Left Atrial Mechanical Function and Incident Ischemic Cerebrovascular Events Independent of AF: Insights From the MESA Study.

OBJECTIVES: This study sought to assess the association of baseline left atrial (LA) phasic function measured with cardia magnetic resonance (CMR) and incident ischemic cerebrovascular events (CVE). BACKGROUND: LA remodeling is a known predictor of atrial fibrillation (AF), which is a risk factor for ischemic CVE. Despite studies showing an association between LA remodeling and ischemic CVE, the association of LA mechanical function with ischemic CVE in a population free of known cardiovascular disease is not fully studied. METHODS: Phasic LA volumes; total, passive, and active LA emptying fractions (LAEF); and peak longitudinal LA strain were measured using feature-tracking CMR in 4,261 MESA (Multi-Ethnic Study of Atherosclerosis) participants (61 ± 10 years of age; 48% male). All individuals were free of clinical cardiovascular disease at baseline. Participants were followed for 11.6 ± 3.5 years for the diagnosis of incident ischemic CVE, defined as ischemic stroke or transient ischemic attack adjudicated by vascular neurologists. RESULTS: During the follow-up, 193 (1.26 per 1,000 person-years) ischemic CVE (134 ischemic strokes and 59 TIAs) occurred. Individuals with incident ischemic CVE had larger LA volumes and lower passive, active, and total LAEFs at baseline. In multivariate analysis adjusted for known CVE risk factors, left ventricular mass and interim AF, total LAEF was associated with incident ischemic CVE (hazard ratio [HR]: 0.85 per SD; 95% confidence interval [CI]: 0.74 to 0.98; p = 0.027). The unadjusted HR for the lowest tertile of total LAEF compared to the highest tertile was 2.0 (95% CI: 1.43 to 2.79; p < 0.001), and the adjusted HR was 1.47 (95% CI: 1.04 to 2.05; p = 0.031). Addition of total LAEF to known clinical risk factors of CVE and left ventricular mass resulted in an improved predictive accuracy (C statistic of 0.76 vs. 0.73, respectively; p = 0.039). CONCLUSIONS: Reduced total LAEF was associated with incident ischemic CVE independent of known cerebrovascular risk factors and incident AF. Assessment of LA function may add further information in stratifying asymptomatic individuals at risk for ischemic stroke.

[Acute colonic pseudo-obstruction after caesarean section; Ogilvie's syndrome]. / Bolle buik na sectio caesarea.

BACKGROUND: Acute pseudo-obstruction of the colon - also known as Ogilvie's syndrome - is a rare clinical presentation in obstetrics. The syndrome is seen more often following caesarean section than vaginal delivery. CASE DESCRIPTION: We present a 38-year-old primigravida who developed Ogilvie's syndrome following secondary caesarean section. Despite conservative management, due to a caecal dilation of over 12 centimetres and impending perforation of the caecum, a hemicolectomy was necessary. CONCLUSION: Ogilvie's syndrome is potentially life-threatening, certainly if perforation of the bowel occurs. Prompt diagnosis and treatment are essential to prevent severe morbidity.

Association of left atrial structure and function and incident cardiovascular disease in patients with diabetes mellitus: results from multi-ethnic study of atherosclerosis (MESA).

AIMS: Diabetes mellitus (DM) is associated with the development of cardiovascular disease (CVD). Morphological changes in the left atrium (LA) may appear before symptoms. We aimed to investigate the association between cardiac magnetic resonance imaging (CMR) measured LA structure and function and incident CVD in asymptomatic individuals with DM. METHODS AND RESULTS: Tissue tracking CMR was used to measure LA size and phasic function (emptying fractions and strain) on all 536 Multi-Ethnic Study of Atherosclerosis (MESA) participants with DM and available CMR at baseline in 2000-2002. At the time of enrolment, all participants were free of clinically recognized CVD, which was defined as MI, resuscitated cardiac arrest, angina, stroke, heart failure, and atrial fibrillation. Cox regression was used to assess the association of LA parameters with incident CVD adjusted for traditional cardiovascular risk factors, LV mass, NT Pro-BNP and maximum LA volume. Kaplan-Meier curves, adjusted for traditional risk factors, were generated for each LA measurement for the 25% of participants with the most abnormal values versus the remaining 75%. After a mean follow up of 11.4 ± 3.4 years, 141 individuals developed CVD. Individuals with incident CVD (mean age 66 years, 66% male vs. mean age 64 years, 50% male) had larger maximum and minimum LA volume index (LAVI) (32.1 vs. 26.8 mm3/m2; 19.4 vs. 14.2 mm3/m2 respectively, P < 0.001 for both), and lower total, passive, and active EF than those without CVD (P < 0.01 for all). In the fully adjusted model, there was a significant association of minimum LAVI, LA total EF, LA passive EF and LA active EF with incident CVD (HR 1.12 per mm3/m2, P < 0.001; HR 0.95 per %, P < 0.001; HR 0.97 per %, P = 0.021; HR 0.98 per %, P < 0.027, respectively). CONCLUSIONS: CMR measured LA minimum volume and LA function as measured by emptying fraction are predictive of CVD in a diabetic multi-ethnic population free of any clinically recognized CVD at baseline.

Cardiac Magnetic Resonance-Measured Left Atrial Volume and Function and Incident Atrial Fibrillation: Results From MESA (Multi-Ethnic Study of Atherosclerosis).

BACKGROUND: Early detection of structural changes in left atrium (LA) before atrial fibrillation (AF) development could be helpful in identification of those at higher risk for AF. Using cardiac magnetic resonance imaging, we examined the association of LA volume and function, and incident AF in a multiethnic population free of clinical cardiovascular diseases. METHODS AND RESULTS: In a case-cohort study embedded in MESA (Multi-Ethnic Study of Atherosclerosis), baseline LA size and function assessed by cardiac magnetic resonance feature-tracking were compared between 197 participants with incident AF and 322 participants randomly selected from the whole MESA cohort. Participants were followed up for 8 years. Incident AF cases had a larger LA volume and decreased passive, active, and total LA emptying fractions and peak global LA longitudinal strain (peak LA strain) at baseline. In multivariable analysis, elevated LA maximum volume index (hazard ratio, 1.38 per SD; 95% confidence interval, 1.01-1.89) and decreased peak LA strain (hazard ratio, 0.68 per SD; 95% confidence interval, 0.48-0.96), and passive and total LA emptying fractions (hazard ratio for passive LA emptying fractions, 0.55 per SD; 95% confidence interval, 0.40-0.75 and hazard ratio for active LA emptying fractions, 0.70 per SD; 95% confidence interval, 0.52-0.95), but not active LA emptying fraction, were associated with incident AF. CONCLUSIONS: Elevated LA volumes and decreased passive and total LA emptying fractions were independently associated with incident AF in an asymptomatic multiethnic population. Including LA functional variables along with other risk factors of AF may help to better risk stratify individuals at risk of AF development.

Left atrial structure and functional quantitation using cardiovascular magnetic resonance and multimodality tissue tracking: validation and reproducibility assessment.

BACKGROUND: Left atrium (LA) strain, volume and function are important markers of cardiovascular disease and myocardial impairment. We aimed to assess the accuracy of LA biplane volume and function measured by Multimodality Tissue Tracking (MTT). Also we assessed the inter-study reproducibility for cardiovascular magnetic resonance (CMR) derived LA volume and function parameters. METHODS: Thirty subjects (mean age: 71.3 ± 8.7, 87% male) including twenty subjects with cardiovascular events and ten healthy subjects, with CMR were evaluated in the Multi-Ethnic Study of Atherosclerosis (MESA). LA volumes were computed by the modified biplane method from 2- and 4-chamber projections and the Simpson's method from short-axis slices using both methods - manual and semi-automated delineation using MTT. LA total, active and passive ejection fractions were calculated. Pearson's correlation and Bland-Altman analysis were used to compare the measurements. In a second sample of 25 subjects (age: 65.7 ± 7.1, 72% males) inter study, intra and inter reader reliability analysis was performed. The intra-class correlation coefficient (ICC) was evaluated. RESULTS: Left atrial MTT structural and functional parameters were not different from manual delineation, yet image analysis was only half as time consuming on average with MTT. Maximal volume MTT was not different between the Simpson's and Biplane methods, functional parameters, however were different. MTT allowed us to measure multiple LA parameters with good-excellent (ICC; 0.88- 0.98, p < 0.001) intra-and inter reader reproducibility and fair-good (ICC; 0.44-0.82, p < 0.05-0.001) inter study reproducibility. CONCLUSIONS: MTT derived LA biplane volume and function is accurate and reproducible and is suited for use in longitudinal studies.