Comparison of Preoperative ECG Screening and Device-Based Vector Analysis in Patients Receiving a Subcutaneous Implantable Cardioverter-Defibrillator

Background and Objectives: Subcutaneous implantable cardioverter-defibrillators (S-ICDs) provide protection against sudden cardiac death from outside the cardiovascular system. ECG screening is a prerequisite for implantation, but the reproducibility of its results post-operatively in the device is only partial. We aimed to compare the results of ECG screening with device-based sensing vector analysis. Materials and Methods: We screened the hospital records of all S-ICD recipients in our clinic. All of them had pre-operative ECG screening performed (primary, secondary, and alternate vectors). The results were compared with device-based vector analysis to determine the relation of the pre- and post-operative vector availability. Results: Complete ECG screening and device-based vector analysis were obtained for 103 patients. At least two acceptable vectors were found in 97.1% of the patients pre-operatively and in 96.1% post-operatively. When comparing vectors in terms of agreement (OK or FAIL) pre- and post-operatively, in 89.3% of the patients, the result for the primary vector was the same in both situations; for the secondary, it was in 84.5%, and for the alternate, it was in 74.8% of patients, respectively. In 55.3% of patients, all three vectors were labeled the same (OK or FAIL); in 37.9%, two vectors had the same result, and in 6.8%, only one vector had the same result pre- and post-operatively. The number of available vectors was the same pre- and post-operatively in 62.1% of patients, while in 15.5%, it was lower, and in 22.3% of patients, it was higher than observed during screening. Conclusions: Routine clinical pre-operative screening allowed for a good selection of candidates for S-ICD implantation. All patients had at least one vector available post-operatively. The final number of vectors available in the device-based analysis in most patients was at least the same (or higher) than during screening. The repeatability of the positive result for a single vector was high.

How likely is the sense-B-noise to affect patients with subcutaneous implantable cardioverter-defibrillators and can we solve that problem in every case?

BACKGROUND

Sense-B-noise is a newly reported possible cause of inappropriate shocks in patients with subcutaneous implantable cardioverter-defibrillators (S-ICDs). The nature of that noise is unknown, it is not related to mechanical failure of the S-ICD system. Reprogramming to the secondary sensing vector is suggested by the producer as a possible solution.

METHODS

We analyzed the medical records of S-ICD recipients from two university clinical centers (Gdansk and Szczecin, Poland). Our aim was to determine the rate of sense-B-noise, and whether the secondary sensing vector would be available for reprogramming if such a problem occurred in our patients.

RESULTS

The sense-B-noise issue affected three patients in our cohort (3%), which corresponds to the incidence of 0.012 events per patient-year of follow-up. The primary vector was permanently used in 47 patients (52%), secondary in 28 (31%), and alternate in 16 (17%), respectively. Therefore, the total number of patients potentially vulnerable to sense-B noise (with the primary or alternate vector programmed permanently) was 63 (69%). Among those 63 patients, 51 individuals (81%) had also the secondary vector available for permanent use.

CONCLUSION

The sense-B-noise affected 3% of patients in our cohort, with an incidence of 0.012 per patient-year of follow-up. Most patients potentially vulnerable to sense-B noise could be reprogrammed to the secondary sensing vector, if necessary. Further investigation of the sense-B-noise issue is needed.

Application of Novel Technologies in Cardiac Electrotherapy to Prevent Complications

(1) Background: Cardiac electrotherapy is developing quickly, which implies that it will face a higher number of complications, with cardiac device-related infective endocarditis (CDRIE) being the most frequent, but not the only one. (2) Methods: This is a retrospective case study followed by a literature review, which presents a patient with a rare but dangerous complication of electrotherapy, which could have been prevented if modern technology had been used. (3) Results: A 34-year-old female was admitted with suspicion of CDRIE based on an unclear echocardiographic presentation. However, with no signs of infection, that diagnosis was not confirmed, though an endocardial implantable cardioverter-defibrillator (ICD) lead was found folded into the pulmonary trunk. The final treatment included transvenous lead extraction (TLE) and subcutaneous ICD (S-ICD) implantation. (4) Conclusions: With the increasing number of implantations of cardiac electronic devices and their consequences, a high index of suspicion among clinicians is required. The entity of the clinical picture must be thoroughly considered, and various diagnostic tools should be applied. Lead dislocation into the pulmonary trunk is an extremely rare complication. Our findings align with the available literature data, where asymptomatic cases are usually effectively treated with TLE. Modern technologies, such as S-ICD, can effectively prevent lead-related problems and are indicated in young patients necessitating long-term ICD therapy.

Left Ventricle Segmental Longitudinal Strain and Regional Myocardial Work Index Could Help Determine Mitral Valve Prolapse Patients with Increased Risk of Ventricular Arrhythmias

Mitral valve prolapse (MVP) could associate with malignant ventricular arrhythmias (VAs). Mitral annular disjunction, a putative mechanism for an arrhythmic substrate, leads to excessive mobility, stretch, and damage of some segments. Speckle tracking echocardiography (STE), with particular attention to the segmental longitudinal strain and myocardial work index (MWI), could be an indicator of the segments we aimed to check. Seventy-two MVP patients and twenty controls underwent echocardiography. Complex VAs documented prospectively after the enrollment was qualified as the primary endpoint, which was noticed in 29 (40%) patients. Pre-specified cut-off values for peak segmental longitudinal strain (PSS) and segmental MWI for basal lateral (-25%, 2200 mmHg%), mid-lateral (-25%, 2500 mmHg%), mid-posterior (-25%, 2400 mmHg%), and mid-inferior (-23%, 2400 mmHg%) segments were accurate predictors of complex VAs. A combination of PSS and MWI increased the probability of the endpoint, reaching the highest predictive value for the basal lateral segment: odds ratio 32.15 (3.78-273.8), p < 0.001 for PSS ≥ -25% and MWI ≥ 2200 mmHg%. STE may be a valuable tool for assessing the arrhythmic risk in MVP patients. Excessively increased segmental longitudinal strain with an augmented regional myocardial work index identifies patients with the highest risk of complex VAs.

Association between the geographic region and the risk of familial atrioventricular nodal reentrant tachycardia in the Polish population

INTRODUCTION Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common regular supraventricular arrhythmias referred for catheter ablation (CA). In Poland, several families with familial AVNRT (FAVNRT) were reported in Podkarpacie Province (PP). OBJECTIVES We aimed to determine the frequency of FAVNRT in PP compared with other south‑eastern provinces of Poland. PATIENTS AND METHODS Clinical data of 1544 patients with AVNRT diagnosed by invasive electrophysi-ological study between 2010 and 2019 were screened for FAVNRT. From January 2017 to June 2019, patients were asked to provide details on family history and origin to obtain 3‑generation pedigrees. Families with at least 2 members with previous CA of AVNRT were divided into those from south‑eastern provinces (SEPs; including PP and bordering provinces [BPs]) and the remaining parts of Poland (RPP). RESULTS There were 932 patients from SEPs and 612 from RPP. FAVNRT was reported in 45 patients (2.91%) from 27 families, with a higher frequency in SEPs than RPP (4.02% vs 1.17%; P = 0.002) and the highest frequency in PP (6.33% vs 2.47% in BPs; P = 0.004). The risk of FAVNRT was higher in PP compared with BPs (odds ratio, 2.67; 95% CI, 1.36-5.23; P = 0.004) and similar in BPs compared with RPP (odds ratio, 2.14; 95% CI, 0.86-5.34; P = 0.1). CONCLUSIONS A relationship exists between the geographic region and frequency of FAVNRT. A greater distance from PP was associated with less frequent FAVNRT. International cooperation and genetic test-ing are needed to confirm the genetic impact of FAVNRT in this part of Central Europe.

Segmental longitudinal strain as the most accurate predictor of the patchy pattern late gadolinium enhancement in hypertrophic cardiomyopathy

BACKGROUND

The prognostic value of myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM) has been well-established. Although cardiac magnetic resonance (CMR) is the method of choice in its revealing as the presence of late gadolinium enhancement (LGE), this technique still has limited availability in daily clinical practice. Two-dimensional speckle tracking echocardiography (2D STE) seems to be helpful in verification which HCM patient has the highest probability of LGE presence and hence needs to be qualified to CMR. While the majority of HCM patients have a patchy pattern of myocardial fibrosis, the aim of this study was to evaluate whether segmental rather than global longitudinal strain is more accurate in the identification of the presence of LGE.

METHODS

Forty-six HCM patients had transthoracic echocardiography and CMR imaging performed. Each patient had global longitudinal strain and rotation parameters calculated, as well as segmental analyses for wall thickness, longitudinal strain, and LGE presence based on 736 segments of the left ventricle (LV). The presence of LGE in CMR was confirmed on a per-segment basis, which was similar to LV segments in the echocardiographic examination. All patients were divided into two groups according to the CMR result: LGE (+) and LGE (-).

RESULTS

Receiver-operating characteristic analyses identified peak global longitudinal strain and peak twisting velocity with the cut-off values -14.4% and 116°/s respectively as the accurate predictors of LGE presence in CMR, whereas segmental longitudinal strain of -12.5% cut-off value had the highest area under the curve value (87.4%, confidence interval 84.5-90.3%), with 93.7% sensitivity, 86.5% negative predictive value, and 55% specificity.

CONCLUSIONS

Segmental longitudinal strain with the cut-off value of -12.5% has the highest discriminatory power for LGE presence and seems to be more adequate than global speckle tracking parameters in identification of HCM patients with strong indications for CMR for more accurate risk stratification.

P1464A question of gender equality. Sex-related differences in survival after primary prevention implantable cardioverter-defibrillator implantation for dilated cardiomyopathy An analysis from POLKARD

OnBehalf

POLKARD Polish ICD Registry

Background

The protective effects of implantable cardioverter defibrillators (ICDs) in the primary prevention of sudden cardiac death of patients presenting with left ventricular (LV) systolic dysfunction are unequivocal. Nevertheless, female underrepresentation has been a consistent finding in all randomized controlled primary prevention ICD trials. Surprisingly, there is a vast body of literature on female primary prevention ICD patients exhibit a lower overall mortality.

Purpose

Therefore, we analyzed data from a large, nationwide POLKARD registry to evaluate the effect of sex on survival after primary prevention cardioverter-defibrillator implantation for dilated cardiomyopathy.

Methods

All patients enrolled in the Polish ICD Registry from 2008 to 2014 were identified. Patients were included in the study if they were designated as receiving an ICD for primary prevention of SCD after documented non-ischeamic cardiomyopathy. Kaplan-Meier survival analysis was used to assess all-cause mortality.

Results

Of the 964 ICD recipients, 241 (25%) were women (mean age of 64± 0,45 years). During a mean follow-up of 5,53 ± 2,48 years 32% of women and 42% of men died. Kaplan-Meier curve depicted a significantly lower mortality for women than for men (p = 0,05). The median survival time was 6,73 years (55 deaths per 1000 person-years) versus 6,37 years (78 deaths per 1000 person-years) for women and men, respectively.

Conclusions

In agreement with previous studies, our data indicate that primary prevention implantation rates for dilated cardiomyopathy are lower in women. However, the reasons are not entirely understood.

P1463Regional variation in survival rates among primary prevention implantable cardioverter-defibrillator recipients in Eastern and Northern Europe POLKARD Polish ICD Registry perspective

Funding Acknowledgements

None.

OnBehalf

POLKARD Polish ICD Registry

Objective

The findings of Danish Study to assess the efficiency of ICD in patients with non ischemic heart failure has recently raised questions about the current strategy of ICD implantation for the primary prevention of sudden cardiac death. POLKARD - Polish ICD Registry is a prospective, non-randomised, central registry of patients who are referred for an implantation of an ICD in Poland. The Registry contains prospectively collected follow-up data including mortality.

Purpose

To compare survival rates between Polish and Danish ‘real-world’ non-ischemic primary prevention cohorts.

Methods

Retrospective analysis of clinical characteristics and long-term follow-up of patients referred for primary prophylactic implantable cardioverter defibrillator (ICD) implantation in Poland between April 2008 and November 2014 was performed. The primary outcome of the trial was all-cause mortality. Results: The polish study cohort was large (964) as compared to Danish population randomized to receive ICD therapy (556). The median follow-up time in DANISH Study and Polish ICD Registry was 67,6 and 77 months, respectively. Compared with patients enrolled in the DANISH Study, patients in the Polish ICD Registry were age-similar. However, the polish study population was male-dominated. What is more, male gender was identified as a risk factor for long-term mortality in polish study population (p = 0.005). In the matched cohorts, there was difference in survival between DANISH Study and Polish ICD Registry patients (all-cause mortality rates: 21,6% - 44 events per 1000 person-years and 39,3% - 72 events per 1000 person-years, respectively).

Conclusions

Our findings imply that survival among patients who receive a primary prevention ICD for non-ischemic cardiomyopathy in clinical practice in Central Europe is different from Northern Europe.

Implantable cardioverter-defibrillators in patients with long QT syndrome: a multicentre study

BACKGROUND

Implantable cardioverter-defibrillator (ICD) therapy has been proven effective in the prevention of sudden cardiac death, but data on outcomes of ICD therapy in the young and otherwise healthy patients with long QT syndrome (LQTS) are limited.

AIM

We sought to collect data on appropriate and inappropriate ICD discharges, risk factors, and ICD-related complications.

METHODS

All LQTS patients implanted with an ICD in 14 centres were investigated. Demographic, clinical, and ICD therapy data were collected.

RESULTS

The study included 67 patients (88% female). Median age at ICD implantation was 31 years (12-77 years). ICD indication was based on resuscitated cardiac arrest in 46 patients, syncope in 18 patients, and malignant family history in three patients. During a median follow-up of 48 months, 39 (58%) patients received one or more ICD therapies. Time to first appropriate discharge was up to 55 months. Inappropriate therapies were triggered by fast sinus rhythm, atrial fibrillation, and T-wave oversensing. No predictors of inappropriate shocks were identified. Risk factors for appropriate ICD therapy were: (1) recurrent syncope despite b-blocker treatment before ICD implantation, (2) pacemaker therapy before ICD implantation, (3) single-chamber ICD, and (4) noncompliance to b-blockers. In 38 (57%) patients, at least one complication occurred.

CONCLUSIONS

ICD therapy is effective in nearly half the patient population; however, the rates of early and late complica-tions are high. Although the number of unnecessary ICD shocks and reimplantation procedures may be lowered by modern programming and increased longevity of newer ICD generators, other adverse events are less likely to be reduced.

Novel insight into the natural history of short QT syndrome

Objectives

This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far.

Background

SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained.

Methods

Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months).

Results

Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 month to 41 years). The rate of CA was 4% in the first year of life and 1.3% per year between 20 and 40 years; the probability of a first occurrence of CA by 40 years of age was 41%. Despite the male predominance, female patients had a risk profile superimposable to that of men (p = 0.49). The yield of genetic screening was low (14%), despite familial disease being present in 44% of kindreds. A history of CA was the only predictor of recurrences at follow-up (p < 0.0000001). Two patterns of onset of ventricular fibrillation were observed and were reproducible in patients with multiple occurrences of CA. Arrhythmias occurred mainly at rest.

Conclusions

SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.

The influence of anesthesia on cardiac repolarization

The drugs and techniques used in contemporary anaesthesia may provoke numerous side effects, including cardiac rhythm disturbances. The prolongation of the repolarization time, reflected by the QT interval in a surface electrocardiogram, is one of the mechanisms that lead to the occurrence of arrhythmias. In the paper, we present the primary mechanism that is responsible for QT interval prolongation and subsequent torsade de pointes ventricular tachycardia. The influence of anesthetics, regional anesthesia and perioperative supportive therapy on cardiac repolarization is described.