VytronUS has announced it has secured $31.6 million in an oversubscribed series B financing.

VytronUS, based in Sunnyvale, Calif., is a medical device company developing technologies for the treatment of cardiac arrhythmias.

The financing round was led by Apple Tree Partners, along with additional new investors, BioStar Ventures, Windham Venture Partners and a strategic investor alongside New Enterprise Associates and other existing investors.

VytronUS indicated the financing will be used for development and validation of VytronUS’s low-intensity collimated ultrasound cardiac imaging and ablation system designed to treat atrial fibrillation and other arrhythmias in forthcoming clinical trials.