Exercise tolerance testing

Abbrevations. CAD. coronary artery disease CHF, congestive heard failure CV, cardiovascular CVA, cerebrovascular accident ED, erectile dysfunction ETT, exercise tolerance test LVD, left ventricular dysfunction MI, myocardial infarction NYHA. New York Heart Association. 

The efficacy of meclofenamic acid as an antiinflammatory agent in horses has been determined in a number of studies using the recommended doses (Table 14.1) (Galbraith McKellar 1996, Johansson et al 1991, Tobin 1979). It is known for its slow onset of action, requiring 36-96 h of therapy before clinical effects are evident (Boothe 1995). It has also been proposed to be particularly effective in the treatment of acute and chronic laminitis, although its superiority over other NSAIDs in the treatment of these conditions has not been definitively proven (Lees Higgins 1985). In one study, meclofenamic acid was shown to decrease the accumulation of lactate and increase the lactate threshold in an exercise tolerance test carried out in seven standardbred horses (Johansson et al 1991). 

Johnsonbaugh RE, Bybee DE, Georges LR Exercise tolerance test Single-sample screening technique to rule out growth hormone deficiency. JAMA 1978 240 664-6. 

ABI, ankle-brachial index CCS, Canadian Cardiovascular Society DB, double-blind ETT, exercise tolerance test ia, intra-arterial ic, intracoronary iv, intravenous MRI, magnetic resonance imaging SAQ, Seattle Angina Questionnaire SPECT, single photon... 

A resting electrocardiogram (ECG) followed by an exercise tolerance test usually are the first tests done in stable patients. 

Like MIRACLE, COMPANION showed that CRT improved heart failure symptoms based on exercise tolerance testing and quality of life surveys. 

Exercise tolerance (stress) testing (ETT) is recommended for patients with an intermediate probability of CAD. Results correlate well with the likelihood of progressing to angina, occurrence of acute MI, and cardiovascular death. Ischemic ST-segment depression during ETT is an independent risk factor for cardiovascular events and mortality. Thallium myocardial perfusion scintigraphy may be used in conjunction with ETT to detect reversible and irreversible defects in blood flow to the myocardium. 

Many studies have demonstrated that nitrates, calcium channel blockers, and blockers increase time to onset of angina and ST depression during treadmill tests in patients with angina of effort (Figure 12-5). Although exercise tolerance increases, there is usually no change in the angina threshold, ie, the rate-pressure product at which symptoms occur. 

The effects of coenzyme Q10 on coronary artery disease and chronic stable angina are modest but appear promising. A theoretical basis for such benefit could be metabolic protection of the ischemic myocardium. Double-blind, placebo-controlled trials have demonstrated that coenzyme Q10 supplementation improved a number of clinical measures in patients with a history of acute myocardial infarction (AMI). Improvements have been observed in lipoprotein a, high-density lipoprotein cholesterol, exercise tolerance, and time to development of ischemic changes on the electrocardiogram during stress tests. In addition, very small reductions in cardiac deaths and rate of reinfarction in patients with previous AMI have been reported (absolute risk reduction 1.5%). 

The precise testing required to diagnose GH deficiency is controversial. Treatment of GH-deficient adults can cause increased lean body mass and bone density, decreased fat mass, increased exercise tolerance, and an improved sense of well-being. Adverse effects often include arthralgias and fluid retention. 

The safety and tolerability of once-daily oral metrifonate has been evaluated in patients with probable mild to moderate Alzheimer s disease in a randomized, doubleblind, placebo-controlled, parallel-group study (9). Metrifonate was given to 29 patients as a loading dose (2.5 mg/kg) for 2 weeks, followed by maintenance dose (1 mg/kg) for 4 weeks 10 patients received placebo. The proportion of patients who had at least one adverse event was comparable in the two groups metrifonate 76%, placebo 80%. Selected adverse events, defined as those for which the incidence in the metrifonate and placebo group differed by at least 10%, were diarrhea, nausea, leg cramps, and accidental injury. The adverse events were predominantly mild and transient. Those who took metrifonate had a significantly lower heart rate. Metrifonate had no clinically important effect on laboratory tests, such as liver function tests, and did not affect exercise tolerance or pulmonary function. 

Russek has found isosorbide dinitrate and pentaerythritol tetranitrate to produce a significant improvement in exercise tolerance as well as exercise ECG tests.A wide variety of nitrate esters have been found to provide relief of angina pectoris. There is no information, however, to suggest a difference in the basic pharmacological action of these compounds. Such differences are presumably due to differences in absorption and rates of metabolism. 

Exercise tolerance (stress) testing (ETT) is recommended for patients with intermediate pretest probability of CAD based on age, gender, and symptoms, including those with complete right bundle branch block or less than 1 mm of rest ST-segment depression (Fig. 15-3). Although ETT is insensitive for predicting coronary artery anatomy, it does correlate well with outcome, such as the likelihood of... 

Tests for general fitness include the 6-minute walking distance and the Harvard step test. For the 6-minute walking distance, the subject simply walks a predetermined route or circuit as fast as possible for 6 minutes. The greater the distance covered, the better are the patient s general fitness and exercise tolerance. For the Harvard step test, the subject steps up and down on a 20-in step at a set rate for 5 minutes. A 1 -minute rest period is followed by measurement of the subject s recovery heart rate. The lower the recovery heart rate, the better is the subject s general fitness. 

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