ABSTRACT
By 2030, more than 12 million Americans will suffer from atrial fibrillation (AF), a heart arrhythmia which
dramatically increases mortality and risk of stroke. Class III antiarrhythmic drugs (sotalol, dofetilide) prescribed
to treat AF reduce both morbidity and mortality, but access to them is restricted by the hospitalization period
required to initiate them. During this time, patient’s hearts are monitored by ECG to observe post-drug effects of
6 consecutive drug dosages over 3 days on the corrected QT interval (QTc) of the ECG. This interval is the
primary determinant of Torsades de Pointes (TdP) risk; TdP is a rare but life-threatening fast ventricular rhythm
which can be provoked by AADs. SafeBeat Rx Inc. develops technology that allows low-risk atrial fibrillation
patients to reproduce this ‘drug loading’ procedure outside a hospital, and thereby start heart rhythm medications
safely at home by titrating drug effects to QTc changes – the SafeBeat Kit analyzes post-drug ECGs taken by
patients at home via a machine learning algorithm, and sends the data to the relevant physicians, who can modify
or continue drug dosages as required. One significant but unresolved problem is that heart rhythms have a strong
circadian variability, often of the same magnitude as drug effects themselves, which is not measured or modeled
during drug initiation. We hypothesize that a smartwatch with ECG measurement capabilities can be used to
differentiate these circadian effects from drug effects by taking several measurements a day. Specifically, (1)
circadian effects in AF patients can be measured with traditional cardiac telemetry models (2) a smartwatch can
reproduce this model and demonstrate clinically equivalent measurements, and (3) these measurements will be
straightforward and acceptable for patients. Having established these, a planned Phase II will continue with full
clinical validation sufficient to apply for FDA 510k clearance for a circadian-adjusted QTc model of drug safety
monitoring. SafeBeat Rx Inc. is the first company to offer an in-home, remote monitoring alternative to drug load
hospitalization. At maximal adoption, the annual US beachhead market of low-risk, early-adopting patients is
calculated at $1.7B for AF alone. The company has filed key IP around this proposition and has licensing
agreements with hardware companies to enable successful scaling to serve the growing AF population.
