[Transient pacemaker dysfunction and spontaneous arrhythmias in symptomatic and asymptomatic patients with ventricular demand pacemakers].

This prospective cross-sectional study include 100 consecutive patients (56 males, 44 females, 29 to 86 (mean = 67.5 +/- 12.2) years) with ventricular inhibited demand pacemakers 0.1 to 94.7 (mean 23.3 +/- 25.4) months after pacemaker implantation. Fifty-two patients were free of symptoms, whereas 48 patients were still complaining of syncope, dizziness, or palpitations. After history, physical examination, and 12-lead standard ECG all patients underwent 24-h Holter monitoring. A computer-aided analysis of spontaneous arrhythmias was done first. In a second run computed-aided analysis of transient pacemaker dysfunctions was performed with a specially designed pacemaker module. There were no significant differences between asymptomatic and symptomatic patients with regard to the incidence of transient pacemaker dysfunctions, with regard to defined types of pacemaker dysfunctions, spontaneous ventricular arrhythmias, and with regard to supraventricular tachycardias. A significant difference between asymptomatic and symptomatic patients was found, however, regarding the Lown classification of ventricular arrhythmias, because asymptomatic patients showed class 0 and I/II arrhythmias more frequently (p < 0.025). In the 100 patients a total of 6609 pacemaker dysfunctions were observed, 5104 failures to sense and 1505 inappropriate inhibitions. Most patients showed up to 240 pacemaker dysfunctions per 24 h. There were no failures to capture. Different types of pacemaker dysfunctions were found with different clinical implications. Due to the Holter findings in nine patients pacemakers were reprogrammed or replaced. After pacemaker implantation the number of patients with severe symptoms significantly decreased compared to the number of patients before pacemaker implantation. Nonetheless, there was a number of patients still complaining of symptoms after pacemaker implantation. In only a few patients did pacemaker implantation worsen symptoms . Our data show that with use of long-term ECG transient pacemaker dysfunctions and spontaneous arrhythmias are more frequent than patients' history and common standard techniques in the pacemaker clinic may suggest Holter monitoring, therefore, is a useful diagnostic tool, not only in symptomatic, but also in asymptomatic pacemaker patients. It allows to obtain a reliable survey of the real amount of transient pacemaker dysfunctions in the individual patient, which is the base for further therapeutic decisions.