Clin Res Cardiol (2021). 10.1007/s00392-021-01933-9

Long Term Follow Up from 2008-2021of Patient Characteristics, ECG Documentation, Scar Characteristics and Ablation strategy on Ablation Success for VT storm
A. Margkarian1, A. I. Khan2, F. Hasan2, V. Mkrtchyan2, H. Bogossian1, B. Lemke3, M. Zarse1
1Institut für Gesundheitssystemforschung, Universität Witten/Herdecke gGmbH, Witten; 2Innere III - Klinik für Kardiologie, Elektrophysiologie und Angiologie, Märkische Kliniken GmbH, Lüdenscheid; 3Märkische Kliniken GmbH, Lüdenscheid;
Introduction: Electrical storm (ES) is a life threatening condition. In our long term follow up  we analyze conditions on their prognostic relevance for long term outcome after ablation 
Methods:In our study we included 160 cases of electrical storm undergoing ventricular ablation by electro-anatomical mapping (139 m/21 f) with a mean age of 68.1 ± 9.9 between 2008 and 2019 and an observation period between 2008 and 2021. During the follow-up visits we reported several tachycardia endpoints. Initially we employed electroanatomical mapping focussing on an exit strategy. With time we used an entrance strategy. We differentiated between anterior, posterior, or lateral scar localization.  At the end of the procedure we performed programmed electrical stimulation with up to four extrastimuli in 110/160 patients.
Results:

Patients (P) suffered from ischemic or non-ischemic heart disease 118 and 42 P, respectively. Most P displayed a severely depressed mean ejection fraction of 30.6 ± 10.6 ranging from 10% to 65%. Most of the P had been on treatment with Class I (n=14), class II (n=136) and class III (n=87) or other (n=10) antiarrhythmic medication. Due to the severity of the underlying disease 40 P died within the observation period after a mean of 16.6 ± 16.1 months) ranging from 0 days to 68 months. None of the P died as a consequence of periprocedural complications but mostly from low output despite successful restoration of underlying basic rhythm. 80 P survived the observation period up to 2021 with a mean follow-up of maximal 80.4 months. Most P with ES were male (139 male vs 21 female) but there were no gender differences in any endpoints. Comparing patients ≥ 70 years with those < 70 years (n=87 range 35.5 to 69.9 years) we saw, as expected, a significant increase in exitus letalis (25/73 vs. 15/87, p=0.007). without differences in the other endpoints.   Ablation success was controlled via programmed electrical stimulation. Non/inducibility of VT after ablation proved to be the most significant prognostic factor for long term success. They had significantly less NSVT (23/110, 20.9% vs. 5/50, 10%, p=0,046), ATPs (20/110, 18.1% vs. 4/50, 8%, p= 0,047), VT storm (39/110, 35.4% vs. 11/50, 22%, p=0,45) and hospitalization (36/110, 32.7% vs. 14/50, 28%, p=0,034). Although we strongly aimed at obtaining a 12 lead ECG in all cases of VT storm in 59/160 patients we did not obtain a 12 lead ECG and had to rely on ICD documentation. Interestingly ablation outcome of patients with documented VT was not superior to those without documentation. Inducing VTs during the ablation procedure by electromechanical feedback of the mapping catheter proved to be Signum malum for ablation success. Three or more induced VTs proved to be a prognostic sign for increased probability of future VT storms (p=0.04). Neither total encircling of the scar nor additional linear lesions improved ablation outcome of the exit strategy in any of the determined endpoints. Aiming at the entrance of the reentry, however, via long/stimulus/QRS interval (38/99, 38.3% vs. 12/61, 19,6%, P=0,007) or mid diastolic potentials significantly improved ablation outcome (37/100, 37% vs. 13/60, 13%, p=0,02).

Conclusions: Ablation of ES is feasible also in very old people and without 12 lead ECG documentation. Non-inducibilty improves, initial induction of > 3 VT morpholgies worsens prognosis for future ES. Not scar localization, but ablation strategy impact ablation success. 

 


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