[Cardiokymography: relative quantification of results in normal probands]

The main problem with cardiokymography (CKG) and the principal reason for its limited clinical application to date is the deficiency of calibration and quantification of results. We tried to improve the value of the procedure by quantification of the results in 14 healthy young men (age: 23, 18-31 years) in place of subjective assessment. Before and after a bicycle exercise stress test CKG tracings were obtained in a lying position at rest, immediately after exercise and after recovery. Two different methods were applied to quantify the CKG tracings (distance method and area method). The relative height of the curves at rest was 89 +/- 72% (68 +/- 39%), immediately after exercise 111 +/- 60% (73 +/- 27%) and, after recovery 121 +/- 88% (78 +/- 49%). The relative change in the height of the curves between rest and exercise was not significant according to both methods (+22 +/- 64%/+5 +/- 32%), but the variation of values in an individual patient between rest and exercise was large. Interobserver variability was rather large, according to two independent investigators. Hence, it was not possible to establish limits of normal values in quantitative CKG, but only mean values.