Cardiopulmonary response to sodium fluoride infusion in the dog

Impact of chronic fluorosis on left ventricular diastolic and global functions

Sixty three patients with endemic fluorosis (36 males/27 females; mean age 33.9+/-8.6years) and 45 age, sex and body mass index (BMI) matched healthy controls (30 males/15 females; mean age 32.7+/-8.8years) were included in this study. Basic echocardiographic measurements, left ventricular diastolic parameters and left ventricular myocardial performance index (MPI) were measured. The left ventricular MPI was calculated as (isovolumic contraction time+isovolumic relaxation time)/aortic ejection time by Doppler. The urine fluoride levels of fluorosis patients were significantly higher than control subjects as expected (1.9+/-0.1mg/l vs 0.4+/-0.1mg/l respectively; P<0.001). Isovolumic relaxation time (IVRT) and deceleration time (DT) were significantly higher in fluorosis patients than in controls (for IVRT 106.9+/-15.6ms vs 96.7+/-12.2ms; P<0.001 and for DT 211.7+/-30.7ms vs 188.0+/-30.0ms; P<0.001, respectively). MPI was significantly higher in fluorosis patients than in controls (0.62+/-0.15ms vs 0.49+/-0.10ms; P<0.001, respectively). We have shown that chronic fluorosis patients had left ventricular diastolic and global dysfunctions.

Alterations in electrocardiographic parameters after subacute exposure of fluoride and ameliorative action of aluminium sulphate in goats

Fluorosis or crippling disease is one of the existing environmental challenges for animal and human beings in most parts of the globe. In the present study, sodium fluoride alone and with aluminium sulphate (ameliorative agent) was administered orally daily for 30 days in healthy goats of group 1 and 2, respectively, to access the effect on the electrocardiogram. All waves of Lead I, Lead II, Lead III, aVR, aVL and aVF in electrocardiographs were recorded before and after 30 days exposure of fluoride. A significant (P < 0.05) increase in P-R, Q-T and S-T intervals were observed in goats of group 1 as compared to their pre treatment values. The T wave duration was also significantly (P < 0.05) prolonged and as a result, bradycardia was observed after subacute exposure of fluoride for 30 days in group 1. But, in group 2, no such changes were observed. On the basis of results, it may be concluded that subacute toxicity of fluoride produces significant changes in different waves of electrocardiogram and aluminium sulphate has ameliorative efficacy.

Recurrent life-threatening ventricular dysrhythmias associated with acute hydrofluoric acid ingestion: Observations in one case and implications for mechanism of toxicity

INTRODUCTION

Hydrofluoric acid (HF) is a weak inorganic acid used for etching and as rust remover. Systemic toxicity is manifested as ventricular dysrhythmias. The mechanisms for these dysrhythmias are not well elucidated.

CASE REPORT

An 82-year-old woman ingested 8 ounces of 7% HF. Shortly after emergency department (ED) arrival, she became pulseless, developing recurrent ventricular dysrhythmias. She was defibrillated 17 times and received several doses of calcium, magnesium, and lidocaine. After three hours, she returned to sustained NSR. She was discharged home after four days.

DISCUSSION

The electrocardiographic findings in this patient demonstrate hypocalcemia, which has been implicated as the culprit in HF-induced arrhythmias. However, despite correction of the hypocalcemia, the ventricular arrhythmias persisted. The proposed mechanisms of systemic HF toxicity and the relevant literature are discussed.

CONCLUSION

Ventricular dysrhythmias due to HF toxicity seem to be independent of either hypocalcemia or hyperkalemia. Systemic toxicity after ingestions may be delayed and precipitous.

The mechanism of fluoride-induced hypocalcaemia

1. Fluoride intoxication leads to sudden cardiac death which has been assumed to result from the accompanying severe hypocalcaemia. The aim of this study has been to investigate the suggestion that fluorapatite formation rather than CaF2 precipitation is responsible for this low calcium. 2. Measurements of free Ca2+ and F- ion concentrations in HEPES buffered solutions containing F-, Ca2+, and phosphate ions at different concentrations in the absence and presence of hydroxyapatite showed that the presence of hydroxyapatite enhanced the decrease of Ca2+ and F- concentration. 3. The ratio of Ca2+:F- clearance was 5:1 which is consistent with formation of fluorapatite. These results support the hypothesis that hydroxyapatite acts as a nucleation catalyst for fluorapatite formation and this process is responsible for the hypocalcaemia induced by fluoride intoxication. 4. The proposed mechanism explains also the metabolic acidosis which is frequently seen in cases of fluoride intoxication.