Type 2 diabetes is associated with higher risk of 3rd degree atrioventricular block: a Danish nationwide registry study

Background

Type 2 diabetes (T2DM) is suggested to affect the function of the cardiomyocytes and electrical pathways which could cause conduction abnormalities and cardiac arrhythmias, such as 3rd degree atrioventricular block. The association of T2DM and 3rd degree atrioventricular block has never been confirmed in large nationwide studies.

Purpose

To determine the association between T2DM and 3rd degree atrioventricular block.

Method

This nationwide nested case-control study design included patients older than 18 years, diagnosed with 3rd degree atrioventricular block between 1st of July 1995 and 31st of December 2018. Five controls from the risk set of each case of 3rd degree atrioventricular block were matched on age and sex to fit a Cox regression model with time-dependent exposure (T2DM) and time-dependent covariates and baseline hazard function stratified for age and sex. Subgroup analysis was conducted with Cox models for each subgroup.

Results

We identified 31.177 cases with 3rd degree atrioventricular block that were matched with 155.885 controls. The mean age was 78 years and 60% were males. Cases had higher prevalence of T2DM (20% vs 7.8%), hypertension (70% vs 43%) myocardial infarction (16% vs 6.6%), and heart failure (21% vs 5.9%) compared to the control group. In a Cox analysis T2DM was significantly associated with a higher rate of 3rd degree atrioventricular block [HR 2.61 (95% CI: 2.54–2.71)]. The association remained in several subgroup analyses of diseases suspected to be associated with 3rd degree atrioventricular block. There was a significant interaction with sex and age groups and comorbidities of interest including hypertension, atrial fibrillation, heart failure and myocardial infarction (Figure 1).

Conclusion

T2DM is associated with a higher rate of 3rd degree atrioventricular block. The findings were consistent across subgroups.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work was funded by the independent research foundation Skibsreder Per Henrik, R. og Hustrus Fond

Diagnostic Yield of Genetic Testing in Young Patients With Atrioventricular Block of Unknown Cause

Background

The cause of atrioventricular block (AVB) remains unknown in approximately half of young patients with the diagnosis. Although variants in several genes associated with cardiac conduction diseases have been identified, the contribution of genetic variants in younger patients with AVB is unknown.

Methods and Results

Using the Danish Pacemaker and Implantable Cardioverter Defibrillator (ICD) Registry, we identified all patients younger than 50 years receiving a pacemaker because of AVB in Denmark in the period from January 1, 1996 to December 31, 2015. From medical records, we identified patients with unknown cause of AVB at time of pacemaker implantation. These patients were invited to a genetic screening using a panel of 102 genes associated with inherited cardiac diseases. We identified 471 living patients with AVB of unknown cause, of whom 226 (48%) accepted participation. Median age at the time of pacemaker implantation was 39 years (interquartile range, 32–45 years), and 123 (54%) were men. We found pathogenic or likely pathogenic variants in genes associated with or possibly associated with AVB in 12 patients (5%). Most variants were found in the LMNA gene (n=5). LMNA variant carriers all had a family history of either AVB and/or sudden cardiac death.

Conclusions

In young patients with AVB of unknown cause, we found a possible genetic cause in 1 out of 20 participating patients. Variants in the LMNA gene were most common and associated with a family history of AVB and/or sudden cardiac death, suggesting that genetic testing should be a part of the diagnostic workup in these patients to stratify risk and screen family members.

Sex differences in echocardiographic predictors of bradycardia detected by implantable loop recorder in patients with syncope and palpitations

OBJECTIVE

Our aim was to investigate whether echocardiography may aid in identifying patients, specifically men, at risk of bradycardia as detected by implantable loop recorders (ILR) in patients evaluated for syncope and palpitations.

METHODS

We included ambulatory patients undergoing ILR implantation for syncope (84%), presyncope (9%), and palpitations (8%). Echocardiographic examination was performed prior to implantation (2.9 months [IQR 1.0-6.0 months]). Echocardiograms were analyzed for conventional and speckle tracking parameters. We examined time to first event of bradycardia, defined as (a) heart rate <30 beats/min and (b) ≥4 beats, including sinus arrest, asystole, sinoatrial block, and second- and third-degree atrioventricular nodal block. We applied Cox proportional hazards models.

RESULTS

A total of 285 patients we enrolled, and during a median time of 2.7 years [IQR 1.0, 3.3 years] of continuous heart rhythm monitoring, 84 (29%) had bradycardia detected by ILR. Patients with bradycardia were older (61 ± 19 years vs 55 ± 18 years, P = .01) and more frequently men (62% vs 44%, P = .01). Sex modified the association between echocardiographic parameters and bradycardia (P interaction <0.05 for all), such that left ventricular LV mass index (HR: 1.02 per 1g/m² increase [1.01-1.04], P < .001), LV ejection fraction (HR: 1.04 per 1% decrease [1.01-1.08], P = .02), and global longitudinal strain (HR: 1.09 per 1% decrease [1.01-1.19], P = .03) were associated with bradycardia in men but not women (P > .05 for all in female). After adjusting for baseline clinical characteristics, medical therapy, and loop indication, the abovementioned parameters remained significantly associated with incident bradycardia in men.

CONCLUSION

Echocardiographic parameters of LV structure and function may potentially be more useful for predicting bradycardia in men than women, among patients undergoing ILR implantation for syncope, presyncope, and palpations.

Safety of Same-Day Discharge After Percutaneous Coronary Intervention in Selected Patients With Non-ST Elevation Acute Coronary Syndrome

OBJECTIVES

We aimed to investigate the safety of same-day discharge (SDD) after percutaneous coronary intervention (PCI) for non-ST segment elevation acute coronary syndrome (NSTEACS), and to investigate the reduction in duration of hospitalization achievable by SDD.

BACKGROUND

Previous studies have established the safety of SDD after elective PCI, while the safety of SDD after non-elective PCI for acute coronary syndrome has only been sparsely studied.

METHODS

A single-center, observational, retrospective study of 923 consecutive procedures in patients with NSTEACS who had PCI was performed. The procedures were divided into 2 groups based on postprocedural management: SDD (n = 195) and non-SDD (n = 728).

RESULTS

No differences were seen in the total number of adverse events at 1 month (1.5% SDD vs 1.4% non-SDD; P=.74), 3 months (2.5% SDD vs 2.3% non-SDD; P=.80), and 6 months (3.5% SDD vs 3.3% non-SDD; P=.84) after discharge, and there were no deaths in the SDD group. No difference was found in unplanned rehospitalizations within 6 months (20.5% SDD vs 25.3% non-SDD; P=.17), while unplanned revascularizations were more frequent in non-SDD patients (5.6% SDD vs 13.4% non-SDD; P<.01). Median duration of hospitalization was 1.3 days shorter for SDD patients than for non-elderly, uncomplicated non-SDD patients.

CONCLUSIONS

SDD after PCI in a selected group of NSTEACS patients was associated with low rates of adverse events, unplanned rehospitalizations, and revascularizations. SDD was associated with a shorter hospitalization duration.

Risk factors and a 3-month risk score for predicting pacemaker implantation in patients with atrial fibrillations

Objectives

To identify risk factors and to develop a predictive risk score for pacemaker implantation in patients with atrial fibrillation (AF).

Methods

Using Danish nationwide registries, patients with newly diagnosed AF from 2000 to 2014 were identified. Cox proportional-hazards regression computed HRs for risk factors of pacemaker implantation. A logistic regression was used to fit a prediction model for 3-month risk of pacemaker implantation and derived a risk score using 80% of the data and its predictive accuracy estimated using the remaining 20%.

Results

Among 155 934 AF patients included, the median age (IQR) was 75 (65–83) and 51.3% were men. During a median follow-up time of 3.4 (1.2–5.0) years, 8348 (5.4%) patients received a pacemaker implantation. Risk factors of pacemaker implantation were (in order of highest risk first) age above 60 years, congenital heart disease, heart failure at age under 60 years, prior syncope, valvular AF, hypertension, ischaemic heart disease, male sex and diabetes mellitus. The derived risk score assigns points ranging from 1 to 14 to each of these risk factors. The 3-month risk of pacemaker implantation increased from 0.4% (95% CI: 0.2 to 0.8) at 1 point to 2.6% (95% CI: 1.9 to 3.6) at 18 points. Area under the receiver operator characteristics curve was 62.9 (95% CI: 60.3 to 65.5).

Conclusion

We highlighted risk factors of pacemaker implantation in newly diagnosed AF patients and created a risk score. The clinical utility of the risk score needs further investigation.

GARFIELD-AF model for prediction of stroke and major bleeding in atrial fibrillation: a Danish nationwide validation study

OBJECTIVES

To externally validate the accuracy of the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) model against existing risk scores for stroke and major bleeding risk in patients with non-valvular AF in a population-based cohort.

DESIGN

Retrospective cohort study.

SETTING

Danish nationwide registries.

PARTICIPANTS

90 693 patients with newly diagnosed non-valvular AF were included between 2010 and 2016, with follow-up censored at 1 year.

PRIMARY AND SECONDARY OUTCOME MEASURES

External validation was performed using discrimination and calibration plots. C-statistics were compared with CHA₂DS₂VASc score for ischaemic stroke/systemic embolism (SE) and HAS-BLED score for major bleeding/haemorrhagic stroke outcomes.

RESULTS

Of the 90 693 included, 51 180 patients received oral anticoagulants (OAC). Overall median age (Q1, Q3) were 75 (66-83) years and 48 486 (53.5%) were male. At 1-year follow-up, a total of 2094 (2.3%) strokes/SE, 2642 (2.9%) major bleedings and 10 915 (12.0%) deaths occurred. The GARFIELD-AF model was well calibrated with the predicted risk for stroke/SE and major bleeding. The discriminatory value of GARFIELD-AF risk model was superior to CHA₂DS₂VASc for predicting stroke in the overall cohort (C-index: 0.71, 95% CI: 0.70 to 0.72 vs C-index: 0.67, 95% CI: 0.66 to 0.68, p<0.001) as well as in low-risk patients (C-index: 0.64, 95% CI: 0.59 to 0.69 vs C-index: 0.57, 95% CI: 0.53 to 0.61, p=0.007). The GARFIELD-AF model was comparable to HAS-BLED in predicting the risk of major bleeding in patients on OAC therapy (C-index: 0.64, 95% CI: 0.63 to 0.66 vs C-index: 0.64, 95% CI: 0.63 to 0.65, p=0.60).

CONCLUSION

In a nationwide Danish cohort with non-valvular AF, the GARFIELD-AF model adequately predicted the risk of ischaemic stroke/SE and major bleeding. Our external validation confirms that the GARFIELD-AF model was superior to CHA₂DS₂VASc in predicting stroke/SE and comparable with HAS-BLED for predicting major bleeding.

3153Rate versus rhythm control and mortality in atrial fibrillation patients: a Danish nationwide cohort study

Background

Treatment of AF patients with rate or rhythm drug therapy have shown no difference in mortality in clinical trials. However, the generalizability of these trials to real-world populations can be questioned.

Purpose

We aimed to investigate the all-cause and cardiovascular (CV) mortality risk in a nationwide AF cohort by treatment strategy (rate vs. rhythm) and by individual drug classes.

Methods

We queried the Danish nationwide registries from 2000 to 2015 to identify patients with AF. A rate control strategy included the use of one or more of the following medications: beta-blocker, digoxin, and a class-4 calcium channel blocker (CCB). A rhythm control strategy included the use of an anti-arrhythmic drug (amiodarone and class-1C). Primary outcome was all-cause mortality. Secondary outcome was CV mortality. Adjusted incidence rate ratios (IRR) were computed using Poisson regression with time-dependent covariates allowing patients to switch treatment during follow-up.

Results

Of 140,697 AF patients, 131,793 were on rate control therapy and n=8,904 were on rhythm control therapy. At baseline, patients on rhythm control therapy were younger (71 yrs [IQR: 62–78] vs 74 [65–82], p<0.001) more likely male (63.5% vs 51.7% p<0.001), had more prevalent heart failure (31.1% vs 19.4%, p<0.001) and ischemic heart disease (40.1% vs. 23.3%, p<0.001), and had more prior CV-related procedures; PCI (7.4% vs. 4.0% p<0.001) and CABG (15.0% vs. 2.3%, p<0.001).

During a median follow up of 4.0 (IQR: 1.7–7.3) years, there were 64,653 (46.0%) deaths from any-cause, of which 27,025 (19.2%) were CVD deaths. After appropriate adjustments and compared to rate control therapy, we found a lower IRR of mortality and CV mortality in those treated with rhythm control therapy (IRR: 0.93 [95% CI: 0.90–0.97] and IRR 0.84 [95% CI: 0.79–0.90]). Compared with beta-blockers, digoxin was associated with increased risk of all-cause and CV mortality (IRR: 1.26 [95% CI: 1.24–1.29] and IRR: 1.32 [95% CI: 1.28–1.36]), so was amiodarone: IRR for all-cause mortality: 1.16 [95% CI: 1.11–1.21] and IRR for CV mortality: 1.12 [95% CI: 1.05–1.19]. Class-1C was associated with lower all-cause (0.43 [95% CI: 0.37–0.49]) and CV mortality (0.35 [95% CI: 0.28–0.44]).

Figure 1. Models were adjusted for age, sex, ischemic heart disease, stroke, chronic obstructive pulmonary disease, chronic kidney disease, valvular atrial fibrillation, bleeding, diabetes, ablation, pacemaker, implantable cardioverter defibrillator, hypertension, heart failure, use of loop diuretics, calendar year, and time on treatment. Abbreviations; CCB; calcium channel blocker, PY; person years.

Conclusions

In a real-world AF cohort, we found that compared with rate control therapy, rhythm control therapy was associated with a lower risk of all-cause and CV mortality. The reduced mortality risk with rhythm therapy could reflect an appropriate patient selection.

Acknowledgement/Funding

The Danish Heart Foundation

Rate or Rhythm Control in Older Atrial Fibrillation Patients: Risk of Fall-Related Injuries and Syncope

OBJECTIVES

Management of atrial fibrillation (AF) with rate and/or rhythm control could lead to fall-related injuries and syncope, especially in the older AF population. We aimed to determine the association of rate and/or rhythm control with fall-related injuries and syncope in a real-world older AF cohort.

DESIGN

A retrospective cohort study.

SETTING

Danish nationwide administrative registries from 2000 to 2015.

PARTICIPANTS

A total of 100 935 patients with AF aged 65 years or older claiming prescription of rate-lowering drugs (RLDs) and/or anti-arrhythmic drugs (AADs) were included. We compared the use of rate-lowering monotherapy with rate-lowering dual therapy, AAD monotherapy, and AAD combined with rate-lowering therapy.

MEASUREMENTS

Outcomes were fall-related injuries and syncope as a composite end point (primary) or separate end point (secondary).

RESULTS

In this population, the median age was 78 years (interquartile range [IQR] = 72-84 y), and 53 481 (53.0%) were women. During a median follow-up of 2.1 years (IQR = 1.0-5.1), 17 132 (17.0%) experienced a fall-related injury, 5745 (5.7%) had a syncope, and 21 093 (20.9%) experienced either. Compared with rate-lowering monotherapy, AADs were associated with a higher risk of fall-related injuries and syncope. The incidence rate ratio (IRR) for the composite end point was 1.29 (95% confidence interval [CI]: 1.17-1.43) for AAD monotherapy and 1.46 [95% CI = 1.34-1.58] for AAD combined with rate-lowering therapy. When stratifying by individual drugs, amiodarone significantly increased the risk of fall-related injuries and syncope (IRR = 1.40 [1.26-1.55]). Compared with more than 180 days of rate-lowering monotherapy, a higher risk of all outcomes was seen in the first 90 days of any treatment; however, the greatest risk was in the first 14 days for those treated with AADs.

CONCLUSION

In AF patients aged 65 years and older, AAD use was associated with a higher risk of fall-related injuries and syncope, and the risk was highest within the first 14 days for those treated with AADs. Only amiodarone use was associated with a higher risk. J Am Geriatr Soc 67:2023-2030, 2019.

Rate and rhythm therapy in patients with atrial fibrillation and the risk of pacing and bradyarrhythmia

BACKGROUND

Management of atrial fibrillation (AF) with rate and rhythm therapy can cause bradyarrhythmia.

OBJECTIVES

To assess overall risk, temporal risk, and subgroup at risk of bradyarrhythmia-related events by rate and/or rhythm therapy drugs.

METHODS

Using Danish nationwide registries, patients with AF between 2000 and 2014 were included if prescribed with rate-lowering drugs (RLDs) or antiarrhythmic drugs (AADs). An adjusted time-dependent Poisson regression model estimated the association between RLDs and AADs with a composite endpoint of pacemaker, temporary pacing, and bradyarrhythmia hospitalization. Secondary outcomes were each individual event.

RESULTS

Among 135,017 AF patients, 9196 (6.8%) patients experienced the composite endpoint with a median follow-up of 3.7 (interquartile range [IQR]: 1.6-7.0) years. Median age was 74 (IQR: 65-82) years and 47.6% were women. With rate-lowering monotherapy as the reference, the incidence rate ratios (IRR) (95% confidence interval) for the composite endpoint were 1.36 (1.29-1.43) for rate-lowering dual therapy, 1.62 (1.43-1.84) for antiarrhythmic monotherapy, and 2.49 (2.29-2.71) for AAD combined with RLDs. Similar trend was found for each secondary outcome. Particularly amiodarone increased the risk. This association was strongest within the first 2 weeks of treatment. In those treated with AAD combined with RLDs, high-risk populations were patients ≥70 years (IRR: 3.35 [2.51-4.45] compared to patients <60 years), and women (IRR: 1.35 [1.15-1.57], compared to men).

CONCLUSIONS

In real-world AF patients, rate-lowering dual therapy, antiarrhythmic monotherapy, and AADs combined with RLDs were positively associated with bradyarrhythmia-related events. The risk was highest in those treated with amiodarone, in the initial 2 weeks of treatment, in women, and in the elderly.

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.

Thiazolidinediones are associated with a decreased risk of atrial fibrillation compared with other antidiabetic treatment: a nationwide cohort study

Aim

The aim of this study was to investigate the association between thiazolidinediones (TZDs) vs. other antidiabetic drugs and risk of atrial fibrillation (AF) in diabetic patients.

Method and results

Diabetes mellitus (diabetes) increases the risk of AF by approximately 34%. TZD is an insulin sensitizer that also has anti-inflammatory effects, which might decrease the risk of AF compared with other antidiabetic drugs. We used data from the Danish nationwide registries to study 108 624 patients with diabetes and without prior AF who were treated with metformin or sulfonylurea as first-line drugs. The incidence of AF was significantly lower with TZD as the second-line antidiabetic treatment compared with other second-line antidiabetic drugs (P < 0.001). The 10 year cumulative incidence [95% confidence interval (95% CI)] of AF was 6.2% (3.1-9.3%) with TZD vs. 10.2% (9.8-10.6%) with other antidiabetic drugs. The decreased risk of AF remained significant after adjusting for age, sex, and comorbidities with a hazard ratio (95% CI) of 0.76 (0.57-1.00), P = 0.047 associated with TZD treatment compared with other antidiabetic drugs.

Conclusion

Use of a TZD to treat diabetes was associated with reduced risk of developing AF compared with other antidiabetic drugs as second-line treatment.

Infective endocarditis and risk of death after cardiac implantable electronic device implantation: a nationwide cohort study

Aims

To determine the incidence, risk factors, and mortality of infective endocarditis (IE) following implantation of a first-time, permanent, cardiac implantable electronic device (CIED).

Methods and results

From Danish nationwide administrative registers (beginning in 1996), we identified all de-novo permanent pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) together with the occurrence of post-implantation IE-events in the period from 2000-2012. Included were 43 048 first-time PM/ICD recipients. Total follow-up time was 168 343 person-years (PYs). The incidence rate (per 1000 PYs) of IE in PM was 2.1 (95% confidence interval [CI]: 1.7-2.6) for single chamber devices and 6.2 (95% CI: 4.5-8.7) for cardiac resynchronization therapy (CRT); similarly, the rate of IE in ICD was 3.7 (95% CI: 2.9-4.7) in single chamber devices and 6.3 (95% CI: 4.4-9.0) in CRT. In multivariable analysis, increased PM complexity served as independent risk factor for IE {dual chamber PM [hazard ratio (HR) 1.39; 95% CI: 1.07-1.80] and CRT [HR: 1.84; 95% CI: 1.20-2.84]}. During follow-up, generator replacement (HR: 2.79; 95% CI: 1.87-4.17) and lead revision (HR: 4.33; 95% CI: 3.25-5.78) in PMs were associated with increased risk. Corresponding estimates in ICDs were 2.49 (95% CI: 1.28-4.86) and 6.58 (95% CI: 4.49-9.63). Risk of death after IE was significantly increased in PM and ICD with HRs of 1.56 (95% CI: 1.33-1.82) and 2.63 (95% CI: 2.00-3.48), respectively.

Conclusion

The risk of IE increased with increasing PM complexity. Other important risk factors were subsequent generator replacement and lead revision. IE was associated with an increased risk of mortality in the area of CIED.

Patients with atrial fibrillation and permanent pacemaker: Temporal changes in patient characteristics and pharmacotherapy

Background

The management of patients with non-valvular atrial fibrillation (NVAF) with rate-lowering or anti-arrhythmic drugs has markedly changed over the last decade, but it is unknown how these changes have affected patients with NVAF with a permanent pacemaker (PPM).

Methods

Through Danish nationwide registries, patients with NVAF and a PPM were identified from 2001 to 2012. Changes in concomitant pharmacotherapy and comorbidities were tested using the Cochran–Armitage trend test and linear regression. Patients with NVAF were identified to calculate the proportional amount of PPM implants.

Results

A total of 12,231 NVAF patients with a PPM were included in the study, 55.6% of which were men. Median age was 78 years (interquartile range 70–84). From 2001 to 2012, the number of NVAF patients with a PPM increased from 850 to 1344, while the number of NVAF patients increased from 67,478 to 127,261. Thus, the proportional amount of NVAF patients with a PPM decreased from 1.3% to 1.1% (p = 0.015). Overall 45.9% had atrial fibrillation (AF) duration less than one year and the proportion declined from 55.5% to 42.4% (p <0.001). Diabetes mellitus increased from 7.2% to 16.8% (p <0.001). Heart failure (HF) decreased from 36.7% to 29.3% (p = 0.010) and ischemic heart disease (IHD) decreased from 32.4% to 26.1% (p <0.001). Beta-blocker use increased from 38.1% to 58.0% (p <0.001), while digoxin and anti-arrhythmic drug use decreased over time.

Conclusion

From 2001 to 2012, the absolute number of NVAF patients with a PPM increased while the proportional amount decreased. The number of NVAF patients receiving a PPM within one year of AF diagnosis decreased. The prevalence of DM increased, while the prevalence of HF and IHD was high but decreasing. The use of beta-blockers increased markedly, while use of digoxin and anti-arrhythmic drugs decreased over time.

Risk of Ischemic Stroke, Hemorrhagic Stroke, Bleeding, and Death in Patients Switching from Vitamin K Antagonist to Dabigatran after an Ablation

Background

Safety regarding switching from vitamin K antagonist (VKA) to dabigatran therapy in post-ablation patients has never been investigated and safety data for this is urgently needed. The objective of this study was to examine if switch from VKA to dabigatran increased the risk of stroke, bleeding, and death in patients after ablation for atrial fibrillation.

Methods

Through the Danish nationwide registries, patients with non-valvular atrial fibrillation undergoing ablation were identified, in the period between August 22nd 2011 and December 31st 2015. The risk of ischemic stroke, hemorrhagic stroke, bleeding, and death, related to switching from VKA to dabigatran was examined using a multivariable Poisson regression model, where Incidence rate ratios (IRR) were estimated using VKA as reference.

Results

In total, 4,236 patients were included in the study cohort. The minority (n = 470, 11%) switched to dabigatran in the follow up period leaving the majority (n = 3,766, 89%) in VKA treatment. The patients in the dabigatran group were older, were more often males, and had higher CHA2DS2-VASc, and HAS-BLED scores. The incident rates of bleeding and death were almost twice as high in the dabigatran group compared with the VKA group. When adjusting for the individual components included in the CHA2DS2-VASc and HAS-BLED scores, the multivariable Poisson analyses yielded a non-significant IRR (95%CI) of 1.64 (0.72–3.75) for bleeding and of 1.41 (0.66–3.00) for death associated with the dabigatran group, compared to the VKA group. A significant increased risk of bleeding was found in the 110mg bid group with an IRR (95%CI) of 4.49(1.40–14.5).

Conclusion

Shifting from VKA to dabigatran after ablation was associated with twice as high incidence of bleeding compared to the incidence in patients staying in VKA treatment. The only significant increased risk found in the adjusted analyses was for bleeding with 110mg bid dabigatran and not for 150mg bid. Since there was no dose-response for bleeding, the switch from VKA to dabigatran in itself was not a risk factor for bleeding.

Effects of pharmacological modulation of the ATP-sensitive potassium channels on the development of warm-up angina pectoris

The aim of this study was to examine the effect of pharmacological modulation of the ATP-sensitive potassium channels in the development of warm-up angina pectoris. Thirty-one patients with stable angina pectoris, a positive exercise test and angiographically documented coronary artery disease underwent three exercise tests 90 min after receiving either glibenclamide 10.5 mg (an ATP-sensitive potassium channel blocker), pinacidil 25 mg (an ATP-sensitive potassium channel opener) or placebo in a blinded fashion. There was a 30-min recovery period between the first and the second test and 60 min between the second and the third test. The rate-pressure product at 1-mm ST-segment depression (ischemic threshold) and the maximum ST-segment depression (STD) adjusted to the highest rate-pressure product common to the three tests were analyzed. In the placebo group, there was a significant increase in the ischemic threshold during the second and third test and a significant decrease in the maximum adjusted STD during the second test which was lost during the third test. This apparent adaptation to exercise-induced ischemia was not seen in the glibenclamide-treated patients. In the pinacidil-treated patients, there was a paradoxical decrease in ischemic threshold during the second test with no change in maximum adjusted STD which tended to be lower than in the placebo-treated patients on each exercise test. This study confirms that the warm-up phenomenon can be induced during repeated exercise testing. The blockade of this phenomenon by glibenclamide suggests that the ATP-sensitive potassium channels may be involved in this potential protective mechanism. At the same time, the paradoxical response in the pinacidil-treated patients flags a warning that drugs acting on the sarcolemmal ATP-sensitive potassium channels may have a direct effect on the ST-segment that may interfere with the interpretation of the electrocardiogram.

Pharmacological modulation of the ATP sensitive potassium channels during repeated coronary occlusions: no effect on myocardial ischaemia or function

BACKGROUND

Repeated episodes of myocardial ischaemia may lead to ischaemic preconditioning. This is believed to be mediated by the ATP sensitive potassium channels.

OBJECTIVE

To examine the effect of pharmacological modulation of the ATP sensitive potassium channels during repeated coronary occlusions.

DESIGN

Double blind, double dummy study.

METHODS

38 patients with a proximal stenosis of the left anterior descending coronary artery and no visible coronary collateral vessels underwent three identical 90 second balloon occlusions, each followed by five minutes of reperfusion. The patients were randomised to pinacidil 25 mg, glibenclamide 10.5 mg, or matching placebo 90 minutes before the start of the procedure. Myocardial ischaemia was measured by continuous monitoring of ECG ST segment changes. Changes in left ventricular function were recorded with a miniature radionuclide detector, and angina was scored on the Borg scale.

RESULTS

In all patients the first balloon occlusion led to significant ST segment elevation, a clear decrease in left ventricular ejection fraction, and angina pectoris. This response was not attenuated at the second or third balloon occlusion, either in the placebo group or in the patients pretreated with pinacidil or glibenclamide.

CONCLUSIONS

Under the given experimental conditions, this randomised and double blind study did not support the view that the human myocardium has an intrinsic protective mechanism that is activated by short lasting episodes of ischaemia.

[Vasospastic angina pectoris following abortion induced by prostaglandin analogue]

A case of vasospastic angina pectoris with loss of consciousness, bradycardia and seizures induced by medical abortion following administration of mifepristone and gemeprost is reported. The patient had a history of smoking and migraine, and former treatment with ergot alkaloids or serotonin agonists had also resulted in chest pain and lipothymia. The case underlines the importance of obtaining a detailed history of vasospastic disorders in women referred for medical abortion.

Continuous monitoring of global left ventricular ejection fraction during percutaneous transluminal coronary angioplasty

Continuous monitoring of left ventricular (LV) function during percutaneous transluminal coronary angioplasty (PTCA) was performed in 40 patients (53 +/- 2 years) with a miniature, nuclear detector system after labeling the patients' red blood cells with technetium-99m. Balloon dilation (113 seconds, range 60 to 240) induced on average a 0.12 ejection fraction (EF) unit (19%) decrease in the LVEF, which was explained by a 34% increase in end-systolic counts. Balloon dilation of the left anterior descending artery (n = 23) produced a decrease in the LVEF of 0.17 +/- 0.13 EF units compared with the decrease of 0.06 +/- 0.07 EF units in patients undergoing dilation of the left circumflex artery (n = 9) and 0.05 +/- 0.04 EF units in patients treated for a stenosis of the right coronary artery (n = 8), (p = 0.02). Balloon deflation was associated with an immediate return to pre-PTCA levels. In 10 patients with 2 identical balloon occlusions, the second occlusion led to a significantly less decrease in the LVEF (0.41 +/- 0.14 vs 0.44 +/- 0.15) and electrocardiographic ST-segment deviation (88 +/- 54 microV vs 65 +/- 42 microV) than the first. We conclude that PTCA is associated with an abrupt transient decrease in the LVEF. The effect of balloon occlusion of the left anterior descending artery is more pronounced than balloon occlusion of the left circumflex and the right coronary arteries. Neither single nor multiple balloon occlusions were associated with post-PTCA global LV dysfunction, whereas the lesser degree of LV dysfunction and electrocardiographic signs of myocardial ischemia during the second of 2 identical balloon occlusions suggests that preconditioning can be induced during PTCA.

Monitoring of left ventricular ejection fraction with a miniature, nonimaging nuclear detector: accuracy and reliability over time with special reference to blood labeling

BACKGROUND

The purpose of this study was to determine the accuracy of determinations of left ventricular ejection fraction (LVEF) by a nonimaging miniature nuclear detector system (Cardioscint) and to evaluate the feasibility of long-term LVEF monitoring in patients admitted to the coronary care unit, with special reference to the blood-labeling technique.

METHODS AND RESULTS

Cardioscint LVEF values were compared with measurements of LVEF by conventional gamma camera radionuclide ventriculography in 33 patients with a wide range of LVEF values. In 21 of the 33 patients, long-term monitoring was carried out for 1 to 4 hours (mean 186 minutes), with three different kits: one for in vivo and two for in vitro red blood cell labeling. The stability of the labeling was assessed by determination of the activity of blood samples taken during the first 24 hours after blood labeling. The agreement between Cardioscint LVEF and gamma camera LVEF was good with automatic background correction (r = 0.82; regression equation y = 1.04x + 3.88) but poor with manual background correction (r = 0.50; y = 0.88x - 0.55). The agreement was highest in patients without wall motion abnormalities. The long-term monitoring showed no difference between morning and afternoon Cardioscint LVEF values. Short-lasting fluctuations in LVEFs greater than 10 EF units were observed in the majority of the patients. After 24 hours, the mean reduction in the physical decay-corrected count rate of the blood samples was most pronounced for the two in vitro blood-labeling kits (57% +/- 9% and 41% +/- 3%) and less for the in vivo blood-labeling kit (32% +/- 26%). This "biologic decay" had a marked influence on the Cardioscint monitoring results, demanding frequent background correction.

CONCLUSION

A fairly accurate estimate of LVEF can be obtained with the nonimaging Cardioscint system, and continuous bedside LVEF monitoring can proceed for hours with little inconvenience to the patients. Instability of the red blood cell labeling during long-term monitoring necessitates frequent background correction.