Bystander cardiopulmonary resuscitation and long-term outcomes in out-of-hospital cardiac arrest according to location of arrest.

Aims: Bystander cardiopulmonary resuscitation (CPR) has increased in several countries following nationwide initiatives to facilitate bystander resuscitative efforts in out-of-hospital cardiac arrest (OHCA). We examined the importance of public or residential location of arrest on temporal changes in bystander CPR and outcomes. Methods and results: From the nationwide Danish Cardiac Arrest Registry, all OHCAs from 2001 to 2014 of presumed cardiac cause and between 18 and 100 years of age were identified. Arrests witnessed by emergency medical services personnel were excluded. Of 25 505 OHCAs, 26.4% (n = 6738) and 73.6% (n = 18 767) were in public and residential locations, respectively. Bystander CPR increased during 2001-2014 in both locations: from 36.4% [95% confidence interval (CI) 30.6-42.6%] to 83.1% (95% CI 80.0-85.8%) in public (P < 0.001) and from 16.0% (95% CI 13.2-19.3%) to 61.0% (95% CI 58.7-63.2%) in residential locations (P < 0.001). Concurrently, 30-day survival increased in public from 6.4% (95% CI 4.0-10.0%) to 25.2% (95% CI 22.1-28.7%) (P < 0.001), and in residential from 2.9% (95% CI 1.8-4.5%) to 10.0% (95% CI 8.7-11.4%) (P < 0.001). Among 2281 30-day survivors, 1-year risk of anoxic brain damage/nursing home admission during 2001-2014 decreased from 18.8% (95% CI 6.6-43.0%) to 6.8% (95% CI 3.9-11.8%) in public (P < 0.001), whereas the corresponding change was insignificant in residential locations from 11.8% (95% CI 3.3-34.3) to 17.6% (95% CI 12.7-23.9%) (P = 0.52). Conclusion: During 2001-2014, bystander CPR and 30-day survival more than doubled in both public and residential OHCA locations. A significant decrease in anoxic brain damage/nursing home admission was observed among 30-day survivors in public, but not among survivors from residential OHCAs.

Non-invasively quantified changes in left ventricular activation predict outcomes in patients undergoing cardiac resynchronization therapy.

BACKGROUND: Changes in left ventricular (LV) activation after cardiac resynchronization therapy (CRT) influence survival but are difficult to quantify noninvasively. METHODS AND RESULTS: We studied 527 CRT patients to assess whether noninvasive quantification of changes in LV activation, defined by change (Δ) in QRS area (QRSA), can predict outcomes after CRT. The study outcome was time until LV assist device(LVAD), cardiac transplant, or death. The three-dimensional QRSA was measured from clinical 12 lead ECGs which were transformed into vectorcardiograms using the Kors method. QRSA was calculated as (QRSx2 + QRSy2 + QRSz2 )1/2 ; ΔQRSA was calculated as post-QRSA minus pre-QRSA, where a negative value represents a reduction in LV activation delay. Kaplan-Meier plots and multivariable Cox proportional hazards models were used to relate ΔQRSA area with outcomes after stratifying the population into quartiles of ΔQRSA. The median baseline QRSA of 93.6 µVs decreased to 59.7 µVs after CRT. Progressive reductions in QRSA with CRT were associated with a lower rate of LVAD, transplant, or death across patient quartiles (P < .001). In Cox regression analyses, ΔQRSA was associated with outcomes independent of QRS morphology and other clinical variables (Q1[greatest decrease] vs Q4[smallest change=reference], HR 0.45, CI, 0.30-0.70, P < .001). There was no interaction between ΔQRSA and QRS morphology. CONCLUSIONS: CRT induced ΔQRSA was associated with clinically meaningful changes in event-free survival. ΔQRSA may be a novel target to guide lead implantation and device optimization.

Association between T-wave discordance and the development of heart failure in left bundle branch block patients: Results from the Copenhagen ECG study.

BACKGROUND: In left bundle branch block (LBBB), discrepancies between depolarization and repolarization of the heart can be assessed by similar direction (concordant) or opposite direction (discordant) of the lateral T-waves compared to the direction of the QRS complex and by the QRS-T angle. We examined the association between discordant T-waves and high QRS-T angles for heart failure development in primary care LBBB patients. METHODS: Between 2001 and 2011, we identified 2540 patients from primary care with LBBB without overt heart failure. We examined the development of heart failure in relation to two ECG measures: (1) LBBB as either discordant (two or three monophasic T-waves in the opposite direction of the QRS complex in leads I, V5 or V6) or concordant, and (2) the frontal plane QRS-T angle in quartile groups. RESULTS: In total, 244 of 913 patients (26.7%) with discordant LBBB developed heart failure compared to 302 of 1627 patients (16.7%) with concordant LBBB. Multivariable Cox regression comparing discordant with concordant LBBB showed a hazard ratio (HR) of 2.58 (95% Confidence interval [CI] 1.71-3.89) for heart failure development within 30 days of follow-up and a HR of 1.45 (95%CI 1.19-1.77) after 30 days. For QRS-T angle, comparing the highest quartile (160°-180°) with the lowest quartile (0°-110°) we found a HR of 2.25 (95%CI 1.26-4.02) within 30 days and a HR of 1.67 (95%CI 1.25-2.23) after 30 days. CONCLUSION: T-wave discordance in lateral ECG leads and a high QRS-T angle are associated with heart failure development in primary care LBBB patients.

The relationship between serum potassium concentrations and electrocardiographic characteristics in 163,547 individuals from primary care.

AIMS: Potassium disturbances are common and associated with increased morbidity and mortality, even in patients without prior cardiovascular disease. We examined six electrocardiographic (ECG) measures and their association to serum potassium levels. METHODS AND RESULTS: From the Copenhagen General Practitioners' Laboratory, we identified 163,547 individuals aged ≥16 years with a first available ECG and a concomitant serum potassium measurement during 2001-2011. Restricted cubic splines curves showed a non-linear relationship between potassium and the Fridericia corrected QT (QTcF) interval, T-wave amplitude, morphology combination score (MCS), PR interval, P-wave amplitude and duration. Therefore, potassium was stratified in two intervals K: 2.0-4.1 mmol/L and 4.2-6.0 mmol/L for further analyses. Within the low potassium range, we observed: QTcF was 12.8 ms longer for each mmol/L decrease in potassium (p < 0.0001); T-wave amplitude was 43.1 µV lower for each mmol/L decrease in potassium (p < 0.0001); and MCS was 0.13 higher per mmol/L decrease in potassium (p < 0.001). Moreover, P-wave duration and PR interval were prolonged by 2.7 and 4.6 ms for each mmol/L decrease in potassium (p < 0.0001), respectively. Within the lowest potassium range (2.0-4.1 mmol/L) P-wave amplitude was 3.5 µV higher for each mmol/L decrease in potassium (p < 0.0001). Within the high potassium range associations with the above-mentioned ECG parameters were much weaker.

Association between socioeconomic factors and ICD implantation in a publicly financed health care system: a Danish nationwide study.

Aims: For patients surviving out-of-hospital cardiac arrest (OHCA) with a shockable rhythm, implantable cardioverter defibrillator (ICD) is recommended for non-reversible causes of arrest. We aimed to determine factors associated with implantation of ICD and survival in patients surviving non-AMI OHCA in a nationwide register covering all OHCAs in Denmark. Methods and results: We identified 36 950 OHCAs between 2001 and 2012, 1700 of whom were ICD naïve, ≥18 years, of non-AMI cardiac aetiology and surviving until discharge. Six hundred fifty eight patients had ICD implanted during index admission. Association to ICD implantation during index admission was analysed in logistic regression, survival was assessed using Cox regression. Implantable cardioverter defibrillator implantation increased during the study period [odds ratio (OR) 1-year increase: 1.04, 95% confidence intervals (95% CI): 1.00-1.08, P = 0.03]. Non-shockable rhythm and age ≥70 years were associated with lower odds of ICD implantation (ORnon-shockable: 0.27, 95% CI: 0.19-0.37, P < 0.001, OR70-79 years: 0.71, 95% CI: 0.52-0.98, P = 0.04, OR≥80 years: 0.13, 95% CI: 0.07-0.22, P < 0.001). Non-AMI ischaemic heart disease, highest income tertile and chronic heart failure were associated with higher odds (ORIHD: 2.51, 95% CI: 1.77-3.60, P < 0.001, ORhighest income tertile: 1.58, 95% CI: 1.06-2.23, P = 0.02, ORHF: 1.77, 95% CI: 1.35-2.32, P < 0.001). Implantable cardioverter defibrillator implantation was associated with a lower risk of mortality (HR: 0.70, 95% CI: 0.53-0.92, P = 0.01). Conclusion: Implantable cardioverter defibrillator implantation rates increased over the study period. CHF, previous IHD and high income were associated with ICD implantation, while older age and non-shockable rhythm was associated with lower odds of ICD implantation. Implantable cardioverter defibrillator implantation was associated with higher survival rates.

Use of renal replacement therapy after out-of-hospital cardiac arrest in Denmark 2005-2013.

OBJECTIVES: Renal replacement therapy (RRT) is used to treat acute kidney injury as part of multi organ failure. Use and prognostic implications after out-of-hospital cardiac arrest (OHCA) is not well known. This study aims to assess incidence and use of RRT and whether RRT post-arrest was associated with 30-day mortality in Denmark in the years 2005-2013. METHODS: The Danish Cardiac Arrest Registry holds information on all OHCA patients in Denmark from 2005 to 2013. We identified 3,012 one-day survivors of OHCA ≥18 years, with presumed cardiac aetiology of arrest, admitted to ICU without previous RRT. Change in use of RRT during the study period was assessed using competing risk analysis. Mortality was assessed with Cox regression. RESULTS: On average, RRT was performed in 6% of the patient population with an average annual 1% increase, HR: 1.01, CI: 0.95-1.07, p = .69. Hazard of RRT was lower in patients receiving bystander cardiopulmonary resuscitation (CPR) (p < .001), patients with a shockable primary rhythm (p = .009) and elderly patients (p = .03). Socioeconomic factors did not influence hazard of RRT, but patients admitted to tertiary centres had higher hazard of RRT (p = .009). Use of RRT was associated with increased mortality in multivariate Cox regression (HR: 1.28, CI: 1.06-1.55, p = .01). CONCLUSION: Use of RRT as part of post resuscitation care following OHCA did not increase from 2005 to 2013; use was more common in tertiary centres and in patients with negative prehospital predictors (no bystander CPR, non-shockable rhythm). RRT was associated with increased mortality.

Association of Bystander Cardiopulmonary Resuscitation and Survival According to Ambulance Response Times After Out-of-Hospital Cardiac Arrest.

BACKGROUND: Bystander-initiated cardiopulmonary resuscitation (CPR) increases patient survival after out-of-hospital cardiac arrest, but it is unknown to what degree bystander CPR remains positively associated with survival with increasing time to potential defibrillation. The main objective was to examine the association of bystander CPR with survival as time to advanced treatment increases. METHODS: We studied 7623 out-of-hospital cardiac arrest patients between 2005 and 2011, identified through the nationwide Danish Cardiac Arrest Registry. Multiple logistic regression analysis was used to examine the association between time from 911 call to emergency medical service arrival (response time) and survival according to whether bystander CPR was provided (yes or no). Reported are 30-day survival chances with 95% bootstrap confidence intervals. RESULTS: With increasing response times, adjusted 30-day survival chances decreased for both patients with bystander CPR and those without. However, the contrast between the survival chances of patients with versus without bystander CPR increased over time: within 5 minutes, 30-day survival was 14.5% (95% confidence interval [CI]: 12.8-16.4) versus 6.3% (95% CI: 5.1-7.6), corresponding to 2.3 times higher chances of survival associated with bystander CPR; within 10 minutes, 30-day survival chances were 6.7% (95% CI: 5.4-8.1) versus 2.2% (95% CI: 1.5-3.1), corresponding to 3.0 times higher chances of 30-day survival associated with bystander CPR. The contrast in 30-day survival became statistically insignificant when response time was >13 minutes (bystander CPR vs no bystander CPR: 3.7% [95% CI: 2.2-5.4] vs 1.5% [95% CI: 0.6-2.7]), but 30-day survival was still 2.5 times higher associated with bystander CPR. Based on the model and Danish out-of-hospital cardiac arrest statistics, an additional 233 patients could potentially be saved annually if response time was reduced from 10 to 5 minutes and 119 patients if response time was reduced from 7 (the median response time in this study) to 5 minutes. CONCLUSIONS: The absolute survival associated with bystander CPR declined rapidly with time. Yet bystander CPR while waiting for an ambulance was associated with a more than doubling of 30-day survival even in case of long ambulance response time. Decreasing ambulance response time by even a few minutes could potentially lead to many additional lives saved every year.

Alcohol consumption and mortality in patients undergoing coronary artery bypass graft (CABG)-a register-based cohort study.

BACKGROUND: Previous studies have shown that compared with abstinence and heavy drinking, moderate alcohol consumption is associated with a reduced risk of mortality among the general population and patients with heart failure and myocardial infarction. We examined the association between alcohol consumption and mortality in coronary artery bypass graft (CABG) patients. METHOD: We studied 1,919 first-time CABG patients using data on alcohol consumption and mortality obtained from Danish national registers from March 2006 to October 2011. Alcohol consumption was divided into the following groups: abstainers (0 units/week), moderate consumers (1-14 units/week), moderate-heavy drinkers (15-21 units/week) and heavy drinkers (>21 units/week). Hazard ratios (HR) of all-cause mortality were calculated using Cox proportional hazard regression analysis. RESULTS: The median follow-up was 2.2 years [IQR 2.0]. There were 112 deaths, of which 96 (86 %) were classified as cardiovascular. Adjustments for age and sex showed no increased risk of all-cause mortality for the abstainers (HR 1.61, 95 % CI, 1.00-2.58) and moderate-heavy drinkers (HR 1.40, 95 % CI, 0.73-2.67) compared with moderate consumers. However, heavy drinkers had a high risk of all-cause mortality compared with moderate consumers (HR 2.44, 95 % CI, 1.47-4.04). A full adjustment showed no increase in mortality for the abstainers (HR 1.59, 95 % CI, 0.98-2.57) and moderate-heavy drinkers (HR 1.68, 95 % CI, 0.86-3.29), while heavy drinkers were associated with an increased mortality rate (HR 1.88, 95 % CI, 1.10-3.21). There was no increased risk of 30-day mortality for the abstainers (HR 0.74, 95 % CI, 0.23-2.32), moderate-heavy drinkers (HR 0.36, 95 % CI, 0.07-1.93) and heavy drinkers (HR 2.20, 95 % CI, 0.65-7.36). CONCLUSION: There was no increased risk of mortality for abstainers (0 units/week) or moderate-heavy drinkers (15-21 units/week) following a CABG. Only heavy drinking (>21 units/week) were significantly associated with an increased mortality rate. These results suggest that only heavy drinking present a risk factor among CABG patients.

Fascicular heart blocks and risk of adverse cardiovascular outcomes: Results from a large primary care population.

BACKGROUND: Fascicular heart blocks can progress to complete heart blocks, but this risk has not been evaluated in a large general population. OBJECTIVE: The purpose of this study was to investigate the association between various types of fascicular blocks diagnosed by electrocardiographic (ECG) readings and the risk of incident higher degree atrioventricular block (AVB), syncope, pacemaker implantation, and death. METHODS: We studied primary care patients referred for ECG recording between 2001 and 2015. Cox regression models were used to estimate hazard ratios (HRs) as well as absolute risks of cardiovascular outcomes. RESULTS: Of 358,958 primary care patients (median age 54 years; 55% women), 13,636 (3.8%) had any type of fascicular block. Patients were followed up to 15.9 years. We found increasing HRs of incident syncope, pacemaker implantation, and third-degree AVB with increasing complexity of fascicular block. Compared with no block, isolated left anterior fascicular block (LAFB) was associated with 0%-2% increased 10-year risk of developing third-degree AVB (HR 1.6; 95% confidence interval [CI] 1.25-2.05), whereas right bundle branch block combined with LAFB and first-degree AVB was associated with up to 23% increased 10-year risk (HR 11.0; 95% CI 7.7-15.7), depending on age and sex group. Except for left posterior fascicular block (HR 2.09; 95% CI 1.87-2.32), we did not find any relevant associations between fascicular block and death. CONCLUSION: We found that higher degrees of fascicular blocks were associated with increasing risk of syncope, pacemaker implantation, and complete heart block, but the association with death was negligible.

Strong and Bitter Vegetables from Traditional Cultivars and Cropping Methods Improve the Health Status of Type 2 Diabetics: A Randomized Control Trial.

Vegetables rich in bitter-tasting phytochemicals may exert enhanced beneficial effects against key factors associated with type two diabetes (T2D). This study investigates whether selected cultivars of bitter and strong-tasting (BST) Brassica and root vegetables exert greater health benefits on T2D patients compared to equivalent modern mild and sweet tasting (MST) vegetables. A 12-week randomized, controlled, parallel intervention study involved 92 T2D patients, who were allocated three different diets: (1) 500 g daily of bitter and strong-tasting (BST) vegetables; (2) 500 g daily of mild and sweet-tasting (MST) vegetables; (3) 120 g daily MST normal diet (control). Both vegetable diets contained root vegetables and cabbages selected based on sensory differences and content of phytochemicals. Prior to and after the study, all participants underwent an oral glucose tolerance test (OGTT), 24 h blood pressure measurements, DEXA scans, and fasted blood samples. Both diets high in vegetables significantly reduced the participants' BMI, total body fat mass, and HbA1c levels compared to control, but in the BST group, significant differences were also found regarding incremental area under the curve glucose 240 min (OGTT) and fasting glucose levels. A high daily intake of root vegetables and cabbages showed significant health improvements in both vegetable groups. BST vegetables had the greatest impact on insulin sensitivity, body fat mass, and blood pressure compared to control; moreover, they further improved glycemic control compared to MST vegetables.

Socioeconomic differences in outcomes after hospital admission for atrial fibrillation or flutter.

AIMS: To examine socioeconomic differences in care and outcomes in a 1-year period beginning 30 days after hospital discharge for first-time atrial fibrillation or flutter (AF) hospitalization. METHODS AND RESULTS: This nationwide register-based follow-up cohort study investigated AF 30-day discharge survivors in Denmark during 2005-2014 and examined associations between patient's socioeconomic status (SES) and selected outcomes during a 1-year follow-up period beginning 30 days post-discharge after first-time hospitalization for AF. Patient SES was defined in four groups (lowest, second lowest, second highest, and highest) according to each patient's equivalized income. SES of the included 150 544 patients was: 27.7% lowest (n = 41 648), 28.1% second lowest (n = 42 321), 23.7% second highest (n = 35 656), and 20.5% highest (n = 30 919). Patients of lowest SES were older and more often women. Within 1-year follow-up, patients of lowest SES were less often rehospitalized or seen in outpatient clinics due to AF, or treated with cardioversion or ablation and were slightly more often diagnosed with stroke and heart failure (HF) and significantly more likely to die (16.1% vs. 14.9%, 11.3% and 8.1%). Hazard ratios for all-cause mortality were 0.64 (95% confidence interval 0.61-0.68) for highest vs. lowest SES, adjusted for CHA2DS2-VASc score, chronic obstructive pulmonary disease, rate- and rhythm-controlling drugs, and cohabitation status. CONCLUSION: In 30-day survivors of first-time hospitalization due to AF, lowest SES is associated with increased 1-year all-cause and cardiovascular mortality and fewer cardioversions, ablations, readmissions, and outpatient contacts due to AF. Our findings indicate a need for socially differentiated rehabilitation following hospital discharge for first-time AF.

Associations between left bundle branch block with different PR intervals, QRS durations, heart rates and the risk of heart failure: a register-based cohort study using ECG data from the primary care setting.

AIM: Left bundle branch block (LBBB) is associated with an increased risk of heart failure (HF). We assessed the impact of common ECG parameters on this association using large-scale data. METHODS AND RESULTS: Using ECGs recorded in a large primary care population from 2001 to 2011, we identified HF-naive patients with a first-time LBBB ECG. We obtained information on sex, age, emigration, medication, diseases and death from Danish registries. We investigated the association between the PR interval, QRS duration, and heart rate and the risk of HF over a 2-year follow-up period using Cox regression analysis.Of 2471 included patients with LBBB, 464 (18.8%) developed HF during follow-up. A significant interaction was found between QRS duration and heart rate (p<0.01), and the analyses were stratified on these parameters. Using a QRS duration <150 ms and a heart rate <70 beats per minute (bpm) as the reference, all groups were statistically significantly associated with the development of HF. Patients with a QRS duration ≥150 ms and heart rate ≥70 bpm had the highest risk of developing HF (HR 3.17 (95% CI 2.41 to 4.18, p<0.001). There was no association between the PR interval and HF after adjustment. CONCLUSION: Prolonged QRS duration and higher heart rate were associated with increased risk of HF among primary care patients with LBBB, while no association was observed with PR interval. Patients with LBBB with both a prolonged QRS duration (≥150 ms) and higher heart rate (≥70 bpm) have the highest risk of developing HF.

Age-specific trends in incidence and survival of out-of-hospital cardiac arrest from presumed cardiac cause in Denmark 2002-2014.

BACKGROUND: The general cardiovascular health has improved throughout the last few decades for middle-aged and older individuals, but the incidence of several cardiovascular diseases is reported to increase in younger people. We aimed to assess the age-specific incidence and mortality rates associated with out-of-hospital-cardiac-arrest (OHCA) between 2002 and 2014. METHODS: We used the Danish Cardiac Arrest Register to identify patients with OHCA of presumed cardiac etiology. We calculated the annual incidence rates (IR) and 30-day mortality rates (MR) in 7 age groups (18-34 years, 35-44 years, 45-54 years, 55-64 years, 65-74 years, 75-84 years and ≥85 years, and ≤50 vs. >50 years). RESULTS: Between 2002 and 2014, IR of OHCA decreased in individuals aged 65-74 and 75-84 years (158.08 to 111.2 and 237.5 to 217.09 per 100,000 person-years) and increased in the oldest from 201.01 to 325.4 pr. 100.000 person-years. In 18-34-years incidence of OHCA increased from 1.7 to 2.6 per 100.000 person-years. When stratifying into age ≤50 vs. >50 years, the IR deviated in those >50 years (from 117.8 in 2002 to 91 in 2008 to 117.4 in 2014100,000 person-years). The prevalence of acute myocardial infarction and heart failure prior to OHCA increased in the younger patient group in contrast to the older segment (AMI: ≤50 years: 10% to 16%, vs. >50 years: 25% to 23%, heart failure: ≤50 years 6% to 14%, vs. >50 years: 21% to 24%). CONCLUSION: Over the last decades, incidence rates of OHCA decreased in individuals aged 65-84, but increased in individuals older than 85. An increase was also observed in younger individuals, potentially indicating a need for better cardiovascular disease prevention in younger adults.

Uncertainty in classification of death from fatal myocardial infarction: A nationwide analysis of regional variation in incidence and diagnostic support.

AIMS: The usefulness of mortality statistics relies on the validity of death certificate diagnosis. However, diagnosing the causal sequence of conditions leading to death is not simple. We examined diagnostic support for fatal acute myocardial infarction (AMI) and investigated its association with regional variation. METHODS AND RESULTS: From Danish nationwide registers, we identified the study population (N = 3,244,051) of whom 36,669 individuals were recorded with AMI as the underlying cause-of-death between 2002 and 2015. We included clinical diagnoses, procedures, and claimed prescriptions related to atherosclerotic disease to evaluate the level of diagnostic support for fatal AMI in three diagnostic groups (Definite; Plausible; Uncertain). Adjusted mortality rates, rate ratios, and odds ratios were estimated for each AMI category, stratified by hospital region using multivariable regression models. More than one-third (N = 12,827, 35%) of deaths reported as fatal AMI had uncertain diagnostic support. The largest regional variation in AMI mortality rate ratios, varying from 1.16 (95%CI:1.02;1.31) to 1.62 (95%CI:1.43;1.83), was found among cases with uncertain diagnostic supportive data. Substantial inter-regional differences in the degree to which death occurs outside hospital [OR: 1.01 (95%CI:0.92;1.12) - 1.49 (95%CI:1.36;1.63)] and general practitioners determining the cause-of-death at home were present. Minor regional differences [OR: 0.96 (95%CI:0.85;1.07) - 1.16 (95%CI:1.04;1.29)] in in-hospital AMI mortality were observed. CONCLUSION: There is significant regional variation associated with recording AMI as a cause-of-death. This variation is predominately based on death certificate diagnoses without diagnostic supportive evidence. Studies of fatal AMI should include a stratification on supportive evidence of the diagnosis.

Risk of Developing Hypokalemia in Patients With Hypertension Treated With Combination Antihypertensive Therapy.

Little is known about the occurrence of hypokalemia due to combination therapy for hypertension. Using data from Danish administrative registries, we investigated the association between different combinations of antihypertensive therapy and risk of developing hypokalemia. Using incidence density matching, 2 patients without hypokalemia were matched to a patient with hypokalemia (K, <3.5 mmol/L) on age, sex, renal function, and time between index date and date of potassium measurement. Combination therapies were subdivided into 10 groups including ß-blockers (BB)+thiazides (BB+thiazides), calcium channel blockers (CCB)+renin angiotensin system inhibitors (RASi)+thiazides (CCB+RASi+Thiazides), calcium channel blockers+thiazides (CCB+thiazides), and ß-blockers+renin angiotensin system inhibitors+thiazides (BB+RASi+thiazides). We used conditional logistic regression to estimate the odds of developing hypokalemia for different combinations of antihypertensive drugs within 90 days of combination therapy initiation. We matched 463 patients with hypokalemia to 926 patients with normal potassium concentrations. The multivariable analysis showed 5.82× increased odds of developing hypokalemia if administered CCB+thiazides (95% CI, 3.06-11.08) compared with CCB+RASi. Other combinations significantly associated with increased hypokalemia odds were BB+thiazides (odds ratio, 3.34 [95% CI, 1.67-6.66]), CCB+RASi+thiazides (odds ratio, 3.07 [95% CI, 1.72-5.46]), and BB+RASi+thiazides (odds ratio, 2.78 [95% CI, 1.41-5.47]). Combinations of thiazides with CCB, RASi, or BB were strongly associated with increased hypokalemia risk within 90 days of treatment initiation.

Survival of patients with and without diabetes following out-of-hospital cardiac arrest: A nationwide Danish study.

BACKGROUND: Research regarding out-of-hospital cardiac arrest (OHCA) survival of diabetes patients is sparse and it remains unknown whether initiatives to increase OHCA survival benefit diabetes and non-diabetes patients equally. We therefore examined overall and temporal survival in diabetes and non-diabetes patients following OHCA. METHODS: Adult presumed cardiac-caused OHCAs were identified from the Danish Cardiac Arrest Registry (2001-2014). Associations between diabetes and return of spontaneous circulation upon hospital arrival and 30-day survival were estimated with logistic regression adjusted for patient- and OHCA-related characteristics. RESULTS: In total, 28,955 OHCAs were included of which 4276 (14.8%) had diabetes. Compared with non-diabetes patients, diabetes patients had more comorbidities, same prevalence of bystander-witnessed arrests (51.7% vs. 52.7%) and bystander cardiopulmonary resuscitation (43.2% vs. 42.0%), more arrests in residential locations (77.3% vs. 73.0%) and were less likely to have shockable heart rhythm (23.5% vs. 27.9%). Temporal increases in return of spontaneous circulation and 30-day survival were seen for both groups (return of spontaneous circulation: 8.8% in 2001 to 22.3% in 2014 (diabetes patients) vs. 7.8% in 2001 to 25.7% in 2014 (non-diabetes patients); and 30-day survival: 2.8% in 2001 to 9.7% in 2014 vs. 3.5% to 14.8% in 2014, respectively). In adjusted models, diabetes was associated with decreased odds of return of spontaneous circulation (odds ratio 0.74 (95% confidence interval 0.66-0.82)) and 30-day survival (odds ratio 0.56 (95% confidence interval 0.48-0.65)) (interaction with calendar year p=0.434 and p=0.243, respectively). CONCLUSION: No significant difference in temporal survival was found between the two groups. However, diabetes was associated with lower odds of return of spontaneous circulation and 30-day survival.

Vectorcardiographic QRS area is associated with long-term outcome after cardiac resynchronization therapy.

BACKGROUND: Recent studies have suggested that vectorcardiographic measures predict left ventricular (LV) reverse remodeling and clinical outcome in patients receiving cardiac resynchronization therapy (CRT). OBJECTIVES: The objectives of this study were to compare predictive abilities of different vectorcardiographic measures (QRS area and sum absolute QRS-T integral) and transformation methods (Kors and inverse Dower) and to assess the independent association between the best predictor and outcomes in CRT recipients. METHODS: This retrospective study included CRT recipients with a digital baseline electrocardiogram, QRS duration ≥120 ms, and ejection fraction ≤35%. The end point was a composite of heart transplantation, LV assist device implantation, or all-cause death. Analyses were performed for the overall cohort and for a prespecified subgroup of patients with left bundle branch block (LBBB). RESULTS: Of 705 included patients with a mean age of 66.6 ± 11.5 years, 492 (70%) were men, 374 (53%) had ischemic heart disease, and 465 (66%) had LBBB. QRS area from vectorcardiograms derived via the Kors transformation demonstrated the best predictive value. In multivariable Cox regression, patients with a smaller QRS area (≤ 95 µVs) had an increased hazard in the overall cohort (adjusted hazard ratio 1.65; 95% CI 1.25-2.18 P < .001) and in the LBBB subgroup (adjusted hazard ratio 1.95; 95% CI 1.38-2.76 P < .001). QRS area was associated with outcome in patients with QRS duration <150 ms (unadjusted hazard ratio 3.85; 95% CI 2.02-7.37 P < .001) and in patients with QRS duration ≥150 ms (unadjusted hazard ratio 1.76; 95% CI 1.32-2.34 P < .001). CONCLUSION: Vectorcardiographic QRS area is associated with survival free from heart transplantation and LV assist device implantation in CRT recipients.

The Association Between Serum Calcium Levels and Short-Term Mortality in Patients with Chronic Heart Failure.

BACKGROUND: Patients with chronic heart failure have vulnerable myocardial function and are susceptible to electrolyte disturbances. In these patients, diuretic treatment is frequently prescribed, though it is known to cause electrolyte disturbances. Therefore, we investigated the association between altered calcium homeostasis and the risk of all-cause mortality in chronic heart failure patients. METHODS: From Danish national registries, we identified patients with chronic heart failure with a serum calcium measurement within a minimum 90 days after initiated treatment with both loop diuretics and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. Patients were divided into 3 groups according to serum calcium levels, and Cox regression was used to assess the mortality risk of <1.18 mmol/L (hypocalcemia) and >1.32 mmol/L (hypercalcemia) compared with 1.18 mmol/L-1.32 mmol/L (normocalcemia) as reference. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. RESULTS: Of 2729 patients meeting the inclusion criteria, 32.6% had hypocalcemia, 63.1% normocalcemia, and 4.3% hypercalcemia. The highest mortality risk was present in early deaths (≤30 days), with a HR of 2.22 (95% CI; 1.74-2.82) in hypocalcemic patients and 1.67 (95% CI; 0.96-2.90) in hypercalcemic patients compared with normocalcemic patients. As for late deaths (>30 days), a HR of 1.52 (95% CI; 1.12-2.05) was found for hypocalcemic patients and a HR of 1.87 (95% CI; 1.03-3.41) for hypercalcemic patients compared with normocalcemic patients. In adjusted analyses, hypocalcemia and hypercalcemia remained associated with an increased mortality risk in both the short term (≤30 days) and longer term (>30 days). CONCLUSION: Altered calcium homeostasis was associated with an increased short-term mortality risk. Almost one-third of all the heart failure patients suffered from hypocalcemia, having a poor prognosis.

Data concerning AED registration in the Danish AED Network, and cardiac arrest-related characteristics of OHCAs, including AED coverage and AED accessibility.

The data presented in this article is supplemental data related to the research article entitled "Automated external defibrillator accessibility is crucial for bystander defibrillation and survival: a registry-based study" (Karlsson et al., 2019). We present detailed data concerning: 1) the type of location for deployed and registered automated external defibrillators (AEDs) in the nationwide Danish AED Network; 2) the number of registered AEDs in the nationwide Danish AED Network, and changes in AED registration (according to year and type of AED location); 3) the number of AEDs being withdrawn from the AED network between the years 2007-2016. We also report data on baseline cardiac arrest-related characteristics of out-of-hospital cardiac arrests (OHCAs) that occurred in Copenhagen, Denmark, between 2008 and 2016. Cardiac arrest-related characteristics are further described according to AED accessibility (accessible vs. inaccessible AED at the time of OHCA) for OHCAs covered by an AED (AED ≤200 m route distance of an OHCA). Finally, we report data on distance to the nearest accessible AED for bystander defibrillated OHCAs covered by an AED ≤200 m route distance where the AED was inaccessible at the time of OHCA.

Clinical implications of electrocardiographic bundle branch block in primary care.

OBJECTIVES: Electrocardiographic bundle branch block (BBB) is common but the prognostic implications in primary care are unclear. We sought to investigate the relationship between electrocardiographic BBB subtypes and the risk of cardiovascular (CV) outcomes in a primary care population free of major CV disease. METHODS: Retrospective cohort study of primary care patients referred for electrocardiogram (ECG) recording between 2001 and 2011. Cox regression models were used to estimate hazard ratios (HR) as well as absolute risks of CV outcomes based on various BBB subtypes. RESULTS: We included 202 268 individuals with a median follow-up period of 7.8 years (Inter-quartile range [IQR] 4.9-10.6). Left bundle branch block (LBBB) was associated with heart failure (HF) in both men (HR 3.96, 95% CI 3.30 to 4.76) and women (HR 2.51, 95% CI 2.15 to 2.94) and with CV death in men (HR 1.80, 95% CI 1.38 to 2.35). Right bundle branch block (RBBB) was associated with pacemaker implantation in both men (HR 3.26, 95% CI 2.74 to 3.89) and women (HR 3.69, 95% CI 2.91 to 4.67), HF in both sexes and weakly associated with CV death in men. Regarding LBBB, we found an increasing hazard of HF with increasing QRS-interval duration (HR 1.25, 95% CI 1.11 to 1.42 per 10 ms increase in men and HR 1.23, 95% CI 1.08 to 1.40 per 10 ms increase in women). Absolute 10-year risk predictions across age-specific and sex-specific subgroups revealed clinically relevant differences between having various BBB subtypes. CONCLUSIONS: Opportunistic findings of BBB subtypes in primary care patients without major CV disease should be considered warnings of future HF and pacemaker implantation.