Atrial electromechanical conduction delay in patients with neurocardiogenic syncope

Left atrial function evaluation by 2D speckle-tracking echocardiography in patients with vasovagal syncope

OBJECTIVES

Evidence indicates left atrial (LA) involvement in vasovagal syncope (VVS). The LA regulates left ventricular filling during the cardiac cycle. We aimed to assess LA function in patients with VVS by 2D speckle-tracking echocardiography.

METHODS

Sixty-nine consecutive patients with VVS were recruited. Based on the head-up tilt test (HUTT) results, the study population was divided into two groups: HUTT+ (n = 45) and HUTT- (n = 24). Fifty-one consecutive subjects were enrolled as the control group. LA myocardial deformation parameters were measured by 2D speckle-tracking echocardiography to evaluate LA function.

RESULTS

Maximal, minimal, and pre-P LA volumes were lower in patients with VVS. Strain and strain rate during reservoir, conduit, and contraction phases in VVS patients with HUTT+ or HUTT- were not statistically significantly different from those in the control group. Additionally, the volumetric parameters of LA function showed no difference in statistical significance between the three study groups.

CONCLUSIONS

While LA phasic function was not different between the two groups of VVS patients with HUTT+ or HUTT- and the control group, LA size during the three LA phases was smaller in patients with VVS.

Evaluation of atrial fibrillation risk in patients with vasovagal syncope

BACKGROUND

This study aimed to determine whether autonomic dysfunction in patients with vasovagal syncope with a positive tilt test may cause an alteration in atrial electromechanical properties and pose a risk for subsequent atrial arrhythmias, especially atrial fibrillation.

METHODS

The data of 27 patients with vasovagal syncope and a matched control group comprising 28 healthy individuals were compared. All patients underwent a tilt table test. Atrial electromechanical intervals (PA) were measured from the mitral lateral annulus, mitral septal annulus, and tricuspid annulus with tissue Doppler imaging. Left atrium volumes were measured with the disc method in apical four-chamber imaging.

RESULTS

Although atrial electromechanical intervals such as lateral PA, septal PA, and tricuspid PA durations were significantly longer (p = 0.009, p = 0.002, p = 0.011, respectively), interatrial, right intra-atrial, and left intra-atrial durations were similar in the vasovagal syncope group and the control group (p = 0.298, p = 0.388, p = 0.069, respectively). Left atrial volumes (maximum, minimum, and presystolic) were significantly increased in the vasovagal syncope group when compared with the control group (p = 0.001, p = 0.001, p = 0.007, respectively). There was no difference between vasovagal syncope types in terms of atrial electromechanical intervals.

CONCLUSION

Interatrial and intra-atrial intervals were similar in the vasovagal syncope group and the control group. However, an increase in atrial volumes and a prolongation of certain atrial electromechanical intervals were observed in patients with vasovagal syncope. These findings suggest an alteration in atrial electromechanics caused by autonomic dysfunction that can lead to subsequent atrial arrhythmias, especially atrial fibrillation.

Novel functional advanced echocardiography for the assessment of myocardial mechanics in children with neurocardiogenic syncope - a blinded prospective speckle tracking head-up tilt-table challenge study

Background

Data on left ventricular (LV) function in patients with neurocardiogenic syncope (NS) is conflicting in adults and lacking in children. The aim of this study was to analyze LV myocardial performance in children with NS at rest and during head-up tilt-table (HUTT) testing.

Methods

This is the first study to combine HUTT and speckle-tracking echocardiography (STE) in children with NS. 43 consecutive normotensive pediatric patients with NS (mean age 13.9 ± 2.6 years, 51% female) and 41 sex- and age-matched healthy controls were included in the study. The study groups consisted of 21 patients with a positive HUTT reaction (HUTT+) and 22 with a negative HUTT reaction (HUTT-). STE was used to analyze peak systolic LV myocardial strain and strain rate.

Results

Conventional echocardiographic parameters were similar in all analyzed groups. When compared to healthy controls, children with NS had depressed levels of circumferential strain rate (p = 0.032) and significantly depressed longitudinal strain rate (p <  0.001) at rest. Interestingly, during HUTT testing LV global strain and strain rate were similar in both groups. LV strain rate was lowest in HUTT+ followed by HUTT- and control subjects both at rest and during HUTT.

Conclusions

Resting LV longitudinal strain rate is attenuated in children with NS, especially in those with a positive HUTT response. This is further evidence that NS patients feature altered cardiac mechanics rendering them prone to vasovagal perturbations that can ultimately result in collapse.

Trial registration

Witten/Herdecke University ethics committee clinical study number: UWH-73-2014.