Factors influencing estimated oxygen uptake during exercise testing soon after myocardial infarction

To determine the extent to which oxygen uptake (VO₂) estimated from exercise testing in healthy adults is applicable to patients tested soon after myocardial infarction, v?O₂ was measured during symptom-limited treadmill testing 3 and 11 weeks after the acute event. Twenty-two men (Group I) underwent treadmill testing using a “standard” modified Balke protocol (3 miles/h [80 m/min] with 2.5 percent increments in grade every 3 minutes) 3 and 11 weeks after infarction. Twenty-five clinically similar men (Group II) underwent treadmill testing using a standard protocol at 3 weeks but an “accelerated” protocol (3 miles/h with 5 percent increments in grade every 3 minutes) at 11 weeks. Measured and estimated values of peak v?O₂ were nearly identical for both groups of patients performing the standard protocol at 3 weeks (mean ± standard deviation 20.5 ± 4.7 versus 20.4 ± 6.1 and 22.1 ± 4.1 versus 22.5 ± 4.5 ml/kg per min for Groups I and II, respectively). Measured and estimated values of peak v?O₂ were also similar for patients completing the standard protocol at 11 weeks (26.3 ± 7.6 versus 26.7 ± 6.9 ml/kg per min). In contrast, estimated values of peak v?O₂ were significantly higher than measured values in patients completing the accelerated protocol at 11 weeks (30.8 ± 4.3 versus 27.7 ± 5.0 ml/kg per min (probability [p] = 0.001). Holding onto the treadmill handrails significantly increased estimated peak v?O₂ (32.7 to 37.9 ml/kg per min) but did not affect measured peak v?O₂ (32.1 to 31.8 ml/kg per min). These results indicate that v?O₂ for patients performing treadmill exercise testing after myocardial infarction can be estimated from data derived from healthy adults so long as the exercise intensity is increased slowly and holding onto the handrails is avoided.     

Long-term effect of cardioversion on peak oxygen consumption in chronic atrial fibrillation: A 2-year follow-up

Restoration of sinus rhythm may improve functional capacityin atrial fibrillation in the short-term. Little is known, however,about its long-term effect on functional status. The aim ofthe present study was to evaluate the long-term effect of cardioversionon peak oxygen consumption (VO₂) in patients with chronic atrialfibrillation. Patients with such a condition and due to undergoelectrical cardioversion were eligible for the study. Patients underwent treadmill exercise testing with measurementof peak VO₂ before cardioversion, and at 1 month and 2 yearsthereafter. Based on the rhythm present at those times aftercardioversion, patients were categorized into three groups:those in sinus rhythm after 1 month and 2 years (Group I); thosein sinus rhythm after 1 month, but with atrial fibrillationafter 2 years (Group II); and those who were in atrial fibrillationboth at 1 month and 2 years following cardioversion (Group III).Thirty-nine patients were included, and underlying heart diseasewas present in 24 of them (62%). In the comparison of the baseline characteristics of Group I(n = 17), Group II (n =11), and Group III (n = 11), underlyingheart disease was more frequent in Group I (88%, 45%, and 36%,respectively); otherwise they were similar. In Group I, peakVO₂ showed an insignificant increase from 21.1 ± 50 to22.3 ± 50 ml. min ^–1. kg^–1 1 month aftercardioversion. After 2 years of sinus rhythm, peak VO₂ showeda further increase to 23.8 ±5.0 ml. min^–1. kg^–1(P<0.05). In Group II patients, peak VO₂ improved after 1month of sinus rhythm (from 25.2 ± 7 to 27.8 ±8 ml. min^–1. kg^–1, P<0.05) but returned to baselineafter 2 years, when atrial fibrillation had relapsed. In GroupIII patients, peak VO₂ was unchanged 1 month after cardioversion,when atrial fibrillation had already relapsed. After 2 years,however, peak VO₂ had decreased from 22.1 ± 4.0 to 20.6± 4.0 (P<0.05), when compared to baseline. In conclusion, restoration of sinus rhythm is associated witha modest but significant improvement of peak VO₂, which persistsafter the first month following cardioversion. In addition,in patients with sustained atrial fibrillation functional capacitydecreases during long-term follow-up. These findings suggestthat, to prevent progressive deterioration of functional capacityin atrial fibrillation, a treatment approach aimed at restoringand maintaining sinus rhythm may be warranted.     

The effect of beta-blockade therapy on the response to exercise training in postmyocardial infarction patients

Cardiac rehabilitation after a myocardial infarction has been shown to improve exercise capacity. Beta blockade has been shown to be effective in treating angina and reducing mortality, but studies are controversial as to whether beta-blockade therapy attenuates the effects of training. We attempted to study the effects of beta blockade (metoprolol) on the response to training in patients enrolled in a cardiac rehabilitation program after an uncomplicated myocardial infarction. We studied 27 patients with a recent uncomplicated myocardial infarction who were subdivided in two groups: Group 1 (13 patients) not taking a beta blocker, and Group 2 (14 patients) taking metoprolol (mean 142 ± 57 mg daily). All patients underwent a maximal cardiopulmonary exercise test before and after a 3-month training program. The training intensity was designed to approximate the ventilatory threshold. Results showed an increase in peak VO₂ in both Group 1 (27%, p<0.01) and Group 2 (33%, p<0.001), and an increase in VO₂ at the ventilatory threshold (39% in Group 1 and 28% in Group 2, p<0.01). The mean changes in exercise capacity were not different between groups. It was concluded that metoprolol did not influence the beneficial effects of a cardiac rehabilitation program in postmyocardial infarction patients.     

Exercise performance of the high risk acute myocardial infarction patient after cardiac rehabilitation

Sixty-five subjects with a recent acute myocardial infarction (AMI), 50 men and 15 women aged 39 to 79 years (mean 62 +/- 9), were entered into a 12-week phase II cardiac rehabilitation program. Group I subjects were those with an ejection fraction greater than 40% (mean 56) and group II subjects were those with an ejection fraction less than 40% (mean 28). Subjects were further classified into those with or without myocardial ischemia (Ia, IIa and Ib, IIb, respectively) based on a treadmill stress test before entry. Work performance during the training sessions was similar for all subgroups, although group IIb had the lowest values for work rate and time of exercise for each individual activity. Subgroup analysis, as determined by a pre- and postprogram treadmill stress test, showed there was no significant difference in time of exercise, peak oxygen consumption and change in submaximal heart rate (decrease) for groups Ia, Ib or IIa. However, group IIb had poor performance in time of exercise (delta = 2 +/- 2 minutes), peak oxygen consumption (delta = 3 +/- 5 ml/min) and submaximal heart rate (delta = 0.4 +/- 17 beats/min) compared with the 3 other subgroups. These subjects also did not demonstrate an improvement of these values in the posttraining period. Patients who have had AMI and have both significant left ventricular dysfunction and myocardial ischemia did not have an adequate training response after 12 weeks of a formal phase II cardiac rehabilitation program.(ABSTRACT TRUNCATED AT 250 WORDS)     

Chronotropic competence in endurance trained heart transplant recipients: heart rate is not a limiting factor for exercise capacity

Objectives. The purpose of this study was to show that the chronotropic potential of the well trained heart transplant recipient (HTR) does not limit exercise capacity.Background. Chronotropic incompetence is considered to be the main limiting factor of the functional capacity of heart transplant recipients. However, no systematic study had been published on patients who had spontaneously undergone heavy endurance training for several years.Methods. Heart rate (HR) and respiratory gas exchanges (VO₂, VCO₂, VE) were measured in 14 trained HTRs (T-HTRs) during exercise tests on a bicycle, on a treadmill and by Holter electrocardiography during a race.Results. Peak values observed in T-HTRs during the treadmill test were higher than those reached during the bicycle test (VO_2peak:39.8 ± 6.9 vs. 32.5 ± 7.8 ml·kg⁻¹·min⁻¹, p < 0.001; HR_peak: 169 ± 14 vs. 159 ± 16 bpm, p < 0.01). During treadmill exercise VO_2peakand HR_peakvalues observed were very close to the mean predicted VO_2pmaxand HR_pmax. The maximum heart rate during the race (HR_race) was greater than HR_peakvalues during the treadmill test (179 ± 14 vs 169 ± 14 bpm, p < 0.01) and slightly above the mean predicted values (HR_race/HR_pmax× 100 = 101 ± 10%). The treadmill exercise test yields more reliable data than does the bicycle test.Conclusions. Extensive endurance training enables heart transplant recipients to reach physical fitness levels similar to those of normal sedentary subjects; heart rate does not limit their exercise capacity.     

Role of myocardial ischemia in the genesis of stress-induced S-T segment elevation in previous anterior myocardial infarction

This study tests the hypothesis that myocardial ischemia is responsible for exercise-induced S-T segment elevation in patients with previous anterior myocardial infarction (MI). Exercise stress testing in conjunction with thallium imaging of the myocardium was performed in 28 patients with previously documented anterior MI. Thallium images were analyzed by computer for the presence of initial uptake defects and evidence of abnormal clearance of the isotope from the myocardium (that is, imaging evidence of ischemia). Total S-T segment elevation (∑ST) in precordial leads V₁ to V₆ at rest was subtracted from ∑ST at peak stress in order to quantitate the extent of S-T elevation induced by stress (ΔST). Two groups of patients were identified; 1 with stress-induced S-T elevation (Group I, ΔST ≥ 4.0 mm) and 1 without this abnormality (Group II, ΔST < 4.0 mm). Evidence of abnormal thallium washout from myocardial scan segments occurred in 12 of 15 Group I patients versus 9 of 13 Group II patients (difference not significant). In addition, abnormal tracer washout from anterolateral or septal scan segments occurred in 5 patients in each group. Likewise, abnormal thallium clearance from inferior or posterior scan segments occurred in 8 of 15 Group I patients versus 7 of 13 Group II patients (difference not significant). The patient with the greatest amount of stress-induced S-T elevation (S-T 11.5 mm) had no evidence of ischemia during the stress test. However, Group I patients did have larger anterolateral plus septal initial thallium uptake defect scores than did those of Group II (10 of 15 with defect score ≥ 350 in Group I versus 1 of 13 in Group II, p <0.002). Similarly, resting left ventricular ejection fraction ≥ 30% was present in only 4 of 15 Group I patients versus 13 of 13 in Group II (p <0.001). Finally, multiple stepwise linear regression analysis demonstrated that ΔST correlated best with the extent of initial anterolateral plus septal thallium uptake defect score (F = 17.3, p < 0.001) and to a lesser extent with resting ejection fraction (F = 5.2, p < 0.05) and change in heart rate from rest to peak stress (F = 8.1, p < 0.01; corrected multiple correlation coefficient = 0.76, p < 0.001). Thus, in patients with previous anterior MI (1) exercise-induced myocardial ischemia occurs as often with as without S-T segment elevation, (2) myocardial ischemia is not required for the production of stress-induced S-T segment elevation, and (3) stress-induced S-T elevation primarily reflects the extent of previous anterior wall damage and to a lesser extent an increase in heart rate between rest and peak stress.     

Relation between QRS changes and left ventricular function after coronary artery bypass grafting

Preoperative and serial postoperative electrocar-diograms (ECGs) were reviewed in 104 patients undergoing rest and exercise radionuclide angiocardiography before and 1 to 12 months after coronary artery bypass grafting (CABG). Five patient groups were defined by ECG findings before and after CABG: Group I—normal ECG before and no ECG change after CABG; Group II—prior myocardial infarction by ECG before but no QRS change after CABG; Group III—all patients with a minor QRS change (< 0.04-second Q wave, loss of R-wave amplitude) after CABG; Group IV—all patients with a major QRS change (≥ 0.04-second Q wave) after CABG; Group V—all patients without new Q waves or loss of R-wave amplitude but with a major QRS change (conduction disturbance) after CABG. Mean resting ejection fraction changed little after CABG in all groups, although the 0.03 increase in Group I was significant (p < 0.05). Group IV had the largest decrease in resting ejection fraction after CABG (0.04), but this was not statistically significant. Mean exercise ejection fraction increased significantly (p < 0.0001) in Groups I, II and III but not in Groups IV and V. QRS changes do not consistently reflect impairment of left ventricular (LV) function after CABG.     

Electrocardiographic responses to atrial pacing and multistage treadmill exercise testing. Correlation with coronary arteriography

Atrial pacing was compared with multistage treadmill exercise testing in 50 patients undergoing diagnostic cardiac catheterization to determine the diagnostic sensitivity of atrial pacing. Coronary artery disease was considered significant if luminal narrowing greater than 75 percent was present. Twenty-one subjects (Group I) had no significant coronary artery disease with vessel narrowing of less than 50 percent. Twelve (Group II) had single vessel disease and 17 (Group III) had disease of two or more vessels.The mean maximal heart rate during atrial pacing was 140/min and during exercise testing was 131/min. A positive atrial pacing test result was obtained in 5 percent of patients in Group I, 17 percent of patients in Group II and 24 percent of patients in Group III. A positive multistage treadmill exercise test result was obtained in 10 percent of patients in Group I, 67 percent of patients in Group II and 94 percent of patients in Group III. These differences are statistically significant (P < 0.001). The sensitivity of atrial pacing was 20 percent compared with 83 percent for multistage treadmill exercise testing. The specificity of atrial pacing was 95 percent compared with 90 percent for multistage treadmill exercise testing. Thus, atrial pacing is an insensitive test in the diagnosis of ischemic heart disease and does not improve the diagnostic value of multistage treadmill exercise testing.     

Recumbent Ergometer vs Treadmill Cardiopulmonary Exercise Test in HFpEF: Implications for Chronotropic Response and Exercise Capacity

BackgroundCardiopulmonary exercise testing (CPET) can identify mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF), but exercise modalities with differing body positions (eg, recumbent ergometer, treadmill) are broadly used. In this study, we aimed to determine whether body position affects CPET parameters in patients with HFpEF.MethodsSubjects with stable HFpEF (n = 23) underwent noninvasive treadmill CPET, followed by an invasive recumbent-cycle ergometer CPET within 3 months. A comparison group undergoing similar studies included healthy subjects (n = 5) and subjects with pulmonary arterial hypertension (n = 6).ResultsThe peak oxygen consumption (VO₂peak) and peak heart rate were significantly lower in the recumbent vs the upright position (10.1 vs 13.1 mL/kg/min [Δ–3 mL/kg/min]; P < 0.001; and 95 vs 113 bpm [Δ–18 bpm]; P < 0.001, respectively). No significant differences were found in the minute ventilation to carbon dioxide production ratio, end-tidal pressure of carbon dioxide or respiratory exchange ratio. A similar pattern was observed in the comparison groups.ConclusionsCompared to recumbent ergometer, treadmill CPET revealed higher VO₂peak and peak heart rate response. When determining chronotropic incompetence to adjust beta-blocker administration in HFpEF, body position should be taken into account.     

Doppler echocardiographic analysis of the transmitral flow velocity profile in patients with ventricular septal defects

Using continuous-wave Doppler echocardiography, we evaluated the mitral flow velocity pattern in 30 ventricular septal defect patients, 11 of whom had severe pulmonary vascular obstructive disease (Group I); 10 of whom had severe pulmonary hypertension without pulmonary vascular obstructive disease (Group II); and 9 of whom had no pulmonary hypertension and hemodynamically unimportant left-to-right shunts (Group III). In addition, 25 healthy subjects (Group IV) were studied for comparative purposes. The peak velocity of early left ventricular filling (E) was significantly lower in Group I than in all the other groups (p < 0.01). The peak velocity of late left ventricular filling (A) was significantly higher (p < 0.01) in Group I than in Group III, or than in normal individuals (Group IV) (p < 0.01). The ratio A/E was the most prominent difference between Group I patients and the other groups, with Group I having a significantly higher ratio (p < 0.01), which was 1 or greater in 9 of 11 patients. In contrast, none of the remaining ventricular septal defect patients or normal subjects had an A/E ratio of 1 or greater. Group II had increased mitral flow velocities, while Group III had normal mitral flow velocity profiles. A positive correlation between the magnitude of the left-to-right shunt and early mitral flow velocity peak (r = 0.86) and late peak (r = 0.81) was found, regardless of the degree of pulmonary hypertension. These results indicate that significant alterations of the mitral flow velocity pattern, which mimic the abnormalities associated with impaired left ventricular diastolic function (A/E ratio of 1 or greater), occur in ventricular septal defect patients who have severe pulmonary vascular obstructive disease. The transmitral velocity profiles in the ventricular septal defect patients without severe pulmonary vascular obstructive disease were similar to those of the normal patients, although the values relative to the degree of left-to-right shunting were higher in the ventricular septal defect patients.     

Time of eating and cardiorespiratory fitness in patients with heart failure with preserved ejection fraction and obesity

Background and aimsOur objective was to examine the impact of caloric intake before or after the mean time of evening meal on cardiorespiratory fitness (CRF) in patients with heart failure with preserved ejection fraction (HFpEF) and obesity.Methods and resultsTwelve patients with HFpEF and obesity completed a cardiorespiratory exercise test to measure CRF, defined as peak oxygen consumption (VO₂). Three five-pass 24-h dietary recalls were performed for each participant and mean evening meal time was determined for each participant individually as well as the group. Participants were divided into those who ate before (Group I) and after (Group II) the mean time of evening meal, 7:25 PM.Peak VO₂ and exercise time were significantly greater in Group II compared to Group I, moreover, delaying time of evening meal was associated with greater peak VO₂.ConclusionCaloric intake after the mean time of evening meal was associated with better CRF in patients with HFpEF and concomitant obesity. Later nutrient intake may help prevent fasting related stress associated with cardiac metabolic disturbances present in HFpEF. Based on these findings, prospective trials aimed at examining the effects of later evening meal times in patients with HFpEF and obesity are warranted.     

Abnormal cardiovascular regulation in the mitral valve prolapse syndrome

Studies of patients with mitral valve prolapse syndrome have suggested autonomic nervous system dysfunction, but a precise definition of mechanisms is lacking. We measured supine and standing heart rate, blood pressure, cardiac output, oxygen consumption, plasma catecholamines, and blood volume in 23 symptomatic women with both echocardiographic and phonographic signs of MVP and in 17 normal control subjects. An analysis of the results revealed 2 distinct subgroups of patients: those with normal heart rates but increased vasoconstriction (Group I, n = 10) and those with orthostatic tachycardia (Group II, n = 13). Group II patients had heart rates at rest supine of 97 ± 3 compared with 79 ± 2 in Group I patients and 78 ± 8 in control subjects. Estimated total blood volumes were lowest in Group I patients, intermediate in Group II patients, and highest in control subjects (p<0.05). Other measurements at rest supine were similar in patients and controls. After standing for 5 minutes, patients had a higher mean plasma epinephrine value, diastolic blood pressure (81 ± 2 versus 74 ± 3 mm Hg, p < 0.05), and peripheral resistance (1,878 ± 114 versus 1,414 ± 92, dynes s cm^?5, p < 0.01), wider arteriovenous oxygen difference (6.7 ± 0.4 versus 5.3 ± 0.5 vol%), and lower stroke volume index (26 ± 2 versus 33 ± 2 ml/m², p < 0.01) than did the control subjects. Cardiac output was normal in Group II patients but reduced in Group I patients, who demonstrated marked vasoconstriction. No patient had evidence of a “hyperkinetic” circulatory state. A cycle of decreased forward stroke volume, vasoconstriction, and blood volume contraction appears to be present in at least some symptomatic patients with MVP.     

Uses and limitations of exercise Doppler echocardiography in the diagnosis of ischemic heart disease

This study tested the hypothesis that coronary artery disease might be identified by a decrease in Doppler measurements of flow velocity and acceleration. The response of aortic blood flow velocity and acceleration to exercise was determined in 102 subjects (28 young control subjects and 74 older patients) who underwent continuous wave Doppler echocardiographic examination before, during and immediately after near maximal treadmill exercise. Patients were grouped according to the results of thallium perfusion imaging: Group I = normal, Group II = ischemia with or without prior infarction and Group III = prior infarction only. A significant decrease in the level of velocity and acceleration achieved with exercise was observed both in patients in Group I (normal thallium study) (1.2 +/- 0.3 m/s and 36.8 +/- 14 m/s per s, p less than or equal to 0.005) and in patients in Group II (ischemia) (1.1 +/- 0.3 m/s and 27.7 +/- 11 m/s per s, p less than or equal to 0.0005) compared with values in young control subjects (1.4 +/- 0.2 m/s and 52.7 +/- 16 m/s per s). When groups of patients of similar age who differed in the presence (Group II) or absence (Group I) of ischemia on thallium scintigraphy were compared, no difference was found for maximal velocity (1.1 +/- 0.3 versus 1.2 +/- 0.3 m/s, p = NS), but acceleration was significantly lower in Group II (27.7 +/- 11 versus 36.8 +/- 14 m/s per s, p less than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of oral hydralazine on gas exchange in patients with cor pulmonale

Vasodilators lower total pulmonary vascular resistance in some patients with pulmonary hypertension, but If vasodilators worsen arterial oxygenation in cor pulmonale, as they do in some patients with left ventricular failure, the benefits of a decrease in vascular resistance would be offset by a lack of change or a deterioration in systemic oxygen delivery. Measurement was made of arterial and mixed venous blood gases, minute ventilation, shunt fraction, alveolar-arterial oxygen difference, pulmonary arterial pressures, and cardiac output before and four hours after a single dose of hydralazine, 75 mg orally, in six patients (Group I) and before and after 48 hours of hydralazine, 50 to 75 mg orally, every six hours In 10 patients (Group II). Cardiac output increased 36 percent in Group I and 48 percent in Group II. In both groups total pulmonary vascular resistance decreased (8.0 ± 2.8 to 6.1 ± 2.6 units in Group I, p < 0.01; 9.7 ± 3.7 to 5.6 ± 2.1 units in Group II, p < 0.01). Arterial P_O2 increased significantly both in Group I (61 ± 8 to 67 ± 10 torr, p < 0.05) and Group II (50 ± 13 to 54 ± 13, p < 0.05); however shunt fraction and alveolar-arterial oxygen difference were unchanged. The ratio of dead space to tidal volume decreased slightly in both groups, and minute ventilation increased significantly. Systemic oxygen delivery was increased by 39 and 51 percent in Groups I and II, respectively. Thus, gas exchange may be preserved or improved when hydralazine is used in the treatment of cor pulmonale.     

Cineangiography in the diagnosis of aortic dissection

To assess the ability of biplane cineangiography in the diagnostic evaluation of acute dissection of the aorta, 20 patients with acute dissection were studied within 24 hours of surgery or autopsy, or both. Biplane large film aortic angiography was performed in 11 patients (Group I) and biplane aortic cineangiography in 9 (Group II). The morphology of the aortic valve was defined precisely in 5 (50 percent) of 10 patients in Group I and in all 9 patients (100 percent) in Group II (p < 0.02). Aortic regurgitation was diagnosed in all patients in both groups in whom it was present (p = not significant). Intimai tears were localized in 5 (50 percent) of 10 patients in Group I and in 8 (89 percent) of 9 in Group II (p < 0.07). Intimal flaps were not identified angiographically in three patients in Group I and were identified in four patients (100 percent) in Group II (p < 0.01). The presence of retrograde dissection was established in three (38 percent) of eight patients in Group I and in four (100 percent) of four patients in Group II (p < 0.05). There was no difference in the ability to identify a nonclotted false lumen between cine and large film angiography. It is concluded that in addition to improved diagnostic capabilities, technical advantages make cineangiography a good alternative to large film angiography in the diagnostic evaluation of patients with acute dissection of the aorta.     

Peak systolic blood pressure/end-systolic volume ratio: Assessment at rest and during exercise in normal subjects and patients with coronary heart disease

To assess the utility of a recently proposed index of left ventricular performance, the ratio of peak left ventricular systolic pressure to end-systolic volume, equilibrium radionuclide angiography was used to determine end-systolic volume and the systolic blood pressure obtained by cuff sphygmomanometer to determine peak systolic pressure. Data were analyzed at rest and during supine bicycle exercise in 15 normal subjects (Group 1), 50 patients with coronary artery disease (Group II) and 9 patients with obstructive lung disease and no evidence of coronary artery disease on clinical examination including exercise thallium imaging (Group III). In 15 subjects the correlation between the resting angiographic and radionuclide pressure/volume ratio was excellent (r = 0.929, p <0.005).Forty-seven (94 percent) of the 50 patients in Group II had a depressed pressure/volume ratio at rest or an abnormal change in this ratio during exercise, whereas only 43 (86 percent) of this group had an abnormal ejection fraction at rest or during exercise. Additionally, 3 of 15 subjects in Group I had an abnormal ejection fraction response, defined as less than 0.05 ejection fraction unit increase with exercise (specificity 80 percent), whereas all subjects in Group I had a normal increase in pressure/volume ratio (specificity 100 percent). At rest, neither index identified more patients with coronary artery disease than the other. Of the nine patients in Group III, six had an abnormal ejection fraction response to exercise, whereas only one had an abnormal pressure/volume ratio response.It is concluded that the end-systolic pressure/volume ratio is a useful index of left ventricular performance. In some patients during supine exercise stress it may be more sensitive than the ejection fraction response alone in identifying the presence of coronary artery disease.     

The significance of hypotension developing during treadmill exercise testing

The significance of hypotension developing during treadmill exercise testing was evaluated and correlated with the findings at cardiac catherization in two groups of patients. Twenty-five patients (Group I) had a fall in systolic pressure during exercise and were compared to 50 consecutive unselected patients (Group II) with a normal blood pressure response. Clinical characteristics were similar in both groups. Females comprised 48 per cent of the patients in Group I and only 30 per cent in Group II. The incidence of significant coronary artery disease was not different when the two groups were compared as a whole, 56 per cent in Group I and 36 per cent in Group II (P = NS). When males and females were considered separately, it was noted that the incidence of coronary artery disease was higher in hypotensive males (77 per cent) when compared to control males (40 per cent) (p < 0.01). Females in both groups had a lower but comparable incidence of coronary artery disease (25 per cent and 27 per cent, respectively). Resting hemodynamics and angiographic characteristics, such as contraction abnormalities, and the number and distribution of diseased coronary vessels, were similar in both groups of patients. These findings suggest that hypotension in females does not necessarily connote coronary artery disease. Males with hypotension have a higher incidence of coronary artery disease, but the extent and distribution of their disease is no different from that of patients with a normal blood pressure response to exercise.     

Higher Gensini score of coronary arteries in acute inferior myocardial infarction with precordial ST-segment depression.

To investigate the significance of precordial ST-segment depression in acute inferior myocardial infarction, we compared the Gensini score of coronary artery stenosis between 2 groups of patients with and without precordial ST-segment depression. Group I consisted of 28 patients who showed ST-segment depression on admission (greater than or equal to 1 mm in V2-V6) and Group II (n = 16) those without ST-segment depression (less than 1 mm). The Gensini score of the coronary arteries (56 +/- 29 vs. 28 +/- 18; p less than 0.001), the partial score of the infarction-related artery (29 +/- 16 vs. 17 +/- 11; p less than 0.01) and of the infarction-nonrelated artery (27 +/- 24 vs. 11 +/- 12; p less than 0.02) were significantly higher in Group I than in Group II. The Killip score (greater than or equal to II) (34% vs. 6%; p less than 0.05), frequency of arrhythmias (75% vs. 38%; p less than 0.02) and peak CK value (3,676 +/- 2,290 vs. 1,818 +/- 1,153 IU/L; p less than 0.005) were higher in Group I than in Group II. Four patients in Group I died following admission, while no patient died in Group II (N.S.). Autopsy findings from the 4 Group I patients revealed fresh extensive inferior infarction and healed diffuse subendocardial infarction which could not be predicted from electrocardiograms. All patients who survived the acute stage performed treadmill exercise testing and 22 patients underwent exercise thallium-201 single photon emission computer tomography (SPECT). On treadmill exercise test, there was no significant difference between the 2 groups in the frequency of angina pectoris and ST-segment depression. On SPECT, the perfusion defect area under 55% of maximum uptake at the redistribution phase was 45.8 +/- 19.6 cm2 in Group I (n = 14) and 34.7 +/- 21.3 cm2 in Group II (n = 8; N.S.). In conclusion, precordial ST-segment depression in acute inferior myocardial infarction suggested advanced atherosclerosis in both the infarction-related and nonrelated coronary arteries, indicating a larger infarct size.     

Progression of isolated aortic stenosis: Analysis of 29 patients having more than 1 cardiac catheterization

Factors related to progression of nonrheumatic aortic stenosis (AS) were analyzed in 29 adult patients who underwent serial hemodynamic studies over a mean of 71 months. AS was congenital in 8 patients and degenerative in 21. The patients were divided into 2 groups on the basis of the change in aortic valve area between the 2 studies. Twelve patients had a ≥ 25% reduction in aortic valve area (Group I) and 17 patients had < 25% decrease in aortic valve area (Group II). There were no significant differences between the 2 groups in age, interval between studies, cardiac output, left ventricular end-diastolic pressure, left ventricular peak systolic pressure and origin of AS (congenital or degenerative). Group I patients had significantly larger initial aortic valve areas than did Group II patients (1.3 ± 0.9 cm² versus 0.8 ± 0.4 cm², p = 0.02). Also, the initial peak transaortic pressure gradients were lower in Group I than in Group II (27 ±19 versus 58 ± 38 mm Hg, p = 0.01). Group I patients had a significantly greater increase in pressure gradient and a greater reduction in cardiac output than did Group II patients (24 ± 21 mm Hg in Group I versus?0.1 ± 24.5 mm Hg in Group II, p = 0.01, and ?1.0 ± 1.3 liters/min in Group I versus 0.10 ± 1.4 liters/min in Group II, p = 0.03). Thus, AS progressed in 41 % of a selected group of patients who underwent repeated cardiac catheterization. The progression was not predictable. Although 10 patients (34%) had moderate aortic regurgitation (AR) in the second study, it was not related to the origin or rate of progression of AS. Mild AS tends to progress more than severe AS. Congenital AS appears to progress at the same rate as degenerative AS.     

One-stage coronary bypass and abdominal aortic aneurysm repair

A group of 29 patients with simultaneous coronary disease and abdominal aortic aneurysm were treated two protocols: Group I, 16 patients had coronary bypass surgery and then abdominal aortic aneurysm repair at a later date. This required two hospitalizations and two separate surgeries. Group II, 11 patients, underwent coronary bypass surgery and repair of abdominal aortic aneurysm (AAA) in one sitting. Group III, 2 patients, had PTCA prior to AAA repair. There were 3.1 bypass grafts implanted (Group I), vs 2.9 (Groups II) (ns). All abdominal aneurysms were infrarenal and 22 patients had straight tube graft replacement (76%), and seven bifurcated grafts. Two patients with angina also had symptomatic AAA. Period of hospitalization, morbidity, mortality, time of total recovery, hospital costs, and apprehension of patients were analyzed. There was one death in Group I. In this group, the total recovery time was 4.8 months vs 2.4 months for Group II. Hospitalization time was 16.2 days in Group I vs 8.2 days in Group II. The hospital costs were significantly higher in Group I with an average of $58,950 vs $46,553 in Group II. No deaths occurred in Group II. It is recommended that if a patient with severe coronary disease requiring surgery also presents with an AAA of more than 5 cm, he/she should have both conditions operated on in one session rather than staggering the procedures. It saves time, cost, anxiety, and is well tolerated.Presented at the 38th Annual World Congress, International College of Angiology, Köln, Germany, June 1996.