Programmed ventricular stimulation for predicting arrhythmic events in patients with myocardial infarction: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular ejection fraction (LVEF) is at present the main parameter used to guide the implantation of cardioverter-defibrillators (ICD) in patients with ischaemic cardiomyopathy. However, LVEF alone is a poor predictor of ventricular arrhythmias (VA) and sudden cardiac death (SCD). The majority of ICDs implanted for the primary prevention of SCD never deliver appropriate therapies, while being an expensive therapy and being potentially iatrogenic. Therefore, insertion of ICDs based solely on LVEF is not efficient and calls for an improvement in the risk-stratification of post-myocardial infarction patients. Inducibility of ventricular arrhythmias with programmed ventricular stimulation (PVS) has been used in the past to assess the risk of malignant arrhythmias. However, its current role in clinical practice is unknown.

Purpose

The aim of this meta-analysis was to study the role of PVS to predict future arrhythmic events in patients with previous myocardial infarction.

Methods

We performed a systematic review and a random-effect meta-analysis of studies reporting VAs –defined as SCD, sudden cardiac arrest, sustained monomorphic ventricular tachycardia (SMVT) or appropriate ICD therapies– after PVS in patients with ischaemic heart disease. Whenever possible, we used inducibility of SMVT as the positive response to PVS. Otherwise, we used the definition pre-specified in the corresponding study.

The primary outcome was to estimate the positive and negative predictive value (PPV and NPV, respectively) of PVS. Subgroup analyses were performed according to the PVS timing (<1 or ≥1 month after infarction), definition of a positive PVS, use of ICD, or study era (before or after 2000).

We searched in MEDLINE, EMBASE and Cochrane Library electronic databases up to November 2021.

Results

Thirty studies were included with a total of 8253 patients (mean age 58.5 years, mean LVEF 38.8%). A total of 909 arrhythmic events occurred after a mean follow-up of 24.5 months. Overall, 23% (95% confidence interval [CI] 18-29%) of subjects had inducible arrhythmias with PVS. Inducibility was associated with a higher risk of subsequent VAs (odds ratio 6.26, 95% CI 3.97-9.89, p<0.001). The pooled NPV was 95%, (95% CI 93-96%, p<0.001) and the PPV was 25% (95% CI 20-31%, p<0.001). There was significant heterogeneity between studies (I2 78% for the odds ratio, 96% for the NPV and 68% for the PPV). There were no statistically significant differences in any of the values according to the pre-specified subgroups. Meta-regression showed a reduction of the NPV with longer follow-up (B coefficient –0.033; p=0.012).

Conclusion

PVS has a high NPV (95%) and could be useful to rule out subjects at low risk of arrhythmic events. However, it decreases with longer follow-ups and, thus, the arrhythmic risk may need to be reassessed.

An electrocardiographic diagnostic model for differentiating right from left ventricular outflow tract arrythmias origin

Background/Introduction

Several ECG signs have been proposed to discern the focal origin of ventricular outflow tract arrhythmias with a transition ≥V3. Their independent predictive value is unclear.

Purpose

The aim of the study is to establish a predictive model of independent ECG parameters to obtain an acute success in right-sided catheter ablation of isolated premature ventricular contractions (PVCs) or ventricular tachycardia (VT) from the ventricular outflow tract with a transition ≥V3.

Methods

We included 122 patients (62 women, mean age 54±16 years) with documented PVCs or VT showing a lower axis and predominantly negative QRS complexes in V1 and V2 who underwent ablation between January 2014 and June 2020. The achievement of acute ablation success from right endocardial positions was assessed. We performed a predictive model by multivariate logistic regression analysis including the following ECG variables associated with a right origin of the ventricular focus in previous studies: Transitional Zone (TZ) index, V2 transition ratio, V2S / V3R index, R-wave duration index, R/S-wave amplitude index in V2, variable coupling interval, and the presence of QS morphology in lead I.

Results

Two independent predictive ECG variables were identified: the V2S / V3R index (odds ratio 1.223; 95% CI, 1.024–1.460; p=0.026) and a coupling interval variability >60 ms (odds ratio 0.307; 95% CI, 0.129 - 0.731; p=0.008). The area under the curve of this model was 0.733 (Picture 1). Arrhythmias with transition in V3 present a greater electroanatomic overlap and, therefore, a higher probability of right failure (59.3% vs 73.5% in arrhythmias with transitions after V3). In these, the V2 transition ratio is useful to predict the origin of the ectopy.

Conclusion

Two easily identifiable ECG variables (the V2S / V3R index and coupling interval variability >60 ms) predict the acute success of a right-sided approach in the ablation of focal ventricular arrhythmias with predominantly negative QRS complexes in V1 and V2.

Funding Acknowledgement

Type of funding sources: None. Predictive accuracy of the ECG model

Rotational activity presence and its impact in persistent atrial fibrillation follow-up

Introduction

Treatment of atrial fibrillation (AF) remains sub-optimal, with low success in pulmonary vein isolation (PVI) ablation procedures in long-standing-persistent AF patients. The maintenance mechanisms of AF are still under debate. Rotational activity (RA) events, also known as rotors, may play a role in perpetuating AF. The characterisation of these drivers during electroanatomical (EA) guided ablation procedures in relationship with follow-up and recurrence ratios in AF patients is necessary to design new ablation strategies to improve the AF treatment success.

Purpose

We report an AF patient cohort of endocardial mapping and PVI ablation procedures with additional RA events detected during the EA study. We aim to study the presence and distribution of RA in AF patients and its impact on AF recurrence when only PVI ablation is performed.

Methods

75 persistent consecutive AF patients (age 60.7±9.8, 74.7% men) underwent EA mapping and RA detection with an automatic algorithm. The presence of RA was annotated on the EA map based on the unipolar electrograms (EGMs) registered with a 20-pole catheter. RA presence was analysed at different left atrial locations (37.2±14.8 sites per patient). AF recurrence was evaluated in follow-up after treatment.

Results

At follow-up (9±5 months), 50% of the patients presented AF recurrence. Patients with RA had more dilated atria in terms of volumes (p=0.002) and areas (p=0.001). Patients with RA exhibited higher mean voltage EGMs 0.6±0.3 mV vs 0.5±0.2 mV (p=0.036), with shorter cycle lengths 169.1±26.0 ms vs. 188.4±44.2 ms (p=0.044). Finally, patients with RA presented more AF recurrence rates than patients with no RA events (p=0.007). No significant differences were found in terms of comorbidities, e.g., heart failure, hypertension, COPD, stroke, SHD, or diabetes mellitus.

Conclusions

The results show that patients with more RA events and those with RA outside the PVI ablated regions presented higher AF recurrence episodes than those with no RA or events inside the areas affected by radio-frequency ablation. The study suggests that further ablation treatment of the areas harboring RA might be necessary to reduce the recurrence ratio in AF patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III; Sociedad Española de Cardiología

Evaluation of atrial complexity of patients undergoing atrial fibrillation ablation: a clinical computational study

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Supported in part by the Instituto de Salud Carlos III (PI16/01123, DTS16/0160, PI17/010559, PI17/01106 and PI20/01618); Spanish Ministry of Science and Innovation (CIRBER CV); and cofound by FEDER: Fondo Europeo de Desarrollo Regional. EITHealth 19600 AFFINE.

Background

Pulmonary veins (PV) electrical isolation is the cornerstone of atrial fibrillation (AF treatment), but other proarrhythmic areas of the atria may trigger or sustain AF.

Objective

We used computer simulations to analyze AF complexity measured using non-invasive electrocardiographic imaging (ECGi).

Methods

We included 30 patients that underwent PVI. Personalized simulations using biatrial anatomies segmented from MRI images and an automata model for modeling the electrical activity were compared with ECGi results to evaluate the long-term outcome of AF ablation.

Results

Simulation maps closely correlated with the rotors histogram obtained from patients´ ECGi: high entropy areas from simulations matched the areas with higher density of rotor presence on the ECGi. Simulations revealed that successful ablations occurred in patients with rotors mainly located at the PV area, while unsuccessful ablations presented an increased number of high entropy foci, greater distribution of rotors along the atria and lower number of PV rotors. The number of rotors attached to the PV was significantly higher in patients with favorable long-term ablation outcome (1-year AF Freedom: 1.61 ± 0.21 vs. AF: 1.40 ± 0.20; p-value = 0.018).

Conclusion

This simulation approach could improve patient screening and ablation design prior to the intervention providing information of the complexity of the atria. Abstract Figure. Rotor maps, ACM and ACB for 3 patients

Predictors of pacemaker dependency in patients implanted with a pacemaker after Transaortic valve replacement

Introduction and objectives

The development of complete AV block and the need for pacemaker implantation (PM) is the most frequent complication after Transaortic valve replacement (TAVR). In other PM clinical contexts, a higher percentage of ventricular stimulation has been associated with worse prognosis. The objective was to study the existence of predictors of PM dependence.

Methods

We identified 96 consecutive patients who had received a PM post-TAVR (all Core-Valve). We retrospectively analyzed this cohort with the aim of identifying predictors of a high and very high percentage of ventricular pacing (VP), PM dependency and survival.

Results

The mean age was 82.3 years, with a mean logistic EuroSCORE of 17.1, 53% were women and 12% of patients had LVEF < 50%. The indication was complete AV block in 40.5%, and LBBB in 59.5%. Mean survival was 62.7 months, IQR [54.4-71]. The only independent predictor of mortality was the pre-TAVR logistic Euro-SCORE (RR = 1,026, p = 0.033), but not LVEF < 50%, VP > 50%, VP > 85% or PM dependence. In 73 patients PM rhythm was documented at the end of follow-up. Of these, 14 (19.2%) were considered dependent, and 37 (50.7%) presented VP > 50%. The post-TAVR complete AV block recovery rate was 67.8%. In multivariate analysis, female sex (HR = 5.6, p = 0.005), and indication of complete AV block vs. LBBB (HR = 15.7, p = 0.017) were independently associated with PM dependency.

Conclusions

Female sex and indication due to complete AV block were independent predictors of PM dependency during follow up. In our series of patients with mostly normal LVEF, a high percentage of stimulation does not influence prognosis.

Differential Responses of the Septal Ventricle and the Atrial Signals During Ongoing Entrainment: A Method to Differentiate Orthodromic Reciprocating Tachycardia Using Septal Accessory Pathways From Atypical Atrioventricular Nodal Reentry

BACKGROUND

Differential diagnosis between tachycardia mediated by septal accessory pathways (AP) and atypical atrioventricular nodal reentry can be challenging. We hypothesized that an immediate versus delayed pace-related advancement of the atrial electrogram, once the local septal parahisian ventricular electrogram (SVE) has been advanced, may help in this diagnosis.

METHODS AND RESULTS

We focused on differential timing between SVE and atrial signals at the initiation of continuous right ventricular apical pacing during tachycardia. SVE advancement preceding atrial reset was defined as SVE advanced by the paced wave fronts while atrial signal continued at the tachycardia cycle. We analyzed 51 atypical atrioventricular nodal reentry (45% posterior type) and 80 AP tachycardias (anteroseptal [10], parahisian [18], midseptal [12], and posteroseptal [40]). SVE advancement preceding atrial reset was observed in 98% of atrioventricular nodal reentries during 4±1.1 cycles; this phenomena was observed in 6 (8%) of the atrioventricular reentrant tachycardia mediated by septal AP (P<0.001; sensitivity 98%; specificity 93%; positive predictive value 90%; negative predictive value 99%) and lasted 1 single cycle (P<0.001). Right posteroseptal AP tachycardias were distinctly characterized by atrial reset preceding SVE advancement (with ventricular fusion; specificity 100%; positive predictive value 100%). In 11 cases, it was impossible to achieve sustain entrainment. In all of them, the differential responses at the entrainment attempt allowed for appropriate diagnosis.

CONCLUSIONS

The differential response of the SVE and the atrial electrogram at the initiation of continuous right ventricular apical pacing during tachycardia effectively distinguishes between atypical atrioventricular nodal reentry and atrioventricular reentrant tachycardia mediated by septal APs.

Tachycardia-Related Channel in the Scar Tissue in Patients With Sustained Monomorphic Ventricular Tachycardias

Background— Endocardial mapping before sustained monomorphic ventricular tachycardia (SMVT) induction may reduce mapping time during tachycardia and facilitate the ablation of unmappable VT.

Methods and Results— Left ventricular electroanatomic voltage maps obtained during right ventricular apex pacing in 26 patients with chronic myocardial infarction referred for VT ablation were analyzed to identify conducting channels (CCs) inside the scar tissue. A CC was defined by the presence of a corridor of consecutive electrograms differentiated by higher voltage amplitude than the surrounding area. The effect of different levels of voltage scar definition, from 0.5 to 0.1 mV, was analyzed. Twenty-three channels were identified in 20 patients. The majority of CCs were identified when the voltage scar definition was ≤0.2 mV. Electrograms with ≥2 components were recorded more frequently at the inner than at the entrance of CCs (100% versus 75%, P ≤0.01). The activation time of the latest component was longer at the inner than at the entrance of CCs (200±40 versus 164±53 ms, P ≤0.001). Pacing from these CCs gave rise to a long-stimulus QRS interval (110±49 ms). Radiofrequency lesion applied to CCs suppressed the inducibility in 88% of CC-related tachycardias. During a follow-up of 17±11 months, 23% of the patients experienced a VT recurrence.

Conclusions— CCs represent areas of slow conduction that can be identified in 75% of patients with SMVT. A tiered decreasing-voltage definition of the scar is critical for CC identification.