FibriCheck use case: Pill-in-the-pocket

Introduction

Paroxysmal atrial fibrillation (PAF) is defined as atrial fibrillation (AF) that terminates spontaneously or with intervention within 7 days of onset. Multiple trials have shown that spontaneous termination of PAF commonly occurs within 24-48 hours. However, symptomatic PAF patients commonly prefer more rapid termination.

Guideline-based AF management often involves the use of a rhythm control strategy such as antiarrhythmic drugs (AADs) in an attempt to restore and maintain sinus rhythm. The use of an ADD that can quickly restore sinus rhythm and that is only taken at the time of an episode is known as “Pill in the Pocket” (PITP) therapy. The goal of this approach is to terminate symptomatic episodes of AF without the need to visit the emergency department and without the burden of a daily drug regimen. ESC guidelines recommend considering the use of a single self-administered oral dose of AADs (flecainide or propafenone) for patient-led cardioversion in a selected population with infrequent and recent onset AF and no significant structural or ischaemic heart diseases. Success rates with the corresponding time to restore sinus rhythm are listed in the table below.

There are some important elements to take into account when considering the use of PITP therapy in selected, symptomatic PAF patients. Symptom onset should be recognized with reasonable accuracy and the episode should be acute before administering the AADs to avoid unnecessary medication intake. Furthermore, it’s important to be aware that the efficacy of PITP treatment is inversely related to the AF duration. It is most effective the first day, has reasonable efficacy the first 3 days, and is far less likely to work for episodes longer than 7 days. In other words, it’s important to apply the PITP approach as soon as possible to increase the success rates. Last but not least, patients should be on oral anticoagulation if they meet AF guidelines to avoid AF-related strokes during potential AF episodes.

It’s important to consider that some AADs may cause QT prolongation, something which is not visible on PPG. Flecainide, the most commonly used AAD, has a relatively low incidence of QT prolongation. However, it is very important to evaluate the effect of AADs on the QT interval during an (in-office) ECG when initiating a PITP approach.

Sources:

• https://academic.oup.com/eurheartj/article/42/5/373/5899003
• https://doi.org/10.1016/j.amjcard.2020.10.063
• https://doi.org/10.1016/j.amjcard.2019.12.041

FibriCheck use case

The patient has a high symptom-rhythm correlation given that 99.5% of the symptomatic recordings (palpitations) were labeled as AF, while 96.1% of the asymptomatic recordings were labeled as non-AF (regular and non-AF arrhythmia recordings). During the most recent episode, the patient performed multiple FibriCheck recordings. All of them were symptomatic as the patient indicated experiencing palpitations with a mild to moderate severity score based on the modified EHRA score (2x2a score, 2x2b score). During the last measurement of this AF episode (December 19, 10:17), the patient reported flecainide intake (December 19, 10:15) which probably resulted in the conversion into sinus rhythm a few hours later. The successful PITP intervention was documented on FibriCheck on December 19 at 13:24. Documentation and objectivation of the symptomatic AF recordings via FibriCheck support this patient in correctly applying the PITP therapy.