Wearable cardioverter defibrillator: Bridge or alternative to implantation?

The implantable cardioverter-defibrillator(ICD) is effective to prevent sudden cardiac death(SCD) in selected patients with heart disease known to be at high risk for ventricular arrhythmia. Nevertheless, this invasive and definitive therapy is not indicated in patients with potentially transient or reversible causes of sudden death, or in patients with temporary contraindication for ICD placement. The wearable cardioverter defibrillator(WCD) is increasingly used for SCD prevention both in patients awaiting ICD implantation or with an estimated high risk of ventricular arrhythmia though to be transient. We conducted a review of current clinical uses and benefits of the WCD, and described its technical aspects, limitations and perspectives.     

Long-term mortality risk in patients with an implantable cardioverter–defibrillator: Influence of heart rate and QRS duration

Background

A paucity of studies has investigated the role of autonomic cardiac regulation as well as cardiac conduction in relation to prognosis in implantable cardioverter–defibrillator (ICD) patients. Therefore, we examined the association of heart rate and QRS duration with long-term mortality risk in first-time ICD patients, adjusting also for measures of emotional distress.

Methods

Resting heart rate and QRS duration were assessed prior to ICD implantation in 448 patients. Primary study endpoint was all-cause mortality (up to 6.0 year follow-up, median follow-up of 5.6 years (IQR: 1.9)). The impact of heart rate and QRS duration on time to all-cause mortality was separately assessed with Cox proportional hazard regression analysis, adjusting for clinical factors and symptoms of depression and anxiety.

Results

Mean (SD) heart rate was 68.0 ± 13.3 bpm and mean QRS duration was 130.9 ± 36.9 ms. Heart rate of ≥ 80 bpm was associated with increased risk of mortality (HR = 1.86; 95% CI = 1.15–3.00; p = .011) in unadjusted analysis. In adjusted analyses, this relationship remained significant both with depression (HR = 1.86, 95% CI = 1.12–3.09; p = .017) and anxiety (HR = 1.82, 95% CI = 1.10–3.03; p = .021) and clinical measures as covariates. QRS duration of ≥ 120 ms was associated with impaired prognosis in unadjusted analysis (HR = 2.00, 95% CI = 1.27–3.14; p = .003), but was reduced to non-significance in adjusted analysis when medical comorbidities were included (HR = 1.15, 95% CI = 0.70–1.89; p = .60).

Conclusions

This study shows that increased heart rate is associated with impaired prognosis. Since heart rate is a relatively easy measurable parameter of autonomic functioning, heart rate should be included as a measure for risk stratification in daily clinical practice.     

Do baseline characteristics accurately discriminate between patients likely versus unlikely to benefit from implantable defibrillator therapy? Evaluation of the Canadian implantable defibrillator study implantable cardioverter defibrillatory efficacy score in the antiarrhythmics versus implantable defibrillators trial

OBJECTIVE: Our purpose was to evaluate whether baseline characteristics predictive of implantable cardioverter defibrillator (ICD) efficacy in the Canadian Implantable Defibrillator Study (CIDS) are predictive in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. BACKGROUND: ICD therapy is superior to antiarrhythmic drug use in patients with life-threatening arrhythmias. However, identification of subgroups most likely to benefit from ICD therapy may be useful. Data from CIDS suggest that 3 characteristics (age > or =70 years, ejection fraction [EF] < or =0.35, and New York Heart Association class >II) can be combined to reliably categorize patients as likely (> or =2 characteristics) versus unlikely to benefit (<2 characteristics) from ICD therapy. METHODS: The utility of the CIDS categorization of ICD efficacy was assessed by Kaplan-Meier analysis and Cox hazards modeling. The accuracy of the CIDS score was formally tested by evaluating for interaction between categorization of benefit and treatment in a Cox model. RESULTS: ICD therapy was associated with a significantly lower risk of death in the 320 patients categorized as likely to benefit (relative risk [RR] 0.57, 95% confidence interval [CI] 0.37-0.88, P =.01) and a trend toward a lower risk of death in the 689 patients categorized as unlikely to benefit (RR 0.70, 95% CI 0.48-1.03, P =.07). Categorization of benefit was imperfect, as evidenced by a lack of statistical interaction (P =.5). Although 32 of the 42 deaths prevented by ICD therapy in AVID were in patients categorized as likely to benefit, all 42 of these patients had EF values < or =0.35. Neither advanced age nor poorer functional class predicted ICD efficacy in AVID. CONCLUSION: Of the 3 characteristics identified to predict ICD efficacy in CIDS, only depressed EF predicted ICD efficacy in AVID. Thus physicians faced with limited resources might elect to consider ICD therapy over antiarrhythmic drug use in patients with severely depressed EF values.     

Secondary prevention of sudden cardiac death in coronary artery spasm: is implantable cardioverter defibrillator always efficient?

Syncope and/or cardiac arrest in the setting of coronary artery spasm have been associated with atrioventricular block and asystole or ventricular tachyarrhythmias. Ventricular arrhythmias have been predominantly reported in cases of multivessel coronary artery spasm. The present report highlights the case of a young woman who suffered repeated episodes of multivessel coronary artery spasm in association with polymorphic ventricular tachycardia and cardiac arrest. The efficacy of implantable cardioverter defibrillator in secondary prevention of sudden cardiac death due to coronary artery spasm is discussed.     

Can we predict which patients with implantable cardioverter defibrillators receive appropriate shock therapy? A study of 155 patients

BACKGROUND: Appropriate shock therapy (AST) occurs in the minority of patients with implantable cardioverter defibrillators (ICDs). We assessed which patients received AST and whether there were any predictive factors. METHODS: We retrospectively analysed data from 155 patients implanted with ICDs at our institution from a period from February 1984 to February 2001. Stored electrogram data were analysed. We sub-divided patients on the basis of underlying cardiac disease. Various clinical echocardiographic and electrophysiological variables were studied. RESULTS: AST occurred in 53 (34%) of patients (Group 1) and no AST in 102 (64%) of patients (Group 2). Impaired LV function was significantly associated with AST. Group 1 patients had a lower ejection fraction (EF) compared to Group 2 (37.5+/-13% vs. 47.8+/-14%, P<0.0001). Seventy-two percent of patients with AST had an EF <40% vs. 35% of patients in Group 2 (P<0.0001). NYHA Class was also associated with AST, 42% of Group 1 were in NYHA Class III/IV vs. 12% in Group 2 (P<0.001). Programmed electrical stimulation (PES) was a predictor of AST. PES was positive in a greater proportion of patients in Group 1 vs. 2 (88% vs. 64%, P<0.0006). Sub-group analysis showed that patients with dilated cardiomyopathy (DCM) had a high incidence of AST (80%). In these patients PES was a poor predictor of AST being positive in only 25%. CONCLUSION: AST occurs in the minority of our patients. Certain pre-procedural variables predict AST. PES does not appear useful in predicting shock therapy in DCM patients and a negative PES should not preclude ICD implantation in this group.     

Outcomes in heart failure patients referred for consideration of implantable cardioverter defibrillator for primary prophylaxis of sudden cardiac death: What are the risks of waiting?

BACKGROUND:

Clinical trials have confirmed that implantable cardioverter defibrillators (ICDs) reduce mortality in patients with a left ventricular ejection fraction below 30%. The ‘real-world’ prognosis before ICD implantation in such patients is not known. The estimated risk of death is 0.8% per month, and this forms the basis for wait-time recommendations.

OBJECTIVES:

To determine the consequences of waiting for ICD implantation among heart failure patients eligible for primary prophylactic ICD.

METHODS:

The present retrospective study evaluated consecutive patients who were deemed eligible for primary prophylactic ICD implantation. Survival outcomes were tracked for patients who declined an ICD, those who accepted and received an ICD, and patients who accepted an ICD but died while waiting.

RESULTS:

Of 470 patients referred for evaluation, 218 were deemed eligible for an ICD. A total of 174 of 218 patients (79.8%) accepted an ICD; 39 (17.9%) declined, and five (2.3%) were deemed to be at too great a risk for the procedure. The mortality rate at two years among patients who accepted an ICD was 18.8% before ICD implantation and 12.2% after ICD implantation. Among patients who declined ICD implantation, the two-year mortality rate was 5.3%. Among patients waiting for an ICD, five of 19 deaths were out-of-hospital sudden deaths. Of 12 patients who died after ICD implantation, there were no documented out-of-hospital sudden deaths.

CONCLUSION:

Consistent with current estimates, the mortality rate at two years among patients who accepted and were waiting for an ICD implant was 18.8%. After receiving an ICD, the mortality rate was 12.2% at two years.     

Cervical mediastinoscopy in The Netherlands: past or present? A retrospective analysis of 218 procedures

BACKGROUND: Cervical mediastinoscopy (CM) has been considered the gold standard for the evaluation of mediastinal lymph nodes in the staging of non-small cell lung cancer (NSCLC) for many years. Recent publications on the value of PET scanning might reduce the use of CM in the near future. The aim of this study was to analyse the data of our CM procedures for their reliability and contribution in the assessment of mediastinal lymph nodes. METHODS: In the period 1995-1999, 219 patients underwent CM. Data were available on 218 procedures and were analysed retrospectively. CM was performed in 162 men and 56 women with a median age of 56 years [range 29 to 80 years]. RESULTS: Median hospitalisation time was three days. There was no mortality and morbidity was 6%. In 96% of procedures representative lymphoid tissue was obtained. In 24%, biopsies contained malignancy. CONCLUSIONS: CM is a relatively safe procedure with a high diagnostic yield. As long as PET scanning remains available at a limited level, CM remains the gold standard in The Netherlands for patients with apparently operable NSCLC.     

Care of patients after coronary stent implantation: what is important in practice?

The introduction of Drug Eluting Stents was an important step to reduce restenosis rate after coronary stent implantation. Unfortunately, reduction of restenosis was paid off by the price of potential increased late (>30 days) stent thrombosis. However, current data are not completely conclusive with respect to extent and duration of stent thrombosis and cardiovascular risk after drug eluting stent implantation. Until now, especially for patients at risk for stent thrombosis a prolonged (12 instead of 6 months) dual antiplatelet therapy with aspirin and clopidogrel is recommended. Thereby, the quality of physician instructions is predictive for patient's compliance. Premature termination of dual antiplatelet therapy should be avoided; many small surgical interventions (e.g. tooth extraction) can be performed under dual antiplatelet therapy. Patients with "triple therapy" (aspirin, clopidogrel and coumarin derivate) should be monitored carefully, since they have an excessive bleeding risk. An elective coronary angiography after coronary stent implantation is not routinely necessary. However in selected high-risk patients (e.g. left main or multivessel stent implantation) control angiography may be useful. Medical therapy of risk factors (hyperlipidemia, hypertension, and diabetes mellitus) is essential also after coronary stent implantation. It is important to screen patients for diabetes mellitus, since approximately 1/3 of patients after coronary intervention have an otherwise unrecognized diabetes mellitus or glucose tolerance disturbance.     

Is this pacemaker working properly? Prolongation of the atrial escape interval following activation of the ventricular safety pacing algorithm in a dual-chamber implantable cardioverter defibrillator with atrial-based, lower rate timing

With the introduction of various new pacing features and algorithms, 12-lead electrocardiogram analysis of paced rhythms can be a challenging undertaking. An incorrect interpretation may lead to an inappropriate medical decision in the care of such patients. The authors present an interesting paced 12-lead electrocardiogram that posed a diagnostic challenge.     

Repair of abdominal aortic aneurysm in heart transplant patients: before or after left ventricular assist device implantation?

Endovascular abdominal aortic aneurysm repair in decompensated heart failure patients requiring ventricular assist device (VAD) placement needs careful consideration of both complex disease states. We present this clinical dilemma and describe our choice of transcatheter aneurysm repair in the face of advanced refractory heart failure following VAD implantation.     

Predictive value of remission status after 6 months induction therapy in patients with proliferative lupus nephritis: a retrospective analysis

The objective of this study was to evaluate whether remission status after completion of induction therapy can be used to predict long-term renal outcomes, including renal relapse and chronic renal failure (CRF) in patients with proliferative lupus nephritis (LN). Of 201 patients with biopsy proven LN between 1998 and 2008, 117 were reviewed. Fifty nine (50.4%), 33 (28.2%), and 25 (21.4%) were assigned to the complete remission (CR), partial remission (PR), and non-remission (NR) groups, respectively. The 24-h urinary protein level was significantly lower in the CR than in the PR and NR groups. Induction therapy after the first detection of nephritis signs was initiated earlier in the CR than in the PR and NR groups. During follow-up, 36 (39.1%) patients suffered relapse. Multivariate analysis showed that longer latency period and a lack of CR were independent predictors of renal relapse. Seventeen (14.5%) patients experienced CRF. Multivariate analysis showed that higher baseline creatinine concentration and a lack of CR after induction therapy were independent predictors of CRF. We found that renal outcomes were related to remission status after 6 months induction therapy in patients with proliferative LN. Further, poor outcomes were associated with delayed intervention and higher creatinine concentration.