Systolische und diastolische Funktion in Abhängigkeit des AV-Delays in Ruhe und unter Belastung bei Patienten mit AV-Block II/III und VAT-Stimulation

Technical advances in pacemaker technology led to very sophisticated and powerful pacemaker systems confirming their actual benefit to the patients in everyday practice. In this study 16 patients and 13 subjects were investigated at rest and during physical activity. These investigations were repeated two times during a follow-up in the patients group. Using electrocardiographic and echocardiographic parameters variables for the description of the evoked potential of left ventricular electromechanics and left ventricular systolic and diastolic function were measured. All together about 13,000 raw data were collected. Even before the start of the investigation, it was obvious that a direct comparison of the test group with the patient group was only possible with reservation due to the significant differences in both Collectives. Nevertheless, it was of interest to observe how the measured parameters behave in apparently healthy subjects. Mostly a very similar behavior of the variables was documented. Significant differences were often in the absolute values of measured variables due to the delay in conduction through the nonspecific myocardium in the case of the pacemaker group. Regarding to the follow-up investigations it was shown that the results of all three dates hardly distinguished. Often the graphs were parallel or even almost identical. None of variables was a unique Depending on the values evident from examination point. The influence of the Examination date after pacemaker implantation to the variables of systolic and diastolic function seems therefore at least in the first six Months to be of minor importance. Particularly interesting are the results of the pre-ejection period (PEP). The pronounced reduction during exercise in both groups was not described so far in the Literature. This result is of importance for the everyday practice because today´s pacemaker systems do not pay attention to these results. Further statistical evaluations based on larger groups of patients are necessary. In this work it was a problem to recruit a sufficient number of patients with the aforementioned inclusion and exclusion criteria. In particular, the key demand of missing conduction among stress test led to numerous exclusions. This is also a weakness of the work which causes only a purely descriptive statistic due to the small number of patients. The work should be understood as a basis for further statistically higher graded evaluations. The optimization of the AV-Delay will continue to be of great importance. Although the majority of pacemaker patients AV-Optimization could not be provided in clinical practice, the rapid development of biventricular ICD and pacemaker systems for the treatment of chronic Heart failure need much more research in atrioventricular (AV) and intra-and interventricular (VV) synchronicity. In addition to the AV optimization the synchronization of both ventricles (VV Delay) plays an important role. In future pacemaker systems using electrical or even hemodynamic variables can provide an automatic AV-/VV-Optimization. Such complex systems are not available yet.