Cycle Ergometry Is not a Reliable Parameter
We work in an institution that provides follow-up examinations for patients with coronary heart disease and wish to share the following observations.
The authors rightly say that routine CT angiography is not indicated after coronary stent implantation. This is not only because the coronary stenoses diagnosed on CT are often not hemodynamically relevant. The more important reason is that monitoring stents is affected by their structure and size, among others. Further, in patients with known coronary heart disease the coronary vessels are often subject to severe calcification, which can substantially limit diagnostic accuracy. The consensus recommendations from the working groups of the German Cardiac Society/German Society of Pediatric Cardiology do not regard the indication as definite in asymptomatic and symptomatic patients after coronary intervention or bypass surgery, unless the question is only one of bypass graft patency (1).
Regarding ergometry testing, our critical comment would be that the reported criterion of maximum exertion (85% of age-adjusted heart frequency) does not constitute a reliable parameter. The maximum individual heart frequency is subject to large variability and is furthermore affected by cardiac medication (2, 3). Furthermore, especially untrained elderly patients cannot achieve (cardiac) maximum exertion on the exercise bike because of deficits in the peripheral muscles. Exercise on a treadmill can be helpful in this setting as it typically reflects everyday activity more closely, in order to reach as high a degree of maximum exertion as possible and to improve the sensitivity of the exercise ECG, which is limited anyway. Furthermore, it is possible by using combinations with lactate testing and/or spiro-ergometry testing to establish more objective criteria for maximum exertion, but also to finesse the control of the recommended physical training.
Prof. Dr. med. Christof Burgstahler
Prof. Dr. med. Andreas Nieß
Universitätsklinik Tübingen, Abteilung Sportmedizin, Tübingen
|1.||Achenbach S, Barkhausen J, Beer M, et al.: Konsensusempfehlungen der DRG/DGK/DGPK zum Einsatz der Herzbildgebung mit Computertomografie und Magnetresonanztomografie. Röfo 2012; 184: 345–68 MEDLINE|
|2.||Roecker K, Niess A, Horstmann T, Striegel H, Mayer F, Dickhuth HH: Heart rate prescriptions from performance and anthropometrical characters. Med Sci Sports Exerc 2002; 34: 881–7 CrossRef MEDLINE|
|3.||Such M, Meyer T: Die maximale Herzfrequenz. Dtsch Z Sportmed 2010; 61: 310–1.|
|4.||Rassaf T, Steiner S, Kelm M: Postoperative care and follow up after coronary stenting. Dtsch Arztebl Int 2013; 110(5): 72–82. VOLLTEXT|