Arrhythmia Research Technology Inc. announced on Tuesday that it was unable to file its annual Form 10-K report with the Securities and Exchange Commission for the fiscal year ended Dec. 31, despite an extension to April 16. The delay is due to an ongoing internal audit relating to adjustments to the calculation of tax-deferred assets in the company’s Canadian subsidiary, RMDDx Corp. Said chief executive James E. Rouse: “We want our stockholders to know that it is of paramount importance to us to provide confidence and transparency in our financial statements and that we are doing everything possible to ensure that this a one-time only event.’’