Assessment of optimal thresholds for ventricular scar substrate characterization using the high density grid multipolar mapping catheter

Funding Acknowledgements

Type of funding sources: None.

Background

Voltage thresholds for ventricular scar definition are based on historic data collected using catheters with widely spaced bipoles in the absence of contact force. Modern multipolar mapping catheters employ smaller electrodes and interelectrode spacing that theoretically allows for mapping with increased resolution and reduced far-field electrogram (EGM) component. Despite the advancement in technology, historic cut-offs of <0.5mV for dense scar and 0.5-1.5mV for scar borderzone continue to be used in contemporary electrophysiology.

Purpose

We aimed to assess the optimal voltage cut-offs for ventricular scar substrate characterization using the HD Grid multipolar mapping catheter. Voltage cut-offs were assessed against cardiac MRI derived scar. We compared optimal voltage cut-offs using conventional bipolar sampling, the Best Duplicate Algorithm and with the HD wave solution plus best duplicate algorithm on.

Methods

A multicentre study of twenty patients undergoing VT ablation was conducted. Substrate mapping was performed using the high-density HD-grid multipolar mapping catheter. Bipolar voltage maps were co-registered with cardiac MRI obtained prior to the procedure to assess the voltage characteristics of scar defined by cardiac MRI (CMR) (Figure 1). Pre-procedure contrast enhanced CMR data were analysed using ADAS software (Galgo medical). Data points were collected in regions of scar during (1) HD wave mapping with best duplicate algorithm on(Waveon), (2) Mapping with HD wave off and best duplicate on (Waveoff) and (3) with conventional bipolar mapping (Alloff).

Results

The median bipolar voltage for regions of dense CMR scar using (Waveon) HD wave solution and best duplicate algorithm was 0.27mV (IQR 0.14 – 0.46). The median voltage with (Waveoff) HD wave off was 0.29mV (0.15 – 0.45). The median voltage with (Alloff) HD wave off and best duplicate off was 0.32mV (0.19 – 0.5). ROC analysis using AUC suggested the optimal cut-off for endocardial dense scar using (Waveon) HD wave mapping and best duplicate algorithm was 0.30mV (sensitivity: 69.6%, specificity: 60.74%), (Waveoff) cut-off with the best duplicate and without the HD wave mapping was 0.34mV (sensitivity: 69.78%, specificity: 64.46%) and (Alloff) without wave mapping or best duplication was 0.36mV (sensitivity: 84%, specificity: 52%) Figure 2.

Conclusion

Ventricular substrate characterization with newer mapping technology using narrow electrode spacing and smaller electrode size suggests that traditional voltage cut-offs may need revision for delineation of scar characteristics. Additionally, the ability to repeat sample in a region to obtain the best signal (Best Duplicate), and the ability to obviate the effect of wavefront direction using the HD wave solution omnipolar technology, may further increase the fidelity of scar characterization. This has important implications for mapping VT and characterizing channels in order to identify VT circuits.

Integration of structural and functional data in VT ablation -- SENSE2 protocol mapping

Funding Acknowledgements

Type of funding sources: None.

Background

We have previously developed the sense protocol functional substrate mapping technique for VT ablation(1). However, functional substrate characterizaiton can involve protracted mapping time.

Purpose

We incorporated the integration of MRI data using ADAS-3D software into the mapping workflow, to integrate structural mapping information into the functional mapping substrate characterization, in order to improve procedural efficiency.

Methods

CMRs were performed in 20 patients with ischemic related VT and VT therapy in the previous 6 months. These were processed with the ADAS-3D software to characterize the extent of ventricular scars and also ADAS corridors which may correlate with VT channels. Focused substrate maps were then performed in patients, guided by the extent of ADAS scar and corridors, looking at the scar substrate in intrinsic rhythm and then functional channels using single extra pacing from the RV at 20ms above ERP (SENSE2 Protocol). Specifically healthy areas 2cm beyond the scar borderzone based on ADAS were not mapped, in order to reduce substrate mapping time and complete geometries were not created. Following delineation of functional channels pacemapping and entrainment mapping were used to confirm targets for ablation.

The ADAS 3D MRI was integrated into the into the VT substrate map on Ensite-Precision with alignment to the aorta, RV and PA (Figure 1). We compared our data with previous functional mapping data without the integration of MRI.

Results

20 patients (age 70 years; 19 male subjects) underwent ablation. Mean EF 28%. Median procedure time was 161 minutes compared with 246 minutes (in our previous study)(p=<0.001) Mean substrate mapping time was 32 mins vs 63 mins (p=<0.001). Mean ablation time was 22 mins vs 32 mins (p=0.11). 85% (17 of 20) patients were free from symptomatic VT/ anti-tachycardia pacing or implantable cardioverter defibrillator shocks at a median follow-up of 171 days. The mean VT burden was reduced from 22 events per patient in the 6 months’ pre-ablation to 1 event per patient in the median follow up period of 171 days post ablation (p=0.02). Mean shocks per-patient burden decreased from 3.5 to 0.08 in the same time period(p=0.03).

Conclusion

The SENSE2 protocol involves the integration of structural and functional data into the VT workflow for substrate characterization. It enables focused substrate maps to be performed without the need for complete geometry to be created in large ventricles. Outcomes compare favourably with our previous data but with significantly shorter procedure times. This streamlined workflow has the potential to improve care in VT ablation by shortening procedure times with similar outcomes which may reduce risks for the patient.

Figure 1: Comparison of Voltage Map with MRI scar & corridors using ADAS

The role of marshall bundle epicardial connections in atrial tachycardias after atrial fibrillation ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial tachycardias (ATs) are often seen in the context of AF ablation.

Objectives

We evaluated the role of the Marshall bundle (MB) network in left atrial (LA) ATs using high-density high-spatial resolution 3D mapping.

Methods

199 post-AF ablation LA tachycardias were mapped in 140 consecutive patients (112 (80%) males, mean age: 61.8 years); 133 (66.8%) were macro-reentrant and 66 (33.2%) were scar-related re-entry. MB-dependent perimitral AT (PMAT) was diagnosed where the difference between the post pacing interval and the tachycardia cycle length (PPI-TCL) was <20ms in parts of the expected MB-dependent perimitral circuit (within the VOM, the ridge between the left pulmonary veins and LA appendage (LAA), the anterior LA and between 6- and 11-o’clock of the mitral annulus) and the PPI-TCL was >20ms in areas bypassed by the VOM (the distal coronary sinus (CS), the posterior LA and the mitral isthmus). MB-related re-entry was diagnosed by PPI-TCL <20ms at the left lateral ridge, posterior base of LAA, inferolateral LA or VOM ostium; and PPI-TCL >20ms in the septal annulus. Typically, in MB-dependent localized re-entry, the earliest activation was found along the MB-LA endocardial connection or MB-CS epicardial connection. 

Results

The MB network was found to participate in 60 (30.2%) re-entrant ATs, 31 PMATs and 29 localized re-entries. High-frequency multiphasic fragmented electrograms with long duration were often recorded endocardially or epicardially at the MB-LA or MB-CS connections. The amplitude and duration of these signals were 0.5 ± 0.79 mV and 65 ± 40 ms for MB-PMATs and 0.26 ± 0.28mV and 122 ± 67 ms for MB-localized re-entries. Unipolar EGMs at the site of endocardial-epicardial breakthrough had a rS pattern in all MB-related ATs. Of 60 MB-related ATs, 49 (81.6%) terminated with RF ablation, 44 (73.3%) at the MB-LA junction and 5 (8.3%) at the MB-CS junction, while 9 (15%) terminated after 2.5-5 cc of alcohol infusion inside the vein of Marshall (VOM). Of the 31 MB-related macroreentrant ATs, 17 (54.8%) terminated at the MB-LA junction, 5 (16.1%) at the MB-CS junction and 7 (22.6%) with alcohol infusion inside the VOM. Two macroreentries (6.5%) using the MB did not terminate with RF energy either endocardially at the MB-LA junction or epicardially at the MB-CS junction, and we were unable to identify or cannulate the VOM for ethanol infusion. Of the 29 localized re-entrant ATs using the MB, 27 (93.1%) terminated at the MB-LA junction, none terminated at the MB-CS junction and 2 (6.9%) terminated after alcohol infusion. After a mean follow up of 12 months, only 4 patients (6.7%) had AT recurrence.

Conclusions

MB re-entrant ATs accounted for up to 29% of the left ATs after AF ablation. Ablation of the MB-LA or CS-MB connections or alcohol infusion inside the VOM is required to treat these arrhythmias. Abstract Figure.

Safety of catheter ablation of AF without pre- or periprocedural imaging for the detection of LA thrombus

Funding Acknowledgements

Type of funding sources: None.

Background

The need for pre- or peri-procedural imaging to rule out the presence of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation (AF) is unclear in the era of uninterrupted direct oral anticoagulant (DOAC) regimen. We sought to examine the safety of catheter ablation in appropriately selected patients with paroxysmal AF without performing screening for left atrial thrombus.

Methods

Consecutive patients planned for radiofrequency AF catheter ablation between January 2016 and June 2020 were enrolled, and prospectively studied. All subjects were receiving uninterrupted anticoagulation with DOACs for at least 4 weeks before the procedure. All subjects were in sinus rhythm the day of the procedure. The primary outcome of the study was ischemic stroke or transient ischemic attack (TIA) during at 30 days.

Results

A total of 451 patients (age 59.7 ± 10.2 years, 289 males) with paroxysmal AF were included in the study. The mean CHA2DS2-VASc score was 1.4 ± 1.2. The mean left ventricular ejection fraction and left atrial diameter were 60 ± 5% and 39.3 ± 4 mm, respectively. Regarding the anticoagulation regimen, apixaban was used in 197 (43.6%) patients, rivaroxaban in 148 (32.8%) patients, and dabigatran in 106 (23.5%) patients. None of the patients developed clinical ischemic stroke or TIA during the 30-day post-discharged period.

Conclusions

Catheter ablation can be safely performed in low-risk patients with paroxysmal AF without imaging for the detection of left atrial thrombus in the era of uninterrupted DOAC anticoagulation.

Noninvasive risk factors for the prediction of inducibility on programmed ventricular stimulation in post-MI patients with ejection fraction over 40% at SCD risk, insights from the PRESERVE EF study

Funding Acknowledgements

Type of funding sources: None.

Background

Sudden cardiac arrest (SCA) in post myocardial infarction (post-MI) patients with a relatively preserved left ventricular systolic function (LVEF≥40%) has an annual incidence of 1%, in the absence of adequate risk stratification methods and guideline recommendations for primary prevention. In the PRESERVE-EF study we used a two-step SCA risk stratification approach to detect patients at risk for major arrhythmic events. Seven noninvasive risk factors (NIRFs) were extracted from ambulatory electrocardiography (AECG). Patients with at least one NIRF present were referred for invasive programmed ventricular stimulation (PVS). Inducible patients received an ICD.

Purpose

To assess the performance of NIRFs extracted from 24hr AECG, based on the PRESERVE EF criteria, in predicting inducibility.

Methods

The PRESERVE EF study enrolled 575 patients. Two hundred and four of them had at least one NIRF and an indication for PVS, but 52 of them declined. Finally, 41 out of 152 patients who underwent PVS were inducible. For the present analysis data from these 152 patients (mean age 60 ± 10years, LVEF 49 ± 6%, 89% males) were analyzed. Chi-square test, univariate logistic regression and areas under ROC curves were calculated for the PVS inducibility endpoint.

Results

Age, male gender and LVEF for the PVS inducible patients group (n = 41) and the noninducible patients group (n = 111) were, respectively: 61 ± 9years vs 59 ± 10years (p = 0.310), 98% vs 86% (p = 0.048), 45 ± 4% vs 51 ± 7% (p < 0.001). Among NIRFs examined, LVEF ≤ 50%, nsVT≥1/24hour and presence of LPs on SAECG presented high and significant Odds Ratios (ORs) for a positive PVS study end point. A simple risk score based on cutoff points of LVEF ≤ 50%, NSVTepisode≥1/24hour and presence of LPs missed only 1 out of the 41 inducible patients and yielded: OR 14.146 (p = 0.01) with a high sensitivity 98% but low specificity 26% for a positive PVS (AUC = 0.65).

Conclusion

Cut off points of LVEF ≤ 50%, nsVTepisode≥1/24hour and presence of LPs were important predictors of inducibility. A simple risk score based on these predictors achieves high sensitivity but low specificity.  The final decision for an ICD implantation should be based on a positive PVS, which is irreplaceable in risk stratification.

414 Ventricular-arterial interaction predicts response to cardiac resynchronization therapy: a link with improvement of endothelial function and arterial elastic properties

Background

Endothelial dysfunction (ED) is a hall mark of chronic heart failure and has been linked to disease progression, hospitalizations and mortality.

Purpose

to evaluate the impact of cardiac resynchronization therapy (CRT) in ED and to determine predictors of response to CRT

Methods

CRT recipients from 19/07/2016 until 19/10/2018 were studied at baseline and 3 months after. In each visit we evaluated a 12 lead ECG, carotid to femoral pulse wave velocity (cfPWV), flow-mediated dilatation of the brachial artery (FMD), left ventricle ejection fraction (LVEF) and left ventricle (LV) global longitudinal strain (GLS). We evaluated arterial elastance (Ea) to ventricular elastance (Ees) ratio (Ea/Ees) by echocardiography and the ratio of cfPWV to GLS, as valid markers of ventricular-arterial interaction. We also assessed the layer of endothelial glycocalyx by measurement of Perfused Boundary Region (PBR) of the sublingual microvessel range:5-25 microns.

Results

32 patients with a mean age 65.5 (±10.9) years and severe LV systolic dysfunction were enrolled. During follow-up, LVEF, GLS, LVESV and all ED markers exhibited significant improvement (table 1). 23 patients were responders. Among the baseline vascular function markers, only the ratio cfPWV/GLS predicted response to CRT (OR: 0.245, 95%CI: 0.042-0.759, p = 0.044).Threshold analysis showed that the best threshold of cfPWV/GLS for response to CRT was 2.75 (specificity: 0.67%, sensitivity: 0.94%).

Conclusions

After 3 months of CRT, endothelial function, arterial elasticity and ventricular arterial interaction are improved. The baseline ratio cfPWV/GLS, a novel marker of ventricular arterial interaction, can be applied to predict response to CRT.

table 1 Baseline Follow-up Change Measurement mean (sd) mean (sd) mean (sd) p-value SBP (mmHg) 126 (19) 128 (16) 2.18 (11.98) 0,465 DBP (mmHg) 79 (9) 80 (9) 1.06 (8.58) 0,618 LVEF (%) 27 (7) 35 (9) 7.50 (4.77) <0.001 LVESV (mL) 151 (42) 120 (46) -26.91 (17.20) <0.001 GLS (%) 6.47 (2.89) 9.33 (4.18) 2.85 (2.28) <0.001 FMD (%) 5.88 (2.79) 10.25 (3.67) 4.37 (3.34) <0.001 Ea/Ees 2.81 (1.10) 2.04 (0.99) -0.77 (0.47) <0.001 cfPWV 11.11 (2.61) 10.01 (2.45) -1.10 (1.56) 0,003 PBR 5-25(microns) 2.26 (0.20) 2.14 (0.24) -0.13 (0.25) 0,028 cfPWV/GLS 2.18 (1.46) 1.45 (1.11) -0.73 (0.55) <0.001 Measurements at baseline, follow-up and their change during study

Abstract 414 Figure. picture 1

The association of hematological indices with the response to cardiac resynchronization therapy: a single-center study

BACKGROUND

Cardiac resynchronization therapy (CRT) is an established therapeutic option for patients with heart failure (HF) and left ventricular ejection fraction (LVEF) ≤35 % who meet specific criteria according to current guidelines. However, up to 40 % of patients have no response to CRT. Our study aimed to investigate the association between different hematological and biochemical indices and response to CRT.

METHODS

Patients with HF due to ischemic or dilated cardiomyopathy referred to our hospital for CRT implantation from January 2013 to November 2017 were included in the study. Response to CRT was defined as an increase in LVEF ≥10 % or a decrease in left ventricular end-systolic volume (LVESV) ≥15 % at six months of follow-up.

RESULTS

A total of 48 patients (mean age: 66.2 ± 9.5 years, 81.3 % males) were included in the study. Of these HF patients, 29 (60.4 %) had ischemic cardiomyopathy, and 19 (39.6 %) had dilated cardiomyopathy. At six months of follow-up, 37 patients (77.1 %) had responded to CRT. Ten patients (20.8 %) had ventricular tachycardia (VT), 24 (50 %) patients were hospitalized, and two patients (4.2 %) died during the follow-up period. Multivariate analysis demonstrated that age (p =0.03) and creatinine levels (p =0.02) were independent predictors of the response to CRT. No significant associations between hematological markers (white blood cells, neutrophils, lymphocytes, platelets, neutrophil to lymphocyte ratio, red blood cells distribution width) and CRT response were observed.

CONCLUSIONS

A smaller increase in LVEF and a smaller decrease in LVESV were predictive for VT occurrence and hospitalizations in patients receiving CRT. No significant association between hematological markers and response to CRT was found. HIPPOKRATIA 2019, 23(3): 118-125.

Fractures of hamate: a clinical overview

Hamate fractures are exceedingly rare clinical entities. However, the diagnosis and treatment of these injuries are often delayed and can severely handicap the performance of affected laborers or athletes. This review focuses on fractures of the hamate and provides an update on the current consensus as to mechanism, diagnosis, management, and complications after such injuries.

Intermuscular implantation technique for subcutaneous cardioverter-defibrillators

BACKGROUND

The conventional technique for subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation has been associated with pocket complications. The aim of this study was to evaluate the efficacy and safety of an alternative intermuscular technique for S‑ICD implantation.

METHODS

S-ICDs were implanted in ten consecutive patients (ten males, mean age: 46.8 ± 14.7 years). The pocket for the pulse generator was made above the serratus anterior muscular fascia and beneath the latissimus dorsi muscle by detaching the fibrous tissue between the muscles. Electrode implantation was performed using the three- (n = 4) or the two-incision technique (n = 6).

RESULTS

All S‑ICDs were successfully implanted in the absence of any procedure-related complications with a successful 65-J standard polarity defibrillation threshold testing, apart from one patient with Brugada syndrome who needed device repositioning more dorsally. During a mean follow-up of 16.5 ± 7.3 months, no major complications requiring surgical repair were encountered, while patients demonstrated high levels of comfort and satisfaction with the cosmetic result. One patient experienced an inappropriate shock due to noise detection, which was resolved after reprogramming to a different sensing vector.

CONCLUSION

The intermuscular technique is a safe and efficacious approach for S‑ICD implantation. This technique could lead to fewer pocket-related complications and better cosmetic results.

Multicystic nephroma in an elderly man. Case report

Multicystic nephroma is a relatively rare tumor of the kidney presenting unclear histological origin. Abdominal mass is a common onset sign in children while abdominal flank pain or abdominal discomfort, hematuria and recurrent urinary tract infections usually affect adults. Preoperative diagnosis is impossible especially in the adult variant of the tumor where clear cells carcinoma with cystic degeneration must always be suspected. We herein report a case of a 77 year old man complaining of flank abdominal pain and recurrent episodes of urinary tract infection due to a right-sided multicystic nephroma successfully treated with nephrectomy.

Stercoral perforation of the sigmoid colon. A case report and brief review of the literature

Stercoral perforation of the colon due to fecaloma is a rare disease and less than 100 cases have been described in the literature. The disease mainly involves the rectosigmoid colon. The condition is correlated with longstanding decubitus, chronic constipation, abuse of laxatives and/or constipating agents (anticholinergics, neuroleptics, etc). We report a case of 82-year old woman who presented a covered colonic perforation due to fecaloma, related with a history of longstanding decubitus because of senile dementia, chronic constipation and use of anticholinergic drugs.

Seasonality of violent suicides in the Athens greater area

The aim of the study was to ascertain suicide seasonality in the Greek population and to associate this seasonal variation with age, sex, and suicide method. Studying seasonality can be of help in establishing a public health policy, related with suicide prevention. This is an epidemiologic study based on forensic evidence. We studied the deaths caused by self-injury (trauma), namely deaths by violent suicide (not self-poisoning). Statistically significant suicide seasonality was established with a peak in May. This seasonal variation is attributed mainly to males. As for the method, suicide by hanging peaks in June and by shooting in April. It was also observed that seasonality for individuals above the age of 45 peaks in early May.

20-GHz broadly tunable and stable mode-locked semiconductor amplifier fiber ring laser

We present an actively mode-locked fiber ring laser that uses a single active semiconductor optical amplifier device to provide both gain and gain modulation from an external optical pulse train. The laser source generated 4.3-ps pulses at 20 GHz over a 16-nm tuning range and is stable against environmental changes and simple to build.

Optical clock repetition-rate multiplier for high-speed digital optical logic circuits

Repetition-rate multiplication has been shown by use of a fiber ring oscillator with a semiconductor optical amplifier as the gain medium and by use of fast saturation and recovery of the amplifier from an external optical pulse train. Repetition-frequency multiplication up to 6 times and up to 34.68-GHz frequency have been achieved.

Increased frequency of HLA B17 antigen in girls with Turner syndrome and their fathers

HLA-A, -B and -DR antigen distribution was studied in 49 girls with Turner Syndrome (TS), in 43 of their parents, as well as in 433 controls. No increased frequency of DR3, DR4 was found in our group. However, an increased frequency of HLA B17 antigen was disclosed (18.3% in TS versus 6.4% in the controls, p < 0.001 and pc < 0.01). Furthermore, the HLA B17 antigen was of paternal origin in 77.7% of the cases. The interpretation of the present findings is quite difficult. Most likely, the findings are related to the chromosomal abnormality rather than to autoimmunity. It is quite possible that genes within the region of class I genes create unfavorable circumstances leading to the loss of the sex chromosome or, alternatively, genes in this region confer protection and prevent miscarriage of the affected fetus.

Hexamethylmelamine as second-line therapy in platin-resistant ovarian cancer

A total of 61 patients with recurrent or persistent clinically measurable platin-resistant epithelial ovarian carcinoma were treated with 260 mg/m2 oral hexamethylmelamine daily for 14 days, repeated at 4-week intervals. Platin resistance was defined as progression or stable disease during cis- or carboplatin treatment (used alone or in combination with other drugs), or relapse within 6 months after the end of that therapy. Fifty patients were evaluable for response and 57 for toxicity. The objective response rate was 14% (3 complete and 4 partial responses). The response rate was higher in patients with relapse within 6 months than in patients with progression or stable disease on platin-based therapy. This observation underscores the importance of defining response and time to progression after first-line chemotherapy. The median duration of response was 8 months and the median survival in responding patients was 9+ months versus 5 months for patients with progression on hexamethylmelamine. Nausea and vomiting requiring antiemetic treatment occurred in 8 (14%) patients and reversible peripheral neuropathy in 3 patients. Two patients developed agitation, insomnia, and depression during hexamethylmelamine therapy. In conclusion, the 14% objective response rate and the occurrence of complete responses with oral hexamethylmelamine treatment in a group of ovarian cancer patients with true platin resistance are noteworthy.