Left ventricular strain and strain rate analyses during DSE can be used in the assessment of hemodynamic significance of coronary artery stenosis in patients with moderate and high risk for CAD.

Global longitudinal strain is highly sensitive and specific in detecting hemodynamically significant coronary artery stenosis in moderate- to high-risk patients without known CAD. This is the first study showing that GLS is more sensitive and specific compared with early and late diastolic SR parameters or visual assessment in detecting CAD.

Background and Objectives: Chronic atrial stimulation might impair left atrial (LA) function. We aimed to assess the impact of atrial pacing burden on LA volumetric and functional parameters after implantation of a dual-chamber pacemaker. Materials and Methods: The prospective study included 121 subjects with sinus node disease (SND) or atrioventricular block (AVB) that received a dual-chamber pacemaker. After device implantation, the subjects were divided into three groups: (1) SND with a lower rate (LR) set to 60 bpm and rate response enabled; (2) AVB with an LR set to 60 bpm and no rate response; and (3) AVB with an LR set to 40 bpm and no rate response. Subjects were followed at one and three months. Two subsets of patients with high and low atrial pacing burdens accompanied by low ventricular pacing percentage were analyzed. LA function was evaluated with volumetric and strain parameters from transthoracic echocardiography. Results: The high atrial low ventricular pacing group consisted of 38 subjects, and the low atrial low ventricular group consisted of 22 subjects. When looking at the change in volumetric parameters, we observed a tendency for volumes to increase in both groups; however, only minimal LA volume reached statistical significance at three months in the high atrial pacing group. A trend towards the lowering of an active emptying fraction at one month (p = 0.076) became significant at three months (p = 0.043), and was also only observed in the same group. Moreover, a decrease in the tendency to reach statistical significance at three months for reservoir and contractile strain parameters and stiffness index was only observed in the high atrial pacing group. Meanwhile, in the low atrial pacing burden group, all parameters remained significantly unchanged. Conclusions: The burden of right atrial pacing in patients with preserved left ventricular function negatively influences functional and morphologic LA parameters. Moreover, negative effects take place soon after pacemaker implantation and appear to be sustained.

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Funding Acknowledgements Type of funding sources: None. Background. Dual-chamber pacemaker implantation is a standard interventional treatment strategy for symptomatic sinus syndrome (SSS) or advanced atrioventricular block (AVB). It is already known that right ventricular pacing might have detrimental effects on cardiac function. However, knowledge about atrial pacing effect on left (LA) and right (RA) atria function is still lacking. Purpose. To assess the impact atrial pacing on left and right atria morphologic and functional parameters in patients after dual-chamber pacemaker implantation. Methods. We conducted a prospective study that included patients who received a dual-chamber pacemaker for an indication of AVB or SSS. A base rate of 40 bpm and no rate response in case of clear AVB indication or a base rate of 60 bpm and rate response if indication was SSS were chosen. A transthoracic echocardiography was done the next day after pacemaker implantation and after 1 and 3 months. To remove the impact of right ventricular pacing, patients with high VP percentage (>40%) were excluded from analysis. Patients were divided into two groups – group A with high AP (>50%), and group B – low AP (<50%). LA expansion fraction reflecting reservoir function, emptying - reflecting conduit, and active emptying reflecting "atrial kick" were analysed. To compare means the Mann Whitney U test, and for categorical variables – X² test were used. Results A total of n = 78 patients underwent dual-chamber implantation and signed informed consent. Due to significant structural heart disease or reduced ejection fraction (<50%) 7 patients were excluded from further analysis. Out of those, n = 21 were excluded due to a high VP percentage. Group A consisted of n = 26 and group B of – n = 24 patients. Average AP in group A was 63,5% and 68,3% at 1 and 3 months and 5,6% and 7,2% in group B respectively. The mean age (group A 74,5 SD 8,6 years vs group B 78,1 SD 8,0 years, p = 0,266), gender distribution (group A males 45,5% vs group B 48,4%, p = 0,774), and mean BMI (group A 26,4 SD 4,8 kg/m2 vs group B 29,5 SD 3,7 kg/m2, p = 0,202) did not differ significantly between the two groups. The mean left ventricular end diastolic diameter (LVEDD) and indexed LVEDD were not significantly different at baseline and did not change during the follow up period. The baseline LA and RA morphometric and functional parameters presented was not different at baseline between the two groups. The change in LA and RA functional parameters presented in figures. A tendency for a lower LA expansion fraction, active emptying fraction and LA ejection fraction were observed in group A. The trend was contant during 1 and 3 month follow-up periods. RA morphometric parameters did not change significantly between the two groups.  Conclusion Impaired LA function in a higher percentage of atrial pacing is seen early after pacemaker implantation and could progress over time. Though, even longer observational period is needed. Abstract Figure.  Abstract Figure.