Characterisation of heart rate response to exercise in the sick sinus syndrome.

Patients with sick sinus syndrome have abnormalities of the sinoatrial node. We have measured the heart rate response to exercise in 7 patients with sick sinus syndrome without significant associated heart disease (group A) mean age 53.4 years, and compared this with 7 'normal' patients who were age-matched to within 5 years (group B), and 7 younger, well-trained subjects (group C). All underwent maximal treadmill exercise. Although maximum oxygen consumption (VO2max), 1/min per kg, in group A was not significantly different from group B (23.8 +/- 4.7 vs 19.9 +/- 0.8, mean +/- SE) maximum heart rate, beats/min, in group A was significantly lower than in group B (124 +/- 8.9 vs 163 +/- 3.7, P less than 0.001). At the end of 3 minutes of Bruce Stage I exercise, group A patients had a heart rate less than 130/minute (95% confidence level), whereas group B patients had heart rates greater than 134/minute. VO2 was plotted against heart rate (HR). Patients in group A had a significantly lower slope (deltaHR 5.20 +/- 0.33/delta1 ml VO2/kg per min, P less than 0.001). There was no significant difference in the slopes between groups A and C. On exercise patients with sick sinus syndrome have a normal VO2, but a reduced heart rate response as compared with age-matched normal patients. This abnormal heart rate response to the physiological stimulus of exercise may be of help in the evaluation of patients with sick sinus syndrome who do not have significant underlying heart disease.     

Prolonged and fractionated right atrial electrograms during sinus rhythm in patients with paroxysmal atrial fibrillation and sick sinus node syndrome

Intraatrial catheter mapping of the right atrium was performed during sinus rhythm in 92 patients: Group I = 43 control patients without paroxysmal atrial fibrillation or sick sinus node syndrome; Group II = 31 patients with paroxysmal atrial fibrillation but without sick sinus node syndrome; and Group III = 18 patients with both paroxysmal atrial fibrillation and sick sinus node syndrome. Atrial electrograms were recorded at 12 sites in the right atrium. The duration and number of fragmented deflections of the atrial electrograms were quantitatively measured. The mean duration and number of fragmented deflections of the 516 atrial electrograms in Group I were 74 +/- 11 ms and 3.9 +/- 1.3, respectively. The criteria for an abnormal atrial electrogram were defined as a duration of greater than or equal to 100 ms or eight or more fragmented deflections, or both. Abnormal atrial electrograms were observed in 10 patients (23.3%) in Group I, 21 patients (67.7%) in Group II and 15 patients (83.3%) in Group III (Group II versus Group I, p less than 0.001; Group III versus Group I, p less than 0.001). The mean number of abnormal electrograms per patient with an abnormal electrogram was 1.3 +/- 0.7 in Group I, 2.5 +/- 1.9 in Group II and 3.5 +/- 2.5 in Group III (Group I versus Group II, p less than 0.01; Group II versus Group III, p less than 0.05). A prolonged and fractionated atrial electrogram characteristic of paroxysmal atrial fibrillation can be closely related to the vulnerability of the atrial muscle.(ABSTRACT TRUNCATED AT 250 WORDS)     

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)     

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)     

Abnormal heart rate recovery immediately after cardiopulmonary exercise testing in heart failure patients

An attenuated heart rate recovery (HRR) immediately after exercise has been shown to be predictive of mortality. It is not known whether HRR predicts mortality when measured in patients with heart failure. The present study was undertaken to evaluate the ability of HRR to predict mortality in patients with heart failure. We studied 84 NYHA class II or III chronic congestive heart failure patients who had a left ventricular ejection fraction < or = 40%. All patients underwent symptom limited cardiopulmonary exercise testing. The value for the HRR was defined as the difference in heart rate between peak exercise and one-minute later; a value < or = 18 beats per minute was considered abnormal. The patients were divided into 2 groups according to the value of HRR. Those with abnormal HRR were assigned to group I and those with normal HRR were assigned to group II. The 2 groups were compared with each other regarding baseline characteristics and exercise capacity assessed by peak VO2. There were 26 patients (31%) in group I and 58 patients (69%) in group II. Group II patients had better performance on treadmill exercise testing than group I patients. They had greater exercise duration (7.5 +/- 3.8 minutes versus 5 +/- 3.5 minutes, P = 0.006), better heart-rate reserve (79 +/- 25% versus 63 +/- 27%, P = 0.01), and higher values of maximal heart-rate (141 +/- 18 beats/min versus 132 +/- 17 beats/min, P = 0.04). Group II patients also had higher peak VO2 values (16.8 +/- 4.4 mL/kg/min versus 14.4 +/- 3.6 mL/kg/min, P = 0.01). When we separated the groups according to beta-blocker usage, beta-blockers had no prominent effect on HRR. In the follow-up period (mean 14.1 +/- 6.1 months), the presence of abnormal HRR and lower peak VO2 (< or = 14 mL/kg/min) were the only significant predictors of mortality in our patient population (adjusted hazard ratio [HR] 5.2, 95% CI, 1.3 to 24, P = 0.03 and adjusted HR 13, 95% CI, 2.1 to 25.6, P = 0.005, respectively). It seems that the attenuated HRR value one minute after peak exercise appears to be a reliable index of the severity of exercise intolerance in heart failure patients and this study supports the value of HRR as a prognostic marker among heart failure patients referred for cardiopulmonary exercise testing for prediction of prognosis.     

The total heart beats per 24 hours by ambulatory electrocardiography and the changes of heart rate by treadmill exercise test in sick sinus syndrome

To study the clinical implications of the total number of heart beats per 24 hours (THB), 24 hour ambulatory electrocardiography and treadmill test were performed by sixty patients with sick sinus syndrome (SSS, 58 +/- 12 years old) who underwent overdrive suppression test. Results were compared with thirty control subjects (58 +/- 12 years old). The THB was 74 +/- 11 thousand beats in the SSS group and 99 +/- 10 thousand beats in the control group. The THB and the maximal heart rate (MHR) achieved during the treadmill test were significantly lower in the SSS group than in the control group. However, the exercise duration in patients with SSS was similar to that of the control subjects. The exercise duration and the MHR were correlated to age, but not to the THB in the patients with SSS. There was no significant relationship between the total heart beats per 24 hours and the maximal sinus node recovery time (max. SNRT). We conclude that the THB, independent of the max. SNRT, can be a useful index in diagnosing and assessing the quantity of bradycardia in patients with SSS. The tolerance of exercise and the MHR were not correlated with the THB, in patients with SSS.     

Altered adaptive responses to training by nonselective beta-adrenergic blockade in coronary artery disease

To examine the alterations in adaptive responses to training by nonselective beta-adrenergic blockade in patients with coronary artery disease (CAD), 26 patients were studied. Thirteen patients, aged 48 +/- 2 years (mean +/- standard error) were treated with beta-adrenergic blocking agents and another 13, aged 55 +/- 2 years, were control subjects. The 2 groups were similar in terms of initial maximal attainable O2 consumption (VO2max): 24 +/- 1 vs 25 +/- 2 ml/kg/min, patients and control subjects, respectively), and intensity (87 +/- 3.0 vs 88 +/- 2% of attainable VO2max), frequency (4 +/- 0.2 vs 4.0 +/- 0.3 days/week), and duration (12 months) of training. Maximal attainable VO2 increased to the same extent (36% vs 35%) in both groups. Heart rate (HR) at rest decreased to a similar extent in both groups (p less than 0.001). During submaximal exercise at the same exercise intensities, HR decreased in both groups, but to a larger extent in the control group than in the beta-blocker group after training. In the later, the reduced HR during submaximal exercise was solely due to training-induced bradycardia at rest. In contrast, the slower HR during submaximal exercise in control subjects after training was attributable to both bradycardia at rest and a smaller increase in HR during submaximal exercise. In both groups, the half-time of HR deceleration after cessation of exercise decreased (p less than 0.005) after training. However, the training-induced decrease in the half-time was significantly larger (p less than 0.025) in control subjects than in patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Time integral of oxygen pulse for exercise submaximal levels in patients with heart insufficiency--correlation with maximal oxygen consumption]

Maximal oxygen consumption (VO2max) has an important prognostic value in patients with congestive heart failure (CHF). However, it requires a maximal exercise test, not often available for these patients. To overcome this limitation, we examined whether a simple time integral of oxygen pulse (OP) to submaximal exercise levels correlates with VO2max. METHODS: We performed a maximal symptom-limited treadmill exercise test, while measuring breath-by-breath oxygen consumption, using the CAEP protocol, in 24 patients with CHF (51 +/- 11 years, 18 males, sinus rhythm). No exercise was terminated due to ischemia or arrhythmias. All patients attained anaerobic threshold. Besides standard parameters, OP (ml) and time integral of OP (OPTI) were calculated at 2 minutes (OP-2 min and OPTI-2 min) and at 4 minutes (OP-4 min and OPTI-4 min) of exercise. Patients were divided in two groups according to VO2max: group I--VO2max > or = 16 ml/kg/min (14 patients) and group II--VO2max < 16 (10 patients). RESULTS: Age, sex, body surface and CHF etiology were similar in both groups. Exercise duration, maximal OP, time to anaerobic there shold, VO2 and OP at anaerobic there shold were higher in group I (p < 0.05). Comparing group I vs group II--OP-2 min: 6.2 +/- 1.5 vs 5.0 +/- 1.2 ml (p = 0.026); OP-4 min: 7.6 +/- 1.9 vs 5.4 +/- 1.2 (p = 0.001); OPTI-2 min: 3.1 +/- 1.1 vs 2.2 +/- 0.9 (p = 0.021) and OPTI-4 min: 15.2 +/- 4.4 vs 9.3 +/- 3.1 (p = 0.0007). The best correlation with VO2max was obtained for OPTI-4 min (r = 0.696). An OPTI-4 min value > or = 10 occurred in 13 patients of group I and in two patients of group II (p = 0.00013), with a predictive value of 87% for VO2max > 16 (sensitivity = 93%, specificity = 80%)--kappa index = 0.739. CONCLUSIONS: OPTI-4 min can be a useful tool for assessing cardiocirculatory functional status in patients with CHF and unable to perform a maximal exercise test.     

Effect of coronary artery disease on Doppler-derived parameters of aortic flow during upright exercise

Recent advances in Doppler echocardiography have made possible noninvasive determination of stroke volume, cardiac output and peak ejection velocity at rest. To determine the ability of Doppler to measure these variables and the effect of altered left ventricular (LV) function during upright treadmill exercise, 20 normal subjects (group I) and 17 patients with coronary artery disease (CAD) (group II) were studied. Stroke index response was similar in both groups. The increase in cardiac index was more rapid in group I subjects and reached a higher peak value at maximal exercise (8.6 +/- 2.5 vs 5.5 +/- 2.2 liters/min, p less than 0.001). Peak ejection velocity increased rapidly during exercise in group I subjects; it increased much less in group II patients. Differences were significant at each stage of exercise. Peak ejection velocity was 1.56 +/- 0.32 and 0.89 +/- 0.26 m/s in group I vs group II patients, respectively, at maximal exercise. Three responses were seen in group II subjects. Three patients, all with 1-vessel CAD and normal LV function at rest, showed a normal response, with an increase in peak ejection velocity of at least 80% (type I response). In 8 patients peak ejection velocity increased less than 80% (type II response) and in 6 patients it decreased at maximal exercise (type III). Type II and III responses were seen in patients with more severe CAD and LV dysfunction at rest. These data show a progressive difference in Doppler-derived variables in exercise between normal subjects and patients with CAD, which is greatest in patients with LV dysfunction at rest and multivessel CAD.     

Initial and final exercise heart rate transients: influence of gender, aerobic fitness, and clinical status

STUDY OBJECTIVES: To compare the independent and additive data provided by initial and final heart rate (HR) exercise transients, and to analyze both according to gender, aerobic fitness, clinical status, and medication usage. DESIGN: Retrospective study. SETTING: Exercise medicine clinic. PATIENTS: A total of 544 subjects (363 men) with a mean (+/- SD) age of 50 +/- 14 years (age range, 10 to 91 years), including asymptomatic and coronary artery disease patients. MEASUREMENTS AND RESULTS: HR transients were obtained from the following two exercise protocols: 4-s exercise test (4sET) followed by a maximal cardiopulmonary cycling exercise test (CPET). The initial HR transient was represented by the cardiac vagal index (CVI), which was obtained by the 4sET, and the final transient (ie, HR recovery [HRR]) was determined by the following equation: CPET maximal HR - the 1-min postexercise HR. Transients were modestly related (r = 0.22; p < 0.001) when adjusted for age, aerobic fitness, clinical status, and negative chronotropic action drug usage. The transients were unrelated to gender (vs CVI, p = 0.10; vs HRR, p = 0.15). Subjects with a measured maximum oxygen uptake (VO2max) exceeding 100% of the predicted maximal aerobic power showed higher CVIs than those in less aerobically fit subjects (VO2max < 50% subgroup, p = 0.009; VO2max < 75% subgroup, p = 0.034). Both transient results differed for asymptomatic and cardiac subjects (CVI, 1.32 +/- 0.02 vs 1.42 +/- 0.02, respectively [p = 0.001]; HRR, 33 +/- 1 beats/min (bpm) vs 37 +/- 1 bpm, respectively [p = 0.009]). CONCLUSIONS: The initial and final HR transients were modestly related, suggesting a potentially complementary clinical role for both measurements in the assessment of autonomic function in patients with coronary artery disease. Although both HR transients tended to behave similarly under the influence of several variables, the initial HR transient, measured during 4sET, was more likely to discriminate distinct subgroups compared with the final HR transient.     

Effect of amiodarone and disopyramide on the results of electrocardiographic exercise stress testing in patients with coronary disease

The study was designed to assess the influences of antiarrhythmic therapy on exercise tolerance in patients with coronary artery disease and ventricular arrhythmias. Subjects for this study were subdivided into 3 groups: group I - 46 patients treated with amiodarone 1,200 mg daily during 10 days and 200-600 mg daily within next days, group II - 79 patients receiving disopyramide 300-600 mg daily, group III - 129 patients with combined administration of disopyramide 300-600 mg daily and propranolol 30-240 mg daily. propranolol 30-240 mg daily. Submaximal exercise stress testing was performed in each patient before treatment and after the medication for 4 weeks (group I) and for 2 weeks (groups II, III). The following parameters have been evaluated: maximal archived workload, maximal heart rate blood pressure response, double product (maximal heart rate x maximal systolic blood pressure), reasons for ending the test (target heart rate, typical angina, exhaustion, ST-segment depression greater than or equal to 2 mm, occurrence of ventricular arrhythmia, blood pressure greater than 250/120 mm Hg, significant drop in systolic pressure). Positive result of exercise ECG was defined: horizontal or down-sloping ST-segment depression greater than or equal to 1 mm and/or typical chest pain. The data from the first and second tests were estimated for significance of differences between the mean values with following results: 1) maximal achieved workload, 86 +/- 46 and 103 +/- 49 W (p less than 0.02) in group I; 101 +/- 64 and 106 +/- 50 W (NS) in group II; 107 +/- 55 and 119 +/- 54 W, W (p less than 0.01) in group III.(ABSTRACT TRUNCATED AT 250 WORDS)     

Unexplained sinus bradycardia: clinical significance and long-term prognosis in apparently healthy persons older than 40 years

The significance of sinus bradycardia (SB) in clinically healthy, non-endurance-trained, middle-aged and older persons is unknown. From 1,172 normal volunteers, aged 40 to 96 years, enrolled in the Baltimore Longitudinal Study of Aging, 47 subjects, aged 58 +/- 13 years, with SB (less than 50 beats/min) were identified by rest electrocardiography and were compared with a group of control subjects matched for age and sex. The prevalence of unexplained SB was approximately 4% and was nearly identical in men and women. At the latest follow-up examination, after a mean follow-up of 5.4 years, the SB group had a higher prevalence of associated conduction abnormalities (first-degree atrioventricular [AV] block, left-axis deviation, and complete or incomplete right bundle branch block) than the control group (43% vs 19%, p less than 0.05). On maximal treadmill exercise testing, performed in 44 patients within 1 visit of their most recent examination showing SB, maximal heart rate (157 +/- 18 beats/min) did not differ significantly from that of control subjects (163 +/- 19 beats/min); exercise duration, however, was greater in the former group, 11.0 +/- 2.8 vs 9.7 +/- 3.1 minutes (p less than 0.05). No patients with SB had syncope, high-degree AV block or other manifestation of sick sinus syndrome during follow-up. Angina pectoris, myocardial infarction, congestive heart failure or cardiac death occurred in 8% of patients with SB and 11% of control subjects over the observation period (difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)     

Physiologic changes with maximal exercise in asymptomatic valvular aortic stenosis assessed by Doppler echocardiography.

OBJECTIVES. We hypothesized that the physiologic response to exercise in valvular aortic stenosis could be measured by Doppler echocardiography. BACKGROUND. Data on exercise hemodynamics in patients with aortic stenosis are limited, yet Doppler echocardiography provides accurate, noninvasive measures of stenosis severity. METHODS. In 28 asymptomatic subjects with aortic stenosis maximal treadmill exercise testing was performed with Doppler recordings of left ventricular outflow tract and aortic jet velocities immediately before and after exercise. Maximal and mean volume flow rate (Qmax and Qmean), stroke volume, cardiac output, maximal and mean aortic jet velocity (Vmax, Vmean), mean pressure gradient (delta P) and continuity equation aortic valve area were calculated at rest and after exercise. The actual change from rest to exercise in Qmax and Vmax was compared with the predicted relation between these variables for a given orifice area. Subjects were classified into two groups: Group I (rest-exercise Vmax/Qmax slope > 0, n = 19) and Group II (slope < or = 0, n = 9). RESULTS. Mean exercise duration was 6.7 +/- 4.3 min. With exercise, Vmax increased from 3.99 +/- 0.93 to 4.61 +/- 1.12 m/s (p < 0.0001) and mean delta P increased from 39 +/- 20 to 52 +/- 26 mm Hg (p < 0.0001). Qmax rose with exercise (422 +/- 117 to 523 +/- 209 ml/s, p < 0.0001), but the systolic ejection period decreased (0.33 +/- 0.04 to 0.24 +/- 0.04, p < 0.0001), so that stroke volume decreased slightly (98 +/- 29 to 89 +/- 32 ml, p = 0.01). The increase in cardiac output with exercise (6.5 +/- 1.7 to 10.2 +/- 4.4 liters/min, p < 0.0001) was mediated by increased heart rate (71 +/- 17 to 147 +/- 28 beats/min, p < 0.0001). There was no significant change in the mean aortic valve area with exercise (1.17 +/- 0.45 to 1.28 +/- 0.65, p = 0.06). Compared with Group I patients, patients with a rest-exercise slope < or = 0 (Group II) tended to be older (69 +/- 12 vs. 58 +/- 19 years, p = 0.07) and had a trend toward a shorter exercise duration (5.3 +/- 2.9 vs. 7.3 +/- 4.9 min, p = 0.20). There was no difference between groups for heart rate at rest, blood pressure, stroke volume, cardiac output, Vmax, mean delta P or aortic valve area. With exercise, Group II subjects had a lower cardiac output (7.4 +/- 2.4 vs. 11.5 +/- 4.6 liters/min, p = 0.005) and a smaller percent increase in Vmax (3 +/- 9% vs. 22 +/- 14%, p < 0.0001). CONCLUSIONS. Doppler echocardiography allows assessment of physiologic changes with exercise in adults with asymptomatic aortic stenosis. A majority of subjects show a rest-exercise response that closely parallels the predicted relation between Vmax and Qmax for a given orifice area. The potential utility of this approach for elucidating the relation between hemodynamic severity and clinical symptoms deserves further study.     

Clinical significance of symptomatic and silent myocardial ischemia during exercise test in patients with effort angina pectoris--investigation of hemodynamic responses during supine ergometer exercise test

Thirty one patients with stable effort angina who had no prior myocardial infarctions underwent symptom-limited ergometer exercise test. Hemodynamic responses during exercise were assessed to determine whether or not the limiting symptoms were related to the severity of exercise-induced myocardial ischemia. Twenty-two subjects (Group I) were limited by angina and nine (Group II) were limited by other symptoms. There were no differences in age, sex distribution, prevalence of diabetes mellitus, and left ventricular ejection fraction between the two groups. Multivessel coronary artery diseases, however, were more frequent in group I (16/22 vs 3/9: p less than 0.05). Maximal work load (46.6 +/- 16.0 vs 62.5 +/- 13.4 W: p less than 0.05), exercise duration (4.7 +/- 2.0 vs 7.2 +/- 1.4 min: p less than 0.005), and maximal oxygen consumption (12.4 +/- 4.1 vs 19.3 +/- 3.3 ml/kg/min: p less than 0.005) were significantly lower in group I. The magnitude of ST depression was not different between the two groups (2.0 +/- 0.8 vs 1.8 +/- 0.7 mm: NS). At maximal exercise, heart rate, mean blood pressure, cardiac index, and stroke work index (SWI) were significantly lower in group I (p less than 0.05) and pulmonary capillary wedge pressure was significantly higher in group I (31.1 +/- 6.1 vs 25.1 +/- 5.6 mmHg: p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular pressure/volume relationship in aortic regurgitation

In this study we examined the left ventricular pressure/volume relationship in 39 patients with moderate or severe aortic regurgitation (AR) and 15 normal subjects. The patients with AR were divided into two groups; patients with normal resting ejection fraction (EF greater than or equal to 50%, group I, n = 21) and patients with abnormal EF (group II, n = 18). The patients in group I were younger (p less than 0.005), exercised to a higher workload, and had better exercise tolerance than patients in group II (p less than 0.01). The patients' exercise heart rate and blood pressure were not significantly different between the two groups. During exercise tests nine patients in group I and seven patients in group II had normal EF response (greater than or equal to 5% increase) (p = NS). The peak systolic blood pressure to end-systolic volume index ratio (SBP/ESVI) was higher in normal subjects than in patients in groups I and II, at rest it was (4.3 +/- 1.0 vs 2.6 +/- 1.2 vs 1.6 +/- 0.8, respectively, p less than 0.0001) and during exercise it was (7.6 +/- 1.8 vs 4.2 +/- 1.4 vs 2.6 +/- 1.3, respectively, p less than 0.0001). The resting SBP/ESVI ratio was below the lower normal limit in 12 patients (57%) in group I and in 16 patients (89%) in group II. Also, the exercise SBP/ESVI ratio was below the lower normal limit in 17 patients (81%) in group I and all of the patients (100%) in group II. Multivariate discriminant analysis identified the change in SBP/ESVI (F = 34.8) and resting end-diastolic volume (F = 6.7) as independent predictors of the EF response to exercise. Thus, most patients with AR, including those with normal resting EF or normal EF response to exercise, have abnormal SBP/ESVI at rest or during exercise.     

Maximal coronary vasodilator capacity of orthotopic heart transplants in patients with and without rejection

In cardiac allograft rejection, histopathologic changes suggesting that myocardial ischemia is a component of the rejection process have been documented. To further define the coronary vascular reactivity of human heart transplant, coronary sinus blood flow and coronary resistance were measured before and after intravenous dipyridamole within the first year after transplantation in 8 patients without rejection (group II) and in 5 patients with rejection (group III). All had normal coronary arteriograms. Results were compared to those of 8 control subjects (group I). After dipyridamole, coronary sinus blood flow was increased in groups I, II and III by 303, 212 (p less than 0.01 vs group I) and 45%, respectively (p less than 0.001 vs groups I and II). Coronary resistance was reduced by 77, 73 (not significant vs group I) and 36%, respectively (p less than 0.001 vs groups I and II). Concomitantly, coronary sinus blood oxygen content was increased by 172, 145 (not significant vs group I) and 78%, respectively (p less than 0.001 vs group I, not significant vs group II). Thus, the coronary flow reserve evaluated by the dipyridamole/basal coronary sinus blood flow ratio and the coronary resistance reserve evaluated by the basal/dipyridamole coronary resistance ratio were dramatically impaired in group III (1.56 +/- 0.09 and 1.63 +/- 0.30, respectively, p less than 0.001 vs groups I and II). In contrast, they were almost normal in group II (3.11 +/- 0.42 vs 4.03 +/- 0.52 in group I, p less than 0.02, and 3.83 +/- 0.78 vs 4.45 +/- 0.81 in group I, difference not significant). Thus, the impairment of coronary reserve during heart rejection should be linked to abnormalities of the coronary microvaculature. This emphasizes the important involvement of the coronary circulation in the rejection process.     

The significance of electrophysiologic findings and clinical course in symptomatic sinus node dysfunction (author's transl)

Under investigation in this study were the relationship between hypersensitive carotid sinus reflex (HCSR) and sick sinus snydrome (SSS), the significance of clinical symptomatology versus electrophysiologic test results and the natural course of both syndromes. In 186 symptomatic patients (pts) resting heart rate, maximal corrected sinus node recovery time (CSRTmax) and maximal carotid sinus pressure results (CSPmax) were determined. According to test results, 103 pts had HCSR (I), 33 had HCSR + SSS (II), 30 pts had SSS (III), and 20 pts with normal test results served as controls (IV). Mean age was the same in groups I--IV (p greater than 0.05). Groups I--III had a heart rate less than or equal to 60 bpm. There was no correlation between patients test data and the occurrence of syncopes in each of groups I--III (p greater than 0.05). In 16 pts with SSS, test results remained unchanged 16 months later (p greater than 0.05). More pts (31%) in group II died in a shorter period of time after pacer application (1.4 +/- 1 year) than pts with AV III degrees block (25%, 1.8 +/- 1.6 years) after pacer application. We conclude that the combination HCSR + SSS seems rather frequent. Specific testing separated HCSR from SSS, but failed to predict syncopes and thereby cannot aid in the indication for pacer application. The 16 months prognosis of SSS proved unfavorable. Mortality after pacer application in HCSR + SSS seems less favorable than in AV III degrees block (p less than 0.05), but depends largely on the severity of associated diseases.     

Demonstration of training effect during chronic beta-adrenergic blockade in patients with coronary artery disease

Attenuation of exercise-induced increases in heart rate and cardiac output by chronic beta-adrenergic blockade has been thought to compromise benefit of exercise training in patients with coronary artery disease (CAD). To assess this important issue, 35 CAD patients were evaluated by a 3-month walk-jog-cycle training program: 14 patients received no beta blocker (group 1), 14 received propranolol, 30-80 mg/day (group 2), and seven patients received propranolol, 120-240 mg/day (group 3). The extent of CAD, resting heart rate before training blood pressure and VO2 max were similar (p = NS) in each group. The maximal exercise heart rate (mean +/- SD, 147 +/- 21 beats/min in group 1 vs 120 +/- 10 beats/min in group 2 and 115 +/- 12 beats/min in group 3 (both p less than 0.05 vs group 1). The VO2 max before training was 25 +/- 5.0 ml/kg/min in group 1 vs 23 +/- 3.2 ml/kg/min in group 2 and 26 +/- 2.8 ml/Kg/min in group 3 (all p = NS). Training consisted of three 1-hour periods per week at a heart rate of 70-85% of the maximal pretraining heart rate. In each group, VO2 increased (p less than 0.05) after training: group 1, 27%; group 2, 30%; group 3, 46%. The double product was unchanged after training (p = NS) in each group. These data indicate that substantial training effects may be achieved in CAD patients despite therapeutic doses of beta blockers and a reduced training HR. Thus, there appears to be no indication to reduce beta blockers in CAD patients engaged in cardiac rehabilitation.     

Relationship between insulin resistance assessed by HOMA-IR and exercise test variables in asymptomatic middle-aged patients with type 2 diabetes

We investigated the relationship between index of insulin resistance (IR) and exercise test variables in middle-aged asymptomatic patients with Type 2 diabetes. METHODS: 90 patients (48 men, 42 women; age: 49 +/- 6 yr) were included in the study. We used homeostasis model assessment for IR (HOMA-IR) index as index of IR. All patients were subjected to treadmill exercise test. Four subjects were tested positive (4.4%). Study patients were separated into three groups: group I (no.=26) HOMA-IR index <2.24; group II (no.=26) index 2.24-3.59; group III (no.=38) index >3.59. RESULTS: group I had less frequency of cardiovascular risk factors than group II and III (p=0.001). Systolic blood pressure baseline as well as peak exercise values, were higher in group III than in group I and II (p=0.048 vs p=0.01, respectively). Higher total exercise time and peak workload were found in group I than group II and III (p=0.04). The recovery of heart rate (delta HR(pr)) was similar among the study groups. We found significant negative correlations between HOMA-IR and total exercise time and peak workload. In addition we found significant negative correlations between age vs chronotrophic index (CI), delta HR(pr), and peak workload. There were also similar negative correlations between duration of diabetes vs CI and delta HR(pr). CONCLUSIONS: IR is associated with a variety of cardiovascular risk factors. Some exercise test variables point out changes of autonomic tone during exercise in elevated IR group. Negative correlation between HOMA-IR and peak exercise capacity (METs) may well confirm increased mortality in hyperinsulinemia.     

Pathophysiology of tricuspid insufficiency: analysis of the motion of the tricuspid valve annulus using 2-dimensional echocardiography

We investigated tricuspid annular motion in patients with pulmonary hypertension and in normal controls to determine the greatest minimal diameter and percentage shortening of the tricuspid annulus required for functional tricuspid regurgitation. 73 patients were studied by 2-dimensional echocardiography: a control group of 30 patients (group I); 43 patients had pulmonary hypertension, 9 of whom were still in sinus rhythm (group II), the other 34 patients had atrial fibrillation. 19 of these showed competent tricuspid valve with contrast echocardiography (group III), whereas the 15 remaining patients had functional tricuspid regurgitation (group IV). An analysis of shape and position changes of tricuspid annulus during the heart cycle was performed. The maximal diameter (mm/m2) in the apical 4 chamber view was in group I 17.5 +/- 1.4, in group II 20.7 +/- 3.2 (vs. group I p less than 0.05), in group III 19.0 +/- 3.4 (vs. group II NS) and in group IV 25.7 +/- 6.0 (vs. group III p less than 0.001). The values for the minimal annular diameter (mm/m2) were in group I 13.7 +/- 1.2, in group II 17.4 +/- 3.5 (vs. group I p less than 0.01), in group III 16.6 +/- 3.3 (vs. group II NS) and in group IV 23.6 +/- 5.7 (vs. group p less than 0.001). The percent decrease (%) in group I was 21.5 +/- 3.3, in group II 17.0 +/- 6.9 (vs. group I p less than 0.05), in group III 12.8 +/- 4.7 (vs. group II p less than 0.05) and in group IV 7.9 +/- 3.4 (vs. group III p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)