Usefulness of Hemodynamic Sensors for Physiologic Cardiac Pacing in Heart Failure Patients

Abstract

The rate adaptive sensors applied to cardiac pacing should respond as promptly as the normal sinus node with an highly specific and sensitive detection of the need of increasing heart rate. Sensors operating alone may not provide optimal heart responsiveness: central venous pH sensing, variations in the oxygen content of mixed venous blood, QT interval, breathing rate and pulmonary minute ventilation monitored by thoracic impedance variations, activity sensors. Using sensors that have different attributes but that work in a complementary manners offers distinct advantages. However, complicated sensors interactions may occur. Hemodynamic sensors detect changes in the hemodynamic performances of the heart, which partially depends on the autonomic nervous system-induced inotropic regulation of myocardial fibers. Specific hemodynamic sensors have been designed to measure different expression of the cardiac contraction strength: Peak Endocardial Acceleration (PEA), Closed Loop Stimulation (CLS) and TransValvular Impedance (TVI), guided by intraventricular impedance variations. Rate-responsive pacing is just one of the potential applications of hemodynamic sensors in implantable pacemakers. Other issues discussed in the paper include: hemodynamic monitoring for the optimal programmation and follow up of patients with cardiac resynchronization therapy; hemodynamic deterioration impact of tachyarrhythmias; hemodynamic upper rate limit control; monitoring and prevention of vasovagal malignant syncopes.

Biological pacemaker created by minimally invasive somatic reprogramming in pigs with complete heart block

“…The present study not only confirmed the ability of TBX18 to convert cardiomyocytes to iSANs in pigs but also comprehensively investigated the physiological relevance of such conversion. Ideal pacemakers, either biological or electronic, should respond to the complex interaction between autonomic regulation and physical activity (2, 25, 26). Until now, no study has comprehensively addressed this important limitation of biological pacemaker strategies.…”

Influence of Patient’s Exercise Tolerance on Exercise Heart Rate in Closed Loop Stimulation vs. Accelerometer-based Rate Adaptive Pacing

“…Although AS is specifically designed to support physical activity associated with thoracic movement, CLS is not inferior for this kind of activity and is superior to AS during other forms of exercise, like cycling, mental exertion, or emotional stress [5][6][7][8][9][10]14]. In the randomized crossover PROVIDE study, twice as many chronotropically incompetent patients preferred CLS over AS [5].…”

“…In the CLS mode, the pacemaker couples the pacing rate to the myocardial contraction dynamics by measuring ventricular impedance variation [6][7][8]. As cardiac contractility is regulated by the autonomic nervous innervation, CLS is integrated into the natural cardiovascular control loop and responds to physical, mental, and emotional stress [5,[7][8][9][10].…”

Unusual Closed Loop Stimulator Responsive Pacing in a Patient with Paroxysmal Atrial Fibrillation

“…The first implantable cardiac pacemaker was designed to pace at a fixed rate without any attempt to mimic heart rate changes in physiology. Since then, pacemakers were introduced that adjusted the pacing rate by analyzing various sensor inputs and regulated the pacing rate accordingly . These rate adaption sensors include sensing changes in vibration, acceleration, and impedance.…”