Efficacy on resynchronization and longitudinal contractile function comparing His-bundle pacing with conventional biventricular pacing: a substudy to the His-alternative study

AIMS

His-bundle pacing has emerged as a novel method to deliver cardiac resynchronization therapy (CRT). However, there are no data comparing conventional biventricular (BiV)-CRT with His-CRT with regard to effects on mechanical dyssynchrony and longitudinal contractile function.

METHODS AND RESULTS

Patients with symptomatic heart failure, left ventricular ejection fraction ≤ 35%, and left bundle branch block (LBBB) by strict ECG criteria were randomized 1:1 to His-CRT or BiV-CRT. Two-dimensional strain echocardiography was performed prior to CRT implantation and at 6 months after implantation. Differences in changes in mechanical dyssynchrony (standard deviation of time-to-peak in 12 midventricular and basal segments) and regional longitudinal strain in the six left ventricular walls were compared between the BiV-CRT and His-CRT groups.In the on-treatment analysis, 31 received BiV-CRT and 19 His-CRT. In both groups, mechanical dyssynchrony was significantly reduced after 6 months [BiV group from 120 ms (±45) to 63 ms (±22), P < 0.001, and His group from 116 ms (±54) to 49 ms (±11), P < 0.001] but no significant differences in changes could be demonstrated between groups [-9.0 ms (-36; 18), P = 0.50]. Global longitudinal strain (GLS) improved in both groups [BiV group from -9.1% (±2.7) to -10.7% (±2.6), P = 0.02, and His group from -8.6% (±2.1) to -11.1% (±2.0), P < 0.001], but no significant differences in changes could be demonstrated from baseline to follow-up [-0.9% (-2.4; -0.6), P = 0.25] between groups. There were no regional differences between groups.

CONCLUSION

In heart failure, patients with LBBB, BiV-CRT, and His-CRT have comparable effects with regard to improvements in mechanical dyssynchrony and longitudinal contractile function.

Global constructive work is associated with ventricular arrhythmias after cardiac resynchronization therapy

AIMS

Non-invasive left ventricular (LV) pressure-strain loops provide a novel method for quantifying myocardial work by incorporating LV pressure in measurements of myocardial deformation. Early studies suggest that myocardial work parameters such as global constructive work (GCW) could be useful and reliable in arrhythmia prediction, particularly in patients undergoing cardiac resynchronization therapy (CRT). The aim of this study was to evaluate whether the magnitude of GCW was associated with the occurrence of ventricular arrhythmias in patients after CRT.

METHODS AND RESULTS

Patients on guideline-recommended treatment with a CRT defibrillator (CRT-D) were evaluated by 2D speckle-tracking echocardiography including measurements of GCW at least 6 months after implantation. The primary outcome was a composite of appropriate defibrillator therapy and sustained ventricular arrhythmia under the monitor zone. A total of 162 patients [mean age 66 years (±10), 122 males (75%)] were included. Sixteen (10%) patients experienced the primary outcome during a median follow-up of 18 months (interquartile range: 12-25) after the performance of index echocardiography. Patients with a below-median GCW (<1473 mmHg%) had a hazard ratio (HR) for the outcome of 8.14 [95% confidence interval (CI): 1.83-36.08], P = 0.006 compared with patients above the median in a univariate model and remained an independent predictor after multivariate adjustment for the estimated glomerular filtration rate and QRS duration [HR 4.75 (95% CI: 1.01-22.28), P < 0.05].

CONCLUSION

In patients treated with CRT-D, a GCW below median level was associated with a five-fold increase in the risk of ventricular arrhythmias.

Efficacy of a web-based healthcare innovation to advance the quality of life and care of patients with an implantable cardioverter defibrillator (ACQUIRE-ICD): a randomized controlled trial

AIMS

Modern clinical management of patients with an implantable cardioverter defibrillator (ICD) largely consists of remote device monitoring, although a subset is at risk of mental health issues post-implantation. We compared a 12-month web-based intervention consisting of goal setting, monitoring of patients' mental health-with a psychological intervention if needed-psychoeducational support from a nurse, and an online patient forum, with usual care on participants' device acceptance 12 months after implantation.

METHODS AND RESULTS

This national, multi-site, two-arm, non-blinded, randomized, controlled, superiority trial enrolled 478 first-time ICD recipients from all 6 implantation centres in Denmark. The primary endpoint was patient device acceptance measured by the Florida Patient Acceptance Survey (FPAS; general score range = 0-100, with higher scores indicating higher device acceptance) 12 months after implantation. Secondary endpoints included symptoms of depression and anxiety. The primary endpoint of device acceptance was not different between groups at 12 months [B = -2.67, 95% confidence interval (CI) (-5.62, 0.29), P = 0.08]. Furthermore, the secondary endpoint analyses showed no significant treatment effect on either depressive [B = -0.49, 95% CI (-1.19; 0.21), P = 0.17] or anxiety symptoms [B = -0.39, 95% CI (-0.96; 0.18), P = 0.18].

CONCLUSION

The web-based intervention as supplement to usual care did not improve patient device acceptance nor symptoms of anxiety and depression compared with usual care. This specific web-based intervention thus cannot be recommended as a standardized intervention in ICD patients.

The effect of increased plasma potassium on myocardial function; a randomized POTCAST substudy

Plasma potassium (p-K) in the high-normal range has been suggested to reduce risk of cardiovascular arrythmias and mortality through electrophysiological and mechanical effects on the myocardium. In this study, it was to investigated if increasing p-K to high-normal levels improves systolic- and diastolic myocardial function in patients with low-normal to moderately reduced left ventricular ejection fraction (LVEF). The study included 50 patients (mean age 58 years (SD 14), 81% men), with a mean p-K 3.95 mmol/l (SD 0.19), mean LVEF 48% (SD 7), and mean Global Longitudinal Strain (GLS) -14.6% (SD 3.1) patients with LVEF 35-55% from "Targeted potassium levels to decrease arrhythmia burden in high-risk patients with cardiovascular diseases trial" (POTCAST). Patients were given standard therapy and randomized (1:1) to an intervention that included guidance on potassium-rich diets, potassium supplements, and mineralocorticoid receptor antagonists targeting high-normal p-K levels (4.5-5.0 mmol/l). Echocardiography was done at baseline and after a mean follow-up of 44 days (SD 18) and the echocardiograms were analyzed for changes in GLS, mechanical dispersion, E/A, e', and E/e'. At follow-up, mean difference in changes in p-K was 0.52 mmol/l (95%CI 0.35;0.69), P<0.001 in the intervention group compared to controls. GLS was improved with a mean difference in changes of -1.0% (-2;-0.02), P<0.05 and e' and E/e' were improved with a mean difference in changes of 0.9 cm/s (0.02;1.7), P = 0.04 and ? 1.5 (-2.9;-0.14), P = 0.03, respectively. Thus, induced increase in p-K to the high-normal range improved indices of systolic and diastolic function in patients with low-normal to moderately reduced LVEF.

Treatment-induced increase in total body potassium in patients at high risk of ventricular arrhythmias; a randomized POTCAST substudy

OBJECTIVE

Hypokalemia is associated with increased risk of arrhythmias and it is recommended to monitor plasma potassium (p-K) regularly in at-risk patients with cardiovascular diseases. It is poorly understood if administration of potassium supplements and mineralocorticoid receptor antagonists (MRA) aimed at increasing p-K also increases intracellular potassium.

METHODS

Adults aged≥18 years with an implantable cardioverter defibrillator (ICD) were randomized (1:1) to a control group or to an intervention that included guidance on potassium rich diets, potassium supplements, and MRA to increase p-K to target levels of 4.5-5.0 mmol/l for six months. Total-body-potassium (TBK) was measured by a Whole-Body-Counter along with p-K at baseline, after six weeks, and after six months.

RESULTS

Fourteen patients (mean age: 59 years (standard deviation 14), 79% men) were included. Mean p-K was 3.8 mmol/l (0.2), and mean TBK was 1.50 g/kg (0.20) at baseline. After six-weeks, p-K had increased by 0.47 mmol/l (95%CI:0.14;0.81), p = 0.008 in the intervention group compared to controls, whereas no significant difference was found in TBK (44 mg/kg (-20;108), p = 0.17). After six-months, no significant difference was found in p-K as compared to baseline (0.16 mmol/l (-0.18;0.51), p = 0.36), but a significant increase in TBK of 82 mg/kg (16;148), p = 0.017 was found in the intervention group compared to controls.

CONCLUSIONS

Increased potassium intake and MRAs increased TBK gradually and a significant increase was seen after six months. The differentially regulated p-K and TBK challenges current knowledge on potassium homeostasis and the time required before the full potential of p-K increasing treatment can be anticipated.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03833089).

Long-term cardiovascular outcomes among immigrants and non-immigrants in cardiac resynchronization therapy: a nationwide study

AIMS

To date, potential differences in outcomes for immigrants and non-immigrants with a cardiac resynchronization therapy (CRT), in a European setting, remain underutilized and unknown. Hence, we examined the efficacy of CRT measured by heart failure (HF)-related hospitalizations and all-cause mortality among immigrants and non-immigrants.

METHODS AND RESULTS

All immigrants and non-immigrants who underwent first-time CRT implantation in Denmark (2000-2017) were identified from nationwide registries and followed for up to 5 years. Differences in HF related hospitalizations and all-cause mortality were evaluated by Cox regression analyses. From 2000 to 2017, 369 of 10 741 (3.4%) immigrants compared with 7855 of 223 509 (3.5%) non-immigrants with a HF diagnosis underwent CRT implantation. The origins of the immigrants were Europe (61.2%), Middle East (20.1%), Asia-Pacific (11.9%), Africa (3.5%), and America (3.3%). We found similar high uptake of HF guideline-directed pharmacotherapy before and after CRT and a consistent reduction in HF-related hospitalizations the year before vs. the year after CRT (61% vs. 39% for immigrants and 57% vs. 35% for non-immigrants). No overall difference in 5-year mortality among immigrants and non-immigrants was seen after CRT [24.1% and 25.8%, respectively, P-value = 0.50, hazard ratio (HR) = 1.2, 95% confidence interval (CI): 0.8-1.7]. However, immigrants of Middle Eastern origin had a higher mortality rate (HR = 2.2, 95% CI: 1.2-4.1) compared with non-immigrants. Cardiovascular causes were responsible for the majority of deaths irrespective of immigration status (56.7% and 63.9%, respectively).

CONCLUSION

No overall differences in efficacy of CRT in improving outcomes between immigrants and non-immigrants were identified. Although numbers were low, a higher mortality rate among immigrants of Middle Eastern origin was identified compared with non-immigrants.

His-pacing and biventricular pacing show similar efficiency in resynchronization and improvements in longitudinal contractile function

Background

The clinical role for HIS-pacing in cardiac resynchronization therapy (HIS-CRT) is promising but is yet to be established. The randomised His-alternative study showed better remodelling with HIS-CRT compared to patients receiving conventional biventricular pacing (BIV-CRT) in the per-protocol-analysis.

Purpose

In this substudy we investigated whether HIS-pacing was more efficient compared to BIV-CRT in improving mechanical synchrony and longitudinal contractile function.

Methods

In the His-Alternative study 50 patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and Left bundle branch block were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group. All patients had echocardiography performed including 2D-strain echocardiography to asses global systolic longitudinal deformation (GLS) at baseline and 6 months. Mechanical dyssynchrony was measured as SD of time-to-peak in all 12 segments of the left ventricle (TPS-SD).

Results

There were no significant differences in baseline characteristics between patients receiving HIS-CRT and BIV-CRT with regard to dyssynchrony and longitudinal systolic strain. LVEF was significantly higher at 6 months (48±8% vs. 42±8%; p&lt;0.05) in the HIS-CRT group. However, GLS did not significantly improve more with HIS-CRT compared to BIV-CRT, (−8.7ms ± 2.0 to −11.1 ms ± 2.0 vs −9.1 ms ± 2.7 to −10.8±2.5 ms ± 2.8, P = ns for difference) and regarding resynchronization measured as TPS-SD there was no significant difference either (110 ms ± 51 to 47 ms ± 10 vs. 115 ms ± 42 to 60 ms ± 21, P = ns for difference).

Conclusion

In this substudy, HIS-pacing did not prove more efficient than BIV-CRT in resynchronizing the left ventricle, nor did the observed improvement in longitudinal function differ significantly between methods. However, the number of included patients was rather small and larger studies are needed to fully assess the possible benefits of HIS-CRT.

Funding Acknowledgement

Type of funding sources: None.

Risk of lead explantation after first-time implantation of cardiac implantable electronic device as a function of comorbidity: a nationwide study

Background

The benefit of cardiac implantable electronic devices (CIEDs) is challenged by the risk of procedure-related complications and lead explantation. Whether patient comorbidity burden is associated with risk of lead explantation &lt;6 months of implantation is unknown.

Purpose

We assessed the risk of lead explantation and its association with comorbidity burden within 6 months after first-time CIED implantation.

Methods

The study population comprised patients ≥18 years old with first-time CIED implantation (i.e., pacemaker [PM], implantable cardioverter defibrillator [ICD], and cardiac resynchronisation therapy with defibrillator [CRT-D] or without [CRT-P]) using Danish nationwide registries including the Danish Pacemaker and ICD registry (1 January 2000 to 30 June 2018). Patients were followed from their first-time CIED implantation and 6 months forward. Patient comorbidity burden was categorised in four groups according to the Charlson Comorbidity Index (CCI) score: 0 (none), 1–2 (mild), 3–4 (moderate), and ≥5 (severe). Multivariable cause-specific Cox regression was performed to assess risk of lead explantation according to comorbidity burden, with death as competing risk. Comorbidity burden was adjusted for sex, age, type of CIED, and body mass index categories.

Results

We identified 73,491 patients with first-time CIED implantation including 55,733 (75.8%) with PM, 11,351 (15.5%) with ICD, 2,989 (4.1%) with CRT-P, and 3,418 (4.7%) with CRT-D. In total, 1,049 (1.4%) patients underwent lead explantation. The median age of the study population was 75.1 years [25th-75th percentile 66.2–82.5 years], and 62.1% were male. Patients undergoing lead explantation had higher median CCI score, compared with those not undergoing lead explantation (2 [1–3] and 1 [0–3], respectively). The median age and distribution of sex were similar in both groups. In the multivariable Cox regression model (Figure 1), an increase in patient comorbidity burden was associated with higher hazard ratio [HR] of lead explantation, compared with CCI score 0 (CCI score 1–2: HR=1.38 [95% confidence interval [CI]: 1.12–1.69], CCI score 3–4: HR=1.61 [95% CI: 1.28–2.03], and CCI score ≥5: HR=1.60 [95% CI: 1.25–2.05]).

Conclusion

Risk of lead explantation within 6 months after first-time implantation of cardiac implantable electronic device was 1.4% and associated with higher comorbidity burden.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Independent Research Fund Denmark

History of betablocker treatment breaks and risk of ventricular tachyarrhythmias among patients with heart failure and implantable cardioverter defibrillator: a nationwide cohort study

Background

Beta-blockers have in randomized clinical trials been shown to reduce the risk of life-threatening arrhythmias and sudden cardiac death (SCD) in patients with heart failure (HF), and treatment is a class 1A recommendation in current guidelines. Thus, beta-blocker treatment breaks (i.e. planned break, beta-blocker related side-effects, or poor adherence) may increase risk of life-threatening arrhythmias and SCD. Whether patients with HF and a history of beta-blocker treatment breaks before implantable cardioverter defibrillator (ICD) is associated with increased risk of device related therapy and mortality is largely unknown.

Aims

In patients with HF and an ICD alone or combined with cardiac resynchronization therapy (CRT-D), we examined the association between a history of a beta-blocker treatment breaks prior to device implantation and the risk of appropriate and inappropriate device related therapy (i.e., anti-tachycardia pacing [ATP] or DC shock [DC]), and all-cause mortality.

Methods

Using the Danish Pacemaker and ICD Registry, we identified all patients with HF receiving a first-time ICD (2000–2018). Beta-blocker treatment breaks &gt;60 consecutive days up to 3 years prior to device implantation were identified using the National Prescription Registry. Patients were able to switch between beta-blockers and were required to be in treatment at the time of implantation. We used multivariable Cox regressions to compare the 1-year risks of device-related therapy and all-cause mortality between patients with and without a history of a beta-blocker treatment break.

Results

We identified 9,239 patients with HF and an ICD (82.6% male; median age 67 years). A total of 82.5% had ischemic heart disease, 33.9% atrial fibrillation, and 33.1% of ICDs were secondary prophylaxis. During one-year follow-up, 5.7% of all patients died and appropriate DC and appropriate ATP was identified for 3.9% and 6.7% of patients, respectively. Overall, 14.6% of all HF patients had one or more beta-blocker treatment break &gt;60 days. Compared with HF patients with no history of treatment breaks, a history of treatment breaks &gt;60 days were associated with increased risk of appropriate DC (hazard ratio (HR)=1.33; 95% confidence interval [CI], 1.02–1.73) and appropriate ATP (HR 1.30; CI, 1.06–1.59), but also inappropriate DC and ATP therapy (Figure 1). There was no difference between groups with respect to all-cause mortality (HR=0.96; CI: 0.76–1.22). Treatment breaks of &gt;30 or &gt;90 days were also evaluated and yielded similar results as the main analysis.

Conclusion

Patients with heart failure who had a history of treatment breaks with beta-blockers prior to ICD implantation was associated with a higher 1-year risk of appropriate and inappropriate shocks and anti-tachycardia pacing, but not all-cause mortality.

Funding Acknowledgement

Type of funding sources: None.

Severity of chronic obstructive pulmonary disease and risk of one-year mortality after first-time implantation of implantable cardioverter defibrillator: a nationwide study

Background

Current guidelines, on implantable cardioverter defibrillator (ICD), recommend implantation in patients with an expected survival beyond one year. Information on risk of all-cause mortality among ICD recipients with chronic obstructive pulmonary disease (COPD) according to severity of COPD is lacking.

Purpose

We examined the association between the severity of COPD and risk of all-cause mortality within one year after first-time ICD implantation.

Methods

We identified patients ≥18 years old undergoing first-time ICD implantation with COPD using Danish nationwide registries (1 January 2000 to 31 December 2018). All patients were eligible for one-year follow-up. We used concomitant COPD-related pharmacotherapy six months prior to ICD implantation and COPD hospitalisations one year prior to ICD implantation to determine severity of COPD from mild to very severe according to Table 1. Multivariable Cox regression was used to assess risk of one-year all-cause mortality according to severity of COPD. Severity of COPD was adjusted for sex, age, year of implantation, primary prevention, type of ICD, history of atrial fibrillation, stroke, peripheral artery disease, diabetes, cancer, chronic renal disease, and dialysis.

Results

The study population included 1,536 patients with first-time ICD and COPD. The median age was 69.5 years [25th-75th percentile 63.5–74.3 years], and the majority of patients were males (79.4%). Of these, 896 (58.3%) received an ICD for primary prevention, and 485 (31.6%) had cardiac resynchronisation therapy device with defibrillator (CRT-D). In total, 1,348 (87.8%) patients were diagnosed with heart failure. Patients were grouped according to severity of COPD from mild to very severe: Group 1 (N=666), Group 2 (N=72), Group 3 (N=149), Group 4 (N=445), and Group 5 (N=204). Overall, 154/1,536 (10.0%) ICD recipients with COPD died within one year after first-time ICD implantation. No difference in sex and comorbidities was identified according to the five groups of COPD severity. However, ICD recipients with mild intermittent COPD (Group 1) were the youngest (68.3 years [61.8–73.0 years]). According to our multivariable cox regression in Figure 1, patients with very severe COPD (Group 5) were associated with increased risk of all-cause mortality within one year after first-time ICD implantation (adjusted hazard ratio [HR] 1.90 [95% confidence interval [CI]: 1.21–2.98]), compared with mild intermittent COPD (Group 1). The most common causes of death within one year after ICD implantation were attributed to cardiovascular diseases 95/154 (61.7%), respiratory diseases 15/154 (9.7%), and endocrine disorders 12/154 (7.8%).

Conclusion

In this nationwide study, very severe chronic obstructive pulmonary disease was associated with increased risk of all-cause mortality within one year after first-time implantation of implantable cardioverter defibrillator.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Independent Research Fund Denmark

Carpal Tunnel Syndrome in Patients Who Underwent Pacemaker Implantation and Relation to Amyloidosis, Heart Failure, and Mortality

Advances in treatment warrant earlier diagnosis of cardiac amyloidosis (CA). Common cardiac and extracardiac manifestations of CA, such as pacemaker implantation and carpal tunnel syndrome (CTS), might provide screening opportunities for CA. However the association between CTS and CA in patients undergoing pacemaker implantation has not been well studied. This study examined the association between previous CTS surgery and adverse cardiovascular outcomes in patients who underwent pacemaker implantation. Using Danish nationwide registries, we identified all patients ≥50 years who underwent first-time pacemaker implantation during 2000 to 2018, examining the association between previous CTS surgery and adverse cardiovascular outcomes 5 years after pacemaker implantation. Cumulative incidence functions and Cox proportional hazard models were used to assess the differences. Among 57,315 patients who underwent pacemaker implantation, 2.2% (n = 1,266) had previous CTS surgery. Patients in the CTS cohort were older, more often female, and had more co-morbidities than patients without CTS. The cumulative 5-year mortality was higher among patients with CTS (44.6% [41.1% to 47.9%] versus 40.2% [39.7% to 40.6%], p = 0.04). In the adjusted models, previous CTS surgery was not associated with increased 5-year mortality, but it was associated with an increased rate of hospitalization for new-onset heart failure, (hazard ratio 1.32 [1.11 to 1.57], p = 0.002) and a higher risk of amyloidosis diagnosis after pacemaker implantation (hazard ratio 7.72 [2.96 to 20.10], p <0.0001), compared with no previous CTS surgery. In patients who underwent pacemaker implantation, adjusted models showed that previous CTS surgery was associated with a higher incidence of hospitalization for new-onset heart failure and amyloidosis diagnosis after pacemaker implantation. Screening for CA may be considered in patients undergoing pacemaker implantation.

The CADI-study: Compression after device implantation - To examine the effect of a compressive dressing after device implantation or replacement focusing on the patient"s bleeding, hematomas and pain

Funding Acknowledgements

University Hospital Rigshospitalet, Centre for Cardiac, Vascular, Pulmonary and Infectious Diseases, Denmark

Background

Bleeding and pocket hematomas are a known complication in pacemaker or implantable cardioverter defibrillator (ICD) implantations.  Hematomas are associated with increased risk of infection and pain.

Purpose

To investigate whether a compressive dressing applied for three hours can prevent bleeding, pocket hematomas and pain.

Method

The study was a pseudo-randomized intervention study including patients scheduled for implantation or box change of a pacemaker or an ICD. In alternating months patients either received a compressive dressing (intervention group) or not (control group). Patients were excluded by the implanting physician if there was a clinical indication for a compressive dressing due to seeping bleeding. Patients were followed at the catheterization lab, for three hours at the ward and until the first outpatient control visit (1-3 months). The outcomes were: Bleeding, pocket hematomas and pain. The bleedings were graded as active bleeding or seeping bleeding or hematomas. Hematomas were measured by degree 1 to 3 (3 largest) and size (in cm). Pain was rated by the patient by numerical rank scale (NRS) from 0 to 10 (10 worst). Descriptive statistics were used.

Results

A total of 191 patients were included, 95 patients in the intervention group. After inclusion 24 patients of the 96 patients in the control group were excluded by the implanting physician on clinical indication for a compressive dressing.

Before the intervention there were significantly more patients with bleeding (graded as: Seeping bleeding) in the intervention group (n = 25, (26.9%)) compared to the control group (n = 4, (5.6%), p &lt;0.001). No patients had developed pocket hematomas at the end of the procedure. Furthermore, the pain score was low in both groups (Total n = 19, NRS score ≤ 2.5).

Over the next three hours in the ward, there was no significant difference in the bleeding (graded as: Seeping bleeding) in the groups (intervention: n = 8 vs. control: n = 3, p = 0.55). Two patients in each group had developed a pocket hematoma after three hours (p = 0.36) and the intervention group experienced more pain (intervention: 1.7 (±2.4) vs. control: 1.1(±1.7), p= 0.02).

At the outpatient control 1-3 months after implantation, there was no significant difference between the groups related to bleeding, pocket hematomas and pain.

Conclusion

Compressive dressing did not significantly reduce bleeding or the number of pocket hematomas after pacemaker or ICD implantation. In addition patients reported a slight increase in pain scores related to the compressive dressing.

The results question routine compression after procedure, but should be validated in larger studies.

A Randomized Trial of His Pacing Versus Biventricular Pacing in Symptomatic HF Patients With Left Bundle Branch Block (His-Alternative)

OBJECTIVES

This study sought to compare 2 ways of achieving cardiac resynchronization.

BACKGROUND

Cardiac resynchronization therapy (CRT) in patients with symptomatic heart failure and left bundle branch block (LBBB) can be achieved with His-bundle pacing correcting the bundle branch block (His-CRT). The present study is the largest randomized study comparing His-CRT and biventricular pacing (BiV-CRT) to date.

METHODS

Fifty patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and LBBB according to electrocardiography were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group.

RESULTS

His-corrective pacing was achieved in 72% of the patients in the His-CRT group. Intention-to-treat 6-month follow-up LVEF increased by 16 ± 7% in the His-CRT group compared with 13 ± 6% in the BiV-CRT group (nonsignificant) and improvements were seen in clinical and physical parameters in both treatment arms with no significant differences between the groups. Pacing thresholds were higher for His-CRT compared with BiV-CRT both at implantation (1.8 ± 1.2 V vs. 1.2 ± 0.8 V; p < 0.01) and at 6-month follow-up (2.3 ± 1.4 V vs. 1.4 ± 0.5 V; p < 0.01). The per-protocol LVEF was significantly higher at 6 months (48 ± 8% vs. 42 ± 8%; p < 0.05) and the end-systolic volume was lower (65 ± 22 ml vs. 83 ± 27 ml; p < 0.05) in His-CRT patients compared with BiV-CRT.

CONCLUSIONS

In heart failure patients with LBBB, His-CRT provided similar clinical and physical improvement compared with BiV-CRT at the expense of higher pacing thresholds.

Temporal Incidence of Appropriate and Inappropriate Therapy and Mortality in Secondary Prevention ICD Patients by Cardiac Diagnosis

OBJECTIVES

This study sought to estimate the temporal development in rates and incidences of appropriate and inappropriate implantable cardioverter-defibrillator (ICD) therapy and shocks by cardiac diagnosis in a real-world population of patients with secondary prevention ICDs.

BACKGROUND

Data on cardiac diagnoses and temporal development of ICD therapies in patients with secondary prevention ICDs are limited.

METHODS

Patients (N = 4,587) with a secondary prevention ICD were identified from the Danish Pacemaker and ICD Register (January 1, 2007, to December 31, 2016) and linked to nationwide administrative registers. The outcome of appropriate and inappropriate ICD therapy and all-cause mortality were analyzed by annual event rates, cumulative incidence plots, and Cox regression models.

RESULTS

During a mean follow-up of 3.6 ± 2.4 years, 1,362 patients (30%) experienced appropriate ICD therapy (16.8% shocks), and 350 patients (7.6%) experienced inappropriate ICD therapy (4.6% shocks). From 2007 to 2016, there was a significant temporal reduction in both appropriate and inappropriate ICD therapy from 28.2 (95% confidence interval [CI]: 21.6 to 37.0) to 7.9 (95% CI: 6.8 to 9.1) and 10.0 (95% CI: 6.4 to 15.5) to 1.0 (95% CI: 0.7 to 1.5) per 100 person-years (p for trends <0.001). Multivariate Cox regression analyses showed that arrhythmogenic right ventricular cardiomyopathy was associated with the highest probability of appropriate ICD therapy (hazard ratio: 2.45; 95% CI: 1.77 to 3.39; p < 0.0001), whereas patients with hypertrophic cardiomyopathy had the lowest probability (hazard ratio: 0.62; 95% CI: 0.42 to 0.93; p = 0.0196) when compared to patients with ischemic heart disease.

CONCLUSIONS

In this nationwide real-life cohort of patients with secondary prevention ICDs, we observed a significant temporal decline in delivered appropriate and inappropriate shocks and ICD therapies in the last decade. A large proportion of patients still experienced ICD therapy but with significant differences by cardiac diagnosis.

Risk factors for mortality within one-year after implantable cardioverter defibrillator implantation: a nationwide study

Background

Current guidelines do not recommend implantable cardioverter defibrillator (ICD) implantation in patients with an estimated survival probability of less than one year. There is still an unmet need to identify patients who are unlikely to benefit from an ICD.

Purpose

We determined one-year mortality after ICD implantation and associated risk factors of one-year mortality.

Methods

Using Danish nationwide registries from 2000–2016, we identified patients ≥18 years old undergoing first-time ICD implantation for primary or secondary prevention. Patients were followed for up to one-year from time of ICD implantation. Risk factors associated with one-year mortality after time of ICD implantation were evaluated in multivariable logistic regression models.

Results

A total of 13,344 patients underwent first-time ICD implantation (median age: 66 years [25th-75th percentile 58–72 years], male=81.3%, secondary prevention=54.6%), of which 647 died (4.8%) within one year of follow-up. Compared with ICD patients who survived for one year, those who died were significantly older (72 years vs. 66 years, p&lt;0.001) and had more comorbidities, including congestive heart failure (70.8% vs. 63.4%), atrial fibrillation (36.6% vs. 23.6%), diabetes (30.8% vs. 19.9%), chronic obstructive pulmonary disease (COPD) (17.0% vs. 8.2%), chronic renal disease (13.0% vs. 4.4%), malignancy (9.9% vs. 5.4%), and dialysis (7.3% vs. 2.4%) (p&lt;0.001 for all).

Results from the multivariable logistic regression model are depicted in the Figure. There was a graded relationship between age and one-year mortality, with a greater risk of all-cause mortality with increasing age.

In addition, dialysis, chronic renal disease, COPD, malignancy, diabetes, and congestive heart failure were strongly associated with increased risk of one-year all-cause mortality. However, ischaemic heart disease was associated with a lower risk of all-cause mortality (Figure). The one-year risk of death was 13.2% for both patients receiving dialysis and patients with chronic renal disease, respectively.

The majority of deaths within one year were attributed to cardiovascular causes (408/647, 63.1%) of which chronic ischaemic heart disease (68/647, 10.5%), acute myocardial infarction (50/647, 7.7%), and atherosclerosis (40/647, 6.2%) were the most common. The most common non-cardiovascular cause of death was malignancy (10.5%).

Conclusion

In patients with a first-time ICD implantation, 95% survived for more than one year after implantation. While low mortality rates are indicative of relevant patient selection for ICD implantation, advanced age, dialysis, and several comorbidities were all strongly associated with increased one-year mortality, whereas ischaemic heart disease was associated with a lower risk of one-year mortality. Potential benefit of an ICD in such patients should be carefully evaluated before implantation.

Funding Acknowledgement

Type of funding source: None

Mortality after implantable cardioverter defibrillators in dialysis patients: a nationwide study

Background

Although randomized clinical trials have shown that implantable cardioverter defibrillators (ICDs) reduce mortality in selected patients, patients on dialysis are excluded from these trials. Thus, data on mortality risk after ICD implantation in these patients are sparse.

Purpose

To examine all-cause mortality in patients receiving an ICD according to dialysis status and to identify factors associated with all-cause mortality in patients on dialysis.

Methods

Using Danish nationwide registries from 2000–2017, all patients ≥18 years old undergoing first-time ICD implantation were included. Patients on dialysis were identified prior to ICD implantation and followed for up to five years. The cumulative incidence of all-cause mortality according to dialysis status was assessed. Factors associated with all-cause mortality after ICD implantation in dialysis patients were examined using multivariable Cox proportional hazard regression.

Results

A total of 14,681 ICD patients were identified, of which 218 (1.5%) were on dialysis prior to ICD implantation. Compared with ICD patients not on dialysis, those on dialysis were younger (median age 64 years [IQR: 58–70] vs. 66 years [IQR: 57–72], p=0.02), more likely to receive an ICD for secondary prophylaxis (69.7% vs 53.7%), and had more comorbidities including ischaemic heart disease (60.6% vs. 46.3%), diabetes (28.4% vs. 20.4%), and peripheral vascular disease (10.1% vs. 5.6%) (p for all &lt;0.05).

The median time to death among ICD patients on dialysis and not on dialysis were 1.3 years (IQR: 0.4–2.8 years] and 2.2 years [IQR: 1.0–3.5 years], respectively.

One-year mortality among ICD patients on dialysis (13.0%) was significantly higher compared with ICD patients not on dialysis (4.7%), p&lt;0.001 (Figure). Five-year mortality was significantly higher in ICD patients on dialysis than those not on dialysis (42.2% vs 23.6%), p&lt;0.001 (Figure).

Factors associated with increased risk of all-cause mortality among ICD patients on dialysis were age ≥65 years at time of implantation (reference: age &lt;65 years) (HR 1.90 [95% CI: 1.13–3.19]), primary prophylactic ICD (HR 1.81 [95% CI 1.08–3.05]), and diabetes (HR 1.87 [95% CI 1.14–3.07]). Sex, ischaemic heart disease, heart failure, stroke, chronic obstructive pulmonary disease, and malignancy were not associated with the risk of mortality (p&gt;0.05 for all).

Cardiovascular causes of death were common both in patients with- and without dialysis, 69.6% and 60.0%, respectively.

Conclusion

Five-year mortality in ICD patients on dialysis was 42% and twice as high compared with ICD patients not on dialysis. Age ≥65 years, primary prophylactic indication, and diabetes were factors associated with increased mortality. Careful evaluation of the potential benefit from an ICD implantation in dialysis patients is important considering the overall high mortality rates.

Funding Acknowledgement

Type of funding source: None

Cause-specific death and risk factors of one-year mortality after implantable cardioverter-defibrillator implantation: a nationwide study

AIMS

Current treatment guidelines recommend implantable cardioverter-defibrillators (ICDs) in eligible patients with an estimated survival beyond one year. There is still an unmet need to identify patients who are unlikely to benefit from an ICD.We determined cause-specific one-year mortality after ICD implantation and identified associated risk factors.

METHODS AND RESULTS

Using Danish nationwide registries (2000-2017), we identified 14,516 patients undergoing first-time ICD implantation for primary or secondary prevention. Risk factors associated with one-year mortality were evaluated using multivariable logistic regression. The median age was 66 years, 81.3% were male, and 50.3% received an ICD for secondary prevention. The one-year mortality rate was 4.8% (694/14,516). ICD recipients who died within one year were older and more comorbid compared to those who survived (72 vs. 66 years, p < 0.001). Risk factors associated with increased one-year mortality included dialysis (OR:3.26, CI:2.37-4.49), chronic renal disease (OR:2.14, CI:1.66-2.76), cancer (OR:1.51, CI:1.15-1.99), age 70-79 years (OR:1.65, CI:1.36-2.01), and age ≥80 years (OR:2.84, CI:2.15-3.77). The one-year mortality rates for the specific risk factors were: dialysis (13.8%), chronic renal disease (13.1%), cancer (8.5%), age 70-79 years (6.9%), and age ≥80 years (11.0%). Overall, the most common causes of mortality were related to cardiovascular diseases (62.5%), cancer (10.1%), and endocrine disorders (5.0%). However, the most common cause of death among patients with cancer was cancer-related (45.7%).

CONCLUSION

Among ICD recipients, mortality rates were low and could be indicative of relevant patient selection. Important risk factors of increased one-year mortality included dialysis, chronic renal disease, cancer, and advanced age.

4178Insulin treatment is associated with increased risk of device-treated ventricular tachyarrhythmia in patients with diabetes and heart failure

Background

It is debated whether insulin use is associated with a pro-arrhythmic effect. There is paucity of studies investigating this aspect in patients with heart failure (HF), where use of insulin is associated with an increased mortality risk.

Purpose

We aimed to investigate whether patients receiving insulin had higher risk of device-treated ventricular tachyarrhythmia (VTA) in a population of HF patients with medically treated diabetes and primary prevention implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with defibrillator (CRT-D).

Methods

Information on ICD/CRT-D implantation and therapy, comorbidities, diabetes, diabetes-related complications and medication were obtained through Danish nationwide registers. From 2007 through 2016 we identified all primary prevention ICD/CRT-D implantations in HF patients with diabetes, defined as treatment with antidiabetic medication within one year prior to implantation. Patients were divided into two groups; Insulin treated vs. non-insulin treated patients. Endpoints of interest were VTA, defined as appropriate ICD therapy, and all-cause mortality. Cumulative incidence curves and adjusted Cox proportional Hazards regression analyses were used to assess risk of outcomes. Adjustment variables included age, gender, ischemic heart disease (IHD), left ventricular ejection fraction (LVEF), ICD vs. CRT-D, diuretic use (as a proxy for severity of HF), prior VTA and diabetes-related complications, identified from diagnosis codes for diabetic nephro-, retino-, and neuropathy, multiple diabetic complications and unspecified diabetic complications.

Results

We identified 1240 patients with HF and diabetes with a primary prevention ICD/CRT-D. The majority of patients had type 2 diabetes (94%). Of these 479 patients (39%) were treated with insulin and 761 (61%) were not. Patients were primarily male (85%) with mean age of 66.9±8.3 years, mean LVEF of 25.6±7.5%, 42% had CRT-D and 58% ICD, without differences between the groups. The insulin-treated group had a higher occurrence of diabetes-related complications (81% vs. 42%, p<0.01) and IHD (95% vs. 90%, p<0.01).

During a mean follow-up of 3.1±2.1 years, 74 insulin treated patients (16%) and 86 non-insulin treated patients (11%) experienced VTA (p=0.034), with higher 5-year cumulative incidence of VTA in the insulin group.

Insulin treatment was associated with significantly increased risk of VTA (HR = 1.45; 95% CI [1.04–2.03], p=0.031) and all-cause mortality (HR=1.27; 95% CI [1.03–1.58], p=0.027), as compared with non-insulin treated patients.

Figure 1

Conclusion

In HF patients with diabetes implanted with a primary prevention ICD/CRT-D, treatment with insulin was associated with a significant 45% increased risk of device-treated ventricular tachyarrhythmias and 27% increased risk of all-cause mortality. These findings support further clinical trials to evaluate the safety of insulin in patients with HF and type 2 diabetes.

Importance of beta-blocker dose in prevention of ventricular tachyarrhythmias, heart failure hospitalizations, and death in primary prevention implantable cardioverter-defibrillator recipients: a Danish nationwide cohort study

Aims

There is a paucity of studies investigating a dose-dependent association between beta-blocker therapy and risk of outcome. In a nationwide cohort of primary prevention implantable cardioverter-defibrillator (ICD) patients, we aimed to investigate the dose-dependent association between beta-blocker therapy and risk of ventricular tachyarrhythmias (VT/VF), heart failure (HF) hospitalizations, and death.

Methods and results

Information on ICD implantation, endpoints, comorbidities, beta-blocker usage, type, and dose were obtained through Danish nationwide registers. The two major beta-blockers carvedilol and metoprolol were examined in three dose levels; low (metoprolol ≤ 25 mg; carvedilol ≤ 12.5 mg), intermediate (metoprolol 26-199 mg; carvedilol 12.6-49.9 mg), and high (metoprolol ≥ 200 mg; carvedilol ≥ 50 mg). Time to events was investigated utilizing multivariate Cox models with beta-blocker as a time-dependent variable. From 2007 to 2012, 2935 first-time ICD devices were implanted. During follow-up, 399 patients experienced VT/VF, 728 HF hospitalizations and 361 died. As compared with patients not on beta-blockers, low, intermediate, and high dose had significantly reduced risk of HF hospitalizations {hazard ratio (HR) = 0.68 [0.54-0.87], P = 0.002; HR = 0.53 [0.42-0.66], P < 0.001; HR = 0.43 [0.34-0.54], P < 0.001} and death (HR = 0.47 [0.35-0.64], P < 0.001; HR = 0.29 [0.22-0.39], P = 0.001; HR = 0.24 [0.18-0.33], P < 0.001). For the endpoint of VT/VF, only intermediate and high dose beta-blocker was associated with significantly reduced risk (HR = 0.58 [0.43-0.79], P < 0.001; HR = 0.53 [0.39-0.72], P < 0.001). No significant difference was found between comparable doses of carvedilol and metoprolol on any endpoint (P = 0.06-0.94).

Conclusion

In primary prevention ICD patients, beta-blocker therapy was associated with significantly reduced risk of all endpoints, as compared with patients not on beta-blocker, with the suggestion of a dose-dependent effect. No detectable difference was found between comparable doses of carvedilol and metoprolol.

Incidence of appropriate implantable cardioverter-defibrillator therapy and mortality after implantable cardioverter-defibrillator generator replacement: results from a real-world nationwide cohort

Aims

The safety of omitting implantable cardioverter-defibrillator (ICD) generator replacement in patients with no prior appropriate therapy, comorbid conditions, and advanced age is unclear. The aim was to investigate incidence of appropriate ICD therapy after generator replacement.

Methods and results

We identified patients implanted with a primary prevention ICD (n = 4630) from 2007 to 2016, who subsequently underwent an elective ICD generator replacement (n = 670) from the Danish Pacemaker and ICD Register. The data were linked to other databases and evaluated the outcomes of appropriate therapy and death. Predictors of ICD therapy were identified using multivariate Cox regression analyses. A total of 670 patients underwent elective ICD generator replacement. Of these, 197 (29.4%) patients had experienced appropriate therapy in their 1st generator period. During follow-up of 2.0 ± 1.6 years, 95 (14.2%) patients experienced appropriate therapy. Predictors of appropriate therapy in 2nd generator period was low initial left ventricular ejection fraction (≤25%) [hazard ratio (HR) 1.87, confidence interval (CI) 1.13–1.95] and appropriate therapy in 1st generator period (HR 3.95, CI 2.57–6.06). For patients with appropriate therapy in 1st generator period, 4-year incidence of appropriate therapy was 50.6% vs. 16.4% in those without (P < 0.001). Among patients >80 years with no prior appropriate therapy 8.8% of patients experienced appropriate therapy after replacement. Comorbidity burden and advanced age were associated with reduced device utilization after replacement and a high competing risk of death without preceding appropriate therapy.

Conclusion

A significant residual risk of appropriate therapy in the 2nd generator was present even among patients with advanced age and with a full prior generator period without any appropriate ICD events.

Left axis deviation in patients with left bundle branch block is a marker of myocardial disease associated with poor response to cardiac resynchronization therapy

AIMS

Patients with left axis deviation (LAD) and left bundle branch block (LBBB) show less benefit from cardiac resynchronization therapy (CRT) compared to other LBBB-patients. This study investigates the reasons for this.

METHODS

Sixty-eight patients eligible for CRT were included. Patients were divided into groups according to QRS-axis; normal axis (NA), left axis deviation (LAD) and right axis deviation (RAD). Before CRT implantation CMR imaging was performed to evaluate scar tissue. Echocardiography was performed before and after implantation. The electrical substrate was assessed by measuring interlead electrical delays. Response was evaluated after 8 months by left ventricular (LV) remodelling and clinical response.

RESULTS

Forty-four (65%) patients were responders in terms of LV remodelling. The presence of LAD was found to be independently associated with a poor LV remodelling non-response OR 0.21 [95% CI 0.06-0.77] (p = 0.02). Patients with axis deviation had more myocardial scar tissue (1.3 ± 0.6 vs. 0.9 ± 0.6, P = 0.04), more severe LV hypertrophy (14 (64%) and 6 (60%) vs. 7 (29%), P = 0.05) and tended to have a shorter interlead electrical delay than patients with NA (79 ± 40 ms vs. 92 ± 48 ms, P = 0.07). A high scar tissue burden was more pronounced in non-responders (1.4 ± 0.6 vs. 1.0 ± 0.5, P = 0.01).

CONCLUSIONS

LAD in the presence of LBBB is a predictor of poor outcome after CRT. Patients with LBBB and LAD have more scar tissue, hypertrophy and less activation delay.

Risk of post-discharge fall-related injuries among adult patients with syncope: A nationwide cohort study

Background

Syncope could be related to high risk of falls and injury in adults, but documentation is sparse. We examined the association between syncope and subsequent fall-related injuries in a nationwide cohort.

Methods

By cross-linkage of nationwide registers, all residents ≥18 years with a first-time diagnosis of syncope were identified between 1997–2012. Syncope patients were matched 1:1 with individuals from the general population. The absolute one-year risk of fall-related injuries, defined as fractures and traumatic head injuries requiring hospitalization, was calculated using Aalen-Johansen estimator. Ratios of the absolute one-year risk of fall-related injuries (ARR) were assessed by absolute risk regression analysis.

Results

We identified 125,763 patients with syncope: median age 65 years (interquartile range 46–78). At one year, follow-up was complete for 99.8% where a total of 8394 (6.7%) patients sustained a fall-related injury requiring hospitalization, of which 1606 (19.1%) suffered hip fracture. In the reference group, 4049 (3.2%) persons had a fall-related injury. The one-year ARR of a fall-related injury was 1.79 (95% confidence interval 1.72–1.87, P<0.001) in patients with syncope compared with the reference group; however, increased ARR was not exclusively in older patients. Factors independently associated with increased ARR of fall-related injuries in the syncope population were: injury in past 12 months, 2.39 (2.26–2.53, P<0.001), injury in relation to the syncope episode, 1.62 (1.49–1.77, P<0.001), and depression, 1.37 (1.30–1.45, P<0.001)

Conclusion

Patients with syncope were at 80% increased risk of severe fall-related injuries within the year following discharge. Notably, increased risk was not exclusively in older patients.

Effectiveness of a comprehensive interactive eHealth intervention on patient-reported and clinical outcomes in patients with an implantable cardioverter defibrillator [ACQUIRE-ICD trial]: study protocol of a national Danish randomised controlled trial

BACKGROUND

In Denmark and other countries, there has been a shift in the management of patients with an implantable cardioverter defibrillator (ICD) with remote device monitoring largely replacing in-hospital visits. Less patient-nurse and patient-physician interaction may lead to gaps in patients' quality of care and impede patients' adaptation to living successfully with the ICD. A comprehensive eHealth intervention that include goal-setting, monitoring of symptoms of depression, anxiety, and quality of life, psychological treatment, information provision, supportive tools, online dialogues with nursing staff and access to an online community network, may help fill these gaps and be particularly beneficial to patients who suffer from anxiety and depression. This study will evaluate the effectiveness of the ACQUIRE-ICD care innovation, a comprehensive and interactive eHealth intervention, on patient-reported and clinical outcomes.

METHODS

The ACQUIRE-ICD study is a multicenter, prospective, two-arm, unblinded randomised controlled superiority trial that will enroll 478 patients implanted with a first-time ICD or ICD with cardiac synchronisation therapy (CRT-D) from the six implanting centers in Denmark. The trial will evaluate the clinical effectiveness and cost-effectiveness of the ACQUIRE-ICD care innovation, as add-on to usual care compared with usual care alone. The primary endpoint, device acceptance, assessed with the Florida Patient Acceptance Survey, is evaluated at 12 months' post implant. Secondary endpoints, evaluated at 12 and 24 months' post implant, include patient-reported outcomes, return to work, time to first ICD therapy and first hospitalisation, mortality and cost-effectiveness.

DISCUSSION

The effectiveness of a comprehensive and interactive eHealth intervention that relies on patient-centred and personalised tools offered via a web-based platform targeted to patients with an ICD has not been assessed so far. The ACQUIRE-ICD care innovation promotes and facilitates that patients become active participants in the management of their disease, and as such addresses the need for a more patient-centered disease-management approach. If the care innovation proves to be beneficial to patients, it may not only increase patient empowerment and quality of life but also free up time for clinicians to care for more patients.

TRIAL REGISTRATION

The trial has been registered on https://clinicaltrials.gov/ct2/show/NCT02976961 on November 30, 2016 with registration number [ NCT02976961 ].

The impact of co-morbidity burden on appropriate implantable cardioverter defibrillator therapy and all-cause mortality: insight from Danish nationwide clinical registers

AIMS

In a nationwide cohort of primary (PP-ICD) and secondary prevention (SP-ICD) implantable cardioverter defibrillator (ICD) patients, we aimed to investigate the association between co-morbidity burden and risk of appropriate ICD therapy and mortality.

METHODS AND RESULTS

We identified all patients >18 years, implanted with first-time PP-ICD (n = 1873) or SP-ICD (n = 2461) in Denmark from 2007 to 2012. Co-morbidity was identified in administrative registers of hospitalization and drug prescription from pharmacies. Co-morbidity burden was defined as the number of pre-existing non-ICD indication-related co-morbidities including atrial fibrillation, diabetes, chronic obstructive pulmonary disease, chronic renal disease, liver disease, cancer, chronic psychiatric disease, and peripheral and/or cerebrovascular disease, and divided into four groups (co-morbidity burden 0, 1, 2, and ≥3). Through Cox models, we assessed the impact of co-morbidity burden on appropriate ICD therapy and mortality. Increasing co-morbidity burden was not associated with increased risk of appropriate therapy, irrespective of implant indication [all hazard ratios (HRs) 1.0-1.4, P = NS]. Using no co-morbidities as reference, increasing co-morbidity burden was associated with increased mortality risk in PP-ICD patients (co-morbidity burden 1, HR 2.1; comorbidity burden 2, HR 3.7; co-morbidity burden ≥3, HR 6.6) (all P < 0.001) and SP-ICD patients (co-morbidity burden 1, HR 2.2; co-morbidity burden 2, HR 3.8; co-morbidity burden ≥3, HR 5.8). With increasing co-morbidity burden, an increasing frequency of patients died without having utilized their device, with 72% PP-ICD and 45% SP-ICD patients with co-morbidity burden ≥3 dying without prior appropriate ICD therapy.

CONCLUSION

Increasing co-morbidity burden was not associated with increased risk of appropriate ICD therapy. With increasing co-morbidity burden, mortality increased, and a higher proportion of patients died, without ever having utilized their device.

Incidence and influence of hospitalization for recurrent syncope and its effect on short- and long-term all-cause and cardiovascular mortality

Recurrence of syncope is a common event, but the influence of recurrent syncope on the risk of death has not previously been investigated on a large scale. We examined the prognostic impact of recurrent syncope in a nationwide cohort of patients with syncope. All patients (n = 70,819) hospitalized from 2001 to 2009 in Denmark with a first-time diagnosis of syncope aged from 15 to 90 years were identified from national registries. Recurrence of syncope was incorporated as a time-dependent variable in multivariable-adjusted Cox models on the outcomes of 30-day, 1-year, and long-term all-cause mortality and cardiovascular death. During a mean follow-up of 3.9 ± 2.6 years, a total of 11,621 patients (16.4%) had at least 1 hospitalization for recurrent syncope, with a median time to recurrence of 251 days (33 to 364). A total of 14,270 patients died, and 3,204 deaths were preceded by a hospitalization for recurrent syncope. The long-term risk of all-cause death was significantly associated with recurrent syncope (hazard ratio 2.64, 95% confidence interval 2.54 to 2.75) compared with those with no recurrence. On 1-year mortality, recurrent syncope was associated with a 3.2-fold increase in risk and on 30-day mortality associated with a threefold increase. The increased mortality risk was consistent over age groups 15 to 39, 40 to 59, and 60 to 89 years, and a similar pattern of increase in both long-term and short-term risk of cardiovascular death was evident. In conclusion, recurrent syncope is independently associated with all-cause and cardiovascular mortality across all age groups exhibiting a high prognostic influence. Increased awareness on high short- and long-term risk of adverse events in subjects with recurrent syncope is warranted for future risk stratification.

Comparison of incidence, predictors, and the impact of co-morbidity and polypharmacy on the risk of recurrent syncope in patients <85 versus ≥85 years of age

Recurrent syncope is a major cause of hospitalizations and may be associated with cardiovascular co-morbidities. Despite this, prognostic factors and the clinical characteristics among patients are not well described. Therefore, we identified and analyzed data on all patients >50 years of age discharged after a first-time episode of syncope in the period 2001 to 2009 through nationwide administrative registries. We identified the clinical characteristics of 5,141 patients ≥85 years of age and 23,454 patients <85 years of age. Multivariate Cox models were used to assess prognostic factors associated with the end point of recurrent syncope according to age. We found that those with syncope and ≥85 years were more often women (65% vs 47%) and generally had a greater prevalence of noncardiovascular co-morbidities, whereas the prevalence of cardiovascular co-morbidities was more heterogeneously distributed across age groups. Overall, significant baseline predictors of recurrent syncope were aortic valve stenosis (hazard ratio [HR] 1.48, 95% confidence interval [CI] 1.31 to 1.68), impaired renal function (HR 1.34, 95% CI 1.15 to 1.58), atrioventricular or left bundle branch block (HR 1.32, 95% CI 1.16 to 1.51), male gender (HR 1.18, 95% CI 1.12 to 1.24), chronic obstructive pulmonary disorder (HR 1.10, 95% CI 1.02 to 1.19), heart failure (HR 1.10, 95% CI 1.02 to 1.21), atrial fibrillation (HR = 1.09, 95% CI 1.01 to 1.19), age per 5-year increment (HR 1.09, 95% CI 1.07 to 1.10), and orthostatic medications per increase (HR 1.06, 95% CI 1.03 to 1.09). Atrial fibrillation and impaired renal function both exhibited less prognostic importance for recurrent syncope in the elderly compared with younger population (p for interactions <0.01). In conclusion, predictive factors of recurrent syncope were closely associated with increased cardiovascular risk profile age and gender. The use of multiple orthostatic medications additively increased the risk of recurrences representing a need for strategies to reduce unnecessary polypharmacy.

Unexplained Syncope and Diagnostic Yield of Tests in Syncope According to the ICD-10 Discharge Diagnosis

Background

The etiology of syncope according to the discharge diagnosis from hospital admissions has not been examined before. Therefore the aims of this study were to examine the diagnostic yield of tests and frequency of unexplained cases during admission and after workup after an ICD-10 diagnosis of syncope.

Methods

A retrospective chart review of 600 patients discharged with the primary ICD-10 discharge diagnosis of syncope R55.9 was performed. Causes and clinical characteristics of syncope according to the physician were noted both after initial discharge and after workup.

Results

During a mean follow-up period of 2.5 years (SD: ± 1.30) several diagnostic tests were used (mean number of tests per patient was 4.7 (SD: ± -2.0)) and the mean length of admission was 2.1 days (± 1.5).The final diagnosis after workup was reflex syncope in 21%, cardiac 18%, orthostatic hypotension 10%, other causes 4% and unknown/unexplained syncope in 48% with wide age differences. The diagnostic yield of tests was generally low and differed widely depending on usage during admission or usage during subsequent workup.

Conclusions

The underlying etiology of syncope remains difficult to establish despite the high use of diagnostic tests and the diagnostic yield of many tests implemented in the care path is generally low.

Early echocardiographic deformation analysis for the prediction of sudden cardiac death and life-threatening arrhythmias after myocardial infarction

OBJECTIVES

This study sought to hypothesize that global longitudinal strain (GLS) as a measure of infarct size, and mechanical dispersion (MD) as a measure of myocardial deformation heterogeneity, would be of incremental importance for the prediction of sudden cardiac death (SCD) or malignant ventricular arrhythmias (VA) after acute myocardial infarction (MI).

BACKGROUND

SCD after acute MI is a rare but potentially preventable late complication predominantly caused by malignant VA. Novel echocardiographic parameters such as GLS and MD have previously been shown to identify patients with chronic ischemic heart failure at increased risk for arrhythmic events. Risk prediction during admission for acute MI is important because a majority of SCD events occur in the early period after hospital discharge.

METHODS

We prospectively included patients with acute MI and performed echocardiography, with measurements of GLS and MD defined as the standard deviation of time to peak negative strain in all myocardial segments. The primary composite endpoint (SCD, admission with VA, or appropriate therapy from a primary prophylactic implantable cardioverter-defibrillator [ICD]) was analyzed with Cox models.

RESULTS

A total of 988 patients (mean age: 62.6 ± 12.1 years; 72% male) were included, of whom 34 (3.4%) experienced the primary composite outcome (median follow-up: 29.7 months). GLS (hazard ratio [HR]: 1.38; 95% confidence interval [CI]: 1.25 to 1.53; p < 0.0001) and MD (HR/10 ms: 1.38; 95% CI: 1.24 to 1.55; p < 0.0001) were significantly related to the primary endpoint.

GLS (HR

1.24; 95% CI: 1.10 to 1.40; p = 0.0004) and MD (HR/10 ms: 1.15; 95% CI: 1.01 to 1.31; p = 0.0320) remained independently prognostic after multivariate adjustment. Integrated diagnostic improvement (IDI) and net reclassification index (NRI) were significant for the addition of GLS (IDI: 4.4% [p < 0.05]; NRI: 29.6% [p < 0.05]), whereas MD did not improve risk reclassification when GLS was known.

CONCLUSIONS

Both GLS and MD were significantly and independently related to SCD/VA in these patients with acute MI and, in particular, GLS improved risk stratification above and beyond existing risk factors.

Evaluation of the CHADS2 risk score on short- and long-term all-cause and cardiovascular mortality after syncope

BACKGROUND

Syncope risk stratification is difficult and has not been implemented clinically.

HYPOTHESIS

The CHADS2 score can be applied as a risk stratification tool for predicting mortality after an episode of syncope.

METHODS

All patients discharged from emergency departments with a first-time diagnosis of syncope from 2001 to 2009 where identified from nationwide registers in Denmark and matched on sex and age with a control population. Risk of all-cause or cardiovascular death was analyzed by multivariable Cox models.

RESULTS

A total of 37,705 patients were included. There were a total of 7761 deaths (21%), of which 52% were cardiovascular vs 27 862 (15%) deaths in the control population. The risk of cardiovascular death was significantly increased with increasing CHADS2 score (CHADS2 score: 1-2, hazard ratio [HR]: 9.11, 95% confidence interval [CI]: 8.25-10.07; CHADS2 score: 3-4, HR: 17.32, 95% CI: 15.42-19.47; CHADS2 score: 5-6, HR: 26.66, 95% CI: 21.40-33.21) relative to CHADS2 score of 0. A CHADS2 score of 0 was associated overall with very low event rates (15.1 deaths per 1000 person-years) but was associated with increased relative risk in the syncope population compared to controls. Syncope predicted 1-week, 1-year, and long-term mortality across CHADS2 scores compared to controls but did not reach significance in CHADS2 scores of 5 to 6.

CONCLUSIONS

Increasing CHADS2 score significantly predicts mortality in patients discharged with a diagnosis of syncope, and a CHADS2 score of 0 was associated with a very low absolute mortality. Compared to controls, syncope was associated with increased short- and long-term mortality, particularly in the lower CHADS2 scores.

Validation of a digital video tracking system for recording pig locomotor behaviour

We are introducing a system for automatically tracking pig locomotor behaviour. Transposing methods for the video-based tracking of rodent behaviour engenders several problems. We have therefore improved existing methods, based on image-subtraction, to offer increased flexibility and accuracy in tracking large-sized animals in situations with a constantly changing background. The improved tracking algorithms introduce a reference frame, which does not include the animal and is automatically updated, and implementation of an automatic threshold detection algorithm. This makes the system more robust to the tracking environment, which could even be of the same colour as the animal, and allows the tracking environment to change during recording. We validated the system by estimating the repeatability, accuracy, and basic noise level, and tested the system in different levels of animal activity evoked by administration of apomorphine (APO) to minipigs in an open field test. Seven pigs each received the vehicle and three doses of APO (0.05, 0.1, and 0.3 mg/kg i.m.), and the locomotor behaviour of each session was recorded for 60-min. The calculated coefficient of repeatability was 0.6%, indicating high repeatability and the basic noise level of the tracking system was estimated to be 2%. Administration of the two lowest doses of APO was accompanied by increased locomotor activity of the pigs. Thus, this digital video-based tracking system for automatically tracking the spontaneous locomotor behaviour of pigs is highly reliable and accurate, and was able to detect well-known effects of APO in pig locomotor activity.