Rationale, design, and endpoints of the ‘DEvice-Detected CArdiac Tachyarrhythmic Events and Sleep-disordered Breathing (DEDiCATES)’ study: Prospective multicenter observational study of device-detected tachyarrhythmia and sleep-disordered breathing

Sleep apnea and sudden death in the non-cardiac population: A systematic review

INTRODUCTION

Obstructive sleep apnea (OSA) is one of the main risk factors for cardiovascular diseases and is associated with both morbidity and mortality. OSA has also been linked to arrhythmias and sudden death.

OBJECTIVE

To assess whether OSA increases the risk of sudden death in the non-cardiac population.

METHODS

This is a systematic review of the literature. The descriptors "sudden death" and "sleep apnea" and "tachyarrhythmias" and "sleep apnea" were searched in the PubMed/Medline and SciELO databases.

RESULTS

Thirteen articles that addressed the relationship between OSA and the development of tachyarrhythmias and/or sudden death with prevalence data, electrocardiographic findings, and a relationship with other comorbidities were selected. The airway obstruction observed in OSA triggers several systemic repercussions, e.g., changes in intrathoracic pressure, intermittent hypoxia, activation of the sympathetic nervous system and chemoreceptors, and release of catecholamines. These mechanisms would be implicated in the appearance of arrhythmogenic factors, which could result in sudden death.

CONCLUSION

There was a cause-effect relationship between OSA and cardiac arrhythmias. In view of the pathophysiology of OSA and its arrhythmogenic role, studies have shown a higher risk of sudden death in individuals who previously had heart disease. On the other hand, there is little evidence about the occurrence of sudden death in individuals with OSA and no heart disease, and OSA is not a risk factor for sudden death in this population.

Changes in cardiac conduction time following cardiac resynchronization therapy: rationale and design of the RECOVER study

BACKGROUND

It has been known that ventricular conduction delays play a key role in the cardiac resynchronization therapy (CRT) response of patients with advanced heart failure (HF). However, no study to our knowledge has yet evaluated the serial changes in conduction times measured between different electrodes of CRT devices.

METHODS AND RESULTS

The Reduction or Extension of Conduction Time with Ventricular Electromechanical Remodeling (RECOVER) study (NCT04397224) was designed to investigate serial changes in interelectrode conduction times and to elucidate their prognostic value. We plan to enroll 100 patients implanted with CRT systems with endocardial quadripolar left ventricular leads. Patients will be scheduled for follow-up every 3 months over a period of 2 years, where they will undergo measurement of interelectrode conduction times to evaluate their serial changes. The primary outcome of the RECOVER study is the correlation between the degree of conduction time changes and the CRT response as defined by echocardiography. The time course and prognostic value of the serial changes in conduction times will be investigated as well.

CONCLUSION

The RECOVER study is investigating whether serial changes in interelectrode conduction times can be useful parameters in predicting the CRT response or detecting worsening HF at an early stage.