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Review
. 2021 Aug 6;57(8):808.
doi: 10.3390/medicina57080808.

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope

Călina-Patricia Țentea  1   2 , Csilla-Andrea Eötvös  2   3 , Roxana-Daiana Lazar  1   2 , Giorgia Paștiu  1   2 , Iulia-Georgiana Zehan  1   2 , Mihai Gabriel Andrei  1   2 , Adriana Porca  1   2 , Mihaela Jelnean  1   2 , Roxana Mihaela Chiorescu  1   2 , Larisa-Diana Mocan-Hognogi  1   2 , Sorin Pop  1 , Dan Blendea  1   2
Affiliations
Review

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope

Călina-Patricia Țentea et al. Medicina (Kaunas). .

Abstract

The baseline electrocardiogram (ECG) is less informative in neurally mediated syncope (NMS) than in arrhythmic syncope. However, some of the ECG patterns present in NMS can have diagnostic and prognostic value in such patients. Electrocardiographic documentation of a syncopal spell and thus identification of the ECG changes can be performed during tilt table test (TTT) or during prolonged ECG monitoring. This work reviews the specific ECG patterns in NMS, which are primarily related to the cardioinhibitory reflex. In addition, there are other ECG findings present in patients with NMS that are being analyzed, such as increased heart rate variability as well as specific QRS voltage patterns. In addition to the diagnostic and prognostic value, these ECG patterns in NMS may help improving the selection of patients for pacemaker implant.

Keywords: cardioinhibitory reflex; electrocardiogram; neurally mediated syncope.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Pathophysiology in neurally mediated syncope. LV = left ventricle, SN = sinus note, AV = atrioventricular, AVN = atrioventricular node.
Figure 2
Figure 2
Implantable loop recorder tracing revealing cardioinhibitory response during presyncope in a patient with neurally mediated syncope.
Figure 3
Figure 3
Cardioinhibitory response recorded on telemetry in a patient with neurally mediated syncope. Progressive slowing of sinus rate and first-degree atrioventricular (AV) block (panel (A)), and two episodes of second-degree AV block (panels (B,C)). The association of sinus bradycardia and different types of AV block is highly suggestive for a vagal mechanism for syncope.
Figure 4
Figure 4
Example of cardioinhibitory response captured on electrocardiogram in neurally mediated syncope: the inhibitory effect of vagus stimulation on the sinus node results in progressive bradycardia, followed by asystole without P-waves and acceleration of the sinus rhythm in the second part of the tracing.
Figure 5
Figure 5
Isolated very low QRS voltage in frontal plane leads (red arrowhead).
Figure 6
Figure 6
Examples of flat vectorcardiographic loops in the frontal plane in three patients with neurally mediated syncope—top panel. Vectorcardiographic loops in the frontal plane in three subjects with no history of syncope—bottom panel.
See this image and copyright information in PMC

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