Public health decisions: Actions and consequences

The goal of public health is to promote the best possible health for the whole population. Public health issues are numerous and can be unbelievably complex in form, scope, and possible consequence. Most public health decisions involve assessing several different options, weighing the respective benefits and risks of those options, and making difficult decisions that hopefully provide the greatest benefit to the affected populations. Many risk management decisions involve a variety of societal factors which modify risk assessment choices. The purpose of this paper is to point out difficulties in making decisions that impact public health. The intent of such decisions is to improve public health, but as illustrated in the paper, there can be unintended adverse consequences. Such unplanned issues require continued attention and efforts for responsible officials in the protection of environmental public health. This article presents examples of such events, when in the past, it was necessary to assess and regulate a number of potentially hazardous chemicals commonly used as insecticides, gasoline additives, and wood preservatives.     

Conduction system examination in a case of spontaneous heart block in a dog

This is a serial-section study of the conduction system in a 2-year-old boxer with electrocardiographic evidence of complete A-V block. The following findings were present: a lack of communication between the atria and the A-V node, atrophy of the A-V node, and tenuous connections between the A-V node and the A-V bundle. These were accompanied by acute degenerative changes in the conduction system. These changes are considered to be the result of arteriolosclerotic heart disease.     

Anatomic substrate for preexcitation in idiopathic myocardial hypertrophy with fibroelastosis of the left ventricle

Serial section of the conduction system and both atrioventricular (A-V) rims was performed in three patients who died with known preexcitatlon and idiopathic myocardial hypertrophy with fibroelastosis proved at autopsy. All three patients had type B preexcitation and a leftward and inferior 20 ms vector, suggesting a right free wall anomalous pathway. Patient 1 had no arrhythmia, Patient 2 died suddenly and Patient 3 had recurrent paroxysmal supraventricular tachycardia. Electrophysiologic study in Patients 1 and 3 revealed a bidirectionally conducting anomalous pathway with short refractoriness. Patient 1 had no, and Patient 3 had easily inducible A-V reentrant paroxysmal supraventricular tachycardia. Electrophysiologic study in Patient 3 revealed an anterior right free wall or anteroseptal anomalous pathway, manifested by the shortest stimulus-delta interval with pacing of the right anterior atrium. No electrophysiologic studies were performed in Patient 2.In Patient 1 serial section revealed a large right free wall anomalous pathway with myocardial disarray on the ventricular side of the anomalous pathway. In Patient 2, there were two small anomalous pathways in the right free wall. In Patient 3, no anomalous pathway was found in the right free wall; however, the right atrium was connected to the infundibular septum anterior to the membranous septum. This anomalous pathway had continuity with an anterior A-V nodal-like structure.In summary, (1) all three patients anatomically had a right-sided anomalous pathway (as predicted on electrocardlography in all three and electrophyBiologically in Patients 1 and 3). (2) In Patient 2, myocardial disarray in the Kent bundle may have prevented paroxysmal supraventricular tachycardia. (3) In Patient 3, histologic study revealed an anterior septal anomalous pathway on the right side with an anterior A-V nodal-like structure. Because the anomalous pathway did not show any A-V nodal properties, the significance of this structure is not clear. (4) The relation of the right-sided anomalous pathway to the left-sided fibroelastosis is not known.     

Electrophysiologic studies in tricuspid atresia

Five patients with tricuspid atresia underwent His bundle studies with the recording catheter placed close to the mitral valve ring. Right atrial pacing and measurement of the refractory periods were performed in three. The prolonged intraatrial conduction time found in all patients is thought to be caused by a hypertrophied and dilated right atrium with increased internodal distance due to stretching of internodal pathways. The A-H interval was normal in all; the H-V interval was short in three and normal in two. The pattern of left axis deviation in the group with a short H-V interval is thought to be due to early origin of the posterior branches of the left bundle branch from the bundle of His and early activation of the posteroinferior parts of the left ventricle. The pattern of left axis deviation in the group with a normal H-V interval may be related to the previously reported anomalous course of the left bundle. Atrial pacing produced a normal response. The refractory periods were within normal range, suggesting functional integrity of conduction through the atrioventricular node and bundle branches.     

Predictors and Outcomes of Renal Replacement Therapy After Left Ventricular Assist Device Implantation

ObjectiveTo examine the frequency and outcomes of patients requiring renal replacement therapy (RRT) early after left ventricular assist device (LVAD) implantation.Patients and MethodsWe examined use of in-hospital RRT and outcomes in consecutive adults who underwent continuous-flow LVAD implantation from February 15, 2007, through August 8, 2017. Logistic regression was used to examine predictors of RRT. The associations of RRT with outcomes were examined using Cox proportional hazards regression.ResultsOf 354 patients who underwent LVAD implantation, 54 (15%) required in-hospital RRT. Patients receiving RRT had higher preoperative Charlson Comorbidity Index values (median, 5 vs 4; P=.03), Model for End-Stage Liver Disease scores (mean, 19.0 vs 14.5; P<.001), right atrial pressure (mean, 19.1 vs 13.4 mm Hg; P<.001), and estimated 24-hour urine protein levels (median, 357 vs 174 mg; P<.001) and lower preoperative estimated glomerular filtration rate (eGFR) (median, 43 vs 57 mL/min; P<.001) and measured GFR using ¹²⁵I-iothalamate clearance (median, 33 vs 51 mL/min; P=.001) than those who did not require RRT. Approximately 40% of patients with eGFR less than 45 mL/min/1.73 m² and 24-hour urine protein level greater than 400 mg required RRT vs 6% with eGFR greater than45 mL/min/1.73 m² and without significant proteinuria. Lower preoperative eGFR, higher estimated 24-hour urine protein level, higher right atrial pressure, and longer cardiopulmonary bypass time were independent predictors of RRT after LVAD implantation. Of patients requiring in-hospital RRT, 18 (33%) had renal recovery, 18 (33%) required outpatient hemodialysis, and 18 (33%) died before hospital discharge. After median (Q1, Q3) follow-up of 24.3 (8.9, 49.6) months, RRT was associated with increased risk of death (adjusted hazard ratio [HR], 2.86; 95% CI, 1.90-4.33; P<.001) and gastrointestinal bleeding (adjusted HR, 4.47; 95% CI, 2.57-7.75; P<.001).ConclusionIn-hospital RRT is associated with poor prognosis after LVAD. A detailed preoperative assessment of renal function before LVAD may be helpful in risk stratification and patient selection.