Tord Juhlin

Reduced forced expiratory volume is associated with increased incidence of atrial fibrillation: the Malmö Preventive Project

AIMS Reduced forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) have been associated with increased incidence of cardiovascular diseases. However, whether reduced lung function is also a risk factor for incidence of atrial fibrillation (AF) is still unclear. We aimed to determine whether lung function predicted AF in the Malmö Preventive Project, a large population-based cohort with a long follow-up. METHODS AND RESULTS The study population consisted of 7674 women and 21 070 men, mean age 44.6 years. The cohort was followed on average for 24.8 years, during which time 2669 patients were hospitalized due to AF. The incidence of AF in relationship to quartiles of FEV1 and FVC and per litre decrease at baseline was determined using a Cox proportional hazards model adjusted for age, height, weight, current smoking status, systolic blood pressure, erythrocyte sedimentation rate, and fasting blood glucose. Forced expiratory volume in one second was inversely related to incidence of AF (per litre reduction in FEV1) hazard ratio (HR): 1.39 [95% confidence interval (CI): 1.16-1.68; P = 0.001] for women, and HR: 1.20 (95% CI: 1.13-1.29; P < 0.0001) for men. Forced vital capacity was also inversely related to incidence of AF (per litre reduction in FVC) HR: 1.20 (95% CI: 1.03-1.41; P = 0.020) for women, and HR: 1.08 (95% CI: 1.02-1.14; P = 0.01) for men. This relationship was consistent in non-smokers as well as smokers, and among individuals younger than the median age of 45.8 years or normotensive subjects. CONCLUSION Impaired lung function is an independent predictor of AF. This may explain some risk of AF that is currently unaccounted for.

A prospective study of supraventricular activity and incidence of atrial fibrillation

BACKGROUND Atrial fibrillation (AF) episodes are thought to be started by an electrical trigger reaching susceptible atria. Such a trigger could be present long before the occurrence of sustained symptomatic arrhythmia. OBJECTIVE We sought to determine whether supraventricular extrasystoles (SVESs) and supraventricular tachycardias (SVTs) measured at 24-hour Holter electrocardiogram were associated with an increased incidence of AF. METHODS In 1998-2000, 389 individuals (44% men; mean age 65 years) were examined using 24-hour Holter electrocardiogram. Six individuals with known prevalent AF were excluded. After a mean follow-up of 10.3 years, there were 45 cases of incident AF. Hazard ratios (HRs) were computed using multivariable Cox regression adjusting for age, sex, systolic blood pressure, height, weight, smoking, and homeostatic model assessment of insulin resistance. RESULTS Frequency of SVESs as well as SVT episodes per hour were independent predictors of incident AF (HR per log unit 1.38; 95% confidence interval 1.14-1.68; P = .001 and HR 1.95; 95% confidence interval 1.21-3.13; P = .006, respectively). Further adjustment for education level, alcohol use, use of medication, and physical activity did not substantially alter the results, nor did analysis using competing risks regression accounting for a competing risk of death. The maximum duration of SVT or the heart rate at SVT was not significantly associated with the incidence of AF. CONCLUSION SVESs and SVTs independently predict AF. The prognostic significance was similar for SVESs, SVTs, and a combination of the two. Repeated efforts to detect AF could be of merit in individuals with frequent supraventricular activity.

Evaluation of pre-arrest morbidity score and prognosis after resuscitation score and other clinical variables associated with in-hospital cardiac arrest in southern Sweden

OBJECTIVE To evaluate pre-arrest morbidity score (PAM), prognosis after resuscitation score (PAR) and to identify additional clinical variables associated with survival after in-hospital cardiac arrest (IHCA) treated with cardiopulmonary resuscitation (CPR). METHODS A retrospective observational study involving all cases of IHCA at Skåne University Hospital Malmö 2007-2010. RESULTS Two-hundred-eighty-seven cases of IHCA were identified (61.3% male; mean age 70 years) of whom 20.2% survived until discharge. The odds ratio (95% confidence interval) for death prior to discharge was 6.49 (1.50-28.19) (p=0.013) for PAM>6 and 3.88 (1.95-7.73) (p<0.001) for PAR>4. At PAM- and PAR-scores >5, specificity exceeded 90%, while sensitivity was only 20-30%. The odds ratio for in-hospital mortality was 0.38 (0.20-0.72) (p=0.003) for patients with cardiac monitoring, 9.86 (5.08-19.12) (p<0.001) for non-shockable vs shockable rhythm, 0.32 (0.15-0.69) (p=0.004) for presence of ST-elevation myocardial infarction (STEMI), 0.27 (0.09-0.78) (p=0.016) for patients with independent Activities of Daily Life (ADL) and 13.86 (1.86-103.46) (p=0.010) for patients with malignancies. Heart rate (HR) on admission (per bpm) [1.024 (1.009-1.040) (p=0.002)] and sodium plasma concentration on admission (per mmoll(-1)) [0.92 (0.85-0.99) (p=0.023)] were significantly associated with in-hospital mortality. CONCLUSION PAM- and PAR-scores do not sufficiently discriminate between in-hospital death and survival after IHCA to be used as clinical tools guiding CPR decisions. We confirm that malignancy is associated with increased in-hospital mortality, and cardiac monitoring, shockable rhythm, STEMI and independent ADL, with decreased in-hospital mortality. Interestingly, our results suggest that HR and plasma sodium concentration upon admission may represent new tools for risk stratification.

Is one month treatment with dabigatran before cardioversion of atrial fibrillation sufficient to prevent thromboembolism

AIMS The use of direct oral anticoagulants (DOACs) in patients undergoing elective direct current (DC) cardioversion of non-acute atrial fibrillation (AF) can potentially shorten the time from initiation of anticoagulation treatment to cardioversion, compared with warfarin. The safety of this strategy needs to be investigated. Data from subgroup analysis from clinical trials with DOAC do not clarify whether 4-week treatment with DOAC is sufficient to prevent thromboembolism (TE) after cardioversion. The aim of this retrospective study was to assess the incidence of TE in anticoagulant naive patients converted after one months pre-treatment with dabigatran. METHODS AND RESULTS We scrutinized the medical records of 631 patients where dabigatran had been used prior to elective DC cardioversion. Transoesophageal echocardiography was rarely performed. Thromboembolism within 30 days of cardioversion was the primary endpoint. A total of 570 patients were naive to OAC when dabigatran was initiated. The mean age in this group was 64.2 ± 11 years and 31.7% were women. The mean CHA2DS2-VASc score was 2.0 ± 1.5. The dose of dabigatran was 150 mg b.i.d. in 94% of the patients. The median time from initiation of dabigatran to cardioversion was 32.0 ± 15 days. In 91% cardioversion resulted in sinus rhythm. During the 30-day follow-up, three TE occurred for an incidence of 0.53% (0.18-1.54). CONCLUSION In this retrospective study from clinical material, we found a low incidence of TE when dabigatran was used as TE prophylaxis in association with elective cardioversion. These results indicate that dabigatran is a safe alternative strategy to warfarin during cardioversion in patients with AF.

Risk factor changes and incident atrial fibrillation among middle-aged men in the Malmö Preventive Project cohort

AIMS To determine whether risk factor changes over 6 years were associated with the incidence of atrial fibrillation (AF) among middle-aged men in the Malmö Preventive Project (MPP) cohort. METHODS AND RESULTS In total, 5633 men (mean age 47.0 years at baseline) underwent two screening examinations, separated by an average of 6 years. The annual rate at which systolic blood pressure (SBP), diastolic blood pressure (DBP), weight, fasting blood glucose (FBG), blood glucose at 2-h oral glucose tolerance test (OGTT), and screening spirometry values changed was calculated and analysed in relation to incident AF, using Cox and competing risks regression to determine hazard ratios (HRs) and 95% confidence intervals (CIs). Mean follow-up time ± SD from rescreening was 22.3 ± 7.4 years. Significant associations were found between the annual increase of SBP (HR: 1.04, 95% CI: 1.01-1.07, P = 0.003 per mmHg), DBP (HR: 1.06, 95% CI: 1.01-1.1, P = 0.024 per mmHg), FBG (HR: 2.11, 95% CI: 1.44-3.12, P < 0.0001 per mmol/L), and weight (HR: 1.14, 95% CI: 1.05-1.24, P = 0.003 per kg) on the one hand and incident AF on the other, after full adjustment for baseline age, height, weight, SBP, FBG, smoking status, sedentary lifestyle, anti-hypertensive treatment, screening year, and low socioeconomic status. CONCLUSION The age-adjusted annual rates of increase in SBP, DBP, weight, and FBG in mid-life are associated with AF incidence in men. This raises the question of whether preventive measures directed at individuals with high annual increases, even within the normal range, would reduce AF incidence.

Midlife risk factor exposure and incidence of cardiac arrest depending on cardiac or non-cardiac origin

OBJECTIVE Little is known about midlife risk factors of future cardiac arrest. Our objective was to evaluate cardiovascular risk factors in midlife in relation to the risk of cardiac arrest (CA) of cardiac and non-cardiac origin later in life. METHODS We cross-matched individuals of the population based Malmö Diet and Cancer study (n=30,447) with the local CA registry of the city of Malmö. Baseline exposures were related to incident CA. RESULTS During a mean follow-up of 17.6±4.6years, 378 CA occurred, of whom 17.2% survived to discharge. Independent midlife risk factors for CA of cardiac origin included coronary artery disease {HR 2.84 (1.86-4.34) (p<0.001)}, diabetes mellitus {HR 2.37 (1.61-3.51) (p<0.001)} and smoking {HR 1.95 (1.49-2.55) (p<0.001)}. Dyslipidemia and history of stroke were also significantly associated with an elevated risk for CA of cardiac origin. Independent midlife risk factors for CA of non-cardiac origin included obesity (BMI>30kg/m2) {HR 2.37 (1.51-3.71) (p<0.001)}, smoking {HR 2.05 (1.33-3.15) (p<0.001)} and being on antihypertensive treatment {HR 2.25 (1.46-3.46) (p<0.001)}. CONCLUSION Apart from smoking, which increases the risk of CA in general, the midlife risk factor pattern differs between CA of cardiac and non-cardiac origin. Whereas CA of cardiac origin is predicted by history of cardiovascular disease, dyslipidemia and diabetes mellitus, the main risk factors for CA of non-cardiac origin are obesity and hypertension. In addition to control of classical cardiovascular risk factors for prevention of CA, our results suggest that prevention of midlife obesity may reduce the risk of CA of non-cardiac origin.