Examining the psychosocial impact of implantable cardioverter defibrillators: a literature review

Cognitive behavioral therapy for the treatment of insomnia in patients with cardiovascular diseases: a meta-analysis with GRADE analysis

Insomnia, as a difficulty in initiating and maintaining sleep, coupled with cardiovascular diseases (CVDs) increase the risk of aggravate daytime symptoms, mortality, and morbidity. Cognitive behavioral therapy (CBT) is thought to have a significant impact on insomnia treatment, but in patients with CVDs, there is a paucity of data. To provide a comprehensive appraisal on the impact of CBT on the treatment of insomnia in patients with CVDs. We searched Ovid, Scopus, Web of science, and Cochrane central, to randomized controlled trials (RCTs) from inception till November 2022. Outcomes of interest were insomnia severity index (ISI), Pittsburgh Sleep Quality Index (PSQI), sleep efficiency (SE), Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), and sleep disorders questionnaire (SDQ). Pooled data were analyzed using mean difference (MD) with its 95% confidence interval (CI) in a random effect model using STATA 17 for Mac. Nine RCTs comprising 365 patients were included in the analysis. CBT significantly reduced scores of ISI (MD =  - 3.22, 95%  CI - 4.46 to - 1.98, p < 0.001), PSQI (MD =  - 2.33, 95%  CI - 3.23 to - 1.44, p < 0.001), DBAS (MD =  - 0.94, 95%  CI - 1.3 to - 0.58, p < 0.001), SDQ (MD =  - 0.38, 95%  CI - 0.56 to - 0.2, p < 0.001). Also, it increased the score of SE (MD = 6.65, 95% CI 2.54 to 10.77, p < 0.001). However, there was no difference in terms of ESS. CBT is an easy and feasible intervention with clinically significant improvement in insomnia symptoms. Further large-volume studies are needed to assess sustained efficacy.

PTSD and mood disorders in implantable cardioverter defibrillator patients: is more psychological assessment needed?

INTRODUCTION

The aim of this review is to identify common mood concerns in ICD patients and suggest brief psychological screeners essential for early detection and monitoring in patient care.

AREAS COVERED

Reliable and valid psychological assessment tools are reviewed, including those specifically designed for ICD patient populations.

EXPERT OPINION

Psychological assessment, in combination with cardiologic standard of care, can help overcome many barriers associated with poor implantable cardioverter-defibrillator (ICD) management and related cardiovascular outcomes. Earlier identification and treatment of mood concerns in ICD patients has been shown to improve quality of life (QOL) and patient outcomes. At this time, however, logistical challenges and time restraints, in addition to knowledge of appropriate treatment plans or referral options, remain central barriers to providing integrated, patient-centered care. Ultimately, all cardiology clinics would benefit from a collaborative care team that includes a mental health consultant or in-house psychologists who can provide consultations or referral services. Additionally, all patients that come to the clinics should complete proactive screening measures as routine component of care to assess the presence of mood concerns to improve patient outcomes and aid in treatment planning.

Workforce affiliation in primary and secondary prevention implantable cardioverter defibrillator patients: a nationwide Danish study

BACKGROUND AND AIM

There are a paucity of studies investigating workforce affiliation in connection with first-time implantable cardioverter defibrillator (ICD)-implantation. This study explored workforce affiliation and risk markers associated with not returning to work in patients with ICDs.

METHODS

Using the nationwide Danish registers, patients with a first-time ICD-implantation between 2007 and 2017 and of working age (30-65 years) were identified. Descriptive statistic and logistic regression models were used to describe workforce affiliation and to estimate risk markers associated with not returning to work, respectively. All analyses were stratified by indication for implantation (primary and secondary prevention).

RESULTS

Of the 4659 ICD-patients of working age, 3300 patients (71%) were members of the workforce (employed, on sick leave or unemployed) (primary: 1428 (43%); secondary:1872 (57%)). At baseline, 842 primary and 1477 secondary prevention ICD-patients were employed. Of those employed at baseline, 81% primary and 75% secondary prevention ICD-patients returned to work within 1 year, whereof more than 80% remained employed the following year. Among patients receiving sick leave benefits at baseline, 25% were employed after 1 year. Risk markers of not returning to work were 'younger age' in primary prevention ICD-patients, while 'female sex', left ventricular ejection fraction 'LVEF ≤40', 'lower income', and '≥3 comorbidities' were risk markers in secondary prevention ICD-patients. Lower educational level was a risk marker in both patient groups.

CONCLUSION

High return-to-work proportions following ICD-implantation, with a subsequent high level of employment maintenance were found. Several significant risk markers of not returning to work were identified including 'lower educational level' that posed a risk in both patient groups.

TRIAL REGISTRATION NUMBER

Capital Region of Denmark, P-2019-051.

From evidence-based medicine to digital twin technology for predicting ventricular tachycardia in ischaemic cardiomyopathy

Survivors of myocardial infarction are at risk of life-threatening ventricular tachycardias (VTs) later in their lives. Current guidelines for implantable cardioverter defibrillators (ICDs) implantation to prevent VT-related sudden cardiac death is solely based on symptoms and left ventricular ejection fraction. Catheter ablation of scar-related VTs is performed following ICD therapy, reducing VTs, painful shocks, anxiety, depression and worsening heart failure. We postulate that better prediction of the occurrence and circuit of VT, will improve identification of patients at risk for VT and boost preventive ablation, reducing mortality and morbidity. For this purpose, multiple time-evolving aspects of the underlying pathophysiology, including the anatomical substrate, triggers and modulators, should be part of VT prediction models. We envision digital twins as a solution combining clinical expertise with three prediction approaches: evidence-based medicine (clinical practice), data-driven models (data science) and mechanistic models (biomedical engineering). This paper aims to create a mutual understanding between experts in the different fields by providing a comprehensive description of the clinical problem and the three approaches in an understandable manner, leveraging future collaborations and technological innovations for clinical decision support. Moreover, it defines open challenges and gains for digital twin solutions and discusses the potential of hybrid modelling.

The Gallant™ system heart rhythm management device: making a connection

Implantable cardiac defibrillators have revolutionized the way we prevent sudden cardiac death via arrhythmias. The addition of cardiac resynchronization pacing to defibrillators has broadened that treatment to include patients with heart failure and reduced ejection fraction. As with all technology, new devices and platforms expand the capabilities and interface with patients across the world. This review discusses the evolution from the initial modalities and methods of communication of implantable devices up to the most recent advances in implantable defibrillators and their integration into patient lives and clinical practice. This review is focused on the integration of Bluetooth communication into modern healthcare with the Gallant™ family of devices, the first branded launch by Abbott Laboratories.

Pathogenicity Assignment of Variants in Genes Associated With Cardiac Channelopathies Evolve Toward Diagnostic Uncertainty

BACKGROUND

Accurately determining variant pathogenicity is critical in the diagnosis of cardiac channelopathies; however, it remains unknown how variant pathogenicity status changes over time. Our aim is to use a comprehensive analysis of ClinVar to understand the mutability of variant evaluation in channelopathy-associated genes to inform clinical decision-making around variant calling.

METHODS

We identified 10 genes (RYR2, CASQ2, KCNQ1, KCNH2, SCN5A, CACNA1C, CALM1, CALM2, CALM3, TRDN) strongly associated with cardiac channelopathies, as well as 3 comparison gene sets (disputed long QT syndrome, sudden unexpected death in epilepsy, and all ClinVar). We comprehensively analyzed variant pathogenicity calls over time using the ClinVar database with Rstudio. Analyses focused on the frequency and directionality of clinically meaningful changes in disease association, defined as a change from one of the following three categories to another: likely benign/benign, conflicting evidence of pathogenicity/variant of uncertain significance, and likely pathogenic/pathogenic.

RESULTS

In total, among channelopathy-associated genes, there were 9975 variants in ClinVar and 8.4% had a clinically meaningful change in disease association at least once over the past 10 years, as opposed to 4.9% of all ClinVar variants. The 3 channelopathy-associated genes with the most variants undergoing a clinically significant change were KCNQ1 (20.9%), SCN5A (11.2%), and KCNH2 (10.1%). Ten of the 12 included genes had variant evaluations that trended toward diagnostic uncertainty over time. Specifically, channelopathy-associated gene variants with either pathogenic/likely pathogenic or benign/likely benign assignments were 5.6× and 2×, respectively, as likely to be reevaluated to conflicting/variant of uncertain significance compared to the converse.

CONCLUSIONS

Over the past 10 years, 8.4% of variants in channelopathy-associated genes have changed pathogenicity status with a decline in overall diagnostic certainty. Ongoing clinical and genetic variant follow-up is needed to account for presence of clinically meaningful change in variant pathogenicity assignment over time.

Cardiovascular therapeutics: A new potential for anxiety treatment?

Besides the well‐recognized risk factors, novel conditions increasing cardiovascular morbidity and mortality are emerging. Undesirable emotions and behavior such as anxiety and depression, appear to participate in worsening cardiovascular pathologies. On the other hand, deteriorating conditions of the heart and vasculature result in disturbed mental and emotional health. The pathophysiological background of this bidirectional interplay could reside in an inappropriate activation of vegetative neurohormonal and other humoral systems in both cardiovascular and psychological disturbances. This results in circulus vitiosus potentiating mental and circulatory disorders. Thus, it appears to be of utmost importance to examine the alteration of emotions, cognition, and behavior in cardiovascular patients. In terms of this consideration, recognizing the potential of principal cardiovascular drugs to interact with the mental state in patients with heart or vasculature disturbances is unavoidable, to optimize their therapeutic benefit. In general, beta‐blockers, central sympatholytics, ACE inhibitors, ARBs, aldosterone receptor blockers, sacubitril/valsartan, and fibrates are considered to exert anxiolytic effect in animal experiments and clinical settings. Statins and some beta‐blockers appear to have an equivocal impact on mood and anxiety and ivabradine expressed neutral psychological impact. It seems reasonable to suppose that the knowledge of a patient's mood, cognition, and behavior, along with applying careful consideration of the choice of the particular cardiovascular drug and respecting its potential psychological benefit or harm might improve the individualized approach to the treatment of cardiovascular disorders.

Device nurse intervention facilitates the patients' adaptation to cardiac shock devices in the remote monitoring era

BACKGROUND

A substantial number of patients with shock devices (implantable cardioverter defibrillators [ICDs] or ICDs with resynchronization [CRTDs]) experience psychological distress.

OBJECTIVE

We investigated the device nurse telephone intervention's effect on improving the patient's adaptation to shock devices, quality of life (QOL), and anxiety in the remote monitoring era.

METHODS

The patient's adaptation to the device, health-related QOL, and anxiety were investigated by the modified Implanted Devices Adjustment-Japan score (IDAS), Short Form-36, and State-Trait Anxiety Inventory (STAI) before and 1-year after the device nurse telephone intervention, performed every 3 months. A total of 95 patients (median age 69 years and 25 females) participated. Sixty patients had ICDs and 35 CRTDs. Structural heart disease was observed in 72 patients, and idiopathic ventricular arrhythmias in the others. The mean left ventricular ejection fraction was 46% ± 15%. The median duration since the device implantation was 5.2 years.

RESULTS

The total IDAS score significantly improved from 28.42 ± 7.11 at baseline to 26.77 ± 7.68 (p = 0.0076) at 1 year. Both the state and trait anxiety significantly improved (from 38.9 ± 9.6 to 35.3 ± 9.0 [<0.0001] and 38.8 ± 10.3 to 36.2±9.8 [p = 0.0044], respectively). The prevalence of patients with a state and trait anxiety of more than 40 decreased from 44 (46%) and 38 (40%) patients before the study to 27 (28 %) and 32 (34 %) at 1 year. The SF-36 mental component summary score significantly increased (50.8 ± 8.3 at baseline to 53.1 ± 7.7 at 1 year, p = 0.0031).

CONCLUSIONS

The device nurse intervention facilitated the patient's adaptation to the shock device, increased the health-related QOL, and reduced the patient's anxiety.

Efficacy of antitachycardia pacing alert by remote monitoring of implantable cardioverter-defibrillators for out-of-hospital electrical storm

BACKGROUND

Remote monitoring (RM) has been shown to reduce all-cause mortality in patients with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (ICD/CRT-D). Not all devices transmit an alert for antitachycardia pacing (ATP) therapy, and it is unknown whether differences of RM alert affect the outcomes of electrical storm (ES).

METHODS

We enrolled 42 patients with ICD/CRT-D whose out-of-hospital ES were detected by RM between 2013 and 2020. We divided their 54 episodes into two groups (ATP-alert-on; 22, ATP-alert-off; 32), and clinical outcomes were compared between the two groups.

RESULTS

In 35 of 54 episodes of ES, ventricular tachycardia (VT) could be terminated within 24 h of ES onset just by ATP (ATP-alert-on: 14, ATP-alert-off: 21); however, many patients subsequently received shock delivery for VT. Among the 35 episodes, only in ATP-alert-on group, seven patients were prompted to visit our hospital without ICD shock through confirmation of ES by ATP-alert. Episodes that led to shock delivery 24 h or longer after the ES onset were significantly less common in the ATP-alert-on group (ATP-alert-on: 1/14, ATP-alert-off: 9/21, p = .03). Although there were no significant differences in the number of shock deliveries between episodes in the two groups, the number of ATP deliveries were significantly fewer in the ATP-alert-on group (12[7-26] vs. 29[16-53] in ATP-alert-off group, p = .03). Multivariate logistic regression analyses showed that the only ATP-alert significantly reduced ATP deliveries (HR = 0.14, 95%CI = 0.04-0.57, p = .003).

CONCLUSION

Remote monitoring with an ATP-alert function during electrical storm may reduce appropriate ICD therapy through prompting early review.

Delivering an efficient and effective support group for patients with implantable cardioverter-defibrillators (ICDs): patient perspectives of key concerns and predictors of inclination to attend

BACKGROUND

A subset of patients experience psychological distress following insertion of an implantable cardioverter-defibrillator (ICD) and ICD support groups are recommended, however access to these groups is limited. This study aimed: to gauge a better understanding of patients' key ICD-related concerns; to determine patient interest in a support group and topics deemed helpful to address in a support group; and to examine factors which affect patient inclination to attend.

METHODS

One hundred and thirty nine patients completed the ICD Patient Concerns Questionnaire - Brief (ICDC-B) and a semi-structured survey. Non-parametric tests were used to examine associations and differences in the quantitative data. Qualitative data were analysed using thematic analysis.

RESULTS

42% of respondents said they would attend a support group and inclination to attend was associated with higher ICD concerns and a shorter time since implant. Topics considered important to address in a group were information about heart conditions and devices, the impact of an ICD on daily life and coping with fear of shocks.

CONCLUSION

We concluded that there is interest in further support amongst many patients and that ICD support groups may be delivered efficiently by targeting patients who have higher levels of ICD concerns and within the first few years after implant.

Experiences of adults living with an implantable cardioverter defibrillator for cardiovascular disease: a systematic review of qualitative evidence

OBJECTIVE

The objective of this review was to synthesize the best available qualitative evidence on the everyday life experiences of adults living with an implantable cardioverter defibrillator for cardiovascular disease.

INTRODUCTION

Cardiovascular disease is a rising concern worldwide. The efficacy of the implantable cardioverter defibrillator as a successful treatment for cardiovascular disease has been well documented. Research suggests that living with an implantable cardioverter defibrillator is complex and can cause substantial psychosocial distress that can manifest itself at various intervals over time. The first step to developing evidence-based recommendations related to the management of implantable cardioverter defibrillator-related distress is a critical appraisal and synthesis of relevant literature to gain a more comprehensive understanding of this phenomenon.

INCLUSION CRITERIA

The participants of interest were adults 18 years or older who had an implantable cardioverter defibrillator for the management of cardiovascular disease (e.g. ischemic heart disease, angina, cardiomyopathy, myocardial infarction, congenital defect, arrhythmias, heart failure). The phenomenon of interest was the everyday life experience of adults living with an implantable cardioverter defibrillator. The review considered all qualitative research related to the phenomenon of interest.

METHODS

Key databases searched were PubMed, CINAHL, PsycINFO, Embase, International Bibliography of the Social Sciences, Sociological Abstracts, OpenGrey, MedNar, ProQuest Dissertations and Theses Global, Google, and Google Scholar. Published and unpublished papers and articles from 1990 to July 2018 were included in the search. The JBI approach to critical appraisal, study selection, data extraction, and synthesis for qualitative research was used throughout the review.

RESULTS

Twenty-seven papers were included in the review that yielded 143 findings and 13 categories. The methodological quality of the 27 included studies was moderate to strong. Based on ConQual scores, confidence in the synthesized findings was moderate. From this, three synthesized findings were extracted: i) living under the shadow of uncertainty, ii) orchestrating a new normal, and iii) crafting a positive vision for the future.

CONCLUSIONS

Evidence suggests that while implantable cardioverter defibrillator recipients do experience psychosocial distress, they gradually positively embrace the device as part of their everyday norm. Recommendations for practice and education point to the further development of best practice guidelines for implantable cardioverter defibrillator management, continuing education programs for health care providers, and strategies to support implantable cardioverter defibrillator recipients and their families to cope with the device. Research that examines onset, level, and duration of implantable cardioverter defibrillator psychosocial distress is needed to target specific interventions reflective of this population's needs. While findings suggest the experiences of women living with an implantable cardioverter defibrillator are similar to men, the low number of women in included studies limits the strength of this conclusion.

Resilience, Cardiological Outcome, and Their Correlations With Anxious-Depressive Symptoms and Quality of Life in Patients With an Implantable Cardioverter Defibrillator

Background: Resilience is proven as a protective factor against the development of psychiatric disorders, and it has gained clinical relevance in the development and progression of cardiovascular pathology. The authors performed a longitudinal study on patients with implantable cardioverter defibrillator (ICD) with the primary aim to highlight the possible existence of a correlation between individual resilience capacity, depressive and anxiety symptoms, and quality of life in terms of outcomes. The secondary aim was to analyze the differences between patients with major cardiac events in the follow-up and patients without cardiac events with respect to the previous variables. Materials and Methods: A total of 80 patients enrolled in the Cardiology Unit were evaluated at T₀ and during the follow-up through the following scales: the 14-item Resilience Scale (RS-14), the Hospital Anxiety and Depression Scale (HADS), and the World Health Organization Quality of Life-Brief Version (WHOQOL-Bref). Results: A significant linear correlation between resilience and all the areas of quality of life at T₀, T₁, and T₂ emerged. A negative correlation between resilience and anxiety and depressive symptoms emerged, as well as between depression and anxiety and quality of life. Patients with cardiac events during the follow up have shown a worse quality of life and the onset of anxiety-depressive symptoms over time, without changes to the resilience scores. Patients without cardiac events showed an increasing trend in resilience scores. Discussion: Given the speed and simplicity of use of the RS-14 scale, it seems promising to further investigate the real clinical usefulness of this instrument in the cardiology field.

What Do We Know About Young Adult Cardiac Patients' Experience? A Systematic Review

Background: Studies interested in patients coping with a cardiac illness usually focus on children, teenagers, and adults above the age of 55. Apart from the field of congenital heart diseases, there is a general lack of literature regarding young adult cardiac patients (18-55 years old) who seem to cope with psychosocial issues. Therefore, the objective of this paper was to gather all the research carried out concerning the psychological experiences of young adult cardiac patients. Methods and Results: A comprehensive, systematic review was conducted on quantitative, qualitative, and mixed-method studies in PsycINFO, PubMed, ScienceDirect, and Cochrane Library databases. Out of the 10,747 articles found, 32 were included. While we aimed to include many cardiac diseases, coronary patients dominated the data. Five main themes emerged: emotional states (depression, anxiety, emotional distress, and stress), quality of life (health-related quality of life, physical functioning, and sexuality), adjusting to the medical environment (coping with the disease, health behavior change, financial barriers, and interactions with medical professionals), social life (social support and work), and identity (parenthood, new challenges, and new meanings). The results highlighted that their levels of depression, anxiety, stress, and quality of life were sometimes worse than in the general population and than in older and younger patients coping with a cardiac illness. Social isolation, identity changes, work, and parenthood were the specific challenges that this population had to face. Furthermore, young adult cardiac patients showed worse health behavior profiles than the general population and felt that they lacked information from professionals, especially regarding sexuality. Compared to men, women had worse psychosocial outcomes, especially regarding depression, stress, emotional distress, and quality of life. Conclusions: Young adult cardiac patients are to be considered with their own identity and challenges. They may be in need of specific interventions, some dedicated to women, and better communication is necessary with their families and professional caregivers so as to improve the patient's mental health, quality of life, coping skills, and adherence.

High mean entropy calculated from cardiac MRI texture analysis is associated with antitachycardia pacing failure

BACKGROUND

Antitachycardia pacing (ATP), which may avoid unnecessary implantable cardioverter-defibrillator (ICD) shocks, does not always terminate ventricular arrhythmias (VAs). Mean entropy calculated using cardiac magnetic resonance texture analysis (CMR-TA) has been shown to predict appropriate ICD therapy. We examined whether scar heterogeneity, quantified by mean entropy, is associated with ATP failure and explore potential mechanisms using computer modeling.

METHODS

A subanalysis of 114 patients undergoing CMR-TA where the primary endpoint was delivery of appropriate ICD therapy (ATP or shock therapy) was performed. Patients receiving appropriate ICD therapy (n = 33) were dichotomized into "successful ATP" versus "shock therapy" groups. In silico computer modeling was used to explore underlying mechanisms.

RESULTS

A total of 16 of 33 (48.5%) patients had successful ATP to terminate VA, and 17 of 33 (51.5%) patients required shock therapy. Mean entropy was significantly higher in the shock versus successful ATP group (6.1 ± 0.5 vs 5.5 ± 0.7, P = .037). Analysis of patients receiving ATP (n = 22) showed significantly higher mean entropy in the six of 22 patients that failed ATP (followed by rescue ICD shock) compared to 16 of 22 that had successful ATP (6.3 ± 0.7 vs 5.5 ± 0.7, P = .048). Computer modeling suggested inability of the paced wavefront in ATP to successfully propagate from the electrode site through patchy fibrosis as a possible mechanism of failed ATP.

CONCLUSIONS

Our findings suggest lower scar heterogeneity (mean entropy) is associated with successful ATP, whereas higher scar heterogeneity is associated with more aggressive VAs unresponsive to ATP requiring shock therapy that may be due to inability of the paced wavefront to propagate through scar and terminate the VA circuit.

Decision regret in implantable cardioverter-defibrillator recipients : A cross-sectional analysis on patients that regret their decision after ICD implantation

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) are designed to deliver therapy in the event of malignant ventricular arrhythmias. Despite their benefits, some ICD recipients regret their decision on device implantation.

OBJECTIVES

The aim of this study was to evaluate the incidence, predictors, and consequences of recipients that regretted their decision after implantation.

METHODS

A questionnaire-based cross-sectional survey of consecutive ICD recipients examined during a routine outpatient follow-up visit was conducted. Their level of depression and anxiety was assessed with the hospital anxiety and depression scale (HADS). Quality of life (QOL) was assessed using the Minnesota living with heart failure questionnaire.

RESULTS

Of 434 ICD recipients invited to the study, 423 (97.5%) agreed and completed the survey, 349 (83%) had a primary prevention indication, and 339 (80%) ischemic cardiomyopathy. A total of 41 recipients (9.7%) regretted their decision to undergo ICD implantation. These patients were: (1) younger (63 versus 69 years), (2) more frequently in New York Heart Association (NYHA) ≥2 functional class (63% versus 22%), (3) had higher education levels (more than high-school: 76% versus 60%), (4) felt that preoperative information was lacking (22% versus 4%), (5) had more complications in the perioperative period (15% versus 3%), (6) felt less safe after ICD implantation (54% versus 5%), and (7) considered more frequently ICD deactivation during near end-of-life situations (54% versus 29%). Mean QOL and HADS scores were significantly worse in these patients (36 versus 30 and 12 versus 8.8 points, respectively; p < 0.01 for all).

CONCLUSION

Almost 10% of ICD recipients regretted their decision after implantation. Predictors included younger age, higher education levels, complicated perioperative period, and lack of preoperative information.

Phantom shocks in implantable cardioverter-defibrillator recipients: impact of education level, anxiety, and depression

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are designed to deliver shocks in the event of ventricular arrhythmias. Some ICD recipients experience the sensation of ICD discharge in the absence of an actual discharge (phantom shock, PS).

OBJECTIVES

The aim of this study was to evaluate the incidence, predictors, and consequences of PS in ICD recipients.

MATERIALS AND METHODS

Consecutive ICD recipients were examined during a routine outpatient follow-up (FU) visit. Subjects completed a written survey; their level of depression and anxiety was assessed with the hospital anxiety and depression scale (HADS). Quality of life (QOL) was assessed using the Minnesota living with heart failure questionnaire.

RESULTS

Of 434 patients invited to the study, 423 (97.5%) ICD recipients agreed to and completed the survey; 349 (83%) had a primary prevention indication and 339 (80%) ischemic cardiomyopathy. A total of 27 patients (6.4%) reported a PS during a mean FU of 64 ± 44 months (5.4% in the primary prevention group and 10.8% in the secondary prevention group; p = 0.11). PS were related to higher education (≥bachelor's degree 41% versus 20%; p = 0.03), and more frequent in patients receiving adequate shocks during FU (34% versus 0.5%; p < 0.001). HADS score levels were higher following PS (15 ± 6 versus 8.8 ± 7.4; p < 0.001). The majority of patients reporting PS felt that the information provided to them prior to ICD placement was insufficient (22.2% versus 5.0%), that they needed psychological support after ICD implantation (26% versus 3%), and considered ICD deactivation in near end-of-life situations (59% versus 29%; p < 0.001 for all).

CONCLUSIONS

PS occur in 6.4% of all ICD recipients and are related to higher education and to patients that experienced adequate shocks during FU.

Additional antitachycardia pacing programming strategies further reduce unnecessary implantable cardioverter-defibrillator shocks

BACKGROUND

Antitachycardia pacing (ATP) is routinely used to terminate ventricular tachyarrhythmias (VTs). However, little guidance exists on the most effective programming of ATP.

OBJECTIVE

This study evaluated whether additional ATP sequences are more effective in reducing implantable cardioverter-defibrillator shocks.

METHODS

In patients from the Shock-Less study, the number of overall shocks were compared between patients programmed to ≤3 ATP sequences (VT zone) and ≤1 ATP sequence (fast ventricular tachycardia [FVT] zone) (nominal group) and patients programmed to receive additional ATP sequences in VT (>3) or FVT (>1) zones.

RESULTS

Of the 4112 patients (15% receiving secondary prevention; 77% men; mean age 65.9 ± 12.6 years), 1532 patients (37%) were programmed with additional ATP sequences (1025 with >3 ATP sequences in the VT zone; 699 patients with >1 ATP sequence in the FVT zone). Over a mean follow-up period of 19.6 ± 10.7 months, 4359 VT/FVT episodes occurred in 591 patients. Compared with the nominal group, in patients with additional ATP programming, there was a 39% reduction in the number of shocked VT episodes (0.46 episodes per patient-year vs 0.28 episodes per patient-year; incidence rate ratio [IRR] 0.61; P < .001) and a 44% reduction in the number of shocked FVT episodes (0.83 episodes per patient-year vs 0.47 episodes per patient-year; IRR 0.56; P < .001). The reduction in shocked VT episodes was observed in both primary (IRR 0.68; 95% confidence interval 0.51-0.90; P = .007) and secondary (IRR 0.51; 95% confidence interval 0.35-0.72; P < .001) prevention patients.

CONCLUSION

Programming more than the nominal number of ATP sequences in both the VT and FVT zones is associated with a lower occurrence of implantable cardioverter-defibrillator shocks in clinical practice.

Multi-morbidity burden, psychological distress, and quality of life in implantable cardioverter defibrillator recipients: Results from a nationwide study

BACKGROUND

The prevalence of multi-morbidity in implantable cardioverter defibrillator (ICD) recipients is approximately 25%. Multi-morbidity is associated with poor health and psychological outcomes in this population and may affect ICD recipients' quality-of-life (QOL). The purpose of this study was to determine the prevalence of psychological distress (anxiety, depressive symptoms, and Type-D personality) in ICD recipients with varying levels of comorbidities, and to examine the association between multi-morbidity burden and QOL in this population.

METHODS

All adults listed in the Swedish ICD and Pacemaker Registry in 2012 with an ICD implanted for at least one year were invited to participate in this study. Binary logistic regression was used to predict QOL using the EQ-5D mean index dichotomized based on median QOL scores. Multi-morbidity burden scores were based on quartile groupings.

RESULTS

A total of 2658 ICD recipients participated in the study (with a mean age of 65, 20.6% female, mean implant duration of 4.7 years, with 35.4% implanted for primary prevention of sudden cardiac arrest). Greater multi-morbidity burden, female sex, not working outside the home, history of ICD shock, negative ICD experience, higher levels of ICD-related concerns, and the presence of anxiety, depression, or Type D personality were associated with worse QOL in ICD recipients. Predictors differed by multi-morbidity burden level.

CONCLUSIONS

Multi-morbidity burden and psychological distress is an essential factor related to QOL. This issue should be discussed with potential ICD recipients prior to implant. Further exploration of increased recognition and treatment of psychological distress in ICD recipients is warranted.

Treatment of phantom shocks: A case report

Implantable cardioverter-defibrillators have become standard preventive treatment for patients with ventricular arrhythmias and other life-threatening cardiac conditions. The advantages and efficiency of the device are supported by multiple clinical trials and outcome studies, leading to its popularity among cardiologists. Implantation of the device is not without adverse outcomes. Implantable cardioverter-defibrillator placement has been found to lead to negative psychological and psychosocial sequelae such as apprehension to engage in physical activity, chronic anxiety, decreased physical and social functioning, a nagging fear of being shocked by the device, and the development of "phantom shocks." Defined as patient-reported shocks in the absence of evidence that the implantable cardioverter-defibrillator device has discharged, phantom shocks could impact the mental health of those affected. This article reviews the case of Mr. L, a 47-year-old man with ischemic cardiomyopathy who was seen by the psychiatry consultation team while under cardiologic care because he reported that his implantable cardioverter-defibrillator device had been shocking him despite no objective evidence after interrogating the device. A literature review of phantom shocks, their associated symptomatology, and psychological consequences are outlined and discussed.

The Value of the Tei Index in Predicting Implantable Cardioverter Defibrillator Shocks

Objectives:

An implantable cardioverter defibrillator (ICD) decreases the risk of sudden death in the appropriate patients. However, a relationship between ICD shocks and increased mortality and morbidity has been suspected. This report is an investigation of an association between ICD shocks and the Tei index, an echocardiographic parameter now commonly used to predict cardiovascular events.

Methods:

The basic characteristics of 250 patients with chronic heart failure who had an ICD implanted and 2 years of follow-up device recordings were retrospectively analyzed. Patients who received shock therapy during follow-up were compared with those who did not, based on demographic and other characteristics and the Tei index.

Results:

The mean Tei index value of ICD shock recipients was significantly higher than the score of non-recipients of ICD shock (0.70±0.10 vs 0.56±0.10; p<0.001). The percentage of patients for whom it was primary prevention who received either appropriate or inappropriate ICD shocks was 28.9%, whereas in those who received an ICD for secondary prevention, the percentage was 71.1% (p<0.001). ICD shock recipient patients were older, and had a greater rate of hypertension and smoking pack-years compared with those to whom an ICD shock was not delivered (p<0.001).

Conclusion:

The results of this study demonstrated a relationship between the Tei index and ICD shocks, either appropriate or inappropriate. The Tei index is a simple method to predict ICD shocks.

Inappropriate ICD Shocks in Pediatric and Congenital Heart Disease Patients

Although implantable cardioverter-defibrillators (ICDs) have proven to be life-saving devices, there are frequent complications associated with their use, especially in the pediatric and congenital heart disease populations. Inappropriate shocks are a particularly frequent complication in these groups. This review discusses the causes and implications of inappropriate ICD shocks, and presents potential interventions that may assist in safely reducing the rates of inappropriate shocks in pediatric and congenital heart disease patients with ICDs.

Preliminary Development of an Informational Media Use Measure for Patients with Implanted Defibrillators: Toward a Model of Social-Ecological Assessment of Patient Education and Support

Social work interventions in health care, particularly those that involve working with people being treated for chronic and life-threatening conditions, frequently involve efforts to educate patients about their disease, treatment options, safety planning, medical adherence, and other associated issues. Despite an intuitive notion that patients access information about all of these issues through a variety of media-both inside and outside the clinical encounter, created by professionals and by others-there currently exists no validated means of assessing patients' use of these forms of information. To address this gap, authors first created candidate item measures with input from both physicians and a small group of diverse patients who currently have an implantable cardioverter defibrillator (ICD), a sophisticated cardiac device for which a trajectory model of social work intervention was recently outlined. Authors then surveyed a group of 205 individuals who have these devices, assessing their use of various media to learn about ICDs. They then conducted factor and item analysis to refine and remove poorly performing items while delineating forms of media use by type. The resultant preliminary measure of informational media use can be further refined and adapted for use with any clinical population.

Optimal Implantable Cardioverter Defibrillator Programming

Optimal programming of implantable cardioverter defibrillators (ICDs) is essential to appropriately treat ventricular tachyarrhythmias and to avoid unnecessary and inappropriate shocks. There have been a series of large clinical trials evaluating tailored programming of ICDs. We reviewed the clinical trials evaluating ICD therapies and detection, and the consensus statement on ICD programming. In doing so, we found that prolonged ICD detection times, higher rate cutoffs, and antitachycardia pacing (ATP) programming decreases inappropriate and painful therapies in a primary prevention population. The use of supraventricular tachyarrhythmia discriminators can also decrease inappropriate shocks. Tailored ICD programming using the knowledge gained from recent ICD trials can decrease inappropriate and unnecessary ICD therapies and decrease mortality.

Longitudinal changes in quality of life following ICD implant and the impact of age, gender, and ICD shocks: observations from the INTRINSIC RV trial

PURPOSE

ICDs can improve survival in at-risk patients but no consensus exists with respect to their impact on health-related quality of life (QOL). Moreover, the data are unclear on QOL benefits in specific patient subgroups. We sought to analyze, in the INTRINSIC RV ICD trial population, health-related QOL longitudinally following ICD implant and consider impact of age, gender, and ICD shocks on QOL by employing a global measure of health-related QOL.

METHODS

One thousand five hundred thirty patients had an ICD implanted. One week after implant (n = 1461), 988 patients were randomized to DDDR with AV search hysteresis (n = 502) or VVI (n = 486) programming. QOL data, using the SF-36 short form, were obtained for the 1461 patient cohort, irrespective of randomization status, at baseline and prospectively for 1 year following ICD implant.

RESULTS

Longitudinal mixed-effect analyses revealed significant improvements from baseline across all SF-36 subscales and component scores for the overall study cohort. Women had a substantially lower QOL at baseline, although their improvement after implant was similar to men. Patients <50 years scored consistently worse at baseline but experienced the greatest QOL improvement versus other age groups. Patients with higher NYHA class, angina, and diabetes had greater QOL improvements. There was no significant difference in QOL between patients with and without ICD shocks.

CONCLUSIONS

Our findings indicate that QOL was reportedly better post-implant and suggest that benefits associated with ICD implantation go beyond the direct treatment of arrhythmias, with benefits seen across genders and different age groups. These results further highlight that ICD implantation, in and of itself, does not reduce QOL.

Transaxillary Subpectoral Placement of Cardiac Implantable Electronic Devices in Young Female Patients

Background

The current indications of cardiac implantable electronic devices (CIEDs) have expanded to include young patients with serious cardiac risk factors, but CIED placement has the disadvantage of involving unsightly scarring and bulging of the chest wall. A collaborative team of cardiologists and plastic surgeons developed a technique for the subpectoral placement of CIEDs in young female patients via a transaxillary approach.

Methods

From July 2012 to December 2015, subpectoral CIED placement via an axillary incision was performed in 10 young female patients, with a mean age of 25.9 years and mean body mass index of 20.1 kg/m2. In the supine position, with the patient's shoulder abducted, an approximately 5-cm linear incision was made along one of the deepest axillary creases. The submuscular plane was identified at the lateral border of the pectoralis major, and the dissection continued over the clavipectoral fascia until the subpectoral pocket could securely receive a pulse generator. Slight upward dissection also exposed an entrance to the subclavian vein, allowing the cardiology team to gain access to the vein. One patient with dilated cardiomyopathy underwent augmentation mammoplasty and CIED insertion simultaneously.

Results

One case of late-onset device infection occurred. All patients were highly satisfied with the results and reported that they would recommend the procedure to others.

Conclusions

With superior aesthetic outcomes compared to conventional methods, the subpectoral placement of CIEDs via a transaxillary approach is an effective, single-incision method to hide operative scarring and minimize bulging of the device, and is particularly beneficial for young female or lean patients.

Posttraumatic stress and quality of life with the totally subcutaneous compared to conventional cardioverter-defibrillator systems

BACKGROUND

For prevention of sudden cardiac death, the transvenously implantable cardioverter-defibrillator therapy (tv-ICD) is well accepted. The subcutaneous system (S-ICD^®) is promising in terms of reducing ICD complications. Nevertheless, the impact of the novel generator position on patients' quality of life (QoL) is yet unknown.

OBJECTIVE

This study aimed at comparing QoL and posttraumatic stress with both systems.

METHODS

60 S-ICD^® and 60 case-controlled tv single-chamber ICD patients were asked to respond to three standardized questionnaires. PDS [screening for posttraumatic stress disorders (PTSD)] and PHQ-D (detection of the most predominant psychological disorders) were used to screen for potential mental comorbidities. The SF-12 questionnaire was used to evaluate physical and mental well-being. Groups were compared in terms of QoL and PTSD.

RESULTS

n = 42 (70%) pairs were analyzed (n = 30 male, mean age 44.6 ± 12.2 years). Prior appropriate (p = 0.06) or inappropriate episodes (p = 0.24), ejection fraction (p = 0.28), or underlying cardiac disease did not differ significantly between groups. PDS revealed a PTSD in n = 6 tv-ICD and n = 6 S-ICD^® patients (14.3%) equally. In the PHQ-D questionnaire, n = 4 tv-ICD and n = 2 S-ICD^® patients fulfilled criteria for a major depression (p = 0.68). Panic disorders (n = 2 tv, n = 0 S-ICD^®, p = 0.5), and anxiety disorders (n = 3 S-ICD^®, n = 0 tv-ICD, p = 0.24) did not differ between groups. The physical well-being score was 39.9 ± 12.5 in patients with a tv-ICD compared to 46.6 ± 9.9 in S-ICD^® patients (p = 0.01). The mental well-being score was comparable in both groups (tv-ICD 51.8 ± 10.8 vs. S-ICD^® 51.9 ± 10.4, p = 0.95).

CONCLUSIONS

Our case-control study revealed equal or even better physical well-being of patients with the S-ICD^®. PTSD occurred in almost 15% of ICD patients irrespective of the type of system.

Factors associated with anxiety and depression among patients with implantable cardioverter defibrillator

AIMS AND OBJECTIVES

To identify factors associated with anxiety and depression of patients with implantable cardioverter defibrillators.

BACKGROUND

Implantable cardioverter defibrillator is effective to increase survival from life-threatening arrhythmias, but it lowers health-related quality of life. Anxiety and depression had significant negative association with health-related quality of life. However, knowledge about factors associated with these two negative emotions in this specific population is inadequate.

DESIGN

A cross-sectional descriptive design was conducted. Secondary analysis was performed to address the aim.

METHODS

A convenience sampling of patients with implantable cardioverter defibrillators was performed. Anxiety and depression were measured by the Hospital Anxiety and Depression Scale through face-to-face interview.

RESULTS

Stepwise multivariable regression results showed that older age (aged 60-69 and ≥70: B = 2·08 and 3·31, p = 0·039 and <0·001), self-care dependence (B = 3·47, p < 0·001), being married (B = -2·21, p = 0·004) and having ischaemic heart disease (B = -1·80, p = 0·008) were significantly associated with depression. However, there was no significant factor associated with anxiety.

CONCLUSIONS

Factors associated with depression among patients with implantable cardioverter defibrillator are identified. Older age (aged ≥60) and more self-care dependence have positive, but being married and having ischaemic heart disease have negative association with depression. Strategies to reduce psychological distress are highlighted.

RELEVANCE TO CLINICAL PRACTICE

The study findings direct the care to improve health-related quality of life by reducing and controlling vulnerabilities arising from depression. Patients who are older people (≥aged 60) and more self-care dependent perceive higher depression. Nursing strategies are suggested to reduce depression especially for those who are older people and more self-care dependent. Early screening is essential to provide immediate care for reducing vulnerabilities arising from depression. Performing comprehensive assessment for self-care ability and providing adequate assistance are crucial. Family involvement may reduce depression through providing physical and psychosocial support.

The Significance of Shocks in Implantable Cardioverter Defibrillator Recipients

Large-scale implantable cardioverter defibrillator (ICD) trials have unequivocally shown a reduction in mortality in appropriately selected patients with heart failure and depressed left ventricular function. However, there is a strong association between shocks and increased mortality in ICD recipients. It is unclear if shocks are merely a marker of a more severe cardiovascular disease or directly contribute to the increase in mortality. The aim of this review is to examine the relationship between ICD shocks and mortality, and explore possible mechanisms. Data examining the effect of shocks in the absence of spontaneous arrhythmias as well as studies of non-shock therapy and strategies to reduce shocks are analysed to try and disentangle the shocks versus substrate debate.

Cognitive-Behavioral Treatment of Posttraumatic Stress in Patients With Implantable Cardioverter Defibrillators: Results From a Randomized Controlled Trial

Approximately 20% of patients with implantable cardioverter defibrillators (ICDs) suffer from posttraumatic stress disorder (PTSD) due to a history of cardiac arrest, device implantation, and ICD shock. There has been very little examination of treatment of PTSD symptoms in these patients. This study evaluated the effect of a specific cognitive-behavioral therapy (CBT) intervention for ICD patients with high levels of PTSD symptoms: a manualized program consisting of 8 telephone sessions with a trained counselor, a patient education book, and a stress management procedure on compact disc. Participants were 193 ICD patients, who were randomized to CBT or usual cardiac care (UCC) who completed self-report surveys at the time of recruitment and 6 and 12 months after initial measurement. Previous publication on the primary research evaluation questions reported that the CBT condition resulted in greater improvement on PTSD and depression symptoms than the UCC for the general population of ICD patients, but did not evaluate the effect on those with elevated symptoms of PTSD. The authors conducted secondary analyses of the effect of treatment on high and low PTSD symptom groups based on a cutoff for the Impact of Event Scale-Revised (Weiss & Marmar, 1997). Participants in the CBT group who had high symptoms experienced significantly greater symptom reduction from baseline to 12 months (d = 2.44, p = .021) than the UCC group (d = 1.12). Participants with low symptoms had small reductions regardless of group assignment (d = 0.16, p = .031). ICD-focused CBT was sufficient to produce a large, statistically significant reduction in PTSD symptoms in ICD patients with indications for treatment.

Fearful Appraisals and Behavioral Responses of a Patient with an Implantable Cardioverter Defibrillator

The implantable cardioverter defibrillator (ICD) is an effective treatment device for potentially malignant arrhythmias, including those leading to sudden cardiac death. However, some patients develop a variety of adjustment problems to the ICD. Clinical behavioral scientists have conceptualized ICD adjustment problems using principles of classical conditioning (i.e., cardiophobia), the learned helplessness paradigm of depression, and cognitive-behavioral models of panic. This case study likens ICD adjustment problems to a cognitive-behavioral model of panic and chest pain illustrating the limits of thesemodels in terms of howType I/Type II threat appraisal by the patient serves as a significant barrier to full symptomresolution. This case study supports the need formodifications in suchmodels and related interventions as they relate to the presence of real comorbid risk factors.

Implantable Cardioverter Defibrillator Therapy and the Need for Concomitant Antiarrhythmic Drugs

Implantable cardioverter defibrillators (ICDs) are increasingly used for the prevention of sudden cardiac death in patients with life-threatening ventricular arrhythmias (VAs); however, there is a potential for severe and debilitating anxiety caused by symptoms associated with ICD therapy and anticipation of shocks. Anxiety is a psycho-logic stressor, including physiologic components that may lead to adrenergic excitation triggering new arrhythmias and ICD therapies. This often requires concomitant antiarrhythmic medication to reduce the frequency of shocks and symptomatic arrhythmias treated by anti-tachycardia pacing. Although published studies have documented the efficacy of currently available antiarrhythmics, they have limitations in patients with heart failure, may affect the defibrillation threshold, and/or have been associated with major side-effects. In conclusion, for the patient with an ICD experiencing symptomatic ventricular tachycardia (VTs) episodes or ICD shocks, there is a need for pharmacologic therapy to reduce the incidence of such events without affecting the performance of the ICD or causing major side-effects.

Impact of the introduction of a standardised ICD programming protocol: real-world data from a single centre

PURPOSE

Randomised trials have shown that empiric ICD programming, using long detection times and high detection zones, reduces device therapy in ICD recipients. However, there is less data on its effectiveness in a "real-world" setting, especially secondary prevention patients. Our aim was to evaluate the introduction of a standardised programming protocol in a real-world setting of unselected ICD recipients.

METHODS

We analysed 270 consecutive ICD recipients implanted in a single centre-135 implanted prior to protocol implementation (physician-led group) and 135 after (standardised group). The protocol included long arrhythmia detection times (30/40 or equivalent) and high rate detection zones (primary prevention lower treatment zone 200 bpm). Programming in the physician-led group was at the discretion of the implanter. The primary endpoint was time-to-any therapy (ATP or shocks). Secondary endpoints were time-to-inappropriate therapy and time-to-appropriate therapy. The safety endpoints were syncopal episodes, hospital admissions and death.

RESULTS

At 12 months follow-up, 47 patients had received any ICD therapy (physician-led group, n = 31 vs. standardised group, n = 16). There was a 47 % risk reduction in any device therapy (p = 0.04) and an 86 % risk reduction in inappropriate therapy (p = 0.009) in the standardised compared to the physician-led group. There was a non-significant 30 % risk reduction in appropriate therapy (p = 0.32). Results were consistent across primary and secondary prevention patients. There were no significant differences in the rates of syncope, hospitalisation, and death.

CONCLUSIONS

In unselected patients in a real-world setting, introduction of a standardised programming protocol, using long detection times and high detection zones, significantly reduces the burden of ICD therapy without an increase in adverse outcomes.

Knowledge of Implantable Cardioverter Defibrillator Purpose and Function Among Nurses in the United States

BACKGROUND

Nurses play a crucial role in patient education and adaptation to having an implantable cardioverter defibrillator (ICD).

OBJECTIVE

The aim of this study was to assess cardiology nurses' knowledge and confidence in providing education and support to ICD recipients.

METHODS

A cross-sectional descriptive survey was used to assess nurses' knowledge and experience caring for ICD recipients in 2 academic medical centers in the Pacific Northwest, using an instrument developed in 2004 in the United Kingdom.

RESULTS

Nurses (N = 74) worked on cardiology units or clinics, primarily held a baccalaureate degree or higher (85%), and had 16 years or more of nursing experience and 6 to 10 years of cardiology experience. The overall average knowledge score was 77%, with knowledge about modern ICD technology averaging 55%. Nurses' confidence, using 10-point scale, in preparing patients to receive an ICD implant was 6.32 ± 2.56, for preparing patients for discharge was 6.14 ± 2.43, and for providing education about ICD shocks was 6.63 ± 2.50. Nurses were most knowledgeable about factors that affect patient retention of knowledge and ICD-related environmental hazards. Nurses lacked knowledge about the basic ICD components, purpose of cardiac resynchronization, and dual-chamber ICDs. Factors associated with higher knowledge scores included past experience caring for a patient with an ICD and working in an electrophysiology outpatient clinic.

CONCLUSIONS

The ICD knowledge of US nurses in 2015 was similar to that reported in the United Kingdom in 2004, with limited knowledge about the complexities of modern ICD devices. Such deficits in knowledge may affect the quality of education provided to ICD recipients in preparing them to live safely with an ICD.

Sleep, Psychosocial Functioning, and Device-Specific Adjustment in Patients with Implantable Cardioverter Defibrillators (ICDs)

Rates of sleep disorders and associated adjustment were examined in patients with implantable cardioverter defibrillators (ICDs; n = 42; Mage = 61.57, SD = 12.60). One night of ambulatory polysomnography, 14 days of sleep diaries, and questionnaires (mood, sleepiness, fatigue, device acceptance) were administered. Controlling for ischemia, MANCOVA examined adjustment by sleep diagnosis. Apnea was most common (28.6%), followed by Insomnia (16.7%) and Comorbid Insomnia/Apnea (11.9%). Patients with insomnia reported poorer mood, greater sleepiness, and lower device acceptance than good sleepers; they also demonstrated poorer mood and less ICD device acceptance than patients with sleep apnea. Patients with comorbid insomnia/apnea also exhibited poorer mood and less ICD device acceptance than good sleepers; however, comorbid patients did not significantly differ from insomnia or apnea patients on any measure. Those with disordered sleep (regardless of type) reported greater fatigue than good sleepers. Assessment (and treatment) of difficulties with sleep, mood, fatigue, and device acceptance may be important for the comprehensive clinical management of ICD patients. Further research appears warranted.

In silico prediction of drug therapy in catecholaminergic polymorphic ventricular tachycardia

Key points

The mechanism of therapeutic efficacy of flecainide for catecholaminergic polymorphic ventricular tachycardia (CPVT) is unclear.

Model predictions suggest that Na⁺ channel effects are insufficient to explain flecainide efficacy in CPVT.

This study represents a first step toward predicting therapeutic mechanisms of drug efficacy in the setting of CPVT and then using these mechanisms to guide modelling and simulation to predict alternative drug therapies.

Abstract

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by fatal ventricular arrhythmias in structurally normal hearts during β‐adrenergic stimulation. Current treatment strategies include β‐blockade, flecainide and ICD implementation – none of which is fully effective and each comes with associated risk. Recently, flecainide has gained considerable interest in CPVT treatment, but its mechanism of action for therapeutic efficacy is unclear. In this study, we performed in silico mutagenesis to construct a CPVT model and then used a computational modelling and simulation approach to make predictions of drug mechanisms and efficacy in the setting of CPVT. Experiments were carried out to validate model results. Our simulations revealed that Na⁺ channel effects are insufficient to explain flecainide efficacy in CPVT. The pure Na⁺ channel blocker lidocaine and the antianginal ranolazine were additionally tested and also found to be ineffective. When we tested lower dose combination therapy with flecainide, β‐blockade and CaMKII inhibition, our model predicted superior therapeutic efficacy than with flecainide monotherapy. Simulations indicate a polytherapeutic approach may mitigate side‐effects and proarrhythmic potential plaguing CPVT pharmacological management today. Importantly, our prediction of a novel polytherapy for CPVT was confirmed experimentally. Our simulations suggest that flecainide therapeutic efficacy in CPVT is unlikely to derive from primary interactions with the Na⁺ channel, and benefit may be gained from an alternative multi‐drug regimen.

The mechanism of therapeutic efficacy of flecainide for catecholaminergic polymorphic ventricular tachycardia (CPVT) is unclear.

Model predictions suggest that Na⁺ channel effects are insufficient to explain flecainide efficacy in CPVT.

This study represents a first step toward predicting therapeutic mechanisms of drug efficacy in the setting of CPVT and then using these mechanisms to guide modelling and simulation to predict alternative drug therapies.