Effects of sublingual isosorbide dinitrate on left ventricular performance during exercise in patients with myocardial infarction

In order to investigate left ventricular performance during exercise in patients with myocardial infarction and evaluate the effects of sublingual isosorbide dinitrate (ISDN) on left ventricular performance, we performed a symptom-limited multigraded exercise test using a bicycle ergometer in supine position. Thirty-seven patients with myocardial infarction were evaluated in order to clarify the hemodynamic responses to exercise with and without sublingual ISDN. Patients were subdivided into 3 groups according to the level of pulmonary capillary pressure (PCP) and cardiac index (CI) at peak exercise as follows: Group I (14 patients); PCP less than 18 mmHg, CI greater than or equal to 5.0 or CI less than 5.0 L/min/m2, Group II (11 patients); PCP greater than or equal to 18 mmHg, CI greater than or equal to 5.0 L/min/m2, Group III (12 patients); PCP greater than or equal to 18 mmHg, CI less than 5.0 L/min/m2. Exercise capacity without ISDN (control study) was correlated with left ventricular performance during exercise. Although left ventricular performance in patients who complained of dyspnea or chest pain at peak exercise was worse than those who complained of leg fatigue, we could not predict hemodynamics during exercise from the level of hemodynamic parameters at rest in each patient. Determinant factors of left ventricular performance during exercise were age, previous history of myocardial infarction, the severity of coronary artery lesion and the extent of left ventricular wall motion abnormality which was estimated by left ventriculogram as an index of infarct size. After sublingual ISDN (ISDN study), exercise capacity was improved. No patient terminated exercise because of chest pain and only one did because of dyspnea.(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of treadmill exercise test in pre- and postoperative children with valvular aortic stenosis

To determine the utility of graded treadmill exercise test (ETT) in estimating severity of obstruction in postoperative patients with aortic stenosis, we compared results to a nonoperated aortic stenosis group. Cardiac catheterization was performed in all patients. The interval between surgery and ETT in the postoperative group was 7.5 years (range 1.1-12.9). Mean and range values for postoperative versus nonoperative aortic stenosis groups respectively were: age 14.5 (7.9-20.8) versus 12.5 years (5.9-19.7); peak left ventricular pressure 150 (101-190) versus 144 mmHg (100-183); peak systolic ejection gradient (PSEG) 41 (15-75) versus 38 mmHg (14-80); left ventricular end-diastolic pressure (LVEDP) 13.4 (7-20) versus 13.5 mmHg (8-20); and cardiac index 3.7 (2.4-5.6) versus 3.8 liters/min/m2 (2.6-4.9) (p for each = NS). ETT in the nonoperated patients correctly identified all those with PSEG greater than or equal to 50 mmHg (sensitivity 100%), but specificity was 56%, (i.e., the proportion correctly identified with PSEG less than 50 mmHg). By contrast, sensitivity and specificity for postoperative aortic stenosis patients were 67% and 63%, respectively. Furthermore, among nonoperated aortic stenosis patients ST depression on ETT identified those with increased left ventricular end-diastolic pressure. For LVEDP greater than or equal to 12 mmHg, sensitivity was 75% and specificity 100%, corresponding values for postoperative aortic stenosis patients were 45% and 33%, respectively. In the nonoperated aortic stenosis group with a PSEG greater than or equal to 50 mmHg, sensitivity and specificity for ETT-induced change in systolic blood pressure of less than or equal to 30 mmHg were 100% and 56%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maximal exercise in children with aortic regurgitation: an adjunct to noninvasive assessment of disease severity

Twenty-five asymptomatic children with chronic aortic regurgitation were evaluated by graded bicycle exercise testing and standard resting M-mode echocardiogram. These results were compared to those of 35 normal controls matched for age and body surface area. Twenty-one patients underwent cardiac catheterization to rule out associated lesions. Patients fell into two groups based upon the left ventricular end-diastolic volume per body surface area (LVEDVI): group I (n = 10) had LVEDVI less than or equal to 2 SD from the mean of normal; group II (n = 15) had LVEDVI greater than or equal to 4 SD from the mean of normal. All had normal shortening fraction and velocity of circumferential fiber shortening. At maximal exercise, patients in group I were found to have no significant differences from normals in maximal workload, total work, percent maximal oxygen consumption, heart rate, blood pressure, or ST segment depression. However, patients in group II had blunted mean maximal exercise heart rate (p less than 0.001), systolic hypertension (p less than 0.05), and increased frequency and maximal amplitude of ST depression (p less than 0.01, p less than 0.001, respectively) compared to normal controls. Within group II the mean maximal amplitude of ST depression was significantly related to increasing LVEDVI (r = 0.53, p less than 0.05). The mean maximal exercise heart rate, systolic blood pressure, and maximal amplitude of ST segment depression were significantly related to LVEDVI for patient groups and normal controls together (r = -0.384, p less than 0.01; r = 0.28, p less than 0.05; r = 0.70, p less than 0.001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Recent myocardial infarction: role of digitalis therapy in patients with left ventricular dysfunction during exercise who participated in a short-term physical training program

In order to verify the usefulness of long-term digitalis therapy during physical rehabilitation in patients with recent myocardial infarction (MI) and left ventricular disfunction during exercise, 24 consecutive pts with PAedP greater than or equal to 25 mmHg (Swan-Ganz cath.) at maximal work load were selected. Pts with angina, ST depression (greater than or equal to 2 mm), complex ventricular arrhythmias (Lown 4-5), symptoms of left ventricular failure were excluded. At random 12 pts were assigned to group A (digoxin therapy) and 12 to group B (no therapy). Serum digoxin level was on average 1.48 ng/ml (range 1-2.85 ng/ml). Both groups performed over 4 weeks the same controlled training program. Before and soon after the end of the training period all pts underwent to an exercise test, standard chest x-ray films, 24 hour ambulatory ECG and two-dimensional echocardiography. No complication was observed during exercise test and training period. Age, myocardial infarction location, cardiac volume and hemodynamic behaviour during the first exercise test were similar in both groups. After training, maximal work capacity was increased in group A by 14% and in group B by 16% without significant changes in PAedP and Cl; at the same work load PAedP was lower in group B (-12%, p less than .02) while LVSWI was increased in both groups (14% and 17% respectively, p less than .05). No significant changes in cardiac volume, left ventricular asynergy, EF, and ventricular premature beats were observed. QT interval at rest decreased significantly only in group A 408 +/- 31 msec vs 371 +/- 34 msec (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical significance of simple heart rate-adjusted ST segment depression in supine leg exercise in the diagnosis of coronary artery disease

To evaluate the clinical significance of simple heart rate-adjusted ST segment depression (delta ST/delta HR) in the diagnosis of coronary artery disease, 42 patients with stable exertional angina underwent supine leg exercise testing and cardiac catheterization. During exercise, heart rate, a multilead electrocardiogram, and pulmonary artery wedge pressure were recorded. The sensitivity and accuracy of the delta ST/delta HR criteria (greater than or equal to 3.0 microV/beat/min) were significantly greater than the conventional analysis of ST segment depression criteria (greater than or equal to 0.2 mV) for detecting three-vessel coronary artery disease at a matched specificity of 72% (100% versus 46%, 81% versus 64%, p less than 0.01). A significant linear correlation was found between maximum pulmonary artery wedge pressure increments during exercise (delta PAWP) or Gensini score and the delta ST/delta HR (delta PAWP: r = 0.51, p less than 0.001; Gensini score: r = 0.47, p less than 0.001). There were no statistically significant differences in the delta PAWP or Gensini score between patients with three-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min and those with one- or two-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min (delta PAWP: 18.1 +/- 2.0 versus 21.9 +/- 3.3, p = NS; Gensini score: 68.5 +/- 6.6 versus 66.3 +/- 11.3, p = NS). These findings demonstrate that delta ST/delta HR is more useful than a conventional analysis of ST segment depression for identifying not only anatomically severe coronary artery disease but also functionally severe coronary artery disease.     

Myocardial blood flow, alternans of ST segment elevation, conduction delay and ventricular arrhythmia during acute myocardial ischemia with and without retrograde blood flow in canine hearts

The technique of retrograde blood flow has been shown to decrease collateral flow into the ischemic myocardium, and to cause severe myocardial ischemia in dogs. Ischemia with retrograde blood flow in dogs is similar to ischemia in human hearts. Therefore, we examined the effect of retrograde blood flow on myocardial blood flow, ST segment elevation, alternans of ST segment elevation, conduction delay and ventricular arrhythmia in dogs. Sixty dogs were divided into two groups. In group A (N = 32), the left anterior descending coronary artery was occluded for 10 min. In group B (n = 28), ischemia was induced by the technique of retrograde blood flow for 10 min. During ischemia, the myocardial blood flow at the ischemic zone measured by a H2 gas clearance method was 11.2 +/- 1.6 in group A and 5.7 +/- 0.7 ml/min/100 g in group B (p less than 0.01). The maximal ST segment elevation was 13.6 +/- 1.9 in group A and 27.2 +/- 2.1 mV in group B (p less than 0.001); the maximal alternans of ST segment elevation was 5.3 +/- 1.1 in group A and 10.1 +/- 1.4 mV in group B (p less than 0.01); the maximal conduction delay was 51.6 +/- 8.4 in group A and 111.1 +/- 6.2 msec in group B (p less than 0.001); and the incidences of ventricular premature beats (greater than 5/min), ventricular tachycardia and fibrillation were 34%, 41% and 22% in group A, and 68%, 79% and 25% in group B (p less than 0.01, p less than 0.01 and not significant, respectively). It is concluded that ischemia with retrograde blood flow can be used to examine occlusive and reperfusion ventricular arrhythmia in dogs, because the incidences of ventricular premature beats and ventricular tachycardia were high, but that of ventricular fibrillation was not high despite the severe ischemia.     

Correlation between resting ST segment depression, exercise testing, coronary angiography, and long-term prognosis

Resting ST segment depression has been identified as a marker for adverse cardiac events in patients with and without known coronary artery disease. To correlate this with exercise testing, coronary angiography, and how it impacts on long-term prognosis, a retrospective study was performed on 476 patients, of whom 223 had no clinical or electrocardiographic evidence of prior myocardial infarction while 253 were survivors of an infarction. All patients performed a standard exercise test and underwent diagnostic coronary angiography within an average of 32 days of their exercise test (range 0 to 90 days). Exclusions were women, those with left bundle branch block, left ventricular hypertrophy, use of digoxin, previous revascularization procedures, or significant valvular or congenital heart disease. Long-term follow-up was carried out for an average of 45 months (+/- 17). Of the patients without prior infarction, 23 (10%) had persistent resting ST segment depression, and of those with a prior history of infarction, 37 (15%) also had resting ST segment depression. Patients with resting ST segment depression and no prior myocardial infarction had a higher prevalence of severe coronary disease (three-vessel and/or left main) (30%) than those without resting ST segment depression (16%) (95% confidence interval [CI] for observed difference -5.0% to 33.9%, p = 0.12). The criterion of greater than or equal to 2 mm of additional exercise-induced ST segment depression was a particularly useful marker in these patients for the diagnosis of any coronary disease (likelihood ratio 3.35, 95% CI 0.56 to 19.93, p = 0.06). Patients with resting ST segment depression and a prior myocardial infarction had a 2.5 times higher prevalence of severe coronary artery disease compared with patients without resting ST segment depression (43% versus 17% prevalence, respectively, 95% CI for observed difference 9.38% to 42.8%, p less than 0.001) and also had larger left ventricles postinfarction (left ventricular end-diastolic volume index 102 ml/m2 compared with 96 ml/m2, p less than 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)     

Exercise testing in women with chest pain. Are there additional exercise characteristics that predict true positive test results?

Women have a notoriously high rate of false positive exercise test results. Since the exercise ST segment response has low specificity in predicting CAD in women, we examined additional exercise parameters in 200 women with a history of chest pain compatible with angina and having ST segment depression greater than or equal to 1 mm recorded during a Bruce treadmill test. All subsequently had coronary arteriography. Two groups were compared: group A (n = 80) with CAD (greater than or equal to 70 percent stenosis of one or more coronary artery) and group B (n = 120) with angiographically confirmed normal coronary arteries (normal or minimal placquing). The exercise criteria analyzed included: (1) chest pain during exercise, (2) percent target heart rate, (3) extent of ST shift, (4) morphology of the ST segment slope, (5) time to normalization of the ST segment, and (6) total exercise duration. Multivariate analysis (using a stepwise logistic regression model) identified four independent exercise variables associated with the likelihood of CAD: (absence of MVP, p = .003; exercise duration less than 5 min, p = .02; ability to reach target heart rate, p = .027; time to ST normalization greater than or equal to 6 min, p less than .001). False positive exercise test results were more likely to occur when the following exercise test variables were present: ability to exercise to stage 3 of the Bruce protocol and a rapid (less than or equal to 4 minutes) normalization of ST shift after cessation of exercise. Attention to these additional exercise variables allows more careful selection of women requiring more definitive (and expensive) testing.     

Exercise-induced ST segment elevation 2 weeks after uncomplicated myocardial infarction: contributing factors and prognostic significance

To define the prevalence and clinical significance of exercise-induced ST segment elevation during predischarge treadmill testing after uncomplicated acute myocardial infarction confirmed by serum MB creatine kinase (CK) activity, 241 consecutive patients were prospectively investigated with quantitative exercise thallium-201 scintigraphy, rest radionuclide ventriculography and coronary angiography at 10 +/- 3 days. All patients received customary care, and in none was thrombolytic therapy or emergency coronary angioplasty employed. Eighty-two patients (34%) had exercise-induced ST segment elevation of greater than or equal to 1 mm above rest baseline. These patients were similar to the 159 patients without this finding with respect to history of prior infarction, the Norris coronary prognostic index, exercise duration, metabolic equivalents (METs) achieved and peak heart rate-blood pressure product. The frequency of inducible myocardial ischemia and extent of angiographic coronary disease was also comparable in the two groups. Findings associated with larger infarct size and transmural extent of infarction were more common in patients with exercise-induced ST segment elevation than in those without, including higher peak CK values (1,235 +/- 1,037 versus 942 +/- 915 mumol/min per liter, p less than 0.026), lower left ventricular ejection fraction (43 +/- 12 versus 51 +/- 10%, p less than 0.001), a higher prevalence of pathologic Q waves in greater than or equal to 2 contiguous infarct-related leads (80 versus 55%, p less than 0.001), more persistent thallium-201 defects (2.2 +/- 1.1 versus 1.4 +/- 1.1, p less than 0.001), abnormally increased lung uptake of thallium (33 versus 18%, p less than 0.01) and a greater number of akinetic or dyskinetic segments (3.2 +/- 2.5 versus 1.4 +/- 1.9, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Correlation between the ST/heart rate slope and the severity of coronary disease in inferior infarcts. A new criterion of positivity of the ergometric test

We reviewed a group of 80 patients who had bicycle exercise stress testing and cardiac catheterization: 60 patients with known coronary artery disease (CAD) had a remote myocardial infarction, anterior, inferior, Q and no Q wave (post MI), 20 patients evaluated for suspected CAD resulted to have normal coronary arteries or lesions less than 50%. Patients were divided into three groups according to the extent of CAD. Group I with anatomically or functionally high risk CAD: left main (LM) stenosis greater than or equal to 50%, 3 vessels CAD greater than or equal to 70%, proximal left anterior descending stenosis (PLAD) greater than or equal to 90% with another vessel CAD; group II with one or two vessels CAD greater than or equal to 70%; group III with no or insignificant CAD. Linear regression analysis of the heart rate (HR)--related change in ST segment depression (ST/HR slope) was compared with six conventional electrocardiographic exercise test criteria to evaluate whether ST/HR slope can identify with improved accuracy group I. When all 80 patients are assessed together, ST/HR slope greater than or equal to 60 mm/beat/min 10(3) compared with standard electrocardiographic criteria failed to discriminate significantly between high-risk CAD (group I) and less extensive (group II) or insignificant CAD (group III). When only Q wave inferior post MI are considered, ST/HR slope greater than or equal to 60 mm/beat/min. 10(3) compared with ST segment depression greater than or equal to 1 mm identifies group I with 90% +/- 4 versus 75% +/- 6 overall predictive accuracy (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Inferior ST segment depression during acute anterior myocardial infarction: clinical and angiographic correlations

This study was performed to determine whether inferior ST segment depression during early stages of acute transmural anterior myocardial infarction identifies patients with multivessel coronary artery disease and additional inferior ischemia. Coronary and left ventricular angiography were performed within 3.4 months in 33 patients with acute transmural anterior infarction. Initial electrocardiograms, 2 to 5 hours after onset of chest pain, revealed significant ST segment depression (greater than or equal to 0.1 mV) in at least two of leads II, III and a VF in 15 patients (45%) (group B); in 18 patients (group A) this finding was absent. Compared with group A, patients in group B had greater anterior ST elevation (1.2 versus 0.7 mV, p less than 0.025); higher serum peak creatine kinase (2,475 versus 1,147 IU/liter, p less than 0.005); higher Killip scores (2.1 versus 1.3, p less than 0.001); more in-hospital complications (60 versus 17%, p less than 0.05); lower mean left ventricular ejection fraction (34 versus 55%, p less than 0.001); more frequent regional left ventricular dysfunction in anterolateral (91 versus 44%, p less than 0.05), posterolateral (36 versus 0%, p less than 0.05) and inferior (100 versus 6%, p less than 0.005) regions; greater wall motion abnormality scores (10.0 versus 5.5, p less than 0.005); higher frequency of concomitant left circumflex or right coronary artery disease, or both (80 versus 28%, p less than 0.01); more frequent postinfarction angina (100 versus 39%, p less than 0.001) and lower New York Heart Association functional classification scores (1.7 versus 2.4, p less than 0.05) at 6 month follow-up. The time course of inferior ST depression differed from that of anterior ST elevation. Thus, inferior ST depression was maximal in the first 48 hours and decreased (p less than 0.05) thereafter. In contrast, ST elevation in leads V1 to V6 and I appeared to decrease (p = NS) between days 4 and 7. However, inferior ST depression "mirrored" ST elevation in lead aVL, which also decreased (p less than 0.05) after 48 hours. Thus, inferior ST depression during anterior infarction is associated with more extensive infarction, greater morbidity and higher frequency of multivessel coronary disease. Such inferior ST depression might reflect not only "reciprocal change," but also ischemia in adjacent lateral and remote inferior regions.     

Starr-Edwards mitral valve prosthesis and secondary clinical deterioration. Hemodynamic study in 14 patients

The haemodynamic and angiocardiographic data of 19 patients with Starr-Edwards mitral valve prosthesis were analysed to determine the causes of secondary deterioration observed in 14 of them. This was shown to be due to: 1. Surgical complications or progression of pre-existing valvular lesions which were not, or only partially, corrected (3 cases) (adiastole due to pericardial effusion, aortic valve disease and severe tricuspid incompetence); average diastolic pressure gradient CPW-LV 4.7 +/- 1.5 mmHG, the functional valve surface area (FVA) 1.37 +/- 0.2 cm2, LVEDP 17.7 +/- 4 mmHg, LVEDV 57.5 +/- 11 ml/m2, and EF 73.5 +/- 8 p. 100; 2. Deterioration of left ventricular contractility with LVEDP greater than 13 mmHg, LVEDV greater than 100 ml/m2 and EF less than 45 p. 100 (4 cases); CPW-LV gradient 9.8 +/- 4 mmHG, FVSA 1.30 +/- 0.2 cm2, LVEDP 20.5 +/- 8 mmHG, LVEDV 212 +/- 168 ml and EF 38 +/- 21 p. 100; 3. Significant reduction of left ventricular volume (LVEDV 22 ml/m2 1 case); 4. Left atrial thrombosis (1 case); 5. Prosthetic valve dysfunction (5 cases) one paravalvular leak and 4 thromboses. In these 4 cases, the PCW-LV gradient was 15 +/- 5 mmHg, FVSA 0.95 +/- 0.1 cm2 LVEDP 8 +/- 2 mmHg, LVEDV 132.8 +/- 93 ml/m2 and EF 45 +/- 28 p. 100; these results were different to whose found in the other patients and those investigated systematically (PCW-LV gradient 8.2 +/- 3 mmHg, FVSA 1.38 +/- 0.3 cm2, LVEDP 11 +/- 4 mmHg, LVEDV 66.4 +/- 33 ml/m2, EF 53 +/- 13 p. 100). The significant haemodynamic criteria in favour of thrombosis of the prosthesis were: CPW-LV gradient greater than 12 mmHg under basal conditions or after exercise and a FVSA less than 1.1 cm2.     

Prevalence and long-term significance of exercise-induced frequent or repetitive ventricular ectopic beats in apparently healthy volunteers

Frequent or repetitive exercise-induced ventricular ectopic beats are often considered a marker for serious cardiac disease or sudden death, or both. However, the prognostic value of these arrhythmias in an unreferred asymptomatic community-dwelling population over a broad age range is unknown. Of 1,160 subjects aged 21 to 96 years who underwent maximal exercise treadmill testing an average of 2.4 times, 80 (6.9%) developed frequent (greater than or equal to 10% of beats in any 1 min) or repetitive (greater than or equal to 3 beats in a row) ventricular ectopic beats on at least one test. These 80 individuals were significantly older than the group without such arrhythmia (63.8 +/- 12.5 versus 50.0 +/- 16.1 years, p less than 0.0001). A striking age-related increase in the prevalence of frequent or repetitive exercise-induced ventricular ectopic beats was seen in men (p less than 0.0001) but not in women. The prevalence of electrocardiographic abnormalities at rest, exercise-induced ST segment depression and thallium perfusion defects, duration of treadmill exercise, maximal heart rate, systolic blood pressure and rate-pressure product did not differ between these 80 study subjects with frequent exercise-induced ventricular ectopic beats and a control group matched for age and gender. Furthermore, the incidence of cardiac events (angina pectoris, nonfatal myocardial infarction, cardiac syncope or cardiac death) (10% versus 12.5%) as well as noncardiac mortality (each 7.5%) was found to be similar for the study and control groups, respectively, over a mean follow-up period of 5.6 years. No study subjects required antiarrhythmic drugs over this time interval.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cardiac function and peripheral circulatory adjustments in patients with acute myocardial infarction. Observations during the early stage of AMI

Since little is known concerning the effect of different types of cardiac dysfunction on the peripheral circulation in acute myocardial infarction, cardiac and peripheral circulatory hemodynamics were measured simultaneously and sequentially in the Coronary Care Unit in 40 patients with acute myocardial infarction (AMI) using a Swan-Ganz catheter and venous occlusion plethysmography. Patients were classified by clinical assessment (Killip) and into four hemodynamic subsets (HS) according to pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) measures obtained by invasive central hemodynamic monitoring (Forrester): uncomplicated AMI, HS-I (PCWP less than or equal to 18 mmHg, CI greater than 2.2 L/min/m2) 15; pulmonary congestion, HS-II (PCWP greater than 18 mmHg, CI greater than 2.2 L/min/m2) 15; peripheral hypoperfusion, HS-III (PCWP less than or equal to 18 mmHg, CI less than or equal to 2.2 L/min/m2) 4; cardiogenic shock, HS-IV (PCWP greater than 18 mmHg, CI less than or equal to 2.2 L/min/m2) 6. Measurements taken within 48 hours after the onset of AMI showed significantly lower calf blood flow (p less than 0.05) and calf venous capacitance (p less than 0.01) and higher calf vascular resistance (p less than 0.05) in all AMI classifications compared to 10 normal subjects. In uncomplicated AMI group (Killip I and HS-I) calf blood flow and venous capacitance were significantly reduced while calf vascular resistance remained unchanged from normal. In AMI complicated by pulmonary congestion (Killip II and HS-II), in addition to reduced calf venous capacitance, calf blood flow was further significantly reduced (p less than 0.05) due, in part, to a rise in calf vascular resistance (p less than 0.05). In AMI complicated by severe heart failure and shock (Killip III, VI and HS-IV), mean changes in the periphery were not statistically different from those seen in patients with pulmonary congestion alone. In patients with AMI complicated by poor peripheral perfusion (HS-III), the peripheral changes did not show significant differences from those seen in uncomplicated AMI (HS-I). Significant correlations were found between calf blood flow and PCWP (r = -0.37, p less than 0.05) and CVP (r = -0.31, p less than 0.05); calf vascular resistance and PCWP (r = +0.36, p less than 0.05) and systemic vascular resistance (r = +0.43, p less than 0.01). Sequential daily peripheral hemodynamic changes in 14 H-I patients not requiring specific therapy showed that calf blood flow took 5 days, calf vascular resistance 3 days and calf venous capacitance 7 days to return to within normal levels.(ABSTRACT TRUNCATED AT 400 WORDS)     

Comparison of the cardiac output and stroke volume response to upright exercise in children with valvular and subvalvular aortic stenosis

Cardiac output and stroke volume were evaluated in 17 children (mean age 11.5 +/- 3 years) with discrete, membranous subvalvular (Group I, n = 7) and valvular (Group II, n = 10) aortic stenosis during submaximal and maximal (greater than 75% predicted maximal oxygen consumption) upright cycle ergometry. Patients with valvular aortic stenosis were further subdivided on the basis of their aortic valve gradient at rest determined by cardiac catheterization (Group IIA, gradient less than 40 mm Hg; Group IIB, gradient greater than or equal to 40 mm Hg). These patients were matched with 17 control subjects on the basis of age, sex, height and intensity of exercise during maximal exertion. Cardiac and stroke indexes were determined by the acetylene rebreathing method at each exercise level. Stroke volume index in Group I was significantly greater at rest when compared with that in control subjects (69 +/- 13 versus 53 +/- 11 ml/m2, alpha = 0.01, p less than 0.05) and that in patients in Group II (69 +/- 13 versus 47 +/- 12 ml/m2, alpha = 0.01, p less than 0.05). Patients with subvalvular aortic stenosis were unable to increase their stroke volume index from rest to submaximal exercise and also decreased their stroke volume index at maximal exercise levels. In contrast, patients with mild valvular aortic stenosis (Group IIA) displayed a normal exercise response. Patients with severe valvular aortic stenosis (Group IIB) had a blunted stroke volume response at rest and at each level of exercise, as well as signs of myocardial ischemia (ST segment depression) during maximal exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased response of diastolic blood pressure to exercise in patients with coronary artery disease: an index of latent ventricular dysfunction?

OBJECTIVE--To determine whether an abnormal response of diastolic blood pressure during treadmill exercise stress testing correlated with the number of obstructed vessels and with left ventricular systolic function in patients with coronary artery disease. DESIGN--Diastolic blood pressure was measured invasively during exercise stress testing and coronary angiograms and left ventriculograms were obtained at rest in patients with coronary artery disease. The abnormal (> or = 15 mm Hg) diastolic blood pressure response was compared with the number of obstructed coronary arteries and with left ventricular systolic function. SETTING--Two tertiary referral centres. PATIENTS--50 consecutive patients (mean age 57 years) with coronary artery disease. MAIN OUTCOME MEASURES--The increase in diastolic blood pressure during exercise and its correlation with the appearance and disappearance of ST segment deviation, resting left ventricular systolic function, and the number of obstructed coronary arteries. RESULTS--Group 1: 10 (20%) patients (three with one, four with two, and three with three vessel coronary artery disease) (mean (SD) age 54.7 (12) years) had an abnormal diastolic blood pressure response that appeared 1.2 (0.3) min before ST segment deviation and became normal 0.9 (0.3) min after the ST segment returned to normal. Group 2: 40 (80%) patients (12 with one, 16 with two, and 12 with three vessel coronary arteries disease) (aged 56.8 (8.2) years) had a normal diastolic blood pressure response to stress testing. The ejection fraction (46.3 (5)%) and cardiac index (2.6 (0.1) 1/min/m2) in group 1 were less than in group 2 (61.6 (4.2)% and 3.8 (0.3) 1/min/m2 respectively, p < or = 0.001). The end systolic volume was greater in group 1 than in group 2: 38.7 (0.7 ml/m2 v 28.2 (2.1) ml/m2, p < or = 0.001. CONCLUSION--In patients with coronary artery disease an abnormal increase in diastolic blood pressure during exercise stress testing correlated well with left ventricular systolic function at rest but not with the number of obstructed coronary arteries. The abnormal response of diastolic blood pressure probably reflects deterioration of myocardial function.     

Clinical significance of stress-induced ST segment elevation in patients with previous anterior myocardial infarction. Analysis of lactate metabolism with atrial pacing

To clarify the mechanism of stress-induced ST segment elevation in patients with previous anterior myocardial infarction, we examined myocardial lactate metabolism during atrial pacing in 32 patients with previous anterior myocardial infarction (MI group) and 11 control subjects (control group). In the MI group, atrial pacing resulted in new or additional ST segment elevation in leads with Q waves in 15 patients (ST elevation group), ST segment depression in 7 (ST depression group), but induced no appreciable ST segment changes in the remaining 10 patients (ST unchanged group). In all patients, the ST segment changes were identical to the results of exercise stress testing which was carried out prior to the atrial pacing. Lactate extraction ratio increased moderately during the atrial pacing in the control group (p less than 0.01). Although marked reduction of the myocardial lactate extraction ratio was noted in the ST depression group (p less than 0.05), no significant change in the ratio was evoked in the ST elevation group or the ST unchanged group during atrial pacing. Left ventricular end-diastolic pressure (LVEDP) increased markedly in the ST depression group during atrial pacing, but the elevation was less evident in the other groups. The ST elevation group demonstrated the lowest left ventricular ejection fraction and the severest degree of left ventricular asynergy. Thus, the present study indicates that aggravated left ventricular asynergy in the infarcted area and associated left ventricular dysfunction, rather than peri-infarction zone ischemia is a possible mechanism of stress-induced ST segment elevation in leads with Q waves following previous anterior myocardial infarction.     

Treadmill exercise test in patients with hypertrophic cardiomyopathy with and without coronary artery disease

We studied whether the treadmill exercise test can discriminate between normal and significant narrowing of coronary arteries in patients with hypertrophic cardiomyopathy (HCM) accompanied with chest pain, and we compared the extent of myocardial ischemia during exercise. Thirty one patients with HCM were divided into two groups; 21 with normal coronary arteries and 11 with significant narrowing of coronary arteries. The treadmill exercise test was carried out in both groups. The following parameters were more frequently seen in the group with coronary stenosis. (1) short treadmill time (338, sec vs 542, p less than 0.05). (2) delta SBP less than or equal to 60 mmHg (delta: end point minus rest, 10 cases vs 12, 0.05 less than p less than 0.1). (3) significant delta ST depression (0.17 mV vs 0.05, p less than 0.05). (4) large delta ST/delta HR (3.3 microV.min/beats vs 0.7). delta ST/delta HR greater than or equal to 2.0 was the most useful for differentiating the two groups, and it was 90% in index both sensitivity and specificity for diagnosis of HCM with significant narrowing of the coronary arteries. It was concluded that treadmill exercise induced more severe myocardial ischemia in patients with HCM who had significant narrowing of the coronary arteries than in patients with HCM who had angiographically normal coronary arteries. The delta ST/delta HR was the most useful index for diagnosis of HCM with significant narrowing of the coronary arteries.     

Hemodynamic effects of intravenous magnesium sulfate in man

The haemodynamic effects of a single 3 g dose of magnesium sulfate administered by slow (1 min) intravenous injection were evaluated in 16 patients with coronary disease about to be explored by coronary arteriography. The haemodynamic effects were transient, with maximal values at the end of the injection and return to baseline values within less than 3 min. They consisted of peripheral vasodilatation with a decrease in systolic aortic pressure (128 +/- 18 mmHg versus 113 +/- 17 mmHg, p less than 0.05), an increase of cardiac index (3.0 +/- 0.4 versus 3.8 +/- 0.06 1/min/m2, p less than 0.001) and a fall in peripheral arterial resistance (1168 +/- 203 versus 919 +/- 29 dyn/s/cm-5, p less than 0.01). This action was accompanied by a moderate increase in contractility (Vmax) (1.63 +/- 0.34 versus 1.87 +/- 0.47 CIR/s, p less than 0.01) without changes in the relaxation index T (37 +/- 8 versus 67 +/- 9 s-1, NS), but with concomitant increase in heart rate (80 +/- 12 versus 67 +/- 10 beats/min, p less than 1.10(-4]. It is concluded that the haemodynamic effects of magnesium sulfate are moderate and transient and that this substance can be used safely as antiarrhythmic agent, even in case of marked deterioration of the left ventricular function.     

Comparative study of exercise-induced ischaemia in coronaropathy and aortic stenosis

OBJECTIVE: To compare exercise and recovery data between a population of patients with proven CAD and patients with pure aortic stenosis (AS). PATIENTS AND METHODS: Exercise testing results (bicycle ergometry) of 45 patients with AS (34 men, 66+/-12 years, 56+/-20 mmHg peak-to-peak gradient and valve area 0.78+/-0.48cm2) were compared to exercise testing results of 50 patients with CAD (41 men, 65+/-9 years, greater or equal to 70% stenosis on one vessel in 62%, two vessels in 30%, three vessels in 8%). RESULTS: During exercise, 38% patients with AS and 82% patients with CAD had clinical symptoms. In the AS group, exercise duration was longer, heart rate (HR) was higher, maximal systolic and diastolic blood pressure were lower than in CAD group. The increase of systolic blood pressure was lower in the AS group (34+/-21 mmHg versus 47+/-27 mmHg, p<0.02). Maximal load achieved was not significantly different. Exercise ST depression appeared in 76% of AS group and 88% of CAD group (NS). No difference was found in ST depression, Detrano index and ST segment/HR slope. During recovery, no difference was found in HR variations. Clockwise rotation of the ST/HR recovery loop was more frequent in CAD group (35 patients versus 19 patients, p<0.001). CONCLUSION: Most of the exercise and recovery data are similar in patients with AS and CAD. Significant discriminating criteria were the increase of systolic blood pressure during exercise and ST/HR recovery loop.