Same patient as on the preceding tracing; programming change with decrease in the maximal value of the PVARP, and programming of an automatic adaptation of the PVARP and adaptive AV delay; new exercise test with attenuation of the feeling of limitation than during the previous test.
28-year-old woman who underwent surgical implantation of a triple chamber pacemaker (1 atrial lead, 2 left ventricular leads) for congenital complete AV block; device programmed in DDD mode (1 left ventricular lead) at 60-120 bpm; she complained of exercise-induced dyspnea; she underwent exercise testing (repetitive flexing of the legs) with the telemetry head positioned over the pulse generator; the EGM were recorded during vigorous effort with, from one cycle to the next, a sensation of dyspnea (exercise was discontinued at this very moment to obtain a recording of high quality).
The first channel is lead II of the surface ECG, the second is the atrial EGM with the superimposed
markers, and the third channel is lead I;
Exercise testing is an important step in the follow-up of pacemaker recipients, particularly when symptomatic. It should preferably be performed while analyzing the EGM during exercise, using the programmer, with a view to detect a possible dysfunction and perhaps reprogram the device in real time, depending on the observations that were made. Exercise might consist of a simple walk to mimic the efforts of daily life. Repetitive flexing of the legs emulates a more vigorous effort.
These 2 types of exercise tests are of practical interest as they can be performed at the time of the follow-up visits. A standard bicycle exercise test offers the advantage of a continuous 12-lead electrocardiographic follow-up. Another value of the test is the verification of the appropriateness of a programming change.
In this patient, the shortening of the AV delay and PVARP allowed a relocation of the 2:1 point to a better adapted rate of 180 bpm. On the other hand, persistence of an upper triggered rate at 120 bpm explains the Wenckebach function observed on this tracing. In this patient, the periodicity of the pseudo-Wenckebach function was 4:3. With this programming, pseudo-Wenckebach periodicity was observed in this patient for sinus rates between programmed upper rate (120 bpm) and 2:1 point (180 bpm). An increase in sinus rate would increase the proportion of blocked P waves. There was no reason to curb the maximum triggered rate in this young, active patient free from structural heart disease. A reprogramming of the maximum synchronous rate to 180 bpm enabled a consistent atrial tracking over this patient’s entire range of rates, at rest as well as during maximum effort.
