Incidence, Predictors, and Prognosis of Acute Kidney Injury Among Cardiac Arrest Survivors.

BACKGROUND: Acute kidney injury (AKI) is common among cardiac arrest survivors. However, the outcomes and predictors are not well studied. METHODS: This is a cohort study of cardiac arrest patients enrolled from January 2012 to December 2016 who were able to survive for 24 hours post-cardiopulmonary resuscitation. Patients with anuria, chronic kidney disease (stage 5), and end-stage renal disease were excluded. Acute kidney injury (stage 1) or higher was defined using Kidney Disease: Improving Global Outcomes classification. Multivariable adjusted regression models were used to compute hazard ratio (HR) for association of AKI with risk of mortality and odds ratio (OR) with risk of poor neurological outcomes after adjusting for demographics, comorbidities, and medical therapy. Multivariable logistic regression model was used to compute OR for association of various predictors with AKI. RESULTS: Of 842 cardiac arrest survivors, 588 (69.8%) developed AKI. Among AKI patients, 69.4% died compared with 52.0% among non-AKI patients. In multivariable adjusted Cox proportional hazard model, development of AKI post-cardiac arrest was significantly associated with mortality (HR: 1.35; 95% confidence interval [CI]: 1.07-1.71, P = .01) and poor neurological outcomes defined as cerebral performance category >2 (OR: 2.27; 95% CI: 1.45-3.57, P < .001) and modified Rankin scale >3 (OR: 2.22; 95% CI: 1.43-3.45, P < .001). Postdischarge dialysis was also associated with increased risk of mortality (HR: 2.57; 95% CI: 1.57-4.23, P < .001). Use of vasopressors was strongly associated with development of AKI and continued need for postdischarge dialysis. CONCLUSIONS: Acute kidney injury was associated with increased risk of mortality and poor neurological outcomes. There is need for further studies to prevent AKI in cardiac arrest survivors.

Prognostic significance of electrocardiographic right ventricular hypertrophy in the general population.

BACKGROUND: Echocardiographically detected right ventricular hypertrophy (RVH) is associated with cardiovascular disease (CVD) and mortality. However, the prognostic significance of electrocardiographic (ECG)RVH criteria as predictors of poor outcomes in the general population is unclear. METHODS: This study included 7857 participants (59.8 ±â€¯13.4 years, 52.6% women) from the Third National Health and Nutrition Examination Survey. Sixteen different ECG-RVH criteria were created from digitally recorded and centrally processed electrocardiograms. All-cause mortality was ascertained using the National Death Index. Cox proportional hazards analysis was used to examine the association between baseline ECG-RVH criteria and all-cause mortality. RESULTS: The prevalence of RVH varied widely among the criteria. The lowest ECG-RVH prevalence was 0.09% (using S > R in I, II, III) while the highest prevalence was 20.7% (using (R I + S III) - (S I + R III) < 15 mm). During a median follow-up of 14 years, 2812 deaths occurred. The mortality rate was highest among participants with ECG-RVH defined as R:S ratio V5 < 0.75. In multivariable adjusted models, 9 out of the 16 ECG-RVH criteria were significantly associated with all-cause mortality. When ECG-RVH was defined as the presence of any ECG-RVH criteria, each additional ECG-RVH criteria was associated with 6% increased risk of all-cause mortality (HR (95% CI):1.06(1.03,1.10)). CONCLUSIONS: There is a wide variation in the prevalence of ECG-RVH when different criteria are applied in the general population. However, the presence of ECG-RVH by most criteria regardless of prevalence was associated with poor prognosis suggesting that appropriate choice of criteria may enhance the utilization of these ECG markers in risk stratification.

Effects of Prolonged Spaceflight on Atrial Size, Atrial Electrophysiology, and Risk of Atrial Fibrillation.

BACKGROUND: The prevalence of atrial fibrillation (AF) in active astronauts is ≈5%, similar to the general population but at a younger age. Risk factors for AF include left atrial enlargement, increased number of premature atrial complexes, and certain parameters on signal-averaged electrocardiography, such as P-wave duration, root mean square voltage for the terminal 20 ms of the signal-averaged P wave, and P-wave amplitude. We aimed to evaluate changes in atrial structure, supraventricular beats, and atrial electrophysiology to determine whether spaceflight could increase the risk of AF. METHODS: Thirteen astronauts underwent cardiac magnetic resonance imaging to assess atrial structure and function before and after 6 months in space and high-resolution Holter monitoring for multiple 48-hour time periods before flight, during flight, and on landing day. RESULTS: Left atrial volume transiently increased after 6 months in space (12±18 mL; P=0.03) without changing atrial function. Right atrial size remained unchanged. No changes in supraventricular beats were noted. One astronaut had a large increase in supraventricular ectopic beats but none developed AF. Filtered P-wave duration did not change over time, but root mean square voltage for the terminal 20 ms decreased on all fight days except landing day. No changes in P-wave amplitude were seen in leads II or V1 except landing day for lead V1. CONCLUSIONS: Six months of spaceflight may be sufficient to cause transient changes in left atrial structure and atrial electrophysiology that increase the risk of AF. However, there was no definite evidence of increased supraventricular arrhythmias and no identified episodes of AF.