Sex hormones are known to have significant effects on the pathophysiology of cardiovascular disease.
The purpose of this study was to study the association between sex hormone levels and sudden ...cardiac arrest (SCA).
In the ongoing Oregon Sudden Unexpected Death Study (catchment population approximately 1 million), cases of SCA were compared with matched controls. Testosterone and estradiol levels were measured from blood samples drawn at the time of the SCA event in cases and during a routine visit in controls.
Among cases (n = 149, age 64.1 ± 11.7 years, 73.2% male), compared to controls (n = 149, 64.2 ± 11.6 years, 72.5% male), median testosterone levels were significantly lower in males (4.4 vs 5.4 ng/mL, P = .01). Median estradiol levels were higher in male (68 vs 52 pg/mL, P <.001) and female cases (54 vs 36 pg/mL, P <.001). In multivariate analysis, higher testosterone levels were associated with lower SCA odds only in males (odds ratio OR 0.75, 95% confidence interval CI 0.58-0.96, P = .02). Higher estradiol levels were associated with higher SCA odds in both males (OR 2.0, 95% CI 1.5-2.6, P <.001) and females (OR 3.5, 95% CI 1.9-6.4, P <.001). A higher testosterone/estrogen ratio was associated with lower SCA odds in males only (OR 0.5, 95% CI 0.4-0.7, P <.001). In a canine model of SCA, plasma testosterone levels were not significantly altered by the cardiac arrest event.
We observed significant differences in sex hormone levels in patients who suffered SCA, with potential mechanistic implications. The role of sex hormones in the genesis of fatal ventricular arrhythmias warrants further exploration.
Sudden Cardiac Death. Introduction: Sudden cardiac death (SCD) is a large public health problem that warrants on‐going evaluation in the general population. While single‐year community‐based studies ...have been performed there is a lack of studies that have extended evaluation to multiple years in the same community.
Methods and Results: From the on‐going Oregon Sudden Unexpected Death Study, we analyzed prospectively identified SCD cases in Multnomah County, Ore, (population ≈700,000) from February 1, 2002 to January 31, 2005. Detailed information ascertained from multiple sources (first responders, clinical records, and medical examiner) was analyzed. A total of 1,175 SCD cases were identified (61% male) with a mean age of 65 ± 18 years for men versus 70 ± 20 for women (P < 0.001). The overall incidence rate for the period was 58/100,000 residents/year. One‐quarter (24.6%) was ≤55 years of age. The most common initial rhythm was ventricular tachycardia or fibrillation (39% of cases, survival 27%) followed by asystole (36%, survival 0.7%) and pulseless electrical activity (23%, survival 6%). Among subjects that underwent resuscitation, the rate of survival to hospital discharge was 12% and overall survival to hospital discharge irrespective of resuscitation was 8%. Of the 68 survivors, 16 (24%) received a secondary prevention ICD.
Conclusion: We report annualized SCD incidence from a multiple‐year, multiple‐source community‐based study, with higher than expected rates of women and subjects age ≤55 years. The low implantation rate of secondary prevention ICDs is likely to be multifactorial, but there are potential implications for recalibration of the projected need for ICD implantation; larger and more detailed studies are warranted.
(J Cardiovasc Electrophysiol, Vol. 24, pp. 60‐65, January 2013)
In cohort studies, elevated levels of plasma nonesterified free fatty acids (NEFAs) have been associated with increased risk of sudden cardiac death (SCD) in men, but blood samples were drawn several ...years before SCD.
To confirm this relationship by evaluating levels of plasma NEFAs at the time of the SCD event in a group of both men and women.
From the ongoing Oregon Sudden Unexpected Death Study, we compared levels of plasma NEFAs in 149 SCD cases presenting with ventricular fibrillation (mean age 64 ± 12 years; 73% men) and 149 age- and sex-matched controls with coronary artery disease. Plasma was processed from blood drawn at the time of arrest (cases) and at a routine visit (controls). The levels of plasma NEFAs were compared after categorizing into quartiles on the basis of control values. Conditional logistic regression was used to predict adjusted odds ratio for SCD associated with plasma NEFA levels per increased quartile.
The plasma NEFA levels were significantly higher in SCD cases than in controls (median 0.39 mmol/L interquartile range 0.28-0.60 mmol/L vs 0.32 mmol/L interquartile range 0.20-0.49 mmol/L; P = .002). There were no significant differences in body mass index, smoking, and diabetes. The odds ratio for SCD was 1.42 (95% confidence interval 1.14-1.78) per quartile increase in the plasma NEFA level (P = .002). Individuals with plasma NEFA levels above the prespecified cutoff point of 0.32 mmol/L were at increased risk of SCD (odds ratio 2.00; 95% confidence interval 1.20-3.34; P = .008).
These findings strengthen the role of plasma NEFA as a potential biomarker for the assessment of SCD risk.
The global burden of atrial fibrillation (AF) is unknown.
We systematically reviewed population-based studies of AF published from 1980 to 2010 from the 21 Global Burden of Disease regions to ...estimate global/regional prevalence, incidence, and morbidity and mortality related to AF (DisModMR software). Of 377 potential studies identified, 184 met prespecified eligibility criteria. The estimated number of individuals with AF globally in 2010 was 33.5 million (20.9 million men 95% uncertainty interval (UI), 19.5-22.2 million and 12.6 million women 95% UI, 12.0-13.7 million). Burden associated with AF, measured as disability-adjusted life-years, increased by 18.8% (95% UI, 15.8-19.3) in men and 18.9% (95% UI, 15.8-23.5) in women from 1990 to 2010. In 1990, the estimated age-adjusted prevalence rates of AF (per 100 000 population) were 569.5 in men (95% UI, 532.8-612.7) and 359.9 in women (95% UI, 334.7-392.6); the estimated age-adjusted incidence rates were 60.7 per 100 000 person-years in men (95% UI, 49.2-78.5) and 43.8 in women (95% UI, 35.9-55.0). In 2010, the prevalence rates increased to 596.2 (95% UI, 558.4-636.7) in men and 373.1 (95% UI, 347.9-402.2) in women; the incidence rates increased to 77.5 (95% UI, 65.2-95.4) in men and 59.5 (95% UI, 49.9-74.9) in women. Mortality associated with AF was higher in women and increased by 2-fold (95% UI, 2.0-2.2) and 1.9-fold (95% UI, 1.8-2.0) in men and women, respectively, from 1990 to 2010. There was evidence of significant regional heterogeneity in AF estimations and availability of population-based data.
These findings provide evidence of progressive increases in overall burden, incidence, prevalence, and AF-associated mortality between 1990 and 2010, with significant public health implications. Systematic, regional surveillance of AF is required to better direct prevention and treatment strategies.
Different P-wave morphologies during sinus rhythm as displayed on standard ECGs have been postulated to correspond to differences in interatrial conduction.
The purpose of this study was to evaluate ...the hypothesis by comparing P-wave morphologies using left atrial activation maps.
Twenty-eight patients (mean age 49 +/- 9 years) admitted for ablation of paroxysmal atrial fibrillation were studied. Electroanatomic mapping of left atrial activation was performed at baseline during sinus rhythm with simultaneous recording of standard 12-lead ECG. Unfiltered signal-averaged P waves were analyzed to determine orthogonal P-wave morphology. The morphology was subsequently classified into one of three predefined types. All analyses were blinded.
The primary left atrial breakthrough site was the fossa ovalis in 8 patients, Bachmann bundle in 18, and coronary sinus in 2. Type 1 P-wave morphology was observed in 9 patients, type 2 in 17, and type 3 in 2. Seven of eight patients with fossa ovalis breakthrough had type 1 P-wave morphology, 16 of 18 patients with Bachmann bundle breakthrough had type 2 morphology, and both patients with coronary sinus breakthrough had type 3 P-wave morphology. Overall, P-wave morphology criteria correctly identified the site of left atrial breakthrough in 25 (89%) of 28 patients.
In the vast majority of patients, P-wave morphology derived from standard 12-lead ECG can be used to correctly identify the left atrial breakthrough site and the corresponding route of interatrial conduction.
Background: Patients with hypertrophic cardiomyopathy (HCM) have a high incidence of atrial fibrillation. They also have a longer P‐wave duration than healthy controls, indicating conduction ...alterations. Previous studies have demonstrated orthogonal P‐wave morphology alterations in patients with paroxysmal atrial fibrillation. In the present study, the P‐wave morphology of patients with HCM was compared with that of matched controls in order to explore the nature of the atrial conduction alterations.
Methods and Results: A total of 65 patients (45 men, mean age 49 ± 15) with HCM were included. The control population (n = 65) was age and gender matched (45 men, mean age 49 ± 15). Five minutes of 12‐lead ECG was recorded. The data were subsequently transformed to orthogonal lead data, and unfiltered signal‐averaged P‐wave analysis was performed.
The P‐wave duration was longer in the HCM patients compared to the controls (149 ± 22 vs 130 ± 16 ms, P < 0.0001). Examination of the P‐wave morphology demonstrated changes in conduction patterns compatible with interatrial conduction block of varying severity in both groups, but a higher degree of interatrial block seen in the HCM population. These changes were most prominent in the Leads Y and Z.
Conclusion: The present study suggests that the longer P‐wave duration observed in HCM patients may be explained by a higher prevalence of block in one or more of the interatrial conduction routes.
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