Effect of metaraminol during acute inferior wall myocardial infarction accompanied by hypotension: preliminary study.

This study was designed to evaluate the effects of metaraminol (Aramine) in six patients with evolving acute inferior wall myocardial infarction accompanied by hypotension and warm limbs. There were 16 episodes of acute inferior wall ischemia, and the response to therapy was judged by evaluating blood pressure and ST segment and T wave abnormalities. Three patients received intravenous isosorbide dinitrate and two received streptokinase as the initial therapy. The mean ST segment elevation was significantly reduced (from 4.94 +/- 1 to 0.5 +/- 0.7 [p less than 0.0001]) after metaraminol infusion was initiated. The average T wave height also decreased (from 6.8 +/- 2 to -1.3 +/- 2.5 mm [p less than 0.0005]). The average heart rate decreased from 82 +/- 11 to 69 +/- 9 beats/min (p less than 0.05) and the mean arterial blood pressure increased from 81 +/- 12 mm Hg before metaraminol treatment to 126 +/- 8 mm Hg after treatment. All these changes occurred within a few minutes after metaraminol therapy was instituted. In 12 episodes, accelerated idioventricular rhythm appeared concomitantly with the resolution of ST segment elevation. Coronary angiography performed between 4 and 10 days after admission demonstrated significant obstruction in all infarct-related arteries, but none was totally occluded. Left ventricular function was normal in three patients and slightly hypokinetic in the inferior wall in two. These results indicate that in a selected group of patients with acute inferior myocardial infarction, metaraminol administration (in certain hemodynamic circumstances) can alleviate acute ischemia within a few minutes and thereby reduce ischemic injury.

Efficacy and safety of the dual L- and T-type calcium channel blocker, ACT-280778: a proof-of-concept study in patients with mild-to-moderate essential hypertension.

ACT-280778 is an oral, non-dihydropyridine, dual L-/T-type calcium channel blocker. This phase 2a, double-blind, randomized, placebo- and active-controlled study investigated the efficacy and safety of 10 mg ACT-280778. Patients with mild-to-moderate essential hypertension received once-daily placebo (n=53), ACT-280778 10 mg (n=52) or amlodipine 10 mg (n=54) for 4 weeks. The primary end point was the change from baseline to week 4 in placebo-adjusted mean trough sitting diastolic blood pressure (SiDBP) with ACT-280778. Tolerability was assessed by recording treatment-emergent adverse events (TEAEs). Baseline clinical characteristics were similar across groups. No significant difference was observed at week 4 in mean trough SiDBP between placebo (-9.9 (95% confidence limit (CL) -12.7, -7.0) mm Hg) and ACT-280778 (-9.5 (-12.4, -6.5) mm Hg; P=0.86); amlodipine reduced mean trough SiDBP by -16.8 (-19.0, -14.5) mm Hg, confirming assay validity. Change in mean PR interval at week 4 (pre-dose) differed between placebo (-1.0 (95% CL -4.4, 2.3) ms) and ACT-280778 (6.5 (3.5, 9.6) ms); amlodipine did not increase PR interval (1.1 (-1.6, 3.9) ms).Treatment-emergent adverse events (TEAE) frequency was 32.1% (placebo), 32.7% (ACT-280778) and 33.3% (amlodipine). The most common TEAEs were headache, peripheral edema, hypertension and second-degree atrioventricular block. ACT-280778 (10 mg) did not lower blood pressure in mild-to-moderate hypertension.

Effects of isosorbide dinitrates intravenously in high doses over a short period in anterior acute myocardial infarction.

The effects of intravenous isosorbide dinitrate administered in high doses over a short period of time in 17 patients (14 men, 3 women, mean age 67 years) with anterior wall acute myocardial infarction were evaluated. Patients were classified into 2 groups based on the electrocardiographic pattern of acute ischemia. Patients presented with anterior acute myocardial infarction; an electrocardiographic pattern of third-degree ischemia demonstrated a more favorable electrocardiographic and radionuclear angiographic evolution than similar patients who presented with an electrocardiographic pattern of second-degree ischemia.

Multiform accelerated idioventricular rhythm in acute myocardial infarction: electrocardiographic characteristics and response to verapamil.

Thirteen patients with acute myocardial infarction with multiform accelerated idioventricular rhythm (AIVR) occurring during the first 12 hours of monitoring in the coronary care unit are described. This arrhythmia, similar to the more common uniform AIVR, was intermittent, did not cause hemodynamic compromise, and was not related to more serious ventricular arrhythmias. There was no correlation between the bundle branch block pattern of the multiform AIVR and the electrocardiographic location of the myocardial infarction, but there was a perfect correlation between the frontal plane electrical axis of the multiform AIVR and the electrocardiographic location of the myocardial infarction. The presence of fusion beats between the different forms of AIVR suggests multifocality rather than multiformity. Intravenous verapamil (3 to 5 mg bolus) was administered to 6 patients with multiform AIVR in whom the arrhythmias were persistent enough to allow the evaluation of the effect of verapamil on the arrhythmia. Verapamil caused no change in the rate of AIVR in 1 patient, but in a second patient it decreased the rate by 20 beats/min. In 4 patients, verapamil abolished the arrhythmia: in 2 patients carotid sinus pressure (induced sinus slowing) allowed the emergence of the AIVR at a lower rate, and in the remaining 2 patients the arrhythmia was not observed.

The effect of intravenous amiodarone on heart rate in patients with acute myocardial infarction or ischemia and sinus tachycardia.

The effect of intravenous (IV) amiodarone (300 mg) on heart rate was investigated in 22 patients with acute myocardial infarction (18) or ischemia (4) and sinus tachycardia. There were 11 men and 11 women (age range, 48 to 83 years; mean, 63.5). Amiodarone IV slowed the mean heart rate from 109 +/- 14 beats/min to 94 +/- 15 beats/min (p less than 0.0005). There was a linear correlation between the initial heart rate (preamiodarone) and the final heart rate (postamiodarone), (r = 0.6930, p less than 0.0005). Most of the patients with initial heart rates higher than the mean maintained relatively high heart rates (above the mean), while most patients with lower initial heart rates showed low heart rates (below the mean) after amiodarone administration. Patients in Killip class 1 showed a significant reduction in heart rate after receiving amiodarone, from a mean of 105 +/- 10 to 88 +/- 11 beats/min (p less than 0.01). Patients in Killip class 2 also had reduced heart rates (118 +/- 14 to 81 +/- 39 beats/min), but these changes were not statistically significant. Of the three patients in Killip class 3 to 4, the heart rate slowed by 10 beats/min in one, while in the remaining two no changes were observed. There were no significant side effects from the administration of amiodarone.

Significance of the magnitude of a QS wave deflection in evaluating the uninvolved muscle in anterior wall myocardial infarction.

The significance of dynamic changes of the QS wave magnitude, as demonstrated in the precordial leads, within the natural evolution of acute anterior wall myocardial infarction (AAMI) was assessed in 25 patients within two weeks of their admission to the intensive cardiac care unit. Two sets of tests, including 12-lead electrocardiogram and a full radionuclear study, were performed in two time periods: (1) within the first 48 hours of admission; and (2) between the 12th and 15th day after admission. Comparison and correlation between the electrocardiographic data, QS waves in leads V2 and V3 and in V1 to V6 (sigma QV2-3 and sigma QV1-6), and radionuclear regional ejection fractions of the noninfarcted posterior muscle (inferior, infero-apical, and posterolateral regions and posterior index) were done. Significant linear correlations were demonstrated between the electrocardiographic variant differences in percentages (sigma QV2-3 and sigma QV1-6) and the radionuclear variant differences, especially the posterolateral and the infero-apical regions, as well as the posterior radionuclear index (r between 0.5 and 0.75; p less than 0.01). In addition, almost all of the patients who showed deepening of QS waves in the precordial leads also showed an increase in regional ejection fractions in uninvolved myocardium, and vice versa. It is concluded that the dynamic changes of the QS wave magnitude in the precordial leads within the evolution of acute anterior myocardial infarction well reflect the changes of the posterior noninfarcted muscle contraction and therefore offers a simple, inexpensive, and indirect electrocardiographic method for evaluating changes in contraction patterns of noninfarcted myocardium.

Pulmonary function threshold for distinguishing ventilatory- and nonventilatory-limited patients with airflow obstruction.

Patients with chronic obstructive pulmonary disease (COPD) may demonstrate great variability between results on the pulmonary function test (PFT) compared to those on the cardiopulmonary exercise test (CPXT). The purpose of this study was to correlate PFT and CPXT indices and to identify PFT threshold values for predicting exercise capacity in patients with airflow limitation. Fifty-seven patients (48 men and 9 women) of mean age 66.4 +/- 4.8 years with COPD and 40 age-matched control patients underwent PFT and CPXT. Based on the CPXT results, the patients were divided into ventilatory-limited (VL) and nonventilatory-limited (NVL), and the findings were correlated with the PFT indices. Linear regression analysis was used to determine the relationship between dyspnea index (VEmax/MVV) and forced expiratory volume in one second (FEV1). The cutoff value for VL was FEV1 < 38% and for NVL FEV1 > 68%. The prominent limiting symptom (61%) in the VL group was dyspnea sensation, with leg discomfort presenting in only 14%; corresponding rates in the NVL group were 38% and 31%. We conclude that the FEV1 is a reliable index for distinguishing VL from NVL COPD patients during CPXT at two extremes: below 38% of the predicted value (VL) and above 68% of the predicted value (NVL).

Prominent atrial wave and diastasis deflection in the radionuclide diastolic volume curve during exercise--sensitive marker for coronary artery disease.

It is well-known that many patients with coronary artery disease have reduced left ventricular diastolic distensibility with normal systolic function. However, researchers have to data focused on the diastolic rapid filling phase of the radionuclide volume curve in ischemic patients, paying less attention to the ensuing left ventricular filling associated with passive filling ('diastasis') and atrial contraction ('A' wave). We analyzed the radionuclide volume curves of 27 consecutive patients suspected ischemic heart disease, who manifested normal systolic function at rest and during exercise, as assessed by multigated equilibrium technetium-99m radionuclide cineangiography. For all patients, the amplitude of the maximal 'A' deflection relative to the peak of the diastolic curve (presented as percentage units) was calculated manually from the radionuclide left ventricular volume curves obtained at rest and during exercise. Twenty patients (Group I) had transient perfusion defects on thallium scintigraphy (treadmill), and 7 (Group II) did not. Patients in Group I manifested prominent 'A'-deflections during exercise, with a rise of 120 +/- 43% (mean +/- S.D.) from rest to exercise, whereas the patients in Group 11 had only 34 +/- 11% (mean +/- S.D.) rise in 'A' wave amplitude during exercise (P = 0.0001). We conclude that the appearance of a prominent 'A' deflection in the radionuclide left ventricular volume curve during exercise might be a sensitive marker of myocardial ischemia.

Contribution of cardiopulmonary indices in the assessment of patients with silent and symptomatic ischemia during exercise testing.

Cardiopulmonary and radionuclear indices were used to evaluate and compare cardiac function during exercise testing in patients with symptomatic and silent ischemia. The study comprised 58 patients aged 35-74 years, divided into three groups: Group I-20 patients (controls) with neither ST depression nor chest pain; Group II-22 patients with ST depression > 1 mm and no chest pain; Group III-16 patients with both ST depression and chest pain. All patients in Groups II and III demonstrated significant coronary artery disease. No antianginal medication was taken at least 24 h before testing. All patients underwent a cardiopulmonary exercise test and a multigated acquisition radionuclear study. The following variables were measured: oxygen consumption (VO2), CO2 output (VCO2), minute ventilation (VE), O2-pulse, ventilatory anaerobic threshold (VAT), left ventricular ejection fraction (LVEF) at rest (r) and at maximal effort (ex). Probability values were significant for all variables (P < 0.01-0.0001) except left ventricular ejection fraction-rest (P not significant between the three groups). No significant differences in extent of coronary artery disease were noted between Groups II and III. These findings suggest that during exercise testing patients with silent ischemia have better overall cardiac function than patients with symptomatic ischemia. Their value for both cardiopulmonary and radionuclear indices are closer to those of the control group than to the symptomatic group, regardless of the severity of the coronary artery disease Summary of results: (mean +/- 1 S.D.) Group VO2-max O2-Pulse max VAT (%) VAT (ml/min) LVEF-rest delta LVEF (ex-r) I 25.2 +/- 6.3 15.7 +/- 3.4 51.2 +/- 6.6 1075 +/- 289 54.7 +/- 7 5.4 +/- 4.85 II 22.4 +/- 2.8 14.5 +/- 2 47.0 +/- 5.3 854 +/- 136 52 +/- 10 1.2 +/- 6.7 III 16.0 +/- 2.5 11.4 +/- 2 41.6 +/- 7.7 683 +/- 105 51 +/- 8.5 -5.87 +/- 6.3

Significance of prominent atrial-wave and diastasis deflection in radionuclide diastolic volume curve during exercise in detection of coronary artery disease.

BACKGROUND: Exercise testing with multigated acquisition technetium radionuclide cineangiography (MUGA) is a useful modality that can discriminate systolic and diastolic performance in patients with ischemic heart disease. However, some patients may have abnormal left ventricular filling dynamics with normal regional and global systolic function. HYPOTHESIS: The purpose of the study was to assess exercise-induced diastolic dysfunction as expressed by a prominent atrial (A) wave or diastasis deflection at the left ventricular volume curve, in patients with different degrees of ischemic heart disease. METHODS: In all, 32 men and 7 women aged 35-70 years (mean 54 +/- 8.6 years) underwent MUGA at rest and during exercise for analysis of the radionuclide volume curve. Within 6 weeks, thallium-201 scintigraphy and coronary angiography were performed and the patients were categorized into three groups: (1) disease-free (n = 10), (2) single-vessel disease (> 50% stenosis) (n = 19), and (3) double-vessel disease or more (n = 10). A waves or diastasis deflections were compared among the groups. RESULTS: Significant differences (p < 0.01) were noted in A-wave deflection relative to peak diastolic volume curve during exercise (Aexe/T) between Group 1 and Groups 2 and 3. Group 1 manifested only a mild rise in A-wave deflection from rest (20.20 +/- 8.49%) to exercise (25.85 +/- 8.49%), whereas Groups 2 and 3 exhibited a significant increase from 25.89 +/- 9.55% and 28.40 +/- 12.6%, respectively, to 60.21 +/- 22.5% and 63.0 +/- 22.86%, respectively. Group 2 had a significantly (p < 0.05) higher maximal heart rate than Group 3. CONCLUSIONS: The addition of prominent A-wave or diastasis deflection to a normal systolic response during exercise testing with multigated radionuclide cineangiography might be a sensitive marker of coronary artery disease. The A wave represents diastolic dysfunction of the left ventricle, considered an early event in the ischemic cascade.

Relationship between late potentials and the predischarge electrocardiographic pattern in patients with acute anterior wall myocardial infarction.

HYPOTHESIS: The presence of late potentials on the signal-averaged electrocardiogram (SAECG) identifies patients at high risk for development of ventricular tachyarrhythmias after myocardial infarction (MI). METHODS: The electrocardiogram and left ventricular function in 65 patients recovering from a first acute anterior wall MI were analyzed. We compared the pattern of the ST segment (isoelectric or elevated) and of the T wave (positive or negative) with the SAECG using an orthogonal bipolar lead configuration (X, Y, Z) with bidirectional Butterworth filtering (Simson's method). RESULTS: Abnormal SAECG was found in 17 (26%) patients; 11 of 18 patients with ST elevation had abnormal SAECG, and only 6 of 47 patients with isoelectric ST segment developed abnormal SAECG (p < 0.0001, odds ratio = 10.74). Of 19 patients with positive T waves, 10 had abnormal SAECG, and abnormal SAECG was found in 7 of 46 patients with negative T waves (p < 0.003, odds ratio = 5.27). When both parameters were considered together, 9 of 12 patients with ST elevation and positive T wave developed abnormal SAECG, and 35 of 40 patients with isoelectric ST and negative T wave had normal SAECG (p < 0.0002). Left ventricular ejection fraction was similar in patients with abnormal SAECG (43 +/- 14%) and normal SAECG (46 +/- 11%). CONCLUSION: These findings suggest that patients with anterior wall MI and a predischarge pattern of ST elevation and positive T wave have a higher incidence of abnormal SAECG and therefore may have a worse prognosis, especially related to the subsequent development of ventricular arrhythmias.

Relationship between pulmonary function and unsupported arm exercise in patients with COPD.

UNLABELLED: In patients with chronic obstructive pulmonary disease (COPD) the limitation on unsupported arm exercise (UAE) is predominantly respiratory muscle function-dependent. It is characterized by neuromechanical dysfunction (thoracoabdominal dyssynchrony) of the inspiratory muscles (diaphragm, accessory), superimposed by lung mechanics dysfunction. The undergoing mechanism is probably multifactorial. To study the relationship of resting pulmonary function and UAE performance in patients with COPD. Twenty-one patients, mean age 63 +/- 7 years, with COPD [forced expiratory volume in the first second (FEV1) 42 +/- 12% of predicted] underwent assessment of resting lung function (inspiratory capacity 57 +/- 17%; functional residual capacity 204 +/- 38% of predicted), maximal inspiratory pressure (67 +/- 14 cmH2O), upper arm circumference (30 +/- 2 cm), and symptom-limited cardiopulmonary UAE assessments. UAE consisted of bilateral anterior arm elevation to shoulder level at a rate of 40 arm strokes.minute-1. A series of stepwise multiple regression models were fitted to the data to predict exercise time from resting pulmonary function indices. RESULTS: Statistically significant correlations (r) were found between exercise time and inspiratory capacity (% of predicted) (r = 0.67, p = 0.0008), maximal inspiratory pressure (cmH2O) (r = 0.47, p = 0.03), upper arm circumference (r = 0.74, p = 0.0001), FEV1 (% of predicted) (r = 0.62, p = 0.0026), oxygen uptake (r = 0.56, p = 0.0085) and functional residual capacity (% of predicted) (r = -0.41, p = 0.06, borderline). Inspiratory capacity (% of predicted), functional residual capacity (% of predicted), upper arm circumference (cm) and FEV1 (% of predicted) explained 77% of the variance in exercise time. Therapeutic strategies that aim to increase inspiratory capacity or decrease functional residual capacity, or increase inspiratory muscle strength and upper arm/torso muscle endurance are likely to alleviate symptoms and improve UAE performance in patients with COPD.

[The effect of omega-3 fatty acids on risk factors for cardiovascular diseases].

UNLABELLED: Cardiovascular disease (CVD) is associated with dyslipidemia and frequently with insulin resistance, both of which are in general no alleviated by antilipidemic drugs. Our objective was to examine whether a dietary supplement containing omega-3 fatty acids (n-3 FA) can reduce the levels of serum lipids, fasting insulin and glucose in documented CVD patients treated by statins or bezafibrates. In a double-blind placebo-controlled trial of parallel design, 52 patients, age 69.2 years +/- 3.6 treated by antilipidemic drugs, were randomly assigned to receive daily 7 gr of a dietary concentrated supplement containing 67% n-3 FA (185 mg EPA and 465 mg/g DHA) in a form of spread (Yamega Ltd, Israel) or olive oil spread (placebo) and recommended to reduce the consumption of omega-6 fatty acids for 12 weeks. The average values +/- SD before and after dietary supplementations were compared. RESULTS: 44 patients (23 in the n-3 FA group) completed the study. In the n-3FA group we observed a significant decrease (p < 0.05) of total cholesterol (12.2%). LDL-cholesterol (16.8%), triglycerides (36.1%), insulin in hyperinsulinemic subjects (> 20 microunits/ml) (34.9%), and no significant changes in HDL-cholesterol and glucose. No hyperglycemia was detected. In the olive oil group we observed a significant decrease (p < 0.05) in the LDL-cholesterol values of 15.5% and no significant changes in the other parameters. No side effects were reported during the study in any of the participants. Our findings demonstrate that the incorporation of the dietary supplement containing EPA and DHA omega-3 fatty acids reduces significantly the above risk factors for CVD.

Assessment of functional results after percutaneous transluminal coronary angioplasty by cardiopulmonary exercise test.

Twenty-nine patients with documented coronary artery disease underwent cardiopulmonary exercise tests before and following a percutaneous transluminal coronary angioplasty (PTCA). The patients medication regimen and exercise protocols remained the same in both cases. Following PTCA, significant improvement (p < 0.001-0.0001) was noted in oxygen consumption (1,526.8 +/- 470.0 vs. 1,686.2 +/- 390 ml/min), oxygen pulse (12.40 +/- 2.73 vs. 13.44 +/- 2.9 ml/beat), oxygen pulse score (7.62 +/- 1.29 vs. 8.85 +/- 1.26 points) and in the ventilatory anaerobic threshold (993.1 +/- 177.6 vs. 1,089.8 +/- 150.9 ml/min) but not (p > 0.05) in maximal heart rate (128.7 +/- 16.9 vs. 132.0 +/- 17.2 beats/min). Thus, a cardiopulmonary exercise test is an effective method to assess functional results following PTCA.

The natural course of electrocardiographic stages of acute inferior myocardial infarction in regard to R/Q ratio group classification.

Forty-three patients with their first acute inferior wall myocardial infarction (IWMI) were divided into three groups according to the R/Q ratio in standard lead II. This was done to correlate these groups with the characteristic course of electrocardiographic stages. The R/Q ratio was measured on the ninth day of follow-up study, and the electrocardiographic stages were followed from the onset of the IWMI up until the ninth day. Patients with R/Q greater than 2 (group I) had a more rapid progression through the electrocardiographic stages, along with a better clinical course than patients with a lower R/Q ratio. Patients in group III, with R/Q less than 1, had a slower electrocardiographic stage progression, which correlates well with a more complicated clinical course. Group II was an intermediate group in both the electrocardiographic and clinical course. Rapid stage evolution in the first 12 hours of the IWMI was followed by a more rapid progression through stages during the rest of the follow-up period. It is suggested that the R/Q ratio in lead II can be used as a marker of the severity of IWMI, since it correlates well with the course of electrocardiographic stages. The greater the R/Q ratio, the more rapid the progression of electrocardiographic stages, and the better the clinical course. This may be an additional simple and inexpensive electrocardiographic tool for following the natural course of IWMI.

Unstable angina with tachycardia: clinical and therapeutic implications.

We prospectively evaluated 19 patients with prolonged chest pain not evolving to myocardial infarction and accompanied with reversible ST-T changes and tachycardia (heart rate greater than 100 beats/min) in order to correlate heart rate reduction with ischemic electrocardiographic (ECG) changes. Fourteen patients (74%) received previous long-term combined treatment with nifedipine and nitrates. Continuous ECG monitoring was carried out until heart rate reduction and at least one of the following occurred: (1) relief of pain or (2) resolution of ischemic ECG changes. the study protocol consisted of carotid massage in three patients (16%), intravenous propranolol in seven patients (37%), slow intravenous amiodarone infusion in two patients (10%), and intravenous verapamil in four patients (21%) with atrial fibrillation. In three patients (16%) we observed a spontaneous heart rate reduction on admission. Patients responded with heart rate reduction from a mean of 125 +/- 10.4 beats/min to 84 +/- 7.5 beats/min (p less than 0.005) and an ST segment shift of 4.3 +/- 2.13 mm to 0.89 +/- 0.74 mm (p less than 0.005) within a mean interval of 13.2 +/- 12.7 minutes. Fifteen (79%) had complete response and the other four (21%) had partial relief of pain. A significant direct correlation was observed for heart rate reduction and ST segment deviation (depression or elevation) (r = 0.7527 and 0.8739, respectively). These patients represent a unique subgroup of unstable angina, in which the mechanism responsible for ischemia is excessive increase in heart rate. Conventional vasodilator therapy may be deleterious, and heart rate reduction in mandatory.

Effect of controlled exercise training in coronary artery disease patients with and without left ventricular dysfunction assessed by cardiopulmonary indices.

Cardiopulmonary indices were used to evaluate the effect of controlled exercise training prescribed on the basis of the heart rate at the ventilatory anaerobic threshold in coronary artery disease patients with and without impaired left ventricular function. Fifty-two patients aged 38-75 years were divided into four groups. The first three groups included patients with a left ventricular ejection fraction of > 45% at rest, as follows: group 1, 10 patients with single-vessel disease; group 2, 12 patients with two-vessel disease; group 3, 10 patients with three-vessel disease. Group 4 comprised 20 patients with left ventricular dysfunction (ejection fraction < 35%). The left ventricular ejection fraction was assessed by multigated acquisition radionuclear study. All patients underwent a cardiopulmonary exercise test before and after the program which lasted 6-9 months. The variables measured were oxygen consumption (VO2), CO2 output, minute ventilation, O2 pulse, and ventilatory anaerobic threshold. Significant improvements in maximal VO2, maximal O2 pulse, and ventilatory anaerobic threshold level were observed in groups 1, 2, and 4 (p < 0.1-0.0001), but not in group 3. These findings indicate that the overall cardiac function, as evaluated by cardiopulmonary indices, improves in patients with one- or two-vessel disease with good left ventricular function and in patients with impaired left ventricular function following an exercise training program. Severe coronary disease seems to limit improvement, even in the presence of a good left ventricular function. The results validate the heart rate at the ventilatory anaerobic threshold as the optimal training heart rate in coronary artery disease patients and the cardiopulmonary exercise test as a sensitive tool for evaluating exercise training results.

Relation between aerobic capacity and extent of myocardial ischemia in patients with normal cardiac function.

BACKGROUND: The relation between aerobic capacity and extent of exercise-induced myocardial ischemia has not been investigated. Fifty patients with coronary artery disease (>/=50% stenosis) without myocardial infarction underwent cardiopulmonary exercise testing followed by quantitative thallium perfusion imaging. Results were compared with those of age- and sex-matched healthy controls with a low likelihood of coronary artery disease. Patients with Q-wave infarction, pulmonary disease, and peripheral vascular disease were excluded. Cardiopulmonary exercise testing and thallium perfusion imaging parameters were correlated for extent of global ischemia, occurrence of increased pulmonary thallium uptake, and transient ventricular dilatation during exercise. RESULTS: Patients with global ischemia <20% (group 1, n = 25) had normal cardiopulmonary exercise testing results, similar to the control group, except for workload and maximal predicted heart rate, which were reduced. However, patients with ischemia >/=20% (group 2, n = 25) had poor cardiopulmonary exercise testing results compared with the controls. The ventilatory anaerobic threshold showed the most significant decrease of all cardiopulmonary exercise testing parameters (48% +/- 6% vs 57% +/- 6%, P <.0001), and it was the only parameter to correlate with extent of ischemia (r = -0.5; P <.003) as well as frequency of increased pulmonary uptake and transient ventricular dilatation (r = -0.33, P =.03). CONCLUSIONS: Ventilatory anaerobic threshold is significantly related to extent of myocardial ischemia and signs of heart failure during exercise. However, patients with mild to moderate exercise-induced ischemia may have normal cardiopulmonary exercise testing performance.

Natural course of electrocardiographic components and stages in the first twelve hours of acute myocardial infarction.

Time course evolution of R, Q, T and ST components of the electrocardiogram during the first 12 hours of an acute myocardial infarction was studied. A comparison between anterior-extensive and anteroseptal wall infarctions (anterior group), and inferior-extensive and inferior wall infarction (inferior group) showed appearance of significant Q waves within two hours in both groups. R wave loss was nearly a mirror image of Q wave development in both groups. T waves became negative and ST more isoelectric earlier in the inferior than in the anterior group. When combined variations of the four electrocardiographic components were analyzed, four stages of acute infarction were delineated. Stage I--tall R, no Q, ST elevation and positive T; Stage II--significant Q wave appearance; Stage III--negativity of T waves; and Stage IV--ST isoelectric. The inferior group reached stages III-IV within 12 hours; the anterior group remained mostly in stage II. An early appearance of Q waves correlated well with rapid progression to stages III-IV within 12 hours in both infarction groups.