549 The role of conventional and speckle tracking echocardiography in the evaluation of leadless endocardial pacing with Micra-AV

Aims: Micra-AV pacing system is a leadless pacemaker (LP) implanted in the right ventricle which can provide atrio-ventricular (AV) synchronous pacing. Echocardiographic data assessing left ventricle contractility 24–48 h after Micra AV implantation are lacking. To evaluate via conventional echocardiography and speckle-tracking echocardiography (STE), which was the best pacing modality (VVI vs. VDD) able to ensure the most efficient hemodynamic performance assessed by left ventricle ejection fraction (LF-EF) and global longitudinal strain (GLS). Methods and results: We studied nine patients with high degree AV-block, enrolled in our Institution in a range of time of 5 months. All patients had first degree AV block (PQ interval between 160 and 340 ms). They were considered suitable candidates for MICRA-AV implantation according to current guidelines. Both LF-EF and GLS were performed 24–48 h after device implantation by two experienced echocardiographic physicians. The mean age of the population was 79 6 8 years (8 were male, 89%). Risk factors more represented were hypertension and dyslipidaemia. The maximum PQ interval was 256 6 51 ms. VDD pacing modality allows better LV-EF values than those obtained with a VVI stimulation (with a difference that was statistically significant difference, P-value 1⁄4 0.008). Similarly, we obtained better GLS values during VDD pacing as respect to VVI (P-value 1⁄4 0.008). Conclusions: Left ventricle ejection fraction and LV-GLS improve early after leadless MICRA-AV implantation during VDD as compared to VVI pacing modalit

Improvement of myocardial contractility with leadless endocardial single-lead atrial sensing ventricular pacing in patients with prolonged PQ interval

Aim: Micra AV represents a leadless endocardial pacing system able to detect atrial contractions providing atrioventricular synchrony. A reduction of myocardial contractility may be detected in case of first-degree atrioventricular block (AVB). Materials & methods: In six patients with first-degree AVB (PQ interval >= 220 msec) was evaluated the left ventricle global longitudinal strain (LV GLS) by speckle tracking (ST) echocardiography during single-lead atrial sensing ventricular pacing (VDD) stimulation as compared with spontaneous rhythm (SR), 24-48 h after Micra AV implantation. Results: A statistically significant difference between the two modalities was observed (LV GLS during SR: -14.7% [interquartile range (IQR) 5.5], LV GLS during VDD pacing: -16.1% [IQR 5.2]; p value = 0.041). Conclusion: Our preliminary results suggest an improvement of myocardial contractility with VDD pacing as compared with SR.What is this article about?The Micra AV is an electronic device placed in the heart chambers capable to supply the electrical activity of the heart. A reduction of cardiac contractility may be observed in patients with electrical disorders of the heart.What were the results?In six patients affected by electrical cardiac disorders, we observed an improvement of cardiac contractility using Micra AV as compared with the spontaneous electrical activity of the heart.What do the results of the study mean?The results of this study suggest that in patients carrying this electronic device should be preferred a specific modality of activation of the device as compared with the spontaneous electrical activity of the heart in order to improve the contractility of the cardiac walls.An improvement of myocardial contractility was observed during VDD pacing as compared with spontaneous rhythm in 6 patients with first-degree AVB after 24-48 h from Micra AV implantation

The Role of TOMM40 in Cardiovascular Mortality and Conduction Disorders: An Observational Study

Abstract: Aims: TOMM40 single nucleotide polymorphism (SNP) rs2075650 consists of allelic variation c.275-31A > G and it has been linked to Alzheimer disease, apolipoprotein and cholesterol levels and other risk factors. However, data on its role in cardiovascular disorders are lacking. The first aim of the study is to evaluate mortality according to TOMM40 genotype in a cohort of selected patients affected by advanced atherosclerosis. Second aim was to investigate the relationship between Xg and AA alleles and the presence of conduction disorders and implantation of defibrillator (ICD) or pacemaker (PM) in our cohort. Materials and Methods: We enrolled 276 patients (mean age 70.16 ± 7.96 years) affected by hemodynamic significant carotid stenosis and/or ischemia of the lower limbs of II or III stadium Fontaine. We divided the population into two groups according to the genotype (Xg and AA carriers). We evaluated several electrocardiographic and echocardiographic parameters, including heart rate, rhythm, presence of right and left bundle branch block (LBBB and RBBB), PR interval, QRS duration and morphology, QTc interval, and left ventricular ejection fraction (LVEF). We clinically followed these patients for 82.53 ± 30.02 months and we evaluated the incidence of cardiovascular events, number of deaths and PM/ICD implantations. Results: We did not find a difference in total mortality between Xg and AA carriers (16.3 % vs. 19.4%; p = 0.62). However, we found a higher mortality for fatal cardiovascular events in Xg carriers (8.2% vs. 4.4%; HR = 4.53, 95% CI 1.179–17.367; p = 0.04) with respect to AA carriers. We noted a higher percentage of LBBB in Xg carriers (10.2% vs. 3.1%, p = 0.027), which was statistically significant. Presence of right bundle branch block (RBBB) was also higher in Xg (10.2% vs. 4.4%, p = 0.10), but without reaching statistically significant difference compared to AA patients. We did not observe significant differences in heart rate, presence of sinus rhythm, number of device implantations, PR and QTc intervals, QRS duration and LVEF between the two groups. At the time of enrolment, we observed a tendency for device implant in Xg carriers at a younger age compared to AA carriers (58.50 ± 0.71 y vs. 72.14 ± 11.11 y, p = 0.10). During the follow-up, we noted no statistical difference for new device implantations in Xg respect to AA carriers (8.2% vs. 3.5%; HR = 2.384, 95% CI 0.718–7.922; p = 0.156). The tendency to implant Xg at a younger age compared to AA patients was confirmed during follow-up, but without reaching a significant difference(69.50 ± 2.89 y vs. 75.63 ± 8.35 y, p = 0.074). Finally, we pointed out that Xg carriers underwent device implantation 7.27 ± 4.43 years before AA (65.83 ± 6.11 years vs. 73.10 ± 10.39 years) and that difference reached a statistically significant difference (p = 0.049) when we considered all patients, from enrollment to follow-up. Conclusions: In our study we observed that TOMM40 Xg patients affected by advanced atherosclerosis have a higher incidence of developing fatal cardiovascular events, higher incidence of LBBB and an earlier age of PM or ICD implantations, as compared to AA carriers. Further studies will be needed to evaluate the genomic contribution of TOMM40 SNPs to cardiovascular deaths and cardiac conduction diseases