Implantable defibrillator therapy: more than defibrillation...

During the past 25 years, the implantable cardioverter-defibrillator (ICD) has evolved from the treatment of last resort to the gold standard for patients at high risk for life­threatening ventricular tachyarrhythmias. Patients at high risk include those who survived life-threatening ventricular tachyarrhythmias, and patients with cardiac diseases who carry an increased risk for these tachyarrhythmias. We performed a clinical assessment during implantation and follow-up of our patients in Rotterdam. Part I Prognosis and follow-up of patients with an ICD In Chapter 1, the clinical benefit of ICD therapy, survival, and adverse events of patients who received an ICD at the Erasmus MC Rotterdam are described. Our data confirm the benefit from ICD implantation, especially for those patients with a poor left ventricular function. In Chapter 2, defibrillation efficacy testing is investigated. The role of a second defibrillation threshold test after implantation appears questionable. With the advances in ICD technology, defibrillation thresholds are low and stable, which changed the mode of death in ICD patients from instantaneous arrhythmic death to heart failure. Our data demonstrate that despite the advanced ICD technology, a subset of patients may require a second defibrillation efficacy test to confirm a poor prognosis. The feasibility of remote monitoring of ICD therapy is discussed in Chapter 3. The expanding indications for ICD therapy and the complexity of current devices have a high impact on follow-up policy. Currently, the quality of medical supervision only depends on scheduled regular follow-up visits, which is time consuming and expensive. Too long follow-up intervals may have the disadvantage of a delay in the awareness of changes of the clinical course of the underlying disease or in the technical status of the device. TransmiHet concept van de implantable cardioverter-defibrillator (ICD) heeft de afgelopen 25 jaar een grote ontwikkeling doorgemaakt. De eerste generatie defibrillatoren was uitsluitend in staat om ventrikelfibrilleren te herkennen en te onderbreken door middel van een elektrische shock. De volgende generaties defibrillatoren werden uitgerust met functies om verschillende ritmestoornissen te herkennen en te behandelen. Vanuit klinisch oogpunt is er een verschuiving opgetreden van secundaire preventie naar primaire preventie van plotse dood ten gevolge van ventriculaire ritmestoornissen. Dit proefschrift beschrijft zowel de klinische als technische aspecten van defibrillator therapie. Deel 1 Prognose en follow-up van ICD patiënten Hoofdstuk 1 beschrijft zowel het klinische voordeel als de potentiële complicaties van defibrillator therapie bij patiënten, bij wie een ICD in het Erasmus MC werd geïmplanteerd. De rol van het testen van de defibrillatie effectiviteit wordt in Hoofdstuk 2 behandeld. Door de technische vooruitgang kunnen ventriculaire ritmestoornissen effectief met lage energie gedefibrilleerd worden. Vanuit dit technisch oogpunt is een tweede defibrillatie test niet nodig, echter vanuit klinisch oogpunt kan deze test een slechte prognose bij een kleine groep patiënten bevestigen. Veranderingen in de klinische status van de ICD patiënt worden vaak pas vastgesteld bij het volgende poliklinisch bezoek. In Hoofdstuk 3 wordt de mogelijkheid van het op afstand waarnemen van zowel klinische als technische aspecten van defibrillator therapie beschreven. Het verzenden van opgeslagen data in de ICD heeft een potentiële meerwaarde voor de klinische follow-up van de patiënt. Ter illustratie wordt in Hoofdstuk 4 een voorbeeld van het op afstand waarnemen van ICD data gepresenteerd. Bij interpretatie van de ontvangen data werd een malfunctie van de ventriculaire elektrode vastgesteld. Deel 2 Onderscheiden van ritmestoornissen door de ICD Hoofdstuk 5 behandelt een voorbeeld van een opgeslagen registratie van een ventriculaire ritmestoornis, die na nauwkeurige analyse een ander ontstaansmechanisme heeft dan het op eerste oog doet lijken. In Hoofdstuk 6 wordt een nieuw tweekamer detectie algoritme, SMART, geëvalueerd. Na de vergelijking van de atriale en ventriculaire frequentie worden enkelkamer detectie criteria toegepast om een ritmestoornis te classificeren. Ventriculaire ritmestoornissen worden met behulp van dit algoritme betrouwbaar waargenomen. Ondanks een goede discriminatie tussen atriale en ventriculaire ritmestoornissen, worden atriale ritmestoornissen met een stabiele atrioventriculaire geleiding vooral verkeerd geclassificeerd. De ontwikkeling van detectie algoritmen om onterechte therapie ten gevolge van atriale ritmestoornissen te vermijden, wordt in Hoofdstuk 7 gepresenteerd. De classificatie van de ritmestoornis door de ICD is primair gebaseerd op de timing van ventriculaire signalen. De originele eenkamer detectie algoritmen zijn in de tweekamer ICD geïmplementeerd. De toevoeging van atriale informatie heeft tot betere en geavanceerde detectie algoritmen geleidt. Echter, onderzoeken die eenkamer met tweekamer detectie algoritmen vergeleken, lieten geen afname van onterechte therapie zien. Hoofdstuk 8 gaat over klinische variabelen die een verhoogd risico op onterechte therapie kunnen voorspellen. Uit onderzoek blijkt dat de aanwezigheid van atriale ritmestoornissen in het verleden en het voorkomen van trage ventriculaire ritmestoornissen, beide een verhoogd risico op onterechte therapie voorspellen. De beslissing om een tweekamer defibrillator bij patiënten met atriale ritmestoornissen te implanteren is een open vraag. Onterechte therapie werd namelijk in gelijke mate bij zowel eenkamer als tweekamer defibrillatoren waargenomen. Een gerandomiseerd onderzoek tussen eenkamer en tweekamer detectie algoritmen wordt in Hoofdstuk 9 gepresenteerd. De resultaten van dit onderzoek laten geen verschil zien in de discriminatie

Poor health status and distress in cardiac patients: The role of device therapy vs. underlying heart disease

AimsImplantable cardioverter defibrillator (ICD) therapy, which includes the risk of shocks, is considered the primary culprit of reductions in patient reported outcomes (PROs; e.g. health status and distress), thereby negating the role of underlying disease severity. We examined the relative influence of living with an ICD vs. congestive heart failure (CHF) on PROs and compared (i) ICD patients without CHF (ICD only), (ii) CHF patients without an ICD (CHF-only), and (iii) CHF patients with an ICD (ICD + CHF).Methods and resultsSeparate cohorts of ICD and CHF patients (N = 435; 75% men) completed PROs at baseline, 6 and 12 months. Groups differed on physical health status only at baseline (F(2,415) = 7.15, P = 0.001) and on anxiety at 12 months (F(2,415) = 4.04, P = 0.01); ICD + CHF patients had the most impaired physical health status but the lowest anxiety level followed by the ICD only and CHF only patients. Congestive heart failure only patients had the most impaired mental health status and reported the highest level of anxiety as compared to the ICD only (P < 0.001) and ICD + CHF groups (P = 0.009), while the two latter groups did not differ. The effect sizes ranged from very small (0.03) to moderate-large (0.69). Groups did not differ in depression scores.ConclusionCongestive heart failure patients reported worse PROs as compared to ICD patients, although the magnitude of the differences was relatively small. This suggests that the well being of patients is not necessarily negatively influenced by the implantation of an ICD, and that underlying heart disease may have at least an equal if not greater influence on PROs

Prospective blinded evaluation of a novel sensing methodology designed to reduce inappropriate shocks by the subcutaneous implantable cardioverter-defibrillator

Background: Most inappropriate shocks from the subcutaneous implantable cardioverter-defibrillator (S-ICD) are caused by cardiac oversensing. A novel sensing methodology, SMART Pass (SP; Boston Scientific Corporation, Natick, MA), aims to reduce cardiac oversensing. Objective: The purpose of this study was to evaluate the effect of SP on shocks in ambulatory patients with S-ICD. Methods: Patients implanted in 2015–2016 and enrolled in a remote patient monitoring system were included and followed for 1 year. Shocks were adjudicated by 3 independent blinded reviewers as appropriate or inappropriate. Shock incidence was calculated for patients with SP programmed enabled or disabled at implantation, censoring patients when SP programming changed or at the last transmission. The SP setting (enabled vs disabled) was modeled as a time-dependent Cox regression variable. Results: The cohort consisted of 1984 patients, and a total of 880 shocks were adjudicated. At implantation, SP was enabled in 655 patients (33%) and disabled in 1329 patients (67%). SP reduced the risk for the first inappropriate shock by 50% (P <.001) and the risk for all inappropriate shocks by 68% (P <.001) in multivariate analysis adjusted for age and device programming. The incidence of inappropriate shocks was 4.3% in the SP enabled arm vs 9.7% in the SP disabled arm. The incidence of appropriate shocks was similar (5.2

ICDs at higher age and clinical risk factors

Background The implantable cardioverter defibrillator (ICD) is effective in preventing sudden cardiac death. However, in elderly patients (aged 75 years or older) the role of ICDs is still not well-defined and controversial. Methods We retrospectively analysed all clinical and survival data of all ICD patients who were ≥75 years at the date of implantation in the Erasmus MC, Rotterdam, the Netherlands and the University Hospital, Basel, Switzerland. Kaplan- Meier survival analysis was performed, and mortality predictors were identified. Mortality of the cohort was compared with a random sample of patients aged 60-70 years originating from the same database and to an age- and sex-matched cohort of Dutch persons. Results The study cohort consisted of 179 patients aged 75 years or older who were implanted between February 1999 and July 2008. The median follow-up time was 2.0 (IQR 2.8) years. Survival rates after 1, 2 and 3 years were 87, 82, 75 %, respectively. Survival was similar for primary and secondary prevention. Mortality in this study population could be predicted by combining four clinical risk factors: QRS duration >120 ms, NYHA class > II, renal failure and atrial fibrillation (AF). Survival was worse compared with the group of ICD patients aged 60-70 years and to the age- and sex-matched group of elderly persons. However, survival was not significantly worse when comparing elderly ICD patients without additional risk factors to the general population. Conclusions Elderly patients still have an acceptable survival probability independent of prevention indication, certainly if there are no additional clinical risk factors. The presence or absence of additional clinical risk factors should be taken into account when making the decision for imp

Clinical outcome of ablation for long-standing persistent atrial fibrillation with or without defragmentation

Objective To assess the outcome and associated risks of atrial defragmentation for the treatment of long-standing persistent atrial fibrillation (LSP-AF). Methods Thirty-seven consecutive patients (60.4±7.3 years; 28 male) suffering from LSP-AF who underwent pulmonary vein isolation (PVI) and linear ablation were compared. All patients were treated with the Stereotaxis magnetic navigation system (MNS). Two groups were distinguished: patients with (n =20) and without (n =17) defragmentation. The primary endpoint of the study was freedom of AF after 12 months. Secondary endpoints were AF termination, procedure time, fluoroscopy time and procedural complications. Complications were divided into two groups: Major (infarction, stroke, major bleeding and tamponade) and minor (fever, pericarditis and inguinal haematoma). Results No difference was seen in freedom of AF between the defragmentation and the non-defragmentation group (56.2 % vs. 40.0%, P=0.344). Procedure times in the defragmentation group were longer; no differences in fluoroscopy times were observed. No major complications occurred. A higher number of minor complications occurred in the defragmentation group (45.0 % vs. 5.9 %, P=0.009). Mean hospital stay was comparable (4.7±2.2 vs. 3.4±0.8 days, P=0.06). Conclusion Our study suggests that complete defragmentation using MNS is associated with a higher number of minor complications and longer procedure times and thus compromises efficiency without improving efficacy

Value of implantable loop recorders in patients with structural or electrical heart disease

Purpose: In patients with structural heart disease (SHD) or inherited primary arrhythmia syndrome (IPAS), the occurrence of unexplained syncope or palpitations can be worrisome as they are at increased risk of sudden cardiac death. An implantable loop recorder (ILR) can be a useful diagnostic tool. Our purpose was to compare the diagnostic yield, arrhythmia mechanism, and management in patients with SHD, patients with IPAS, and those without heart disease. Methods: Retrospective single-center study in consecutive patients who underwent an ILR implantation. Results: Between March 2013 and December 2016, a total of 94 patients received an ILR (SHD, n = 20; IPAS, n = 14; no SHD/IPAS, n = 60). The type of symptoms at the time of implantation was similar between groups. During a median follow-up of 10 months, 45% had an ILR-guided diagnosis. Patients with IPAS had a lower diagnostic yield (14%) in comparison to the other groups (no SHD/IPAS 47%, P = 0.03; SHD 60%, P = 0.01, respectively). Furthermore, patients with SHD had a higher incidence of nonsustained VT in comparison to patients without SHD/IPAS (30 versus 3%, P < 0.01). ILR-guided therapy was comparable between groups. In the SHD group, a high proportion (10%) received an implantable cardioverter-defibrillator; however, this was not statistically significantly higher than the other groups (no SHD/IPAS 3%, IPAS 0%, P = 0.08). Conclusions: In comparison to patients without heart disease, the diagnostic yield of an ILR was lower in patients with IPAS and the prevalence of ILR-diagnosed nonsustained VT was higher in patients with SHD

Ventricular tachycardia in ischemic cardiomyopathy; a combined endo-epicardial ablation as the first procedure versus a stepwise approach (EPILOGUE) - study protocol for a randomized controlled trial

Background: The role of epicardial substrate ablation of ventricular tachycardia (VT) as a first-line approach in patients with ischemic heart disease is not clearly defined. Epicardial ablation as a first-line option is standard for patients with nonischemic dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Several nonrandomized studies, including studies on patients with ischemic heart disease, have shown that epicardial VT ablation improves outcome but this approach was often used after a failed endocardial approach. The aim of this study is to determine whether a combined endo-epicardial scar homogenization as a first-line approach will improve the outcome of VT ablation. Methods/Design: The EPILOGUE study is a multicenter, two-armed, nonblinded, randomized controlled trial. Patients with ischemic heart disease who are referred for VT ablation will be randomly assigned to combined endo-epicardial scar homogenization or endocardial scar homogenization only (control group). The primary outcome is recurrence of sustained VT during a 2-year follow-up. Secondary outcomes include procedural success and safety. Discussion: This study is the first randomized trial that evaluates the role of a combined endo-epicardial scar homogenization versus endocardial scar homogenization for the treatment of ischemic scar-related VT. Trial registration:NL4816807814v0

Worldwide experience with a totally subcutaneous implantable defibrillator: Early results from the EFFORTLESS S-ICD registry

Aims The totally subcutaneous implantable-defibrillator (S-ICD) is a new alternative to the conventional transveno

Performance of the subcutaneous implantable cardioverter-defibrillator in patients with a primary prevention indication with and without a reduced ejection fraction versus patients with a secondary prevention indication

Background: The subcutaneous implantable defibrillator (S-ICD) provides an alternative to the transvenous ICD for the prevention of sudden cardiac death, but has not been well studied in the most commonly treated transvenous ICD patient population, namely, primary prevention (PP) patients with left ventricular dysfunction. Objective: The analyses in the present study were designed to compar

Emerging electromagnetic interferences between implantable cardioverter-defibrillators and left ventricular assist devices: Authors' reply

Aims To investigate the prevalence of electromagnetic interference (EMI) between left ventricular assist devices (LVADs) and implantable cardioverter-defibrillators (ICDs)/pacemakers (PMs). ................................................................................................................................................................................................... Methods and results A retrospective single-centre study was conducted, including all patients undergoing HeartMate II (HMII) and HeartMate 3 (HM3) LVAD implantation (n = 106). Electromagnetic interference was determined by the inability to interrogate the ICD/PM. Overall, 85 (mean age 59 ± 8, 79% male) patients had an ICD/PM at the time of LVAD implantation; 46 patients with HMII and 40 patients with HM3. Among the 85 LVAD patients with an ICD’s/PM’s, 11 patients (13%) experienced EMI; 6 patients (15%) with an HMII and 5 patients (11%) with an HM3 (P = 0.59). Electromagnetic interference from the HMII LVADs was only present in patients with a St Jude/Abbott device; 6 of the 23 St Jude/Abbott devices. However, in the HM3 patients, EMI was mainly present in patients with Biotronik devices: 4 of the 18 with only one (1/25) patient with a Medtronic device. While initial interrogation of these devices was not successful, none of the 11 cases experienced pacing inhibition or inappropriate shocks. ................................................................................................................................................................................................... Conclusion In summary, the prevalence of EMI between ICDs in the older and newer type of LVAD’s remains rather high. While HMII patients experienced EMI with a St Jude/Abbott device (which was already known), HM3 LVAD patients experience EMI mainly with Biotronik devices. Prospective follow-up, preferably in large registries, is warranted to investigate the overall prevalence and impact of EMI in LVAD patient