Additionally, a study investigated the therapeutic efficacy of trans-endocardial injection of muscle-derived stem cells overexpressing the Cx43 gene in human subjects with advanced HF, initial results showed promise in the potential of Cx43 as a therapeutic method for treating cardiac arrhythmias with increased myocardial viability, better exercise capacity, and potential for reverse remodeling [131]. This evidence concerns the gene GJA1 and cardiac rhythm disease.