Implantation of a VDD implantable cardioverter-defibrillator lead via a persistent left superior vena cava

A persistent left superior vena cava (LSVC) represents a challenging congenital abnormality for transvenous cardiac device implantation. In the current case a secondary prophylactic VDD implantable cardioverter-defibrillator (ICD) implantation was planned in a 75-year-old woman presenting with ischemic cardiomyopathy and elevated stroke risk. Since no venous communication to the right side was identified intraoperatively, the lead was placed via the persistent LSVC. The far-field signal on the floating atrial dipole could be successfully blanked out, and appropriate device function with high and stable atrial sensing was demonstrated at follow-up.

Cardiac device implantation and device usage in Fabry and hypertrophic cardiomyopathy

Background Fabry disease (FD) is a treatable X-linked condition leading to progressive cardiac disease, arrhythmia and premature death. We aimed to increase awareness of the arrhythmogenicity of Fabry cardiomyopathy, by comparing device usage in patients with Fabry cardiomyopathy and sarcomeric HCM. All Fabry patients with an implantable cardioverter defibrillator (ICD) implanted in the UK over a 17 year period were included. A comparator group of HCM patients, with primary prevention ICD implantation, were captured from a regional registry database. Results Indications for ICD in FD varied with 72% implanted for primary prevention based on multiple potential risk factors. In FD and HCM primary prevention devices, arrhythmia occurred more frequently in FD over shorter follow-up (HR 4.2, p < 0.001). VT requiring therapy was more common in FD (HR 4.5, p = 0.002). Immediate shock therapy for sustained VT was also more common (HR 2.5, p < 0.001). There was a greater burden of AF needing anticoagulation and NSVT in FD (AF: HR 6.2, p = 0.004, NSVT: HR 3.1, p < 0.001). Conclusion This study demonstrates arrhythmia burden and ICD usage in FD is high, suggesting that Fabry cardiomyopathy may be more ‘arrhythmogenic’ than previously thought. Existing risk models cannot be mutually applicable and further research is needed to provide clarity in managing Fabry patients with cardiac involvement.

Process Mapping Strategies to Prevent Subcutaneous Implantable Cardioverter-Defibrillator Infection

Background: Infection remains a major complication of cardiac implantable electronic devices (CIEDs) and can lead to significant morbidity and mortality. Extrathoracic devices that avoid epicardial or transvenous leads, such as the subcutaneous implantable cardioverter-defibrillator (S-ICD), can reduce the risk of serious infection-related complications, such as bloodstream infection and infective endocarditis. While the 2017 AHA/ACC/HRS guidelines include recommendations for S-ICD use for patients at high risk of infection, currently, there are no clinical trial data that address best practices for the prevention of S-ICD infections. Therefore, an expert panel was convened to develop consensus on these topics. Methods: An expert process mapping methodology was used to achieve consensus on the appropriate steps to minimize or prevent S-ICD infections. Two face-to-face meetings of high-volume S-ICD implanters and an infectious diseases specialist, with expertise on cardiovascular implantable electronic device infections, were conducted to develop consensus on useful strategies pre-, peri-, and post-implant to reduce S-ICD infection risk. Results: Expert panel consensus of recommended steps for patient preparation, S-ICD implantation, and post-operative management were developed to provide guidance in individual patient management. Conclusion: Achieving expert panel consensus by process mapping methodology for S-ICD infection prevention was attainable, and the results should be helpful to clinicians in adopting interventions to minimize risks of S-ICD infection.

Rationale and study design of the MINERVA study: Multicentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction—UK multicentre collaboration

IntroductionThe purpose of this study is to assess the ability of two new ECG markers (Regional Repolarisation Instability Index (R2I2) and Peak Electrical Restitution Slope) to predict sudden cardiac death (SCD) or ventricular arrhythmia (VA) events in patients with ischaemic cardiomyopathy undergoing implantation of an implantable cardioverter defibrillator for primary prevention indication.Methods and analysisMulticentre Investigation of Novel Electrocardiogram Risk markers in Ventricular Arrhythmia prediction is a prospective, open label, single blinded, multicentre observational study to establish the efficacy of two ECG biomarkers in predicting VA risk. 440 participants with ischaemic cardiomyopathy undergoing routine first time implantable cardioverter-defibrillator (ICD) implantation for primary prevention indication are currently being recruited. An electrophysiological (EP) study is performed using a non-invasive programmed electrical stimulation protocol via the implanted device. All participants will undergo the EP study hence no randomisation is required. Participants will be followed up over a minimum of 18 months and up to 3 years. The first patient was recruited in August 2016 and the study will be completed at the final participant follow-up visit. The primary endpoint is ventricular fibrillation or sustained ventricular tachycardia >200 beats/min as recorded by the ICD. The secondary endpoint is SCD. Analysis of the ECG data obtained during the EP study will be performed by the core lab where blinding of patient health status and endpoints will be maintained.Ethics and disseminationEthical approval has been granted by Research Ethics Committees Northern Ireland (reference no. 16/NI/0069). The results will inform the design of a definitive Randomised Controlled Trial (RCT). Dissemination will include peer reviewed journal articles reporting the qualitative and quantitative results, as well as presentations at conferences and lay summaries.Trial registration numberNCT03022487.

Clinical features and antiarrhythmic therapy in patients with catecholaminergic polymorphic ventricular tachycardia

Aims. To evaluate the long-term efficacy of antiarrhythmic therapy in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).Methods. CPVT was diagnosed in 11 patients between the ages of 3-12 years with a minimum follow-up of 10 years. The data analyzed was obtained from existing medical records that included symptoms, family screenings, treadmill tests, electrocardiography, echocardiography, implanted cardioverter-defibrillator data (ICD), and medical treatments.Results. Cardiac events were registered in 75% of patients on beta-blocker therapy. Supraventricular arrhythmias such as atrial and atrioventicular nodal tachycardia, atrial fibrillation and atrial flutter were detected using various ECG diagnostic methods in all patients, which is significantly higher than reported in similar studies. A combination of anti-arrhythmic therapy and beta-blocker treatment reduced the number of cardiac events by 50% as compared to only beta-blocker treatment.Conclusion. Multiple supraventricular arrhythmias have a high prevalence in patients with CPVT and can trigger ventricular arrhythmia. Combined antiarrhythmic therapy is effective because it prevents cardiac events in patients with CPVT. Combined antiarrhythmic therapy improves the prognosis of patients with CPVT and may help to avoid or postpone ICD implantation.

Genetic Clues on Implantable Cardioverter-Defibrillator Placement in Young-Age Hypertrophic Cardiomyopathy: A Case Report of Novel MYH7 Mutation and Literature Review

Background: Hypertrophic cardiomyopathy (HCM) is the second most common cardiomyopathy in childhood with a life-threatening risk. Implantable cardioverter-defibrillator (ICD) placement is recommended for early prevention if there are two or more clinical risk factors. Pediatric patients with HCM are at a higher risk of sudden cardiac death (SCD), but there are limited reports on indications for ICD implantation in children. Herein we describe the case of Myh7 mutation-induced HCM and cardiac arrest in a patient and evaluated information originating from genetic background to guide ICD administration.Case Presentation: The patient was a girl aged 7 years and 8 months who had been diagnosed with cardiomyopathy in utero 8 years prior. She had had recurrent cardiac arrests within the last 4 years. Electrocardiography indicated abnormalities in conduction, and ST segment changes. Echocardiography indicated significant left ventricular hypertrophy and hypertrophic systolic interventricular septum. Cardiac magnetic resonance imaging depicted general heart enlargement with hypertrophy, and delayed enhancement in myocardium with perfusion defect was also evident. Whole exon sequencing identified a de novo c.2723T&gt;C (p.L908P) heterozygous mutation in the MYH7 gene. MYH7 p.L908P predicted unstable protein structure and impaired function. The patient was scheduled for ICD implantation. There were no complications after ICD implantation, and she was discharged from hospital on the 10th day. Regular oral beta-blockers, amiodarone, spironolactone, and enalapril were administered, and she was required to attend hospital regularly for follow-up. During follow-up there were no cardiac arrests. Literature review of clinical prognoses associated with genetic mutations of MYH7, MYBPC3, TNNI3, TNNT2, and TPM1 in pediatric HCM patients with and without ICD implantation indicated that they were totally differently. Previous reports also indicated that gene mutations predicted earlier onset of cardiac hypertrophy, and increase likelihood of SCD.Conclusion: Variant burden and variant type contribute to the risk of adverse events in pediatric HCM. Early recognition and intervention are vital in children. Gene mutation could be considered an indication for early ICD placement during standard risk stratification of HCM patients. Whether this extends to the majority of pediatric patients requires further investigation.

CIED guideline recommendations in the setting of advisories

Subcutaneous implantable cardioverter defibrillators (S-ICDs) are currently indicated for patients who meet ICD implantation criteria for the prevention of sudden cardiac death (SCD). In December 2020, a unique cardiac implantable electronic device (CIED) situation arose as both the S-ICD generator and electrode were under a device advisory. We would recommend all future CIED implantation guidelines receive a caveat regarding checking current CIED advisories, in order to avoid future similar scenarios.

Periodic Repolarization Dynamics Identifies ICD-responders in Non-ischemic Cardiomyopathy: A DANISH Substudy

Background: Identification of patients with non-ischemic cardiomyopathy who benefit from prophylactic implantation of a cardioverter-defibrillator (ICD) remains an unmet clinical need. We hypothesized that periodic repolarization dynamics (PRD), a marker of repolarization instability associated with sympathetic activity, could be used to identify patients that benefit from prophylactic ICD-implantation. Methods: Heart-failure (DANISH) study, in which patients with non-ischemic cardiomyopathy, left-ventricular ejection fraction (LVEF) ≤35% and elevated N-terminal pro-brain natriuretic peptides (NT-proBNP) were randomized to ICD-implantation or control group. Patients were included in the PRD-substudy if they had a 24-hour Holter monitor recording at baseline with technically acceptable ECG signals during the night hours (00:00-06.00 AM). PRD was assessed using wavelet analysis according to previously validated methods. Primary endpoint was all-cause mortality. Cox-regression models were adjusted for age, sex, NT-proBNP, estimated glomerular filtration rate, LVEF, atrial fibrillation, ventricular pacing, diabetes mellitus, cardiac resynchronization therapy and mean heart rate. We proposed PRD ≥10deg 2 as exploratory cut-off value for ICD-implantation. Results: Seven-hundred and forty-eight of the 1,116 DANISH patients qualified for the PRD-substudy. During a mean follow−up period of 5.1±2.0 years, 82 of 385 patients died in the ICD group and 85 of 363 patients died in the control group (p−value=0.40). In Cox-regression analysis, PRD was independently associated with mortality (HR 1.28 [1.09−1.50] per SD increase; p−value = 0.003). Moreover, PRD was significantly associated with mortality in the control group (HR 1.51 [1.25−1.81]; p<0.001) but not in the ICD-group 1.04 [0.83−1.54]; p−value=0.71). There was a significant interaction between PRD and the effect of ICD−implantation on mortality (p−value 0.008), with patients with higher PRD having the greater benefit in terms of mortality reduction. ICD-implantation was associated with an absolute mortality reduction of 17.5% in the 280 patients with PRD ≥10deg 2 (HR 0.54 [0.34-0.84]; p−value=0.006; number needed to treat 6), but not in the 468 patients with PRD<10deg 2 (HR 1.17 [0.77−1.78]; p−value=0.46; p−value for interaction 0.01). Conclusions: Increased PRD identified patients with non-ischemic cardiomyopathy, where prophylactic ICD-implantation led to significant mortality reduction.

Long-term Follow-up of the The Danish Study to Assess theEfficacy of ICDs in Patients with Non-ischemic Systolic HeartFailure on Mortality (DANISH)

Background: The Danish Study to Assess the Efficacy of Implantable Cardioverter-Defibrillators (ICDs) in Patients with Non-ischemic Systolic Heart Failure on Mortality (DANISH) found that primary-prevention ICD implantation was not associated with an overall survival benefit in patients with non-ischemic systolic heart failure during a median follow-up of 5.6 years, though there was a beneficial effect on all-cause mortality in patients ≤70 years. This study presents an additional four years of follow-up data from DANISH. Methods: In DANISH, 556 patients with non-ischemic systolic heart failure were randomized to receive an ICD and 560 to receive usual clinical care and followed until June 30, 2016. In this long-term follow-up study, patients were followed until May 18, 2020. Analyses were conducted for the overall population and according to age (≤70 and >70 years). Results: During a median follow-up of 9.5 years (25 th -75 th percentile, 7.9-10.9 years), 208/556 patients (37%) in the ICD group and 226/560 patients (40%) in the control group died. Compared with the control group, the ICD group did not have significantly lower all-cause mortality (HR 0.89 [95%CI,0.74-1.08]; P=0.24). In patients ≤70 years (n=829), all-cause mortality was lower in the ICD group than the control group (117/389 [30%] vs 158/440 [36%]; HR 0.78 [95%CI,0.61-0.99]; P=0.04), whereas in patients >70 years (n=287), all-cause mortality was not significantly different between the ICD and control group (91/167 [54%] vs 68/120 [57%]; HR 0.92 [95%CI,0.67-1.28]; P=0.75). Cardiovascular death showed similar trends (overall, 147/556 [26%] vs 164/560 [29%], HR 0.87 [95%CI,0,70-1.09], P=0.20; ≤70 years, 87/389 [22%] vs 122/440 [28%], HR 0.75 [95%CI,0.57-0.98], P=0.04; >70 years, 60/167 [36%] vs 42/120 [35%], HR 0.97 [95%CI,0.65-1.45], P=0.91). The ICD group had a significantly lower incidence of sudden cardiovascular death in the overall population (35/556 [6%] vs 57/560 [10%]; HR 0.60 [95%CI,0.40-0.92]; P=0.02) and in patients ≤70 years (19/389 [5%] vs 49/440 [11%]; HR 0.42 [95%CI,0.24-0.71]; P=0.0008), but not in patients >70 years (16/167 [10%] vs 8/120 [7%]; HR 1.34 [95%CI,0.56-3.19]; P=0.39). Conclusions: During a median follow-up of 9.5 years, ICD implantation did not provide an overall survival benefit in patients with non-ischemic systolic heart failure. In patients ≤70 years, ICD implantation was associated with a lower incidence of all-cause mortality, cardiovascular death, and sudden cardiovascular death. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00542945.