Francesca Vassanelli

Infarct transmurality as a criterion for first-line endo-epicardial substrate–guided ventricular tachycardia ablation in ischemic cardiomyopathy

BACKGROUND There is no consensus on the appropriate indications for the epicardial approach in substrate ablation of post-myocardial infarction (MI) ventricular tachycardia (VT). OBJECTIVE The purpose of this study was to investigate whether infarct transmurality (IT) could identify patients who would benefit from a combined first-line endo-epicardial approach. METHODS Before ablation, IT was assessed by contrast-enhanced cardiac magnetic resonance imaging (hyperenhancement ≥75% of the wall thickness in ≥1 segment), echocardiography (dyskinesia/akinesia + hyperrefringency + wall thinning), computed tomography (wall thinning), or scintigraphy (transmural necrosis). Prospectively from January 2011, an endocardial approach was used in patients with subendocardial MI (group 1) and a combined endo-epicardial approach in patients with transmural MI (group 2). Outcomes in both groups were compared with those in patients with transmural MI and only endocardial approach due to previous cardiac surgery or procedure performed before January 2011 (group 3). The primary end point was VT/ventricular fibrillation recurrence-free survival. RESULTS Ninety patients (92.2% men; mean age 67.4 ± 9.8 years) undergoing VT substrate ablation were included: group 1, n = 34; group 2, n = 24; group 3, n = 32. During a mean follow-up duration of 22.5 ± 13.7 months, 5 patients in group 1 (14.7%), 3 patients in group 2 (12.5%), and 13 patients in group 3 (40.6%) had VT recurrences (P = .011). Time to recurrence was the shortest in group 3 (log-rank, P = .018). The endocardial approach in patients with transmural MI was associated with an increased risk of recurrence (hazard ratio 4.01; 95% confidence interval 1.41-11.3; P = .009). CONCLUSION The endocardial approach in patients with transmural MI undergoing VT substrate ablation is associated with an increased risk of recurrence. IT may be a useful criterion for the selection of a first-line combined endo-epicardial approach.

Acute electrocardiographic differences between Takotsubo cardiomyopathy and anterior ST elevation myocardial infarction.

BACKGROUND The aim of this study was to compare ECG findings between anterior ST elevation myocardial infarction (STEMI) and Takotsubo cardiomyopathy (TC) in a similar sample of postmenopausal women. METHODS Between 2008 and 2011, 27 patients with TC were retrospectively enrolled and matched with 27 STEMI patients with the same age and sex taken from the prospective database of our laboratory. RESULTS The absence of abnormal Q waves, the ST depression in aVR and the lack of ST elevation in V1 were significantly associated with TC (respectively: 52% vs 18%, p=0.01; 47% vs 11%, p=0.01; 80% vs 41%, p=0.01). The combination of these ECG findings identified TC with a specificity of 95% and a positive predictive value of 85.7%. CONCLUSIONS The ECG on admission may be useful to distinguish TC from anterior STEMI. The combination of three ECG findings identifies patients with TC with high specificity and positive predictive value.

Myocardial infarction in a young patient with a previous history of repeated thrombophlebitis: combination of factor V Leiden and prothrombin G20210a gene polymorphisms with coronary artery disease

We report a case of myocardial infarction at a young age in a person with a medical history of repeated thrombophlebitis, who was heterozygous for the prothrombin G20210A mutation and homozygous for factor V Leiden mutation. A coronary angiography revealed the presence of a moderate atherosclerotic plaque (60%) in the left anterior descending coronary artery, which gave rise to suspicion of a relationship between prothrombotic gene mutations and atherosclerosis. Genetic screening for inherited thrombophilia, especially in the presence of a strong familiarity or previous venous thrombosis, and the evaluation of atherosclerotic risk factors, may be critical information for primary prevention of arterial thrombosis.

Substrate modification or ventricular tachycardia induction, mapping, and ablation as the first step? A randomized study

BACKGROUND The role and optimal sequence of ventricular tachycardia (VT) induction, mapping, and ablation when combined with substrate modification is unclear. OBJECTIVE The purpose of this study was to test the benefits of starting the scar-related VT ablation procedure with substrate modification vs the standard protocol of VT induction, mapping, and ablation as the first step. METHODS Forty-eight consecutive patients with structural heart disease and clinical VTs were randomized to simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction, mapping, and ablation followed by scar dechanneling (group 2, n = 24). Procedure and fluoroscopy times, the need for external cardioversion, acute results, and VT recurrence during follow-up were compared between groups. RESULTS Thirty-seven patients had ischemic cardiomyopathy, 10 nonischemic cardiomyopathy, and 1 arrhythmogenic cardiomyopathy. Before substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of group 2. Procedure time (209 ± 70 minutes vs 262 ± 63 minutes; P = .009), fluoroscopy time (14 ± 6 minutes vs 21± 9 minutes; P = .005), and electrical cardioversion (25% vs 54%; P = .039) were lower in group 1. After substrate ablation, 16 patients (66%) of group 1 and 12 patients (50%) of group 2 were noninducible (P = .242). End-procedure success (after residual inducible VT ablation) was achieved in 87.5% and 70.8% of patients, respectively (P = .155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank, P = .557). CONCLUSION VT induction and mapping before substrate ablation prolongs the procedure, radiation exposure, and the need for electrical cardioversion without improving acute results and long-term ablation outcomes.

Predicting the difficulty of a lead extraction procedure: the LED index.

Background According to recent surveys, many sites performing permanent lead extractions do not meet the minimum prerequisites concerning personnel training, procedures’ volume, or facility requirements. The current Heart Rhythm Society consensus on lead extractions suggests that patients should be referred to more experienced sites when a better outcome could be achieved. The purpose of this study was to develop a score aimed at predicting the difficulty of a lead extraction procedure through the analysis of a high-volume center database. This score could help to discriminate patients who should be sent to a referral site. Methods A total of 889 permanent leads were extracted from 469 patients. All procedures were performed from January 2009 to May 2012 by two expert electrophysiologists, at the University Hospital of Brescia. Factors influencing the difficulty of a procedure were assessed using a univariate and a multivariate logistic regression model. The fluoroscopy time of the procedure was taken as an index of difficulty. A Lead Extraction Difficulty (LED) score was defined, considering the strongest predictors. Results Overall, 873 of 889 (98.2%) leads were completely removed. Major complications were reported in one patient (0.2%) who manifested cardiac tamponade. Minor complications occurred in six (1.3%) patients. No deaths occurred. Median fluoroscopic time was 8.7 min (3.3–17.3). A procedure was classified as difficult when fluoroscopy time was more than 31.2 min [90th percentile (PCTL)]. At a univariate analysis, the number of extracted leads and years from implant were significantly associated with an increased risk of fluoroscopy time above 90th PCTL [odds ratio (OR) 1.51, 95% confidence interval (CI) 1.08–2.11, P = 0.01; and OR 1.19, 95% CI 1.12–1.25, P < 0.001, respectively). After adjusting for patient age and sex, and combining with other covariates potentially influencing the extraction procedure, a multivariate analysis confirmed a 71% increased risk of fluoroscopy time above 90th PCTL for each additional lead extracted (OR 1.71, 95% CI 1.06–2.77, P = 0.028) and a 23% increased risk for each year of lead age (OR 1.23, 95% CI 1.15–1.31, P < 0.001). Further nonindependent factors increasing the risk were the presence of active fixation leads and dual-coil implantable cardiac defibrillator leads. Conversely, vegetations significantly favored lead extraction. The LED score was defined as: number of extracted leads within a procedure + lead age (years from implant) + 1 if dual-coil – 1 if vegetation. The LED score independently predicted complex procedure (with fluoroscopic time >90th PCTL) both at univariate and multivariate analysis. A receiver-operating characteristic analysis showed an area under the curve of 0.81. A LED score greater than 10 could predict fluoroscopy time above 90th PCTL with a sensitivity of 78.3% and a specificity of 76.7%. Conclusion The LED score is easy to compute and potentially predicts fluoroscopy time above 90th PCTL with a relatively high accuracy.

Ablation of frequent PVC in patients meeting criteria for primary prevention ICD implant: Safety of withholding the implant

BACKGROUND Premature ventricular complex (PVC) ablation has been shown to improve left ventricular ejection fraction (LVEF) and New York Heart Association functional class in patients with left ventricular dysfunction. Both are considered key variables in predicting risk of sudden cardiac death. OBJECTIVE The objective of this study was to assess whether ablation might remove the primary prevention (PP) implantable cardioverter-defibrillator (ICD) indication in patients with frequent PVC. METHODS Sixty-six consecutive patients with PP-ICD indication and frequent PVC [33 (50%) men; mean age 53 ± 13 years; 11 (17%) with ischemic heart disease] underwent PVC ablation. The ICD was withheld and the indication was reevaluated at 6 and 12 months. RESULTS LVEF progressively improved from 28% ± 4% at baseline to 42% ± 12% at 12 months (P < .001). New York Heart Association functional class improved from 2 patients with NYHA functional class I (3%) at baseline to 35 (53%) at 12 months (P < .001). The brain natriuretic peptide level decreased from 246 ± 187 to 176 ± 380 pg/mL (P = .004). The PP-ICD indication was removed in 42 patients (64%) during follow-up, from 38 (92%) of them at 6 months, showing an independent association with baseline PVC burden and successful sustained ablation. In patients with successful sustained ablation, a cutoff value of 13% PVC burden had a sensitivity of 100% and a specificity of 93% (area under the curve 99%) for removing ICD indication postablation. No sudden cardiac deaths or malignant ventricular arrhythmias were observed. CONCLUSION In patients with frequent PVC and PP-ICD indication, ablation improves LVEF and, in most cases, allows removal of the indication. Withholding the ICD and reevaluating within 6 months of ablation seems to be a safe and appropriate strategy.

Multielectrode vs. point-by-point mapping for ventricular tachycardia substrate ablation: a randomized study

Aims Ventricular tachycardia (VT) substrate ablation is based on detailed electroanatomical maps (EAM). This study analyses whether high-density multielectrode mapping (MEM) is superior to conventional point-by-point mapping (PPM) in guiding VT substrate ablation procedures. Methods and results This was a randomized controlled study (NCT02083016). Twenty consecutive ischemic patients undergoing VT substrate ablation were randomized to either group A [n = 10; substrate mapping performed first by PPM (Navistar) and secondly by MEM (PentaRay) ablation guided by PPM] or group B [n = 10; substrate mapping performed first by MEM and second by PPM ablation guided by MEM]. Ablation was performed according to the scar-dechanneling technique. Late potential (LP) pairs were defined as a Navistar-LP and a PentaRay-LP located within a three-dimensional distance of ≤ 3 mm. Data obtained from EAM, procedure time, radiofrequency time, and post-ablation VT inducibility were compared between groups. Larger bipolar scar areas were obtained with MEM (55.7±31.7 vs. 50.5±26.6 cm2; P = 0.017). Substrate mapping time was similar with MEM (19.7±7.9 minutes) and PPM (25±9.2 minutes); P = 0.222. No differences were observed in the number of LPs identified within the scar by MEM vs. PPM (73±50 vs. 76±52 LPs per patient, respectively; P = 0.965). A total of 1104 LP pairs were analysed. Using PentaRay, far-field/LP ratio was significantly lower (0.58±0.4 vs. 1.64±1.1; P = 0.01) and radiofrequency time was shorter [median (interquartile range) 12 (7-20) vs. 22 (17-33) minutes; P = 0.023]. No differences were observed in VT inducibility after procedure. Conclusion MEM with PentaRay catheter provided better discrimination of LPs due to a lower sensitivity for far-field signals. Ablation guided by MEM was associated with a shorter radiofrequency time.

Predicting the difficulty of a transvenous lead extraction procedure: Validation of the LED index: BONTEMPI et al .

A lead extraction difficulty (LED) score was proposed to predict the difficult transvenous lead extraction (TLE) procedures, defined by means of the fluoroscopy time. The aim of this study was to validate the estimation model based on the LED index above 10 on an independent data set of TLE cases.

Tpeak-to-Tend/QT is an independent predictor of early ventricular arrhythmias and arrhythmic death in anterior ST elevation myocardial infarction patients

Background: The aim of our study was to analyse the markers of transmural dispersion of ventricular repolarization, especially Tpeak-to-Tend and Tpeak-to-Tend /QT ratio, in patients with anterior ST elevation myocardial infarction on admission and to evaluate their association with in-hospital life-threatening arrhythmias and mortality. Methods and results: A total of 223 consecutive patients with anterior wall ST elevation myocardial infarction admitted to our Division of Cardiology between January 2010 and December 2012 were prospectively evaluated. A standard electrocardiogram was obtained on admission and then analysed. The primary end point was constituted by in-hospital ventricular arrhythmias and arrhythmic death. At univariate analysis heart rate (odds ratio = 1.03; 95% confidence intervals 1.006-1.05; p=0.001), maximal ST elevation (odds ratio =1.25; 95% confidence intervals 1.10–1.43; p=0.0001), QTc Bazett (odds ratio = 1.01; 95% confidence intervals 1.006–1.02; p=0.002), QT dispersion (odds ratio = 1.02; 95% confidence intervals 1.002–1.04; p=0.02) and both Tpeak-to-Tend and Tpeak-to-Tend/QT (odds ratio = 1.02; 95% confidence intervals 1.01–1.03; p<0.0001 and OR = 1.07; 95% confidence intervals 1.03–1.11; p<0.0001 respectively) were significantly associated with ventricular arrhythmias and arrhythmic mortality. Of note, Tpeak-to-Tend /QT remained a predictor of early ventricular arrhythmias and arrhythmic death (odds ratio = 1.04; 95% confidence intervals 1.003 – 1.10; p=0.03) independently from heart rate and maximal ST elevation. Receiver operating characteristic curve analysis showed that Tpeak-to-Tend /QT values <0.31 had a predictive negative value of 92% for the prediction of the composite outcome. Conclusions: Tpeak-to-Tend /QT was an independent predictor of early ventricular arrhythmias and arrhythmic mortality in patients with anterior ST elevation myocardial infarction. Especially, Tpeak-to-Tend /QT <0.31 may identify a subgroup of ST elevation myocardial infarction patients with low risk of early arrhythmias and arrhythmic death.

Elucidation of hidden slow conduction by double ventricular extrastimuli: a method for further arrhythmic substrate identification in ventricular tachycardia ablation procedures

Aims Identification of local abnormal electrograms (EGMs) during ventricular tachycardia substrate ablation (VTSA) is challenging when they are hidden within the far-field signal. This study analyses whether the response to a double ventricular extrastimulus during substrate mapping could identify slow conducting areas that are hidden during sinus rhythm. Methods and results Consecutive patients (n = 37) undergoing VTSA were prospectively included. Bipolar EGMs with >3 deflections and duration <133 ms were considered as potential hidden slow conduction EGMs (HSC-EGM) if located within/surrounding the scar area. Whenever a potential HSC-EGM was identified, a double ventricular extrastimulus was delivered. If the local potential delayed, it was annotated as HSC-EGM. The incidence of HSC-EGM in core, border-zone, and normal-voltage regions was determined. Ablation was delivered at conducting channel entrances and HSC-EGMs. VT inducibility after VTSA obtained was compared with data from a historic control group. 2417 EGMs were analyzed. 575 (23.7%) qualified as potential HSC-EGM, and 198 of them were tagged as HSC-EGMs. Scars in patients with HSC-EGMs (n = 21, 56.7%) were smaller (35.424.7 vs 67.639.1 cm2; P = 0.006) and more heterogeneous (core/scar area ratio 0.250.2 vs 0.450.19; P = 0.02). 28.8% of HSC-EGMs were located in normal-voltage tissue; 81.3% were targeted for ablation. Patients undergoing VTSA incorporating HSC analysis needed less radiofrequency time (17.411 vs 2310.7 minutes; P = 0.016) and had a lower rate of VT inducibility after VTSA than the historic controls (24.3% vs 50%; P = 0.018). Conclusion Ventricular tachycardia substrate ablation incorporating HSC analysis allowed further arrhythmic substrate identification (especially in normal-voltage areas) and reduced RF time and VT inducibility after VTSA.