SPC365

Assessment of wavefront propagation speed on the right ventricular outflow tract: deceleration zones associated with the presence of low voltage areas

Session: CO 16 - Morte Súbita
Speaker: Leonor Parreira

Congress: CPC 2021
Topic: C. Arrhythmias and Device Therapy
Theme: 04. Arrhythmias, General
Subtheme: 04.1 Arrhythmias, General – Pathophysiology and Mechanisms
Session Type: Comunicações Orais
FP Number: ---
Authors: Leonor Parreira; Pedro Carmo; Dinis Mesquita; Rita Marinheiro; Alexandra Gonçalves; Catalin Marinescu; Lia Marques; José Farinha; Ana Esteves; Pedro Amador; Artur Lopes; Marta Fonseca; Diogo Cavaco; Pedro Galvão Santos; Pedro Adragao

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Background and aims</span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">: Activation wavefront is rapid and uniform in normal myocardium. Fibrosis is associated&nbsp;&nbsp;</span></span></span></span><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">with deceleration zones (DZ) and late activated zones. The presence of low voltage areas (LVAs) in the right ventricular outflow tract (RVOT) of patients with premature ventricular contractions (PVCs) from this origin has&nbsp;</span></span></span></span><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">been described previously. The aim of this study was to evaluate in sinus rhythm, the RVOT endocardial activation duration (EAD) and the presence of DZs, in patients with PVCs and in controls.</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Methods:</span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif"> Consecutive patients with frequent (&gt;10.000/24 h) idiopathic PVCs with inferior axis subjected to 3D electroanatomical mapping and ablation and had an activation and voltage map of the RVOT performed in sinus rhythm. A control group of patients without PVCs that underwent ablation of supraventricular arrhythmias was also studied. Patients with structural heart disease, previous ablation or conduction disease were excluded. The RVOT EAD was measured as the time interval between the earliest and the latest activated region. Also evaluated the number of 10 ms isochrones throughout the RVOT and the maximal number of 10 ms isochrones within 1 cm, and a DZ was defined as a zone with&gt;3 isochrones within 1 cm radius. Low voltage areas (LVA) were defined as areas with local electrogram amplitude &lt;1.5 mV.</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Results:</span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">&nbsp;We studied 42 patients, 29 in the PVC group and 13 control subjects. The two groups did not differ in relation to age, gender and number of points in the map. The site of origin of the PVCs was the RVOT in 23 patients and the LVOT in 6. EAD and number of 10 ms isochrones in the RVOT were significantly higher in the PVC group, respectively 56 (41-66) ms vs 39 (35-41) ms, p=0.001 and 5 (4-6) vs 4 (4-4), p=0.037.&nbsp; Presence of LVAs and DZs were more frequent in the PVC group, respectively 21 (72%) vs 0 (0%), p&lt;0.0001 and 20 (69%) vs 0(0%), p&lt;0.0001. LVAs were more frequent in PVCs from the RVOT than from the LVOT (83% vs 33%, p=0.033). &nbsp;Patients with LVA had longer EAD 60 (52-67) vs 36 (34-40) ms, p&lt;0.0001 (Figure A) and more DZ than patients without LVA 95% vs 0%, p&lt;0.0001 (Figure B and C).</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif">Conclusions:</span></span></strong><span style="font-size:10.0pt"><span style="font-family:&quot;Times New Roman&quot;,serif"> The velocity of the wavefront propagation was slower and DZs were more frequently present in patients with PVCs and were associated with the presence of LVAs.</span></span></span></span></p>