A non-invasive treatment for angina does not lead to enhanced athletic performance
Washington, DC – Each year, about one in 100 Americans experiences severe constricting pain in their chest, often radiating from the precordium to the shoulder and down the arm, due to arterial narrowing of the heart muscle. This is known as "angina pectoris," which occurs when the heart muscle does not get enough blood and oxygen to do its work. It is a serious condition because it is a warning sign of coronary disease.
Fortunately, surgery may not be required. Instead, an enhanced external counterpulsation (EECP®), can be used. This is a noninvasive technique that increases oxygen-rich blood flow to the heart and reduces the heart's workload. It is performed over a series of weeks, with each session lasting from one to two hours. Pressure cuffs on the legs are inflated in sequences and as a result, blood vessels in the legs are gently compressed and the blood is forced back to the heart.
A Short History of EECP®
The American Heart Association has stated that the EECP® device lowers the pressure the heart must pump against, increases the rate of return of blood to the heart, and increases blood pressure while the heart is resting. External counterpulsation also improves the balance between the amount of oxygen the heart needs and the amount it gets. Both of these changes reduce the pain.
In the 1998, the FDA approved EECP® as a treatment for angina. In 1999, Medicare recognized and began reimbursing payment for EECP® as a treatment alternative for patients with functional class III or IV angina and whose disease is not amenable to bypass surgery or angioplasty. As treatment centers opened and practitioners gained experience in treating patients with EECP®, anecdotal reports surfaced about EECP® and enhanced athletic performance. The frequency of patients reporting an increase in endurance during exercise became more and more common.
Literature in the field suggests that the EECP® mechanisms not only improve cardiac function, but also enhance athletic performance. This is supported by evidence that the device has been shown to decrease exercise induced reversible perfusion (blood flow) defects, improve diastolic filling, left ventricular end-diastolic pressure, and left ventricular peak filling rate and end-diastolic volume, and time to peak filling rate. Additionally, experience with EECP® suggests a possible increase in collateral arterial circulation of the myocardium.
A New Study
Researchers from the Nike Sports Research Laboratory (NSRL) set out to investigate the effects of a traditional regimen of EECP® treatments on physiological functions that predicts athletic performance in endurance-related competitive sports. The authors of the investigation, "Enhanced External Counterpulsation for Improving Athletic Performance," are L.G. Myhre, I. Muir, R.W. Schutz, B. Rantala, and T. Thigpen from the Nike Sports Research Laboratory, Beaverton, OR and from the Heart Centers of America, LLC, Portland OR. They will present their findings at the American Physiological Society's (APS) (www.the-aps.org) annual scientific conference, Experimental Biology 2003, being held April 17-21, 2004, at the Washington, D.C. Convention Center.
The researchers determined that certain physiological tests could provide objective evidence that EECP® can enhance athletic performance. Their tests encompassed aerobic capacity, lactate threshold, lactate tolerance, work tolerance time, and postural control.
Nineteen vigorously active males in training, age 33.9+8.2 years and weight of 81.58+11.86 kg, were randomly assigned to treatment (n = 10) and placebo (n = 9) groups. Both groups completed 35 one-hour "treatments" with an EECP® device; the "pressure" used for the placebo group was determined to have no effect for use in clinical cardiology.
The physiological parameters that are among the most useful for predicting performance in endurance sports were measured before and within one week following the completion of the treatment period. These tests included: aerobic capacity (VO2 max), maximum tolerance for lactic acid, work tolerance time (WTT) to exhaustion for standard exercise, and lactate threshold for progressive increments in exercise intensity. Other measures of physiological interest were maximum ventilation for exhausting exercise and maximum heart rate during exhausting exercise.
The effect of 35 EECP® treatments on the physiological parameters studied are summarized as follows:
% Change from Baseline Values
Placebo EECP VO2 max, l/min -0.4 -2.8 VO2 max, ml/ kg/min +0.1 -3.1 Lactate max, mg% -2.1 -3.5 Work tolerance time, min +7.2* +1.5 Lactate threshold +1.3 +0.0 VE max, l/min (STPD) -0.6 -0.3 Heart rate max, bpm +0.2 -0.4
The only significant difference between the groups was a small increase (approx. 40 sec.) in the WTT shown by the Placebo group. The authors noted observed improvement in postural instability and ataxia (inability to coordinate muscle activity during voluntary movement) in patients being treated with EECP®. This offers speculation that there may be a motor or sensory contribution in postural control. If quantified, this may benefit the athlete by improving postural stability and balance.
The researchers concluded, however, that EECP® treatments had no significant effect on the physiological parameters considered to be among the best for predicting performance in endurance-type competitive sports.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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