Adjunctive therapy for recurrent ventricular tachycardia in patients with implantable cardioverter defibrillators

Implantable cardioverter defibrillators (ICDs) are now the mainstay of therapy in patients with sustained ventricular tachycardia (VT), ventricular fibrillation, resuscitated sudden cardiac death, or certain high-risk markers for these arrhythmic events. Although ICDs in such patients can be life-saving, they can impair quality of life when painful or frequent discharges occur or when residual VT symptoms recur prior to delivery of ICD therapies. As such, antiarrhythmic drugs often are employed in an attempt to reduce the triggering tachyarrhythmic events. Recently, studies with beta-blockers, sotalol, amiodarone, and the investigational agent azimilide have been performed to objectify the efficacy, benefits, or risks of such therapies when administered to patients with ICDs. This review describes the considerations important to the use of these therapies in ICD patients and the results and applicability of these investigative studies.     

Cigarette smoking and the risk of supraventricular and ventricular tachyarrhythmias in high-risk cardiac patients with implantable cardioverter defibrillators

Introduction: Nicotine elevates serum catecholamine concentration and is therefore potentially arrhythmogenic. However, the effect of cigarette smoking on arrhythmic risk in coronary heart disease patients is not well established.
Methods and Results: The risk of appropriate and inappropriate defibrillator therapy by smoking status was analyzed in 717 patients who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II. Compared with patients who had quit smoking before study entry (past smokers) and patients who had never smoked (never smokers), patients who continued smoking (current smokers) were significantly younger and generally had more favorable baseline clinical characteristics. Despite this, the adjusted hazard ratio (HR) for appropriate ICD therapy for fast ventricular tachycardia (at heart rates ≥180 b.p.m) or ventricular fibrillation was highest among current smokers  (HR = 2.11 [95% CI 1.11–3.99])  and intermediate among past smokers  (HR = 1.57 [95% CI 0.95–2.58])  , as compared with never smokers (P for trend = 0.02). Current smokers also exhibited a higher risk of inappropriate ICD shocks  (HR = 2.93 [95% CI 1.30–6.63])  than past  (HR = 1.91 [95% CI 0.97–3.77])  and never smokers (P for trend = 0.008).
Conclusions: In patients with ischemic left ventricular dysfunction, continued cigarette smoking is associated with a significant increase in the risk of life-threatening ventricular tachyarrhythmias and inappropriate ICD shocks induced by rapid supraventricular arrhythmias. Our findings stress the importance of complete smoking cessation in this high-risk population.     

Use of implantable cardioverter defibrillators in patients with left ventricular assist devices

Patients with left ventricular assist devices (LVADs) are at high risk of sustained ventricular arrhythmias, but these may be remarkably well tolerated and the association with sudden death is unclear. Many patients who receive an LVAD already have an implantable cardioverter defibrillator (ICD). While it is standard practice to reactivate a previously implanted ICD in an LVAD recipient, this should include discussion of the revised risks and benefits of ICD therapy following LVAD implantation. In particular, patients should be warned that they might receive a significant number of ICD shocks that may not be life saving. When ICDs are reactivated, device programming should minimize the risk of repeated shocks for non-sustained or well-tolerated ventricular arrhythmias. Implantation of a primary prevention ICD after implantation of an LVAD is not supported by current evidence, poses potential risks, and should be the subject of a clinical trial before it becomes standard practice.     

Clinical experience in patients with implantable cardioverter defibrillators

Forty patients (36 men and 4 women) with life-threatening arrhythmia received an implantable cardioverter defibrillator (ICD). Mean age was 63 years (range, 46 to 80 years). All patients had structural heart disease, with coronary artery disease in 32 patients, idiopathic cardiomyopathy in 7 patients, and hypertensive heart disease in 1 patient. Mean left ventricular ejection fraction was 29 +/- 13%. The clinical arrhythmia was out-of-hospital cardiac arrest in 14 patients (35%), symptomatic sustained ventricular tachycardia in 21 patients (53%), and episodes of syncope without documented spontaneous ventricular arrhythmia but ventricular tachycardia that was easily provoked at the time of electrophysiologic testing in 5 patients (13%). Sustained ventricular tachycardia was induced in 37 patients (93%) at basic electrophysiologic testing. The average number of drug failures was 2.9 +/- 1.4 per patient. One patient (2.5%) died perioperatively because of intractable ventricular tachycardia and ventricular fibrillation. During a median follow-up period of 5.5 months (range 2-21 months) 2 sudden deaths occurred. No patient had a serious complication during the follow-up period. Ten patients (25%) received antiarrhythmic drugs to suppress spontaneous ventricular tachycardia. Appropriate shock treatment was received by 18 patients (45%), and inappropriate shock treatment was received by 2 patients (5%). Several issues regarding use of the ICD must be considered, but the device seems to be useful, and it is associated with an acceptable rate of complications and good long-term success at the present time.     

Avoidance behaviors in patients with implantable cardioverter defibrillators

BACKGROUND: Although the implantable cardioverter defibrillator (ICD) has become standard therapy for some malignant cardiac arrhythmias, the shocks delivered by the device are often experienced as aversive. Anecdotal accounts of patients avoiding specific objects or places raise the possibility that conditioned avoidance responses can be established in response to ICD shocks. OBJECTIVE: The objective of the study was to better understand the nature of avoidance behavior among ICD recipients and to examine the relevance of classical conditioning and cognitive models to ICD-related avoidance behavior. METHODS: A total of 143 recipients of ICDs completed an anonymous survey reporting on aspects of their experience with the ICD and whether they had begun avoiding specific places, objects, or activities since receiving an ICD. RESULTS: Fifty-five percent of respondents reported at least 1 category of avoidance since receiving an ICD. The frequency of reported avoidances was highest in activities (39%), followed by objects (27%) and places (17%), which were least avoided. There was no relationship between the reported experience of shocks and avoidance behavior, and little evidence for conditioned avoidance. CONCLUSION: Avoidance that is not medically recommended is common among patients with ICDs. This may have adverse effects on quality of life and perhaps the physical health of some patients. Cognitive models, rather than classical conditioning, seem to explain the majority of avoidance behavior reported in this sample. A brief educational intervention or regular participation in ICD support groups could help to dispel misinformation among patients and discourage inappropriate avoidance.     

植入埋藏式心脏复律除颤器患者的电风暴

埋藏式心脏复律除颤器(ICD)预防心源性猝死,提高患者生存率。电风暴是ICD植入后可能出现的一种严重室性心律失常事件,不仅缩短ICD的寿命,还提示患者预后不良。文章就电风暴的定义、发生率、长期预后、促发因素及治疗进行综述。     

埋藏式心脏转复除颤器的随访

目的报道37例埋藏式心脏转复除颤器(ICD)的随访结果。方法对置入ICD的37例患者进行电话询问和门诊随访,通过常规心电图、动态心电图及ICD存储的资料,对患者病情和ICD工作情况进行分析。结果37例患者共发作室性心动过速/心室颤动(VT/VF)917次(VT745次,VF172次),其中911次(99.3%)治疗成功,6次(0.7%)失败。非持续性VT122次(16.4%),发作均自行停止。623次持续性VT(83.6%)中,537次(86.2%)经抗心动过速起搏(ATP)终止,82次(13.2%)经低能量复律(CV)终止,3次(0.4%)在ATP治疗过程中加速为VF,由高能量除颤(DF)终止。172次VF中,167次(97.1%)经DF终止,1例无效放电5次(2.9%)系因电池提前耗竭而更换了ICD脉冲发生器,2例共8次阵发性心房颤动心室率超过设置的VT频率ICD发生误识别,给予ATP治疗。5例术后1~6个月出现心律失常“电风暴”。5例对电击恐惧造成了不同程度的心理障碍,经教导必要时辅以药物治疗后症状得以缓解。共有19例术后因VT发作频繁而服用胺碘酮/美托洛尔,并根据心律失常发作情况调整用药剂量。结论ICD置入后应加强随访,及时调整工作参数,同时辅助药物、改善心功能和心理治疗。     

植入型心律转复除颤器治疗冠心病伴室性心律失常疗效观察

目的 观察冠心病伴恶性室性心律失常患者植入心律转复除颤器(ICD)治疗后的长期预后.方法 23例冠心病患者,其中男性18例,女性15例,年龄(71.56±10.38)岁.心功能不良16例.22例行血运重建术(经皮冠状动脉介入术20例,冠状动脉搭桥术2例).术后发生晕厥9例,持续性室性心动过速(VT)发作22例,心室颤动(VF)发作5例.植入单腔ICD(VVI)15例,双腔ICD(DDDR)1例,三腔ICD(CRT-D)7例.随访时间平均为(33.37±25.39)个月.结果 (1)死亡2例,因急性心肌梗死和急性左心衰竭死亡各1例.(2)4例患者术后再次住院.原因:1例为心功能不良,3例为ICD多次放电住院.(3)13例(56.5%)发生持续性VT或VF事件.持续性VT发作434次,386次(98.6%)经抗心动过速起搏(ATP)治疗成功.FVT发作25次,ATP治疗FVT总的成功率为84.0%.(4)ICD电风暴3例.(5)ICD误识别及误治疗2例.结论 冠心病伴恶性室性心律失常患者血运重建后用ICD治疗,可防止由于心肌的慢性的瘢痕产生室性心律失常而导致猝死的风险.     

Clinical and electrophysiologic predictors of ventricular tachyarrhythmia recurrence in patients with implantable cardioverter defibrillators

INTRODUCTION: Not all patients experience recurrent sustained ventricular tachyarrhythmias after placement of an implantable cardioverter defibrillator (ICD). We evaluated the clinical and electrophysiologic predictors of ventricular tachycardia (VT) and ventricular fibrillation (VF) recurrence following ICD implantation. METHODS AND RESULTS: Consecutive patients (n = 133) underwent 4 +/- 3 serial electrophysiologic studies (EPS) over 50 +/- 26 months following ICD implantation. Sustained VT/VF could always be induced during follow-up EPS in 49 patients; sustained VT/VF was sometimes induced during follow-up EPS in 47 patients; and sustained VT/VF could never be induced during follow-up EPS in 37 patients. Spontaneous VT/VF requiring ICD therapy occurred in 107 patients during follow-up. Patients with sustained VT/VF that was always inducible or sometimes inducible during follow-up experienced more frequent episodes of VT/VF following ICD implant (20.5, 95% CI 12.7-33.0; and 17.8, 95% CI 11.3-28.1 episodes/patient respectively; vs 3.0, 95% CI 2.0-4.6 episodes/patient for patients with VT/VF never induced, P < 0.001). Inducibility of sustained VT/VF post-ICD implant (P < 0.001) and sustained VT as the presenting arrhythmia (P = 0.02) were independent predictors of spontaneous VT/VF recurrence. CONCLUSION: Reproducibly inducible VT/VF following ICD implantation predicts a high probability of VT/VF recurrence and identifies a cohort of patients who experience frequent episodes of VT/VF over time. Persistent noninducibility of sustained VT/VF identifies a group of patients who experience no or very few episodes of VT/VF recurrence.     

Incidence of nonsustained and sustained ventricular tachyarrhythmias in patients with an implantable cardioverter defibrillator

INTRODUCTION: Nonsustained ventricular tachycardia (NSVT) is a frequent phenomenon in some patients with heart disease, but its association with sustained ventricular tachycardias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) is still not clear. The aim of this study was to determine whether NSVT incidence was associated with sustained VT/VF in patients with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: Retrospective data analysis was conducted in 923 ICD patients with a mean follow-up of 4 months. NSVT and sustained VT/VF were defined as device-detected tachycardias. The incidence rates of NSVT and sustained VT/VF as well as ICD therapies were determined as episodes per patient. The NSVT index was defined as the product of NSVT episodes/day times the mean number of beats per episode, i.e., total beats/day. The NSVT index peak was defined as the highest value on or prior to the day with sustained VT/VF episodes. Patients (n = 393) with NSVT experienced a higher incidence of sustained VT/VF (17.2 +/- 63.0 episodes/patient) and ICD therapies (15.2 +/- 61.4 episodes/patient) than patients (n = 530) without NSVT (sustained VT/VF: 0.5 +/- 6.6 and therapies: 0.5 +/- 5.6; P < 0.0001). Approximately 74% of NSVT index peaks occurred on the same day or <3 days prior to sustained VT/VF episodes. The index was higher for peaks < or =3 days prior to the day with sustained VT/VF (94.3 +/- 140.1 total beats/day) than for peaks >3 days prior to the day with sustained VT/VF (32.7 +/- 55.9 total beats/day; P < 0.0001). CONCLUSION: ICD patients with NSVT represent a population more likely to experience sustained VT/VF episodes with a temporal association between an NSVT surge and sustained VT/VF occurrence.     

Inappropriate discharges by fourth generation implantable cardioverter defibrillators in patients with ventricular arrhythmias.

The study prospectively investigated the incidence, cause and efficient management of inappropriate discharge by the fourth generation implantable cardioverter-defibrillator (ICD) system in 45 patients (mean age, 57+/-16 years). During the follow-up period of 27+/-17 months, 18 patients (40%) experienced one or more inappropriate therapies: sinus and supraventricular tachycardia (15 patients) and T wave oversensing (3 patients). In the 15 patients, re-programming of the tachycardia detection interval and/or additional treatment with beta-blocking agents were effective. In the 3 patients with T wave oversensing, the arrythmia was associated with an increase in T wave amplitude, change in T wave morphology and decreased R wave amplitude, and re-programming of the sensitivity of the local electrogram or changing the number of intervals to detect ventricular tachycardia decreased the number of inappropriate discharges in all 3 patients. In conclusion, inappropriate therapies are common problems in patients treated with the fourth generation ICD system, but most of them can be resolved using the dual-chamber ICD system. However, in patients with T-wave oversensing, it is difficult to avoid inappropriate discharge completely, even if the dual-chamber ICD system is implanted.     

Automatic implantable cardioverter defibrillators and survival of patients with left ventricular dysfunction and malignant ventricular arrhythmias

STUDY OBJECTIVE: To assess survival after insertion of automatic implantable cardioverter defibrillators in high-risk patients who have malignant ventricular arrhythmias and left ventricular dysfunction. DESIGN: Actual survival time compared with arrhythmia-free time in a single group of patients. SETTING: Inpatient services of a tertiary referral center and outpatient follow-up. PATIENTS: Seventy consecutive patients with clinical sustained ventricular tachycardia or fibrillation whose arrhythmia could not be controlled by medication as determined by programmed electrical stimulation, and who had an automatic cardioverter defibrillator implanted. INTERVENTION: All patients received an implantable defibrillator. MEASUREMENTS AND MAIN RESULTS: Two-year survival was 93.4% (95% CI, 87 to 99.8) and projected survival based on recurrence of malignant arrhythmias was 60.3% (CI, 47.3 to 73.3; P less than 0.001). In the 25 patients with left ventricular ejection fraction less than 30%, actual survival was 86.7% (CI, 72.3 to 91.1) and projected survival was 56.9% (CI, 35.9 to 77.9; P = 0.025). Projected survival percentages are similar to survival figures reported in the literature for such high-risk patients. There was only one sudden death; the remaining deaths were not arrhythmic in nature. Of the 65 patients who were alive at the end of follow-up, 13 were in New York Heart Association Class I; 44, Class II; 5, Class III; and 3, Class IV. CONCLUSIONS: The automatic implantable cardioverter defibrillator is probably highly effective in preventing arrhythmic mortality even in high-risk patients. Such treatment does not appear to significantly impair a patient's functional status.     

Quality of life in pediatric patients with implantable cardioverter defibrillators

Psychosocial and quality-of-life (QOL) outcomes in adult patients with implantable cardioverter-defibrillators (ICDs) are well studied. Minimal research exists regarding pediatric adjustment, despite a potentially more challenging adjustment process. The purpose of the present study was to examine psychosocial and QOL functioning of pediatric ICD patients from patient and parent self-reports. Children and primary caregiver dyads from several university hospitals were analyzed using the PedsQL, the Device Severity Index, the ICD and Avoidance Survey, and demographic information. Sixty children (25 female, 35 male) were enrolled. The present pediatric sample reported lower psychosocial and physical QOL scores than healthy children's normative scores. In comparison with a sample of chronically ill children, pediatric ICD patients reported lower physical QOL. Parent-observed QOL reports revealed lower psychosocial and physical QOL than parent-observed healthy norms and lower psychosocial and physical QOL than chronically ill norms. There were no QOL differences by ICD shocks or medical severity. Female patients reported lower psychosocial, physical, and cardiac QOL scores. Children reported better QOL than parent observations on psychosocial and physical health. Finally, 84.7% of children reported avoidance behaviors since ICD implantation, with female children avoiding places more than male children. In conclusion, pediatric ICD patients are comparable to children with other chronic illnesses with the exception of lower physical QOL. Similar to adult samples, female children reported poorer QOL and were more likely to engage in avoidance behaviors. Patients indicated better QOL perceptions than their parents' reports. ICD discharges and medical severity did not negatively affect QOL.     

Effect of spironolactone on ventricular arrhythmias in patients with left ventricular systolic dysfunction and implantable cardioverter defibrillators

Aims/objectivesPatients with implantable cardioverter defibrillators (ICD) often receive an adjunctive anti-arrhythmic therapy. We propose that an addition of spironolactone will reduce the number of clinically significant ventricular arrhythmias and ICD-related therapies.Methods and resultsIn a multicentre retrospective study, 64 patients with ischaemic and non-ischaemic dilated cardiomyopathy whose left ventricular ejection fraction (LVEF) was <35% and with ICD were selected. Amongst these patients, 28 patients were on spironolactone and 36 were not taking spironolactone. The ICD interrogation data were analysed for a maximum of 12 months. Wilcoxon Rank Sum test was used to compare the study and control groups. The outcomes were: (1) the number of shocks/anti-tachycardia pacing (ATP) episodes and (2) the number of episodes of ventricular tachycardia (VT) requiring ATP, non-sustained VT (NSVT), and ventricular fibrillation (VF) over the study period. The spironolactone group had fewer monthly, VTs (P=0.027) (requiring ATP). The two groups did not differ in the number of NSVT or VF per month.ConclusionAddition of spironolactone as an adjunct to ICD therapy in patients with congestive heart failure (CHF) reduces VT requiring ATP, but does not affect NSVT or VF per month.     

Long-term outcome of patients who received implantable cardioverter defibrillators for stable ventricular tachycardia

INTRODUCTION: Evidence is inconclusive concerning the role of implantable cardioverter defibrillators (ICDs) to treat patients with hemodynamically stable ventricular tachycardia (VT). The goal of this study was to estimate future risk of unstable ventricular arrhythmias in patients who received ICDs for stable VT. METHODS AND RESULTS: We reviewed complete ICD follow-up data from 82 patients (age 66.1 +/- 11.3 years; left ventricular ejection fraction 32.3%+/- 11.2%; mean +/- SD) who received ICDs for stable VT. During the follow-up period of 23.6 +/- 21.5 months (mean +/- SD), 15 patients (18%) died, and 10 (12%) developed unstable ventricular arrhythmia, 8 of whom had the unstable arrhythmia as the first arrhythmia after ICD placement. Estimated 2- and 4-year survival in the whole group was 80% and 74%, respectively. Estimated 2- and 4-year probability of any VT and unstable VT was 67% and 77% and 11% and 25%, respectively. There were no differences in age, ejection fraction, sex, underlying heart disease, cycle length, symptoms, baseline electrophysiologic study results, or QRS characteristics of qualifying VT between patients who developed unstable ventricular arrhythmia and patients who did not. Twenty-nine patients (35%) had at least one inappropriate shock, and 11 (13%) underwent further surgery for ICD-related complications. CONCLUSION: Patients who present with hemodynamically stable VT are at risk for subsequent unstable VT. ICD treatment offers potential salvage of patients with stable VT who subsequently develop unstable VT/ventricular fibrillation, although complications and inappropriate shocks are considerable. No predictors could be found for high and low risk for unstable arrhythmias. These findings support ICD treatment for stable VT survivors.     

Wearable cardioverter defibrillator: bridging for implantable defibrillators in left ventricular assist device patients

Heart Failure Reviews - There is currently conflicting data available regarding the use of implantable cardioverter-defibrillators&nbsp;(ICD) in left ventricular assist device (LVAD) patients....