Pulmonary disease exercise testing

No single test is available to confirm the diagnosis of heartfailure. Because the syndrome of heart failure can be caused or worsened by multiple cardiac and noncardiac disorders, accurate diagnosis is essential for development of therapeutic strategies. Heart failure often is suspected initially in a patient based on the symptoms. These frequently will include dyspnea, exercise intolerance, fatigue, and/or fluid retention. However, it must be emphasized that signs and symptoms lack sensitivity for diagnosing heart failure because these symptoms are found frequently with other disorders such as pulmonary disease. Even in patients with known heart failure, there is poor correlation between the presence or severity of symptoms and hemodynamic abnormality. 

Gallagher CG. Exercise limitation and clinical exercise testing in chronic obstructive pulmonary disease. Clin Chest Med 1994 15 305-326. 

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. 

For the growing number of patients with combined pulmonary hypertension and abnormal left ventricular hemodynamics, a careful hemodynamic study can help to delineate the subtleties of both diseases and response to therapies. Exercise catheterization is recommended in those patients with normal hemodynamics at rest, but with a pretest likelihood of PAH and/or other data suggesting exercise-induced symptoms, for instance, exercise echo or cardiopulmonary stress test. Unfortunately, to date there is no consensus as to the best exercise protocols for an appropriate hemodynamic assessment. Among those used include upright bicycle with neck pulmonary arterial (PA) lines at 75% predicted maximum exercise, supine bicycle, supine arm exercise, and supine volume loading. In all cases, it is essential to carefully measure PCWP, cardiac outputs, and PA pressures at consistent parts of the respiratory cycle, and not merely PA pressures. 

---