak ST blood pressure-heart rate product of the group decreased from 26 550 to 17 898 (P less than 0.05), while the symptom scores of dyspnea and chest pain declined from 2.2 +/- 0.8 to 0.8 +/- 0.7 and from 1.4 +/- 1.0 to 0.3 +/- 0.8, respectively (both P less than 0.001). We conclude that beta blockade produces sustained improvement in exercise capacity. Improvement was greatest in those with the least initial impairment, and appears to be related to a reduction in blood pressure-heart rate product.

Adolescent↗
PubMed1983

Rhythm disturbances in hypertrophic cardiomyopathies: relationship to symptoms and the effect of 'complete' beta blockade.

Potentially lethal arrhythmias (PLA) are common in hypertrophic cardiomyopathies and are implicated in sudden death. We have demonstrated that propranolol is effective in controlling symptoms, but have not previously evaluated its effect on PLA. Our protocol for long-term management has been applied to 50 patients followed for 2 to 14 years (mean 5.9 years). No patient was excluded because of disease severity or complications. The only reason for exclusion was non-compliance with the protocol. At entry, Holter monitoring revealed 16 PLA in 13 patients (sustained supraventricular tachycardia (SSVT) in two, sinus node dysfunction (SSS) in three, paired beats (PB) in five, and ventricular tachycardia (VT) in six). All patients were initially begun on propranolol, unless a different beta blocker was indicated. Dosage was adjusted to a standing heart rate of 60 beats/min unless adverse drug effects developed. Holter monitoring during follow-up identified 24 new PLA in 21 patients (SSVT = 1, SSS = 4, His-Purkinje disease = 3, VT = 10, and PB = 6). The total number of identified PLA is now 40 in 30 patients. Concurrent symptoms of syncope, presyncope and palpitations were of limited value in identifying PLA because of a lack of predictive accuracy (76%, 64% and 29%, respectively). Invasive electrophysiologic study or dosage adjustment proved that beta blockade was not responsible for the conduction system disorders observed in 10 patients requiring pacemaker insertion. beta-Blockade completely suppressed VT in two patients, PB in five, and SSVT in two.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

Use of a personal computer in the measurement, calculation, and reporting of noninvasive cardiac data.

Echocardiography, phonocardiography, and carotid pulse tracings enable the cardiologist to measure and calculate over 40 different noninvasive parameters including cardiac chamber size, indices of left ventricular performance, and estimates of mean left atrial pressure. However, the entire procedure requires meticulous measurements and time-consuming calculations, particularly when some of the data must be corrected for heart rate or body size. Because of this, many busy noninvasive cardiac laboratories routinely calculate only a few select parameters in most patients. To solve this problem, we used a personal computer system and developed a program that allows rapid, accurate measurement, calculation, display, reporting, magnetic storage, and retrieval of noninvasive cardiac data. The computer is not dedicated to these tasks alone and with appropriate software can also be used for other clinical, educational, office management, and research purposes.

Computers↗
PubMed1982

Postextrasystolic changes in systolic time intervals in the assessment of hypertrophic cardiomyopathy.

To determine if postextrasystolic changes in systolic time intervals can be used to estimate the severity of resting or provocable left ventricular outflow pressure gradient, we studied the cardiac catheterisation records of 42 patients with hypertrophic cardiomyopathy looking for instances of a single premature beat preceded by a control sinus beat and followed by a postpremature sinus beat. There were 75 such instances in 25 patients. In comparison to the control beat, the pre-ejection period in the postpremature beat was shorter by deltaPEP = -20 +/- 11 ms in 73 of 75 instances, and remained unchanged in two. The ejection time in the postpremature beat was invariably longer by deltaET = 37 +/- 20 ms (range: 10 to 85 ms) and the pre-ejection period/ejection time ratio lower than control by delta(PEP/ET) = -0 . 10 +/- 0 . 05 (range: -0 . 01 to -0 . 25). Total electromechanical systole in the postpremature beat was shorter (11/75), the same (10/75), or longer (53/75) than in the control beat, the overall change being deltaEMS = -18 +/- 22 ms. Both deltaPEP and delta(PEP/ET) correlated poorly with the systolic peak left ventricular-aortic pressure gradient in either the control beat (Gc) or the postpremature beat (Gx), and also with the change in gradient (delta G) from the control to the postpremature beat. In contrast, significant linear correlations were found between delta EMS and either Gc, Gx, or delta G; and also between deltaET and either Gc, Gx, or deltaG. Since internal and external measurements of ejection time are known to be almost identical, the regression equation (deltaG = 1 . 65 delgaET -9) relating deltaET and deltaG should be useful for the non-invasive assessment of the magnitude of provocable left ventricular outflow pressure gradient in patients with hypertrophic cardiomyopathy with spontaneous or externally-induced premature beats.

Blood Pressure↗
PubMed1981

Hypercontractile cardiac state mimicking hypertrophic subaortic stenosis.

Idiopathic hypertrophic subaortic stenosis (IHSS) is a disease manifested as a spectrum of various clinical and laboratory findings. We present the case of a patient with classical clinical and hemodynamic findings of IHSS who lacked all of the typical echocardiographic features of the disease. The case emphasizes the need for diligent use of bedside physical examination and vasoactive manipulation of systolic murmurs whenever functional left ventricular outflow tract obstruction is suspected, since it can occasionally be missed by echocardiography.

Cardiac Catheterization↗
PubMed1981

Determination of systolic time intervals from the first derivative of the indirect brachial arterial pulse.

Technical difficulties occasionally preclude adequate recording of the indirect carotid pulsations needed for measuring the systolic time intervals by the conventional method. Accordingly, in 81 subjects with a wide spectrum of heart diseases, an alternative method was tested based on substituting the first time derivative of the indirect brachial arterial pulse for the carotid pulse. The observed differences between systolic time intervals measured by the two methods were small enough, and their correlation coefficients high enough, to inspire confidence in the use of the proposed method as an alternative way for determining systolic time intervals.

Brachial Artery↗