Ion Channel Remodelling and Arrhythmia Vulnerability in a Rat Model of Hypertensive Heart Disease Using a High-Salt Diet Paradigm Relevant to Northern Nigerian Food Culture

Background: Northern Nigerian cuisine is characterised by high consumption of potash, trona, and preserved meats that contribute to excessive dietary sodium intake, predisposing populations to salt-sensitive hypertension and hypertensive heart disease. Cardiac ion channel remodelling accompanying pressure overload creates the electrophysiological substrate for ventricular arrhythmias. This mechanistic intersection has not been explored in an animal model incorporating Northern Nigerian dietary sodium patterns. Objectives: This study aims to establish a Dahl salt-sensitive rat model fed a diet calibrated to Northern Nigerian sodium intake levels, characterise pressure-overload-induced ion channel expression changes including sodium channel Nav1.5, potassium channels Kv4.2 and Kv4.3, and connexin-43, and assess arrhythmia vulnerability by programmed electrical stimulation and optical voltage mapping. Methods: Sixty Dahl salt-sensitive and twenty Dahl salt-resistant rats will be allocated to high-salt and normal-salt diets. After 12 weeks, cardiac haemodynamics will be assessed by catheterisation. Ion channel protein expression will be quantified by western blot. Connexin-43 lateralisation will be assessed by immunofluorescence. Ventricular arrhythmia inducibility will be determined by transvenous programmed stimulation. Two-way ANOVA with post-hoc testing will compare ion channel and arrhythmia outcomes. Expected Outcomes: High-salt hypertensive rats are hypothesised to demonstrate Nav1.5 downregulation, reduced Kv4.2 expression, and connexin-43 lateralisation, producing a pro-arrhythmic substrate with significantly greater arrhythmia inducibility. Conclusion: Findings will provide original mechanistic evidence linking Northern Nigerian dietary sodium excess to hypertensive cardiac arrhythmogenesis. Keywords: ion channel remodelling, hypertensive heart disease, arrhythmia, high-salt diet, cardiac electrophysiology.