Phantom shocks unmasked: clinical data and proposed mechanism of memory reactivation of past traumatic shocks in patients with implantable cardioverter defibrillators

Addressing PTSD in Implantable Cardioverter Defibrillator Patients: State-of-the-Art Management of ICD Shock and PTSD

PURPOSE OF REVIEW

This paper reviews the unique processes and treatments of post-traumatic stress in implantable cardioverter-defibrillator (ICD) patients and posits specific clinical management recommendations.

RECENT FINDINGS

PTSD is a common presenting problem for a prospective ICD patient and is a common response to ICD shocks. Approximately 32% of patients with sudden cardiac arrest report significant PTSD symptoms. Following ICD shock, approximately 20% experience PTSD from the shocks. Regardless, PTSD can interrupt and undermine clinical management from a cardiologist perspective and create significant disturbance in patients and families. Few cardiology clinics are outfitted to effectively manage psychological distress, in general, and PTSD, in particular. Effective management of PTSD patients can be achieved with both direct care in the cardiac clinic, as well as indirect care via multidisciplinary consultation and expertise. The importance of emotional validation, return to physical activity, and family engagement is emphasized in current management.

Effects of renal denervation therapy on cardiac function and malignant arrhythmia in patients with reduced left ventricular ejection fraction and narrow QRS complexes treated with implantable cardioverter defibrillator

Objective: The purpose of this study was to explore the effects of renal denervation (RDN) on cardiac function and malignant arrhythmia in patients with reduced left ventricular ejection fraction (HFrEF) and narrow QRS treated with an implantable cardioverter defibrillator (ICD).

Methods: A total of 20 eligible HFrEF patients [left ventricular ejection fraction (LVEF) <40%] and narrow QRS complexes (QRS duration <120 ms) were randomized into either the ICD plus RDN group or the ICD only group during 17 April 2014 to 22 November 2016. Clinical data, including clinical characteristics, blood biochemistry, B-type natriuretic peptide, echocardiographic indexes, 6-min walk distance (6MWD), New York Heart Association (NYHA) classification, and count of ICD discharge events before and after the operation were analyzed. Patients were followed up for up to 3 years post ICD or ICD plus RDN.

Results: Baseline clinical data were comparable between the two groups. Higher LVEF (%) (mixed model repeated measure, p = 0.0306) (39.50% ± 9.63% vs. 31.20% ± 4.52% at 1 year; 41.57% ± 9.62% vs. 31.40% ± 8.14% at 3 years), systolic blood pressure (p = 0.0356), and longer 6MWD (p < 0.0001) as well as reduction of NYHA classification (p < 0.0001) were evidenced in the ICD plus RDN group compared to ICD only group during follow-up. Patients in the ICD plus RDN group experienced fewer ICD discharge events (2 vs. 40) and decreased diuretic use; rehospitalization rate (30% vs. 100%, p = 0.0031) and cardiogenic mortality rate (0% vs. 50%, p = 0.0325) were also significantly lower in the ICD plus RDN group than in the ICD only group during follow-up.

Conclusion: ICD implantation plus RDN could significantly improve cardiac function and cardiac outcome as well as increase exercise capacity compared to ICD only for HFrEF patients with narrow QRS complexes.

Stimulant Drugs of Abuse and Cardiac Arrhythmias

Nonmedical use of prescription and nonprescription drugs is a worldwide epidemic, rapidly growing in magnitude with deaths because of overdose and chronic use. A vast majority of these drugs are stimulants that have various effects on the cardiovascular system including the cardiac rhythm. Drugs, like cocaine and methamphetamine, have measured effects on the conduction system and through several direct and indirect pathways, utilizing multiple second messenger systems, change the structural and electrical substrate of the heart, thereby promoting cardiac dysrhythmias. Substituted amphetamines and cocaine affect the expression and activation kinetics of multiple ion channels and calcium signaling proteins resulting in EKG changes, and atrial and ventricular brady and tachyarrhythmias. Preexisting conditions cause substrate changes in the heart, which decrease the threshold for such drug-induced cardiac arrhythmias. The treatment of cardiac arrhythmias in patients who take drugs of abuse may be specialized and will require an understanding of the unique underlying mechanisms and necessitates a multidisciplinary approach. The use of primary or secondary prevention defibrillators in drug abusers with chronic systolic heart failure is both sensitive and controversial. This review provides a broad overview of cardiac arrhythmias associated with stimulant substance abuse and their management.

Phantom Shocks Associated With a Wearable Cardioverter Defibrillator

Wearable cardioverter defibrillators (WCDs) are external devices capable of continuous cardiac rhythm monitoring as well as automatic detection and defibrillation of potentially life-threatening arrhythmias such as ventricular tachycardia (VT) and ventricular fibrillation (VF). They are an alternative approach for patients when an implantable cardioverter defibrillator (ICD) is not appropriate. Although treatment with ICD is considered highly effective for the primary and secondary prevention of sudden cardiac death (SCD) in high-risk patients susceptible to VT and VF, patients may still experience psychological difficulties such as fear of shock, avoidance of normal behaviors and reduced quality of life. One of these phenomena is phantom shock (PS), which is defined as a perception of having received a shock with no evidence of recorded defibrillation upon device interrogation. While PS has been reported in the ICD literature, to the best of our knowledge, we present the first known case of WCD-related PS. We also present a review of the current literature to explore the prevalence of PS, the factors associated with its pathogenesis and interventional studies aimed at reducing its occurrence. We highlight this case because PS is considered a phenomenon that few recognize, which should be discriminated from real device shocks before clinicians initiate treatment, device reprogramming or device discontinuation. We describe the psychosocial factors associated with PS to emphasize the importance of managing any associated psychiatric disorders and psychosocial factors both before and after initiation of device treatment.

[Cardiac implantable electronic devices and health-related quality of life]

Patients, scientists and healthcare providers are increasingly interested in identifying interventions that not only reduce mortality but also improve symptoms, function and health-related quality of life. Health-related quality of life is a strong, independent predictor of mortality, cardiovascular events, hospitalization and treatment costs in patients with cardiac diseases. Remote monitoring of pacemakers has a positive effect on health-related quality of life and functional capacity and is equivalent to monitoring these patients in hospitals. Implantation of an implantable cardioverter defibrillator has a major impact on mental health, with the majority of patients experiencing the fear of ICD shocks as particularly detrimental to the quality of life. Variables, such as age, gender and duration of implantation should be considered in the assessment and planning of strategies for improving the quality of life of patients with electronic implantable cardiac devices.

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.

Nocturnal phantom shock cessation with zolpidem

A 77 year old man with a biventricular ICD-pacemaker complained of painful, electric jolts disturbing him nightly from sleep. Extensive work-up including device interrogation revealed no defibrillations or arrhythmia, and he was subsequently diagnosed with phantom shocks (PS). His nightly PS symptoms terminated after starting zolpidem 10 mg each night. To date, literature review reveals fifteen articles reporting 163 phantom shock (PS) cases. PS affects 5-9% of ICD recipients. Risk factors include psychiatric disease, atrial fibrillation, NYHA functional status III or greater, prior shock storm, and intraoperative awareness during ICD placement, with defibrillation threshold testing. This report describes a successful PS intervention, and reviews the current knowledge available in the pathophysiology and treatment of PS.

ED evaluation and management of implantable cardiac defibrillator electrical shocks

Patients with implantable cardiac defibrillators not infrequently present to the emergency department after experiencing an implantable cardiac defibrillator shock. This review considers the management of such patients in the emergency department, including appropriate, inappropriate, and phantom shocks as well as electrical storm.

Do implantable cardioverter defibrillators contribute to new depression or anxiety symptoms? A retrospective study

OBJECTIVE

In this retrospective cross-sectional study, we evaluated the existence of psychiatric symptoms which appeared after implantation of an implantable cardioverter defibrillator (ICD).

METHODS

Patients with ICDs were diagnosed using the Mini International Neuropsychiatric Interview (MINI) and were excluded if they had any psychiatric diagnosis prior to ICD implantation. Depression and anxiety were evaluated using the HAM-D and HAM-A rating scales and their attitude towards the ICD using a visual analog scale (VAS). Ninety five ICD patients with mean age of 66 years (±11.5) were recruited, 80 (84%) were men.

RESULTS

Four (4%) patients were diagnosed with new-onset MDD and one patient (1%) with anxiety. Twenty seven (28%) were found to have significant depressive symptoms (HAM-D >8), without MDD diagnosis; half of them attributing these symptoms to the device. Seven (8%) patients experienced phantom shocks and had relatively higher depressive scores (HAM-D 10.3 vs. 5.8; F = 3.696; p = 0.058). The MDD rates in our study were rather consistent with those reported for cardiac patients.

CONCLUSIONS

We suggest that ICD contributed little, if any, additional depressive or anxiety symptoms after implantation. We found that the overall attitude towards the device was positive and that shocks and phantom shocks were related to depressive symptoms.

Incidence and predictors of phantom shocks in implantable cardioverter defibrillator recipients

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are designed to deliver shocks or antitachycardia pacing (ATP) in the event of ventricular arrhythmias. During follow-up, some ICD recipients experience the sensation of ICD discharge in the absence of an actual discharge (phantom shock). The aim of this study was to evaluate the incidence and predictors of phantom shocks in ICD recipients.

METHODS

Medical records of 629 consecutive patients with ischaemic or dilated cardiomyopathy and prior ICD implantation were studied.

RESULTS

With a median follow-up of 35 months, phantom shocks were reported by 5.1 % of ICD recipients (5.7 % in the primary prevention group and 3.7 % for the secondary prevention group; p=NS). In the combined group of primary and secondary prevention, there were no significant predictors of the occurrence of phantom shocks. However, in the primary prevention group, phantom shocks were related to a history of atrial fibrillation (p=0.03) and NYHA class <III (p=0.05). In the secondary prevention group, there were no significant predictors for phantom shocks.

CONCLUSION

Phantom shocks occur in approximately 5 % of all ICD recipients. In primary prevention patients, a relation with a history of atrial fibrillation and NYHA class <III were significant predictors for the occurrence of phantom shocks. In the secondary prevention patients, no significant predictors were found.