*2.4. Safety of Exercise Testing*

Cardiovascular events during treadmill- or leg cycle ergometer-based exercise testing are rare. In 1971, a study by Rochmis and Blackburn on 170,000 exercise stress tests performed in over 70 medical centers demonstrated an overall mortality rate of one death per 10,000 tests and a serious cardiac complications rate of 4 per 1000 tests [64]. A further study by Gibbon demonstrated a total cardiac complication rate in men and women of 0.8 (0.3–1.9) complications per 10,000 tests; however, the biggest limitation was the fact that most of the study population was without known coronary disease [65]. A recent study by Pavy including 25,000 patients (34% after coronary artery bypass surgery, 18% after valve surgery, 21% after recent percutaneous coronary intervention) revealed a rate of 1 event per 8484 exercise stress tests [66]. Traditional laboratory-based exercise protocols are often replaced in daily clinical practice with the incremental shuttle walking test (ISWT). In a pilot study by Pepera, the safety of the submaximal ISWT, as well as exercise training, was assessed in 33 patients during a community-based cardiac rehabilitation program of at least 10 weeks duration [67]. Termination criteria for ISWT included: the patient feeling too breathless or fatigued to continue at the required speed, failure to complete the test within the allowed time, reaching 85% of the predicted heart rate (calculated as 210 − (0.65 × age)), or completing all test levels. As expected, no major event was recorded for either the ISWT or training. The most clinically important event was silent ischemia (27% of ISWT), followed by atrial and ventricular ectopic beats (18% and 15%, respectively). Further studies are required, however, due to the small study population used.

## **References**

