Lee M. Pierson

Effects of combined aerobic and resistance training versus aerobic training alone in cardiac rehabilitation.

PURPOSE This study examined the effects of performing combined resistance and aerobic training, versus aerobic training alone, in patients with coronary artery disease. METHODS Thirty-six patients with coronary artery disease were randomized to either an aerobic-only training group (AE) or a combined aerobic and resistance training group (AE + R). Both groups performed 30 minutes of aerobic exercise 3 days/week for 6 months. In addition, AE + R group performed two sets of resistance exercise on seven different Nautilus machines after completion of aerobic training each day. Twenty patients (AE: n = 10; AE + R: n = 10) completed the training protocol with > 70% attendance. RESULTS Strength gains for AE + R group were greater than for AE group on six of seven resistance machines (P < 0.05). VO2peak increased after training for both AE and AE + R (P < 0.01) with no difference in improvement between the groups. Resting and submaximal exercise heart rates and rate-pressure product were lower after training in the AE + R group (P < 0.01), but not in the AE group. AE + R increased lean mass in arm, trunk, and total body regions (P < 0.01), while AE increased lean mass in trunk region only (P < 0.01). Percent body fat was reduced for AE + R after training (P < 0.05) with a between group trend toward reduced body fat (P = 0.09). Lean mass gain significantly correlated with strength increase in five of seven resistance exercises for AE + R. CONCLUSIONS Resistance training adds to the effects of aerobic training in cardiac rehabilitation patients by improving muscular strength, increasing lean body mass, and reducing body fat.

Knee Extensor and Flexor Torque Development With Concentric and Eccentric Isokinetic Training

This study assessed muscular torque and rate of torque development following concentric (CON) or eccentric (ECC) isokinetic training. Thirty-eight women were randomly assigned to either CON or ECC training groups. Training consisted of knee extension and flexion of the nondominant leg three times per week for 20 weeks (SD = 1). Eccentric training increased ECC knee extension and flexion peak torque more than CON training. The ECC group improved acceleration time and time to peak torque with ECC movements versus the CON group. Slow-velocity ECC isokinetic training yielded greater ECC and similar CON torque development gains versus CON training over the course of 20 weeks in young women.

Predicting exercise training outcome from cardiac rehabilitation.

PURPOSE This study was conducted to identify predictors of training effect after 6 months of supervised exercise for cardiac rehabilitation patients. METHODS Data at baseline and after 6 months of supervised exercise from 60 patients with coronary artery disease were used for this study. All the patients exercised 3 days per week for 5 to 9 months. Attendance exceeded 70%. The training effect was independently evaluated by the change in rate-pressure product at a 5-metabolic equivalent (MET) workload (RPP5), and the change in estimated peak METs (METPK) during treadmill testing. Baseline variables were examined to identify predictors of change in RPP5 and METPK separately using multiple linear regression. RESULTS A reduction in RPP5 (-23 +/- 33 bpm x mm Hg x 10(2); P<.0001) and an increase in METPK (2.1 +/- 1.7 METs; P<.0001) were found after training. Baseline fitness was the best predictor of training effect. Inverse relations were found between baseline scores and change scores for RPP5 (r=-0.68; P<.001) and METpk (r=-0.39; P=.002). Beta-blocker status also was useful for predicting change in RPP5. No association was found between training effect and age, revascularization status, or exercise-induced ischemia. CONCLUSIONS Training effect has limited predictability using baseline variables. No baseline patient characteristics other than high initial fitness were related to reduced training effect. Therefore, patients with clinical characteristics similar to those evaluated in this study can achieve a training effect successfully and are eligible for cardiac rehabilitation. The findings of this study support previous research related to this topic.

Relationship between exercise systolic blood pressure and left ventricular geometry in overweight, mildly hypertensive patients.

Objective To examine the association between the graded exercise systolic blood pressure (SBP) response and left ventricular (LV) geometric structure in patients with untreated mild hypertension. Participants The study included 80 sedentary, overweight patients (43 female and 37 male) with unmedicated high normal blood pressure or stage 1–2 hypertension. Methods An echocardiogram was used to determine LV mass and the relative wall thickness (RWT) in relation to the chamber dimension. Participants performed a maximal graded exercise test, and the SBP was recorded at workloads of 2, 4 and 6 metabolic equivalents and at peak exercise. Separate statistical models were used to determine the influence of LV mass indexed for height2.7 (LVMIh) and RWT on submaximal exercise SBP and peak exercise SBP, controlling for resting SBP, age, gender, ethnicity and body mass index. Results A greater RWT was associated with a higher submaximal SBP level (P = 0.038). Neither LVMIh (P = 0.989) nor the interaction of RWT and LVMIh (P = 0.787) were related to the submaximal SBP. None of the main or interaction effects of RWT and LVMIh were associated with the peak exercise SBP level. Conclusion Increases in RWT were associated with higher submaximal exercise SBP responses in a sample of overweight, unmedicated hypertensives. These results suggest that RWT is an important determinant of the association between cardiac mass and exercise SBP response.

Age influences anthropometric and fitness-related predictors of bone mineral in men

Objective. This study assessed the influence of age on the predictors of bone mineral in men. Methods. Middle-age (n = 41, 54 ± 4 yrs) and older (n = 40, 69 ± 5 yrs) men underwent grip and knee extensor strength tests, total body dual-energy X-ray absorptiometry with regional analyses and a graded exercise treadmill test. Results. Bone-free lean mass (BFLM) and, to a lesser extent, fat mass (FM) were correlated with bone mineral variables in middle-age men. In older men, BFLM and, to a lesser extent, FM were related to bone mineral content (BMC) at most sites, but inconsistently to bone mineral density (BMD). Knee extensor strength related to bone mineral (BMC and BMD) at most sites in middle-age men, but none in older men. Grip strength inconsistently related to bone mineral in both groups. Aerobic capacity related to bone mineral in middle-age men, but none in older men. In multiple regression, body weight or BFLM predicted bone mineral in middle-age men (R2 = 0.33–0.68) and BMC in older men (R2 = 0.33–0.50). Predictors of BMD were inconsistent in older men. Conclusions. Relationships of body composition, muscular strength and aerobic capacity to bone mineral are stronger in middle-age versus older men.

Improving Cardiac Rehabilitation Referral Patterns Using Computerized Physician Order Entry Systems

Much of the immense burden of cardiovascular disease is ultimately a consequence of unhealthy lifestyle choices, such as physical inactivity, caloric over-consumption, and tobacco use. Unfortunately, clinicians rarely have sufficient time or resources to meaningfully address these issues. Cardiac rehabilitation is a comprehensive program for the secondary prevention of cardiovascular events for a wide spectrum of patients and is designed to address the lifestyle factors related to cardiovascular disease. While cardiac rehabilitation initially focused on exercise training, it has expanded over time to include cardiovascular education, nutritional counseling, behavioral interventions, and pharmacologic therapy. A large body of literature on cardiac rehabilitation has accrued demonstrating its robust health benefits, 1,2 including a survival benefit among patients with coronary artery disease, 2 and now it is advocated by professional clinical organizations for several cardiovascular conditions. 1 Despite its clinical need, cardiac rehabilitation remains vastly underutilized in the US, with 30% of eligible patients enrolling nationwide. 2 While several reasons exist for this poor utilization, the most critical and potentially most correctable reason is widely acknowledged to be the referral process, as only 1 in 2 patients eligible for cardiac rehabilitation are currently being referred. 3 Opportunities for referral often present themselves during the chaotic hospital discharge process or the first outpatient clinic visit after hospitalization, when busy practitioners are in the midst of dealing with symptoms, further testing, medication titration, and other clinical issues. As a result, cardiac rehabilitation generally lies at the bottom of practitioners’ priority lists for ongoing therapy. Also, it is oftentimes unclear which provider should take responsibility for the referral. Further complicating the referral process, many insurance companies require preauthorization. Finally, even if a referral is eventually made, they are often ineffective, being delayed weeks to months after a cardiovascular event, well past the point when patients may be motivated, willing, or able to attend cardiac rehabilitation.

Discordance of aortic remodeling with clinical outcomes in patients treated with endovascular repair for uncomplicated type B aortic dissection

Uncomplicated type B aortic dissection is managed with anti-impulse therapy since surgery offers no additional long-term survival advantage. In recent years, thoracic endovascular repair (TEVAR) has been forwarded as a treatment strategy that may retard aortic growth, lower rupture risk, and improve clinical outcome compared to medical management in patients with uncomplicated type B aortic dissection. Although aortic remodeling often serves as a surrogate measure of treatment success in trials of aortic dissection, there is, in fact, little evidence to suggest that aortic remodeling confers a clinical advantage in this patient cohort. TEVAR likely will not be widely recommended for the patient with uncomplicated type B aortic dissection until a prospective comparative clinical trial demonstrates a clear clinical advantage of TEVAR over medical management. Measures of aortic remodeling are poor surrogate measures of treatment success in this patient population.

The Influence of Endothelial Function and Myocardial Ischemia on Peak Oxygen Consumption in Patients with Coronary Artery Disease

Impaired endothelial function has been shown to limit exercise in coronary artery disease (CAD) patients and has been implicated in myocardial ischemia. However, the association of endothelial function and ischemia on peak exercise oxygen consumption (VO2) has not been previously reported. A total of 116 CAD patients underwent standard exercise stress testing, during which VO2 was measured. On a separate day, endothelial-dependent and -independent function were assessed by ultrasound using flow-mediated arterial vasodilation (FMD) and sublingual glyceryl trinitrate administration (GTNMD) of the brachial artery. Patients with exercise-induced myocardial ischemia had lower FMD than nonischemic patients (3.64 ± 0.57 versus 4.98 ± 0.36, P = .050), but there was no difference in GTNMD (14.11 ± 0.99 versus 15.47 ± 0.63, P = .249). Analyses revealed that both FMD (P = .006) and GTNMD (P = .019) were related to peak VO2. However, neither the presence of ischemia (P = .860) nor the interaction of ischemia with FMD (P = .382) and GTNMD (P = .151) was related to peak VO2. These data suggest that poor endothelial function, potentially via impaired NO production and smooth muscle dysfunction, may be an important determinant of exercise capacity in patients with CAD, independent of myocardial ischemia.