Effect of implantable loop recorder-based continuous rhythm monitoring on incident atrial fibrillation and stroke: An updated systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: In patients with a history of stroke or those at high risk for developing stroke, a continuous rhythm monitoring strategy using an implantable loop recorder (ILR) is often performed to screen for atrial fibrillation (AF). OBJECTIVES: The purpose of this study was to perform a systematic review (MEDLINE and EMBASE) including randomized controlled trials comparing ILR-based continuous rhythm monitoring vs usual care in patients with a history of stroke or patients at high risk for developing stroke. METHODS: A meta-analysis was performed, and aggregate risk ratio (RR) and risk difference (RD) with 95% confidence interval (CI) were calculated. RESULTS: Four randomized controlled trials with 7237 patients (ILR 2114, non-ILR 5123) were included. ILR vs non-ILR was associated with increased detection of incident AF (RR 3.88; 95% CI 2.23-6.75; P <.00001; number needed to treat [NNT] = 7.7; I2 = 61%), increased appropriate initiation of anticoagulation (RR 2.29; 95% CI 2.07-2.55; P <.00001; NNT = 6.7; I2 = 0), and a 25% lower risk of developing stroke (RR 0.75; 95% CI 0.59-0.95]; P = .02; NNT = 100; I2 = 0%). In patients with history of stroke there was no difference in the risk of developing incident stroke (RR 0.83; 95% CI 0.61-1.14]; P = .25; I2 = 0%). CONCLUSION: Our meta-analysis showed that screening for AF with ILR is associated with increased detection of AF and increased initiation of appropriate anticoagulation therapy in patients with a history of stroke or those with risk factors for stroke. The benefit of stroke risk reduction with ILR remains unclear, and future studies focused on the inclusion of patients without a history of stroke are needed to elucidate this uncertainty.

Interventions in the diagnosis and adoption of pacemaker therapy in sinus node dysfunction patients: Results from the IMPROVE Brady study.

AIMS: IMPROVE Brady assessed whether a process improvement intervention could increase adoption of guideline-based therapy in sinus node dysfunction (SND) patients. METHODS: /Results: IMPROVE Brady was a sequential, prospective, quality improvement initiative conducted in India and Bangladesh. Patients with symptomatic bradycardia were enrolled. In Phase I, physicians assessed and treated patients per standard care. Phase II began after implementing educational materials for physicians and patients. Primary objectives were to evaluate the impact of the intervention on SND diagnosis and pacemaker (PPM) implant. SF-12 quality of life (QoL) and Zarit burden surveys were collected pre- and post-PPM implant. A total of 978 patients were enrolled (57.7 ± 14.8 years, 75% male), 508 in Phase I and 470 in Phase II. The diagnosis of SND and implantation of PPM increased significantly from Phase I to Phase II (72% vs. 87%, P < 0.001 and 17% vs. 32%, P < 0.001, respectively). Pacemaker implantation was not feasible in 41% of patients due to insurance/cost barriers which was unaltered by the intervention. Both patient QoL and caregiver burden improved at 6-months post-PPM implant (P < 0.001). CONCLUSIONS: A process improvement initiative conducted at centers across India and Bangladesh significantly increased the diagnosis of SND and subsequent treatment with PPM therapy despite the socio-economic constraints.

The Registry Evaluating Functional Outcomes of Resynchronization Management (REFORM): quality of life and psychological functioning in patients receiving cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a treatment for heart failure (HF) that improves cardiac, functional, and quality of life (QoL) outcomes. This study was designed to examine the effect of the addition of CRT (CRTD) to the implantable cardioverter defibrillator (ICD) on psychological functioning. METHODS AND RESULTS: Overall, 99 participants completed batteries before and 9 months after ICD or CRTD implantation in a registry of HF patients receiving device treatment in 3 US centers. Measures included validated indices of mental health (State Trait Anxiety Inventory, Patient Health Questionnaire: Depression) and generic and disease/device-specific QoL (Medical Outcomes Study-Short Form-12, Kansas City Cardiomyopathy Questionnaire, Florida Patient Acceptance Survey, Florida Shock Anxiety Scale). Mixed between-within analyses of covariance were employed to compare device groups on each outcome controlling for cardiac and demographic covariates. Clinically significant anxiety was elevated in both groups at both time points (57% CRTD at baseline, 29% CRTD 9 months, 44% ICD at baseline, 45% ICD 9 months). Clinically significant depressive symptoms were high at baseline (38% CRTD, 31% ICD), but dropped at follow-up (16% CRTD, 7% ICD; P = 0.01). Participants with CRTD had improved mental component and disease-specific QoL following CRT; however, CRTD patients had worse QoL, worse mental component QoL at baseline, and worse device acceptance at 9-month follow-up than patients with ICDs (all P < 0.05). CONCLUSIONS: Evidence of low QoL, psychological functioning, and device acceptance provides the impetus to increase research on well-being of HF patients being implanted with CRTD in research and clinical work.

Defibrillation threshold testing does not predict clinical outcomes during long-term follow-up: a meta-analysis.

BACKGROUND: Defibrillation threshold (DFT) testing at the time of implantable cardioverter defibrillator (ICD) implantation is widely used in clinical practice, but reliable data supporting its routine use are lacking. We undertook a meta-analysis to evaluate the efficacy of DFT testing compared to no DFT testing at the time of ICD implantation. METHODS: We searched the MEDLINE and EMBASE databases for studies evaluating the effect of DFT testing on total mortality and ventricular arrhythmias during follow-up. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using random effects modeling. RESULTS: Eight studies involving 5,020 patients (3,068 undergoing DFT and 1,952 not undergoing DFT) were included. Of those, only one study was randomized. Reasons for not performing DFT included patient characteristics (four studies), center's standard practice (three studies), or randomization (one study). Median follow-up was 24 months. Overall, the quality of the included studies was rather poor. On the basis of the pooled estimate across the studies, DFT testing did not reduce total mortality or ventricular arrhythmias at follow-up (RR = 0.94, 95% CI 0.74-1.21; P = 0.65 and RR = 1.19, 95% CI 0.85-1.68; P = 0.30, respectively). No individual study had a major impact on the estimated RR or the statistical significance based on a sensitivity analysis. CONCLUSION: Recognizing the limited quality of current studies in the area of DFT testing and outcomes, available data suggest that DFT testing at the time of ICD implantation does not appear to predict total mortality and ventricular arrhythmias during follow-up. Large randomized controlled trials, adequately powered to detect clinical outcomes, are warranted.

Cardiac resynchronization therapy after atrioventricular junction ablation for symptomatic atrial fibrillation: a meta-analysis.

AIMS: Atrioventricular junction (AVJ) ablation with permanent pacing improves symptoms in selected patients with atrial fibrillation (AF). The optimal pacing modality after AVJ ablation remains unclear. We performed a meta-analysis of randomized controlled trials to examine whether cardiac resynchronization therapy (CRT) is superior to right ventricular (RV) pacing in this patient population. METHODS AND RESULTS: We searched the MEDLINE and EMBASE databases for studies evaluating the effect of CRT vs. RV pacing after AVJ ablation for AF. Pooled risk ratios (RRs) and mean differences with 95% confidence intervals (CIs) were calculated for categorical and continuous outcomes, respectively, using a random effects model. Five trials involving 686 patients (413 in CRT and 273 in RV pacing group) were included in the analysis. On the basis of the pooled estimate across the studies, CRT resulted in a non-significant reduction in mortality (RR = 0.75, 95% CI 0.43-1.30; P= 0.30) and a significant reduction in hospitalizations for heart failure (RR = 0.38, 95% CI = 0.17-0.85; P= 0.02) compared with RV pacing. Cardiac resynchronization therapy did not improve 6 min walk distance (mean difference 15.7, 95% CI -7.2 to 38.5 m; P= 0.18) and Minnesota Living with Heart Failure quality-of-life score (mean difference -3.0, 95% CI -8.6 to 2.6; P= 0.30) compared with RV pacing. The change in left ventricular ejection fraction between baseline and 6 months favoured CRT (mean change 2.0%, 95% CI 1.5-2.4%; P< 0.001). CONCLUSION: Cardiac resynchronization therapy may be superior to RV pacing in patients undergoing AVJ ablation for AF. Further studies, adequately powered to detect clinical outcomes, are required.

Prevention of cardiovascular events by treating hypertension in older adults: an evidence-based approach.

Hypertension in older adults is not well controlled in clinical practice. Isolated systolic hypertension is often more difficult to manage. A systematic PubMed search was conducted to look for evidence showing benefits of lowering blood pressure (BP) in older hypertensive adults. Lowering BP in these individuals significantly reduces the risk of coronary artery disease, stroke, and cardiovascular and all-cause mortality. Based on trial evidence, a low-dose diuretic should be considered the most appropriate first-step treatment for preventing cardiovascular morbidity and mortality. Therapy with >1 medication is often necessary to reduce BP in these patients. There is unequivocal evidence that cardiovascular events can be prevented in older adults, even those older than 80 years, by treating hypertension.

New concepts in physiologic cardiac pacing.

Physiologic pacing is an evolving term used to describe different concepts and technologic developments in implantable devices (including pacemakers and defibrillators) over the past several decades. Currently much of the discussion about optimal physiologic pacing involves fairly recently appreciated deleterious effects of traditional right ventricular pacing. Technologic solutions to the goal of avoiding unnecessary ventricular pacing appear to be available and successful. Although much work is being done to find more physiologic ways to pace the ventricles when necessary, the solutions for this goal are less clear.

Implant experience with an implantable hemodynamic monitor for the management of symptomatic heart failure.

INTRODUCTION: Management of congestive heart failure is a serious public health problem. The use of implantable hemodynamic monitors (IHMs) may assist in this management by providing continuous ambulatory filling pressure status for optimal volume management. METHODS AND RESULTS: The Chronicle system includes an implanted monitor, a pressure sensor lead with passive fixation, an external pressure reference (EPR), and data retrieval and viewing components. The tip of the lead is placed near the right ventricular outflow tract to minimize risk of sensor tissue encapsulation. Implant technique and lead placement is similar to that of a permanent pacemaker. After the system had been successfully implanted in 148 patients, the type and frequency of implant-related adverse events were similar to a single-chamber pacemaker implant. R-wave amplitude was 15.2 +/- 6.7 mV and the pressure waveform signal was acceptable in all but two patients in whom presence of artifacts required lead repositioning. Implant procedure time was not influenced by experience, remaining constant throughout the study. CONCLUSION: Based on this evaluation, permanent placement of an IHM in symptomatic heart failure patients is technically feasible. Further investigation is warranted to evaluate the use of the continuous hemodynamic data in management of heart failure patients.

A new paradigm of cardiovascular risk factor modification.

Atherosclerotic cardiovascular diseases (CVDs) are the leading cause of death and disability in the United States. While multiple studies have demonstrated that modification of atherosclerotic cardiovascular risk factors (CVRFs) significantly reduces morbidity and mortality rates, clinical control of CVDs and CVRFs remains poor. By 2010, the American Heart Association seeks to reduce coronary heart disease, stroke, and risk by 25%. To meet this goal, clinical practitioners must establish new treatment paradigms for CVDs and CVRFs. This paper discusses one such treatment model--a comprehensive atherosclerosis program run by physician extenders (under physician supervision), which incorporates evidence-based CVD and CVRF interventions to achieve treatment goals.