- Email: [email protected]
Effect of age and gender on heart rate recovery after submaximal exercise during cardiac rehabilitation in patients with angina pectoris, recent acute myocardial infarction, or coronary bypass surgery
Effect of Age and Gender on Heart Rate Recovery After Submaximal Exercise During Cardiac Rehabilitation in Patients With Angina Pectoris, Recent Acute Myocardial Infarction, or Coronary Bypass Surgery Paul Kligfield,
MD,
Alison McCormick, RN, Andrew Chai, BS, Abby Jacobson, Paul Feuerstadt, BA, and Steven C. Hao, MD
RN,
The effect of exercise training on the heart rate recovery (HRR) response to submaximal effort was examined in 81 patients during 12 weeks of phase II cardiac rehabilitation. Although HRR after submaximal effort was relatively reduced in older patients with heart disease and in women, its increase during exercise training in men and women of all ages was consistent with enhancement of parasympathetic tone during activities of daily living. 䊚2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:601– 603)
ardiac rehabilitation favorably modulates parasympathetic and sympathetic balance in patients C with heart disease and reduces mortality in patients 1,2
after myocardial infarction.3–5 Reduced heart rate recovery (HRR) after exercise is a strong predictor of mortality that also can be related to autonomic balance.6 –11 Recent studies have indicated that HRR after maximum exercise is a modifiable characteristic that can increase during 12 weeks of cardiac rehabilitation.12 To test whether HRR is modifiable at workloads that reflect ordinary daily activity, we examined the HRR response to submaximal training workloads (in contrast to maximal symptom-limited exercise) during cardiac rehabilitation in patients with established heart disease and in subgroups separated according to age and gender. •••
The study population included 81 consecutive patients (58 men, 23 women; mean age 63 years) who were referred for a 12-week program of cardiac rehabilitation because of stable angina or after they experienced myocardial infarction, coronary artery bypass surgery, or percutaneous intervention. Patients with pacemakers and patients with a significant change in medication during exercise training that may have affected heart rate were excluded. Training exercise levels were adjusted after each training session according to target submaximal heart rate, as calculated by the Karvonen method and by a rating of perceived exertion reported by the patients.13 HRR (in beats per minute) was measured as the difference between the From the Cardiac Health Center, Weill-Cornell Medical Center, The New York-Presbyterian Hospital, New York, New York. Dr. Kligfield’s address is: Division of Cardiology, 525 East 68th Street, New York, New York 10021. E-mail: [email protected]. Manuscript received February 17, 2003; revised manuscript received and accepted May 21, 2003. ©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 1, 2003
FIGURE 1. Median values, interquartile range (25% to 75%), and overall range of average initial, final, and change in HRR (in beats per minute [BPM]) responses to submaximal exercise in 81 patients during cardiac rehabilitation.
heart rate at the end of 30 minutes of submaximal exercise training during each session and the heart rate after 1 minute of walking during the immediate postexercise cool-down period.6 Treadmill MET levels during submaximal exercise were calculated from standard nomograms13 at single training episodes after entry and before discharge from cardiac rehabilitation. Entry HRR findings were averaged from the end of 3 successive exercise training sessions (sessions 4 to 6, to eliminate the effect of variable early adaptation to the program during the first 3 sessions). These findings were compared with HRR findings averaged from the end of 3 successive training sessions before discharge from the program (sessions 31 to 33). In all cases, the type of equipment (treadmill, bicycle) used while obtaining average entry measurements of peak heart rate and recovery heart rate was also used for obtaining the predischarge measurements. Exercise training within heart rate and rating of perceived exertion guidelines were associated with an increase in submaximal work capacity calculated from training-level treadmill performance (4.1 ⫾ 1.3 to 7.5 ⫾ 2.1 METs, p ⬍0.001), with small mean increases in end-exercise treadmill heart rate (99 ⫾ 15 to 106 ⫾ 18 beats/min, p ⬍0.001) and with perceived exertion (2.9 ⫾ 0.6 to 3.4 ⫾ 0.6 U, p ⬍0.001, on a 0 to 10 scale). 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00733-1
601
TABLE 1 Entry and Exit Findings According to Age Group and Gender Ages (yrs) ⱕ65 Yrs (n ⫽ 45)
⬎65 Yrs (n ⫽ 36)
Mean ⫾ SD 95% CI Mean ⫾ SD 95% CI Entry METs 4.5 ⫾ 1.4 3.5 ⫾ 1.0 Exit METs 8.3 ⫾ 1.9 6.5 ⫾ 1.8 Difference in METs 3.8 ⫾ 1.2 3.4–4.2 3.0 ⫾ 1.3 2.5–3.4 Entry HRR (beats/min) 14.6 ⫾ 6.3 9.9 ⫾ 4.8 Exit HRR (beats/min) 17.5 ⫾ 5.4 13.9 ⫾ 6.2 Difference in HRR 2.9 ⫾ 4.9 1.4–4.4 4.0 ⫾ 5.2 2.2–5.7 p value (entry vs exit METs) ⬍0.001 ⬍0.001 p value (entry vs exit HRR) ⬍0.001 ⬍0.001
p value (by age)
after training, there was nevertheless a significant increase in exercise capacity during training in this small group (3.1 ⫾ 1.2 to 5.3 ⫾ 1.6 METs, p ⬍0.001).
⬍0.005 ⬍0.001 ⬍0.010 ⬍0.001 ⬍0.010 NS
•••
The present observations demonstrate that HRR after submaximal exercise is also a modifiable characteristic in cardiac patients that can increase after 12 weeks of exercise training. Most patients in the present series had increased HRR along with submaximal effort tolerance during Gender cardiac rehabilitation. However, a decrease in already low HRR was Men (n ⫽ 58) Women (n ⫽ 23) p value found in ⬍9% of the present popu(by gender) Mean ⫾ SD 95% CI Mean ⫾ SD 95% CI lation, despite modest improvement in initially low submaximal effort Entry METs 4.4 ⫾ 1.2 3.3 ⫾ 1.2 ⬍0.005 tolerance. This small subset included Exit METs 8.1 ⫾ 1.8 5.9 ⫾ 1.8 ⬍0.001 only patients ⬎65 years old and was Difference in METs 3.8 ⫾ 1.3 3.4–4.1 2.6 ⫾ 0.9 2.1–3.0 ⬍0.001 disproportionately female. Entry HRR (beats/min) 13.6 ⫾ 6.0 9.6 ⫾ 5.4 ⬍0.010 Exit HRR (beats/min) 17.5 ⫾ 5.2 11.8 ⫾ 6.0 ⬍0.001 Maximum exercise is rare during Difference in HRR 3.9 ⫾ 5.6 2.4–5.3 2.1 ⫾ 3.2 0.8–3.5 NS the routine activities of daily living, p value (entry vs exit METs) ⬍0.001 ⬍0.001 which generally require only subp value (entry vs exit HRR) ⬍0.001 ⬍0.005 maximal effort. Because cardiac reCI ⫽ confidence interval. habilitation also improves submaximal effort tolerance in cardiac patients at all ages,14 and because For the total population, HRR, averaged over 3 exer- HRR after submaximal exercise also appears to have cise training sessions, increased by a mean of 27% prognostic value,9 the effect of exercise training on during cardiac rehabilitation (12.5 ⫾ 6.1 to 15.9 ⫾ 6.0 HRR after submaximal exercise is relevant to the beats/min, p ⬍0.001). This was associated with a prevalent neurohumoral adaptation in patients with small increase in mean end-exercise heart rate during heart disease.1,2,11,15 The present observations demonthe final 3 training sessions compared with the initial strate that HRR after submaximal exercise is also a 3 sessions (102 ⫾ 18 to 109 ⫾ 19 beats/min, p modifiable characteristic in cardiac patients and that ⬍0.001). Median, interquartile, and range of entry and submaximal HRR can increase after 12 weeks of exit average HRR and average change in HRR are exercise training. shown in Figure 1. Age- and gender-related differences in submaximal As seen in Table 1, submaximal effort capacity exercise HRR findings of our patients parallel differcalculated from treadmill METs and HRR averaged ences that have been found with maximal exercise over 3 sessions, before and after exercise training, testing.12 Whether the lower values for HRR in older were greater in younger than in older patients and patients can be attributed to lower submaximal exergreater in men than in women. However, effort capac- cise heart rates at entry and after training in this group, ity and HRR after submaximal exercise increased with or to separate effects of age on autonomic response to exercise training in both age groups and both genders. effort, remain to be clarified. A mean increase in HRR was not significantly differThe data in the present study indicate that the ent between subgroups as defined by age or gender. effects of exercise training on neurohumoral tone as When patients were grouped according to an age reflected by HRR in cardiac patients are extended to partition of 65 years, HRR increased by a mean of periods of submaximal effort that are associated with 22% in the younger patients and 40% in the older more routine activities of daily living. patients. When patients were grouped according to gender, HRR increased by a mean of 29% in the men and 23% in the women. 1. Malfatto G, Facchini M, Sala L, Branzi G, Bragato R, Leonetti G. Relationship Some regression to the mean can be expected in between baseline sympatho-vagal balance and the autonomic response to cardiac these findings. Seven patients with HRR at entry of rehabilitation after first uncomplicated myocardial infarction. Ital Heart J 2000; ⬍10 beats/min (mean 7.3 ⫾ 1.6) had exit HRR that 1:226 –232. 2. Lucini D, Milani RV, Costantino G, Lavie CJ, Porta A, Pagani M. Effects of was even lower at discharge (mean 6.1 ⫾ 1.5 beats/ cardiac rehabilitation and exercise training on autonomic regulation in patients min, p ⬍0.05); this subset represents ⬍9% of the total with coronary artery disease. Am Heart J 2002;143:977–983. study population. Each of these patients was ⬎65 3. Oldridge NB, Guyatt GH, Fischer ME, Rimm AA. Cardiac rehabilitation after myocardial infarction. Combined experience of randomized clinical trials. JAMA years old and 5 of 7 were women, but despite low 1988;260:945–950. effort tolerance at entry and the lower HRR findings 4. O’Connor GT, Buring JE, Yusuf S, Goldhaber SZ, Olmstead EM, Paffenbarger 602 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 92
SEPTEMBER 1, 2003
RS, Hennekens CH. An overview of randomized trials of rehabilitation with exercise after myocardial infarction. Circulation 1989;80:234 –244. 5. Wenger NK, Froehlicher ES, Smith LK, Ades PA, Berra K, Blumenthal JA, Certo CM, Dattilo AM, Davis D, DeBusk RF. Cardiac rehabilitation. Clinical Practice Guideline No. 17. Rockville, MD: Agency for Health Care Policy and Research and the National Heart, Lung and Blood Institute, 1995. 6. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart rate recovery immediately after exercise as a predictor of mortality. N Engl J Med 1999;341:1351–1357. 7. Watanabe J, Thamilarasan M, Blackstone EH, Thomas JD, Lauer MS. Heart rate recovery immediately after treadmill exercise and left ventricular systolic dysfunction as predictors of mortality. Circulation 2001;104:1911–1916. 8. Nishime EO, Cole CR, Blackstone EH, Pashkow FJ, Lauer MS. Heart rate recovery and treadmill exercise score as predictors of mortality in patients referred for exercise ECG. JAMA 2000;284:1392–1398. 9. Cole CR, Foody JM, Blackstone EH, Lauer MS. Heart rate recovery after submaximal exercise testing as a predictor of mortality in a cardiovascularly healthy cohort. Ann Int Med 2000;132:552–555. 10. Imai K, Sato H, Hori M, Kusuoka H, Ozaki H, Yokoyama H, Takeda H,
Inoue M, Kamada T. Vagally mediated heart rate recovery after exercise is accelerated in athletes but blunted in patients with chronic heart failure. J Am Coll Cardiol 1994;24:1529 –1535. 11. La Rovere MT, Bigger JT, Marcus FI, Mortara A, Schwartz PJ. Baroreflex sensitivity and heart rate variability in prediction of total cardiac mortality after myocardial infarction. Lancet 1998;351:478 –484. 12. Hao SC, Chai A, Kligfield P. Heart rate recovery response to symptomlimited treadmill exercise after cardiac rehabiilitation in patients with coronary artery disease with and without recent events. Am J Cardiol 2002;90:763–765. 13. American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing, and Prescription. 5th Ed. Baltimore: Williams and Wilkins, 1995; VIII:153–240. 14. Chai A, McCormick A, Jacobson A, Kligfield P. Effects of cardiac rehabilitation on the exercise performance of men and women in the fourth through the ninth decades. Cardiovasc Rev Rep 1999;20:376 –380. 15. Tulppo MP, Makikallio TH, Seppanen T, Laukkanen RT, Huikuri HV. Vagal modulation of heart rate during exercise: effects of age and physical fitness. Am J Physiol 1998;274:H424 –H429.
Feasibility to Detect Severe Coronary Artery Stenoses With Upright Treadmill Exercise Magnetic Resonance Imaging Pairoj Rerkpattanapipat, MD, Sanjay K. Gandhi, MD, Stephen N. Darty, RT(N)(MR), R. Taylor Williams, MD, April D. Davis, RTR, Wojciech Mazur, MD, Hollins P. Clark, MD, William C. Little, MD, Kerry M. Link, MD, Craig A. Hamilton, PhD, and W. Gregory Hundley, MD We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively. 䊚2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:603– 606)
lthough investigators have demonstrated the utility of magnetic resonance imaging (MRI) pharA macologic stress testing for detecting left ventricular (LV) myocardial ischemia and viability,1–3 to date, the inability of MRI techniques to assess LV function immediately after upright treadmill exercise has limited the use of MRI in assessing patients referred for treadmill exercise. We placed a treadmill constructed primarily of nonferromagnetic material approximately 20 ft from the end of the MRI table, and developed a method to reacquire prestress slice positions in LV short-axis planes within 60 to 90 seconds of completing upright treadmill exercise. We assessed the feasiFrom the Departments of Internal Medicine (Cardiology Section), Biomedical Engineering, and Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina. Dr. Rerkpattanapipat’s address is: Section on Cardiology, Wake Forest University School of Medicine (Bowman Gray Campus), Medical Center Boulevard, Winston-Salem, North Carolina 27157-1045. E-mail: prerkpat@wfubmc. edu. Manuscript received April 11, 2003; revised manuscript received and accepted May 12, 2003. ©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 1, 2003
bility of this method for identifying LV regional wall motion abnormalities indicative of myocardial ischemia in 27 patients with chest pain who were referred for contrast coronary angiography. •••
Our study was approved by the institutional review board of Wake Forest University Health Sciences, and all subjects gave written informed consent. Our subjects underwent stress MRI and contrast coronary angiography separately at 2 ⫾ 3 months without a change in their medications or clinical status of their coronary artery disease. Patients with contraindications to MRI (intracranial metal or claustrophobia) or upright treadmill exercise4 were excluded from enrollment. Each subject was positioned supine with their feet touching the end of the MRI table. A nonferromagnetic patch was placed at the midline of the neck above the suprasternal notch as a landmark for repositioning the subject after exercise (Figure 1). After electrode patches for MRI cardiac gating and STsegment monitoring were placed and connected to a cardiac monitoring system (In vivo Research, Inc., Orlando, Florida), the subject was advanced into the scanner with a cardiac phased-array surface coil placed over the chest. At baseline, multiphase, fast imaging employing steady-state acquisition images of LV regional wall motion were acquired in the basal, middle, and apical short-axis planes.3 After the postexercise scan sequence was prescanned, the cardiac coil was unplugged, the cradle was undocked manually, and the subject was withdrawn from the scanner bore and escorted to a treadmill (Marquette Medical 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00734-3
603
MD,
Alison McCormick, RN, Andrew Chai, BS, Abby Jacobson, Paul Feuerstadt, BA, and Steven C. Hao, MD
RN,
The effect of exercise training on the heart rate recovery (HRR) response to submaximal effort was examined in 81 patients during 12 weeks of phase II cardiac rehabilitation. Although HRR after submaximal effort was relatively reduced in older patients with heart disease and in women, its increase during exercise training in men and women of all ages was consistent with enhancement of parasympathetic tone during activities of daily living. 䊚2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:601– 603)
ardiac rehabilitation favorably modulates parasympathetic and sympathetic balance in patients C with heart disease and reduces mortality in patients 1,2
after myocardial infarction.3–5 Reduced heart rate recovery (HRR) after exercise is a strong predictor of mortality that also can be related to autonomic balance.6 –11 Recent studies have indicated that HRR after maximum exercise is a modifiable characteristic that can increase during 12 weeks of cardiac rehabilitation.12 To test whether HRR is modifiable at workloads that reflect ordinary daily activity, we examined the HRR response to submaximal training workloads (in contrast to maximal symptom-limited exercise) during cardiac rehabilitation in patients with established heart disease and in subgroups separated according to age and gender. •••
The study population included 81 consecutive patients (58 men, 23 women; mean age 63 years) who were referred for a 12-week program of cardiac rehabilitation because of stable angina or after they experienced myocardial infarction, coronary artery bypass surgery, or percutaneous intervention. Patients with pacemakers and patients with a significant change in medication during exercise training that may have affected heart rate were excluded. Training exercise levels were adjusted after each training session according to target submaximal heart rate, as calculated by the Karvonen method and by a rating of perceived exertion reported by the patients.13 HRR (in beats per minute) was measured as the difference between the From the Cardiac Health Center, Weill-Cornell Medical Center, The New York-Presbyterian Hospital, New York, New York. Dr. Kligfield’s address is: Division of Cardiology, 525 East 68th Street, New York, New York 10021. E-mail: [email protected]. Manuscript received February 17, 2003; revised manuscript received and accepted May 21, 2003. ©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 1, 2003
FIGURE 1. Median values, interquartile range (25% to 75%), and overall range of average initial, final, and change in HRR (in beats per minute [BPM]) responses to submaximal exercise in 81 patients during cardiac rehabilitation.
heart rate at the end of 30 minutes of submaximal exercise training during each session and the heart rate after 1 minute of walking during the immediate postexercise cool-down period.6 Treadmill MET levels during submaximal exercise were calculated from standard nomograms13 at single training episodes after entry and before discharge from cardiac rehabilitation. Entry HRR findings were averaged from the end of 3 successive exercise training sessions (sessions 4 to 6, to eliminate the effect of variable early adaptation to the program during the first 3 sessions). These findings were compared with HRR findings averaged from the end of 3 successive training sessions before discharge from the program (sessions 31 to 33). In all cases, the type of equipment (treadmill, bicycle) used while obtaining average entry measurements of peak heart rate and recovery heart rate was also used for obtaining the predischarge measurements. Exercise training within heart rate and rating of perceived exertion guidelines were associated with an increase in submaximal work capacity calculated from training-level treadmill performance (4.1 ⫾ 1.3 to 7.5 ⫾ 2.1 METs, p ⬍0.001), with small mean increases in end-exercise treadmill heart rate (99 ⫾ 15 to 106 ⫾ 18 beats/min, p ⬍0.001) and with perceived exertion (2.9 ⫾ 0.6 to 3.4 ⫾ 0.6 U, p ⬍0.001, on a 0 to 10 scale). 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00733-1
601
TABLE 1 Entry and Exit Findings According to Age Group and Gender Ages (yrs) ⱕ65 Yrs (n ⫽ 45)
⬎65 Yrs (n ⫽ 36)
Mean ⫾ SD 95% CI Mean ⫾ SD 95% CI Entry METs 4.5 ⫾ 1.4 3.5 ⫾ 1.0 Exit METs 8.3 ⫾ 1.9 6.5 ⫾ 1.8 Difference in METs 3.8 ⫾ 1.2 3.4–4.2 3.0 ⫾ 1.3 2.5–3.4 Entry HRR (beats/min) 14.6 ⫾ 6.3 9.9 ⫾ 4.8 Exit HRR (beats/min) 17.5 ⫾ 5.4 13.9 ⫾ 6.2 Difference in HRR 2.9 ⫾ 4.9 1.4–4.4 4.0 ⫾ 5.2 2.2–5.7 p value (entry vs exit METs) ⬍0.001 ⬍0.001 p value (entry vs exit HRR) ⬍0.001 ⬍0.001
p value (by age)
after training, there was nevertheless a significant increase in exercise capacity during training in this small group (3.1 ⫾ 1.2 to 5.3 ⫾ 1.6 METs, p ⬍0.001).
⬍0.005 ⬍0.001 ⬍0.010 ⬍0.001 ⬍0.010 NS
•••
The present observations demonstrate that HRR after submaximal exercise is also a modifiable characteristic in cardiac patients that can increase after 12 weeks of exercise training. Most patients in the present series had increased HRR along with submaximal effort tolerance during Gender cardiac rehabilitation. However, a decrease in already low HRR was Men (n ⫽ 58) Women (n ⫽ 23) p value found in ⬍9% of the present popu(by gender) Mean ⫾ SD 95% CI Mean ⫾ SD 95% CI lation, despite modest improvement in initially low submaximal effort Entry METs 4.4 ⫾ 1.2 3.3 ⫾ 1.2 ⬍0.005 tolerance. This small subset included Exit METs 8.1 ⫾ 1.8 5.9 ⫾ 1.8 ⬍0.001 only patients ⬎65 years old and was Difference in METs 3.8 ⫾ 1.3 3.4–4.1 2.6 ⫾ 0.9 2.1–3.0 ⬍0.001 disproportionately female. Entry HRR (beats/min) 13.6 ⫾ 6.0 9.6 ⫾ 5.4 ⬍0.010 Exit HRR (beats/min) 17.5 ⫾ 5.2 11.8 ⫾ 6.0 ⬍0.001 Maximum exercise is rare during Difference in HRR 3.9 ⫾ 5.6 2.4–5.3 2.1 ⫾ 3.2 0.8–3.5 NS the routine activities of daily living, p value (entry vs exit METs) ⬍0.001 ⬍0.001 which generally require only subp value (entry vs exit HRR) ⬍0.001 ⬍0.005 maximal effort. Because cardiac reCI ⫽ confidence interval. habilitation also improves submaximal effort tolerance in cardiac patients at all ages,14 and because For the total population, HRR, averaged over 3 exer- HRR after submaximal exercise also appears to have cise training sessions, increased by a mean of 27% prognostic value,9 the effect of exercise training on during cardiac rehabilitation (12.5 ⫾ 6.1 to 15.9 ⫾ 6.0 HRR after submaximal exercise is relevant to the beats/min, p ⬍0.001). This was associated with a prevalent neurohumoral adaptation in patients with small increase in mean end-exercise heart rate during heart disease.1,2,11,15 The present observations demonthe final 3 training sessions compared with the initial strate that HRR after submaximal exercise is also a 3 sessions (102 ⫾ 18 to 109 ⫾ 19 beats/min, p modifiable characteristic in cardiac patients and that ⬍0.001). Median, interquartile, and range of entry and submaximal HRR can increase after 12 weeks of exit average HRR and average change in HRR are exercise training. shown in Figure 1. Age- and gender-related differences in submaximal As seen in Table 1, submaximal effort capacity exercise HRR findings of our patients parallel differcalculated from treadmill METs and HRR averaged ences that have been found with maximal exercise over 3 sessions, before and after exercise training, testing.12 Whether the lower values for HRR in older were greater in younger than in older patients and patients can be attributed to lower submaximal exergreater in men than in women. However, effort capac- cise heart rates at entry and after training in this group, ity and HRR after submaximal exercise increased with or to separate effects of age on autonomic response to exercise training in both age groups and both genders. effort, remain to be clarified. A mean increase in HRR was not significantly differThe data in the present study indicate that the ent between subgroups as defined by age or gender. effects of exercise training on neurohumoral tone as When patients were grouped according to an age reflected by HRR in cardiac patients are extended to partition of 65 years, HRR increased by a mean of periods of submaximal effort that are associated with 22% in the younger patients and 40% in the older more routine activities of daily living. patients. When patients were grouped according to gender, HRR increased by a mean of 29% in the men and 23% in the women. 1. Malfatto G, Facchini M, Sala L, Branzi G, Bragato R, Leonetti G. Relationship Some regression to the mean can be expected in between baseline sympatho-vagal balance and the autonomic response to cardiac these findings. Seven patients with HRR at entry of rehabilitation after first uncomplicated myocardial infarction. Ital Heart J 2000; ⬍10 beats/min (mean 7.3 ⫾ 1.6) had exit HRR that 1:226 –232. 2. Lucini D, Milani RV, Costantino G, Lavie CJ, Porta A, Pagani M. Effects of was even lower at discharge (mean 6.1 ⫾ 1.5 beats/ cardiac rehabilitation and exercise training on autonomic regulation in patients min, p ⬍0.05); this subset represents ⬍9% of the total with coronary artery disease. Am Heart J 2002;143:977–983. study population. Each of these patients was ⬎65 3. Oldridge NB, Guyatt GH, Fischer ME, Rimm AA. Cardiac rehabilitation after myocardial infarction. Combined experience of randomized clinical trials. JAMA years old and 5 of 7 were women, but despite low 1988;260:945–950. effort tolerance at entry and the lower HRR findings 4. O’Connor GT, Buring JE, Yusuf S, Goldhaber SZ, Olmstead EM, Paffenbarger 602 THE AMERICAN JOURNAL OF CARDIOLOGY姞
VOL. 92
SEPTEMBER 1, 2003
RS, Hennekens CH. An overview of randomized trials of rehabilitation with exercise after myocardial infarction. Circulation 1989;80:234 –244. 5. Wenger NK, Froehlicher ES, Smith LK, Ades PA, Berra K, Blumenthal JA, Certo CM, Dattilo AM, Davis D, DeBusk RF. Cardiac rehabilitation. Clinical Practice Guideline No. 17. Rockville, MD: Agency for Health Care Policy and Research and the National Heart, Lung and Blood Institute, 1995. 6. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart rate recovery immediately after exercise as a predictor of mortality. N Engl J Med 1999;341:1351–1357. 7. Watanabe J, Thamilarasan M, Blackstone EH, Thomas JD, Lauer MS. Heart rate recovery immediately after treadmill exercise and left ventricular systolic dysfunction as predictors of mortality. Circulation 2001;104:1911–1916. 8. Nishime EO, Cole CR, Blackstone EH, Pashkow FJ, Lauer MS. Heart rate recovery and treadmill exercise score as predictors of mortality in patients referred for exercise ECG. JAMA 2000;284:1392–1398. 9. Cole CR, Foody JM, Blackstone EH, Lauer MS. Heart rate recovery after submaximal exercise testing as a predictor of mortality in a cardiovascularly healthy cohort. Ann Int Med 2000;132:552–555. 10. Imai K, Sato H, Hori M, Kusuoka H, Ozaki H, Yokoyama H, Takeda H,
Inoue M, Kamada T. Vagally mediated heart rate recovery after exercise is accelerated in athletes but blunted in patients with chronic heart failure. J Am Coll Cardiol 1994;24:1529 –1535. 11. La Rovere MT, Bigger JT, Marcus FI, Mortara A, Schwartz PJ. Baroreflex sensitivity and heart rate variability in prediction of total cardiac mortality after myocardial infarction. Lancet 1998;351:478 –484. 12. Hao SC, Chai A, Kligfield P. Heart rate recovery response to symptomlimited treadmill exercise after cardiac rehabiilitation in patients with coronary artery disease with and without recent events. Am J Cardiol 2002;90:763–765. 13. American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing, and Prescription. 5th Ed. Baltimore: Williams and Wilkins, 1995; VIII:153–240. 14. Chai A, McCormick A, Jacobson A, Kligfield P. Effects of cardiac rehabilitation on the exercise performance of men and women in the fourth through the ninth decades. Cardiovasc Rev Rep 1999;20:376 –380. 15. Tulppo MP, Makikallio TH, Seppanen T, Laukkanen RT, Huikuri HV. Vagal modulation of heart rate during exercise: effects of age and physical fitness. Am J Physiol 1998;274:H424 –H429.
Feasibility to Detect Severe Coronary Artery Stenoses With Upright Treadmill Exercise Magnetic Resonance Imaging Pairoj Rerkpattanapipat, MD, Sanjay K. Gandhi, MD, Stephen N. Darty, RT(N)(MR), R. Taylor Williams, MD, April D. Davis, RTR, Wojciech Mazur, MD, Hollins P. Clark, MD, William C. Little, MD, Kerry M. Link, MD, Craig A. Hamilton, PhD, and W. Gregory Hundley, MD We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively. 䊚2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:603– 606)
lthough investigators have demonstrated the utility of magnetic resonance imaging (MRI) pharA macologic stress testing for detecting left ventricular (LV) myocardial ischemia and viability,1–3 to date, the inability of MRI techniques to assess LV function immediately after upright treadmill exercise has limited the use of MRI in assessing patients referred for treadmill exercise. We placed a treadmill constructed primarily of nonferromagnetic material approximately 20 ft from the end of the MRI table, and developed a method to reacquire prestress slice positions in LV short-axis planes within 60 to 90 seconds of completing upright treadmill exercise. We assessed the feasiFrom the Departments of Internal Medicine (Cardiology Section), Biomedical Engineering, and Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina. Dr. Rerkpattanapipat’s address is: Section on Cardiology, Wake Forest University School of Medicine (Bowman Gray Campus), Medical Center Boulevard, Winston-Salem, North Carolina 27157-1045. E-mail: prerkpat@wfubmc. edu. Manuscript received April 11, 2003; revised manuscript received and accepted May 12, 2003. ©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 1, 2003
bility of this method for identifying LV regional wall motion abnormalities indicative of myocardial ischemia in 27 patients with chest pain who were referred for contrast coronary angiography. •••
Our study was approved by the institutional review board of Wake Forest University Health Sciences, and all subjects gave written informed consent. Our subjects underwent stress MRI and contrast coronary angiography separately at 2 ⫾ 3 months without a change in their medications or clinical status of their coronary artery disease. Patients with contraindications to MRI (intracranial metal or claustrophobia) or upright treadmill exercise4 were excluded from enrollment. Each subject was positioned supine with their feet touching the end of the MRI table. A nonferromagnetic patch was placed at the midline of the neck above the suprasternal notch as a landmark for repositioning the subject after exercise (Figure 1). After electrode patches for MRI cardiac gating and STsegment monitoring were placed and connected to a cardiac monitoring system (In vivo Research, Inc., Orlando, Florida), the subject was advanced into the scanner with a cardiac phased-array surface coil placed over the chest. At baseline, multiphase, fast imaging employing steady-state acquisition images of LV regional wall motion were acquired in the basal, middle, and apical short-axis planes.3 After the postexercise scan sequence was prescanned, the cardiac coil was unplugged, the cradle was undocked manually, and the subject was withdrawn from the scanner bore and escorted to a treadmill (Marquette Medical 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00734-3
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