Acute and long term evaluation of pituitary functions in patients with heart block requiring pacemaker implantation: A pilot study

Abstract

Background: Neuronal hypoxia and neuro-inflammation accompanying conditions like traumatic brain injury, stroke, cerebrovascular accidents and sub-arachnoid haemorrhage has been associated with hypopituitarism. Neuronal insults of similar magnitude and hypopituitarism [Growth Hormone (GH) , gonadotropin and TSH deficiency in 27.2%, 9.0% and 2.2% patients respectively] has also been noted in a single study till date conducted in patients of ventricular arrhythmias requiring cardio-pulmonary resuscitation¹. Patients with heart block, a more frequent form of cardiac arrhythmia usually presents with haemodynamic compromise and may be predisposed for developing either acute or delayed hypopituitarism which has never been studied before.

Aims and objective: Our study was aimed at exploring whether pituitary dysfunction occurs in patients presenting with heart block and requiring pacemaker implantation. We analysed anterior pituitary functions in these cohort of patients during acute hospitalization and later during follow.

Study design: Cross-sectional prospective study

Materials and Methods: Fifty-one patients were included in the study (mean age-65.98±10.9years; 34 men & 17 women) . Pituitary hormonal profile was done within 48 hours of presentation and after a mean follow up of 12.52 ± 2.2 months. Total T3, total T4, free T4, TSH, FSH, LH, Testosterone (in men) , Estradiol (in women) , Prolactin, and random Cortisol were measured in all participants at baseline and in follow-up. Fixed dose Glucagon (weight<90kg-1mg; ≥90kg-1.5mg) stimulation test was done in follow-up to assess GH and cortisol axes.

Results: Among 30 (out of 50) patients who turned up for follow-up, GH, cortisol and TSH deficiency was noted in 50% (n-15) , 13.3% (n-4) and 3.2% (n-1) of subjects, respectively. Pan-hypopituitarism characterised by deficiency of atleast two hormonal axes was seen in 16.7% (n-5) patients.

Conclusion: Significant delayed hypopituitarism especially GH deficiency was seen among patients of heart block.

Implications: This novel finding if reproduced in subsequent studies will result in unearthing of a significant etiology of hypopituitarism which could potentially become the most common cause of acquired adult onset hypopituitarism considering the huge burden of patients with heart block. Heightened cardiovascular risk due to hypopituitarism in these patients may be reversed by active screening and replacement of deficient hormones.