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Unique Features

Implantable Cardiac Devices

OptiVol Fluid Status Monitoring

OptiVol® Fluid Status Monitoring is the only tool available that provides clinicians with daily fluid status monitoring through intrathoracic impedance measurements.

Clinical Need for Fluid Status Monitoring

Heart failure (HF) affects approximately 5.8 million Americans, and is the primary reason for over 1.1 million hospital admissions every year. The estimated direct and indirect cost of heart failure in the US for 2010 was $39.2 billion.1

  • Approximately 50% of HF costs can be attributed to hospitalizations for acute decompensated HF.2
  • Fluid volume overload (congestion) is a major complication for patients with moderate-to-severe HF and a frequent cause of hospital readmissions.3
  • Fluid accumulation in HF patients is often detected too late to avert hospitalization.4
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Current Monitoring

  • Assessing heart failure congestion is challenging.5
  • Regular monitoring using body weight, blood pressure, and clinical symptoms does not always provide clarity and adequate time to prevent hospitalization.6-10

Patient Compliance Remains a Concern

  • Nearly half of hospital readmissions for HF were caused by medication or dietary nonadherence.9

OptiVol Fluid Status Monitoring Does Not Rely on Patient Compliance

OptiVol monitoring, together with Cardiac Compass® Report, is a tool that objectively tracks fluid status and several other physiologic trends, without relying on patient compliance.

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How It Works


OptiVol Fluid Status Monitoring

OptiVol monitoring provides clinicians an opportunity to assess the patient's fluid status via daily impedance measurements taken by an implantable CRT-D or ICD device.1


Many times during the day, electrical impulses travel from the right ventricular lead to the implanted device can. OptiVol Fluid Status Monitoring uses this electrical impulse vector to measure impedance across the thoracic cavity. Trended daily impedance data has been shown to correlate well with pulmonary capillary wedge pressure (PCWP),pulmonary artery diastolic pressure (ePAD)2 and worsening heart failure.3-5


OptiVol Monitoring measures fluid (not just in the lungs)1

MID-HeFT study

The increase in impedance during diuretic therapy was strongly correlated with Pulmonary Capillary Wedge Pressure (PCWP) and net fluid loss.

Thoracic impedance measurements are a part of the recommended factors to consider in management of chronic heart failure – in the Heart Rhythm Society Expert Consensus [ACC/AHA/HRS] on the Monitoring of Cardiovascular Implantable Electronic Devices.6

OptiVol Fluid Index and Impedance Monitoring

OptiVol Monitoring can provide an early indication of heart failure1

OptiVol Monitoring can provide an early indication of heart failure allowing time for clinical intervention.

  • Intrathoracic impedance decreases on average 15 days before symptom onset and 18 days before hospitalization
  • Symptom onset occurs only 3 days before hospitalization
Heart Failure Management Report

OptiVol monitoring, together with Cardiac Compass® Report,* is a tool that objectively tracks fluid status and several other physiologic trends:

  • Atrial tachycardia (AT)/atrial fibrillation (AF) burden
  • Ventricular rate during AT/AF
  • Patient activity
  • Average ventricular rate (day/night)
  • Heart rate variability
  • Percent pacing per day
  • Daily shocks and treated ventricular tachycardia/ventricular fibrillation episodes per day

When used collectively, these data can help clinicians identify patients who are at risk for worsening heart failure.

  • OptiVol Monitoring is not intended to replace assessments which are part of standard clinical practice.

OptiVol Monitoring has been proven to predict worsening heart failure in multiple clinical studies with over 2500 patients 1-9

  • Risk stratify your HF patients for more frequent follow-up with OptiVol and Cardiac Compass trends in office or remotely
  • OptiVol Monitoring automatically tracks fluid status and does not rely on patient compliance

* Heart Failure Management Report



Yu CM, Wang L, Chau E, et al. Intrathoracic impedance monitoring in patients with heart failure: correlation with fluid status and feasibility of early warning preceding hospitalization. Circulation. August 9, 2005;112(6):841-848. [MID-Heft]


Vanderheyden M, Houben R, Verstreken S, et al. Pressures in patients with heart failure continuous monitoring of intra-thoracic impedance and right ventricular. Circ Heart Fail published online Mar 2, 2010.


Small RS, Wickemeyer W, Germany R, et al. Changes in intrathoracic impedance are associated with subsequent risk of hospitalizations for acute decompensated heart failure: clinical utility of implanted device monitoring without a patient alert. J Card Fail. August 2009;15(6):475-481.


Whellan DJ, Al-Khatib SM, Kloosterman EM, et al. Changes in intrathoracic fluid index predict subsequent adverse events: Results of the multi-site program to access and review Trending INformation and Evaluate CoRelation to Symptoms in Patients with Heart Failure (PARTNERS HF) Trial. J Card Fail. 2008;14(9):799. [PARTNERS HF]


Abraham WT. Superior performance of intrathoracic impedance-derived fluid index versus daily weight monitoring in heart failure patients. Results of the Fluid Accumulation Status Trial. Late Breaking Clinical Trials. J Card Fail. Vol. 15 No. 9 2009, p 813. (FAST).


Wilkoff BL, Auricchio A, Brugada J, et al. HRS/EHRA/ACC/AHA/HFSA expert consensus on the monitoring of cardiovascular implantable electronic devices (CIEDs): description of techniques, indications, personnel, frequency and ethical considerations. Heart Rhythm. June 2008;5(6):907-925.


Vollmann D, Nägele H, Schauert P, et al. Clinical utility of intrathoracic impedance monitoring to alert patients with an implanted device of deteriorating chronic heart failure. Eur Heart J. August 2007;28(15):1835-1840.


Catanzariti D, Lunati M, Landolina M, et al. Monitoring intrathoracic impedance with an implantable defibrillator reduces hospitalizations in patients with heart failure. PACE. March 2008;32(3):363-370.


Perego GB, Landolina M, Vergara G, et al. Implantable CRT device diagnostics identify patients with increased risk for heart failure hospitalization. J Interv Card Electrophysiol. December 2008;23(3):235-242. [Italian Clinical Service OptiVol-CRT Group]

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American Heart Association. Heart Disease and Stroke Statistics – 2010 Update.


American Heart Association. Heart Disease and Stroke Statistics – 2004 Update. Dallas, TX: American Heart Association. 2004.


Sackner-Bernstein J. What is heart failure and what are the treatment options? Complex questions. In: Hayes DL, Wang PJ, Sackner-Bernstein J, Asirvatham SJ, eds. Resynchronization and Defibrillation for Heart Failure: A Practical Approach. Oxford, England: Blackwell Publishing; 2004:1-2.


Small RS. Integrating device-based monitoring into clinical practice: insights from a large heart failure clinic. Am J Cardiol. May 21, 2007;99(10A):17G-22G.


Fonarow GC. How well are chronic heart failure patients being managed? Rev Cardiovasc Med. 2006;7(suppl 1):S3-11.


Friedman MM. Older adults’ symptoms and their duration before hospitalization for heart failure. Heart Lung 1997;26:169 –176.


Evangelista LS, Dracup K, Doering LV. Treatment-seeking delays in heart failure patients. J Heart Lung Transplant 2000;19:932–938.


Stevenson LW, Perloff JK. The limited reliability of physical signs for estimating hemodynamics in chronic heart failure. JAMA 1989;261: 884–888.


Vinson JM, Rich MW, Sperry JC, Shah AS, McNamera T. Early readmission of elderly patients with congestive heart failure. J Am Geriatr Soc 1990;38:1290 –1295.


Abraham WT. Superior performance of intrathoracic impedance-derived fluid index versus daily weight monitoring in heart failure patients. Results of the Fluid Accumulation Status Trial. Late Breaking Clinical Trials. J Card Fail. Vol. 15 No. 9 2009, p 813. (FAST).