Due to the abundance of orthologous genes that encode proteins that are comparable to those found in humans, the zebrafish (Danio rerio) has emerged as a promising model for the study of human disease. The zebrafish genome can only be modified with a small set of tools, and many of the methods now in use are either successful in the early stages of development (such as morpholino-based antisense technology) or are phenotypically driven without providing specific gene knockdown (such as chemical mutagenesis). The use of RNA interference has been controversial because off-target effects can make it challenging to interpret phenotypic results. This problem has been handled by developing zebrafish lines with miRNA constructs that are stably integrated and target the desired gene of interest. In this study, we demonstrate that a commercially in a temporary in vivo eGFP sensor test setup, the miRNA backbone is successful in producing eGFP knockdown in zebrafish. We decided to use this technique to knockdown transcripts associated with Long QT syndrome, a human heart disease.