Hemodynamic sensing using subcutaneous photoplethysmography

Turcott, Robert G.; Pavek, Todd

doi:10.1152/ajpheart.00574.2008

Cited by 17 publications

(29 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…9,19–21,24 –26,30,36–40 Although each has a rationale that is mechanistically plausible, consideration of the neurohormonal derangements of heart failure and the therapeutic interventions that have been successful lead us to view SV and its surrogates as parameters that when optimized are most likely to translate into clinical benefit. Specifically, it is now well established that ameliorating the effects of sympathetic tone in these patients leads to improved clinical outcomes.…”

Section: Discussionmentioning

confidence: 99%

Measurement Precision in the Optimization of Cardiac Resynchronization Therapy

Turcott

Witteles

Wang

et al. 2010

Circ: Heart Failure

Self Cite

View full text Add to dashboard Cite

Background Cardiac resynchronization therapy improves morbidity and mortality in appropriately selected patients. Whether atrioventricular (AV) and interventricular (VV) pacing interval optimization confers further clinical improvement remains unclear. A variety of techniques are used to estimate optimum AV/VV intervals; however, the precision of their estimates and the ramifications of an imprecise estimate have not been characterized previously. Methods and Results An objective methodology for quantifying the precision of estimated optimum AV/VV intervals was developed, allowing physiologic effects to be distinguished from measurement variability. Optimization using multiple conventional techniques was conducted in individual sessions with 20 patients. Measures of stroke volume and dyssynchrony were obtained using impedance cardiography and echocardiographic methods, specifically, aortic velocity-time integral, mitral velocity-time integral, A-wave truncation, and septal-posterior wall motion delay. Echocardiographic methods yielded statistically insignificant data in the majority of patients (62%–82%). In contrast, impedance cardiography yielded statistically significant results in 84% and 75% of patients for AV and VV interval optimization, respectively. Individual cases demonstrated that accepting a plausible but statistically insignificant estimated optimum AV or VV interval can result in worse cardiac function than default values. Conclusions Consideration of statistical significance is critical for validating clinical optimization data in individual patients and for comparing competing optimization techniques. Accepting an estimated optimum without knowledge of its precision can result in worse cardiac function than default settings and a misinterpretation of observed changes over time. In this study, only impedance cardiography yielded statistically significant AV and VV interval optimization data in the majority of patients.

show abstract

Section: Discussionmentioning

confidence: 99%

Measurement Precision in the Optimization of Cardiac Resynchronization Therapy

Turcott

Witteles

Wang

et al. 2010

Circ: Heart Failure

Self Cite

View full text Add to dashboard Cite

show abstract

“…61 The technology, which is commonly used in noninvasive pulse oximetry, uses light for noninvasive assessment of microvascular blood volume. In a proof-of-concept canine study, a photoplethysmography sensor was implanted subcutaneously, and waveforms showed an excellent correlation with aortic pressure during rapid ventricular pacing or changes in atrioventricular delay.…”

Section: Future Directionsmentioning

confidence: 99%

“…In a proof-of-concept canine study, a photoplethysmography sensor was implanted subcutaneously, and waveforms showed an excellent correlation with aortic pressure during rapid ventricular pacing or changes in atrioventricular delay. 61 It was proposed that inclusion of this sensor in a pulse generator may allow measurement of a surrogate marker for acute changes in arterial pressure. Furthermore, appropriately filtered photoplethysmography data may provide information on venous capillary flow and respiration and may be used to aid management of sleep-disordered breathing.…”

Section: Future Directionsmentioning

confidence: 99%

Device Sensing

Kaszala

Ellenbogen

2010

Circulation

View full text Add to dashboard Cite

evice therapy for the management of cardiac arrhythmias has evolved from asynchronous pacing in postsurgical heart block and Stokes-Adams attacks 1 to the use of implantable cardioverter defibrillator (ICDs) 2 and cardiac resynchronization therapy for the prevention of sudden cardiac death and the treatment of heart failure. 3 Algorithms have been developed to optimize pacemaker response during arrhythmias and minimize pacing if indicated by cardiac physiology. Over the last several decades, technological advances and a better understanding of cardiac physiology allowed the development and miniaturization of devices that not only monitor and react to the electric signals from intracardiac electrograms but also use physiological signals to optimize pacing function and monitor disease state. It has become a reality to store this information in modern devices and transmit it to a clinical center, even on a daily basis if needed, by use of a transtelephonic or Internet-based route. As current and emerging indications for device therapy have targeted increasingly larger patient populations, 4 we are now able to use implantable devices to monitor patients at risk of adverse cardiac events.Emerging technologies aim to provide continuous hemodynamic information to aid the management of chronic heart failure. Technologies under clinical investigation include impedance-based monitoring of fluid status, hemodynamic assessment based on pulmonary artery pressure and its derivatives, or direct left atrial pressure monitoring. A promising possibility is that the information obtained from monitors may be used to predict and avoid adverse clinical outcomes earlier than changes in clinical parameters would otherwise indicate, which would allow physicians an opportunity for earlier intervention. In the present review, we will discuss currently used sensors in cardiac devices and draw attention to some of the future applications of device sensors. Sensors for Rate Modulation Rate ModulationStudies in the 1970s demonstrated that adequate cardiac output during exercise predominantly relies on increases in heart rate, 5 especially if cardiac dysfunction is present. This notion resulted in increased efforts to develop pacing systems that mimic sinus node function and allow rate modulation in patients with sinus node disease or chronotropic incompetence. Normal cardiovascular response to exercise is very complex. The normal well-concerted response is the result of a prompt change in heart rate caused by the interplay between neural, humoral, and hemodynamic inputs to the heart. A detailed discussion of exercise physiology is beyond the scope of the present review, but it is important to understand some basic principles to appreciate the difficulties in simulating normal chronotropy and to understand the limitations of individual sensors.Aerobic metabolism requires an adequate supply of oxygen transported from the lungs to the tissues by means of the circulation. Thus, both cardiovascular and pulmonary systems play a key role in meeting ...

show abstract

“…It is a sensing technology that has many of the features of an ideal hemodynamic sensor. Notably, it responds in a direct proportion to acute changes in systemic blood pressure 13 . The present study quantitatively evaluated the ability of subcutaneous PPG to discriminate hemodynamically unstable arrhythmias from stable arrhythmias that were simulated by rapid pacing in an acute canine preparation.…”

Section: Introductionmentioning

confidence: 99%

Identification of Hemodynamically Unstable Arrhythmias Using Subcutaneous Photoplethysmography

Turcott

Pavek

2010

Cardiovasc electrophysiol

Self Cite

View full text Add to dashboard Cite

Introduction Determination of hemodynamic status is central to arrhythmia management in the inpatient setting. In contrast, therapy decisions in implantable cardioverter defibrillators (ICDs) are based exclusively on the arrhythmia’s electrical signature. Hemodynamic sensing in ICDs would allow tailoring of therapy according to perfusion status. Subcutaneous photoplethysmography (PPG) is an attractive technology for this application because it responds to changes in arterial pressure and can be readily incorporated into the housing of implanted devices. This study evaluated the accuracy of PPG in identifying hemodynamically unstable simulated arrhythmias in an animal model. Methods and Results Rapid atrial and ventricular pacing was used to simulate arrhythmias in an acute preparation of 7 healthy dogs. Aortic pressure and subcutaneous PPG were simultaneously recorded. Simulated arrhythmias were defined as hemodynamically unstable if aortic pressure decreased by ≥15 mmHg, marginally unstable if pressure decreased by 5–15 mmHg, and hemodynamically stable if pressure either increased or decreased by no more than 5 mmHg. An average of 56 arrhythmias were simulated in each animal. Changes in pressure and PPG output were highly correlated, with correlation coefficient of 0.7–0.9. Subcutaneous PPG identified hemodynamically unstable episodes with a sensitivity of 100% for 6 subjects and 80% for 1 subject. Specificity was more than 90% for 6 subjects and was 50% for 1 subject. Conclusions Subcutaneous PPG detects hemodynamically unstable simulated arrhythmias in an acute canine preparation. If successfully validated in humans, this technology may allow ICD therapy to be specifically tailored according to the hemodynamic status of the arrhythmia.

show abstract

Hemodynamic sensing using subcutaneous photoplethysmography

Cited by 17 publications

References 43 publications

Measurement Precision in the Optimization of Cardiac Resynchronization Therapy

Measurement Precision in the Optimization of Cardiac Resynchronization Therapy

Device Sensing

Identification of Hemodynamically Unstable Arrhythmias Using Subcutaneous Photoplethysmography

Contact Info

Product

Resources

About