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Use of Device Diagnostics in the OutpatientManagement of Heart Failure

Robin Germany, MD, and Christina Murray, MD

Implantable cardiac devices now go far beyond the functionality of early pacemakersand defibrillators. They provide us with an unprecedented amount of informationabout the day-to-day status of our patients with heart failure, providing insight intothe complex clinical picture of these patients. More advanced technology can be seenon the horizon, and the development of strategies to incorporate this information intoour clinics is needed. Traditionally, information from devices has only been accessedby the physicians implanting the device. However, heart failure physicians and theirpatients can benefit from the information now available and from having ways toaccess and use the data. This article focuses on the successful integration of device-based data into patient care in the outpatient clinical setting. © 2007 Elsevier Inc.

All rights reserved. (Am J Cardiol 2007;99[suppl]:11G–16G)

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lthough some practices incorporate device or electrophys-ology (EP) nurses into their practices, cardiologists andeart failure physicians are often removed from routineontact with these specialized nurses. Similarly, not allardiology clinics have programmers in their office. In clin-cs where a programmer is available, clinicians have differ-ng degrees of comfort and expertise in using these devices.n the past, it was necessary only to collect data fromevices at routine intervals to check for appropriate deviceunction. In this new era of data integration, device checksay be beneficial at each clinic visit and perhaps even more

requently, based on the patient’s clinical status. Reportsollected at these intervals can be tailored with a focus onatient management rather than just device management.

evice Interrogation in the Non-Electrophysiologistffice

P nurses can be recruited to develop a process to makeeart failure reports accessible to the treating physician andlso to provide support for the heart failure clinic. This canelp ease the transition in cases in which physicians in thelinic are not accustomed to looking at the data from de-ices. Patients can have their devices interrogated beforehysician contact, and the resulting reports can be printedn full-sized paper and placed on the front of the chart.hese reports focus on the heart failure–related data stored

Heart and Lung Center, Heart Failure Treatment Program, Universityf Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.

Address for reprints: Robin Germany, MD, Heart and Lung Center,eart Failure Treatment Program, University of Oklahoma Health Sciencesenter, 920 Stanton L. Young Boulevard, WP-3120, Oklahoma City, OK3104.

tE-mail address: robin-germany@ouhsc.edu.

002-9149/07/$ – see front matter © 2007 Elsevier Inc. All rights reserved.oi:10.1016/j.amjcard.2007.02.037

n the device and should not replace ongoing device mon-toring by the implanting physician.

With the availability of an interrogation device that doesot have programming capabilities, such as the CardioSighteader (Medtronic, Inc., Minneapolis, MN), medical assis-

ants can retrieve data from all compatible devices. Theedical assistants can then record this information in the

atient’s chart, just as they would vital signs and medica-ions. If the device is not compatible, a device nurse musttill interrogate the device before the physician visit. Afterhis interrogation procedure becomes routine, it adds veryittle time to the patient visit, yet it provides a tremendousmount of insight. These visits do not replace routine EPisits, but the device nurse does not have to see all patientso obtain heart failure data.

ypes of Data Obtained

any different types of information can be garnered fromevice reports (Figure 1). These data allow patient care to beailored for the purposes of both symptom management andafety, including titration of medications and institution ofnticoagulation therapy. In addition to the usual clinicalnformation, data patterns may emerge on these reports. Inome cases, evidence of medication noncompliance may beresent, and in cases where proarrhythmic drugs are beingsed, this should be carefully assessed.

Cardiac rhythm: Most implantable devices provide thebility to monitor episodes of nonsustained ventricularachycardia. Daytime and nighttime heart rates are tracked.or devices with atrial and ventricular leads, hours spent intrial fibrillation and ventricular rate during atrial fibrillationre recorded. When tracked over time, all of these param-ters allow a more comprehensive approach to medication

itration. Other findings, such as previously unsuspected

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aroxysmal atrial fibrillation, may be present in theseeports.

Heart rate variability: Heart rate variability, defined ashe standard deviation of 5-minute median atrial–atrial in-ervals, can be calculated and recorded over time. Heart rateariability has been shown to be predictive of sudden car-iac death in patients with heart failure. A study that ana-

igure 1. Insight into patient status. The Heart Failure Management Repdditional trends to assess patient status (B). In addition to OptiVol data, thatient’s daily atrial fibrillation (AF) burden, ventricular (V) rate during atrR variability, and percent pacing. ICD � implantable cardioverter defib

yzed heart rate variability in 16-minute electrocardio- h

raphic recordings was able to stratify patients into a high-isk category using low HRV and frequent PVCs. The-year sudden cardiac death rate was 23% when thoseredictors were present, versus 3% in patients without eitherredictor.1

Heart rate variability in a population with heart failureas also been shown to be lower in patients with death or

ludes OptiVol (Medtronic, Inc., Minneapolis, MN) fluid trends (A) andt provides up to 14 months of temporally aligned trend information on theyarrhythmia (AT)/AF, patient activity, day and nighttime heart rate (HR),VF � ventricular fibrillation; VT � ventricular tachyarrhythmia.

ort ince reporial tach

ospitalization, and the decrease in heart rate variability was

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13GGermany and Murray/Device Diagnostics in Outpatient Management of Heart Failure

een up to 3 weeks before the event.3 Cardiac resynchroni-ation therapy has been shown to improve heart rate vari-bility, possibly by shifting autonomic control away fromympathetic dominance.2 We have used these data in ourlinic to help determine the frequency of follow-up.

Percentage of atrial/ventricular pacing: The percent-ge of atrial and ventricular pacing is important in theanagement of patients with heart failure. Multiple recent

rials have found worsened left ventricular ejection fractionnd other clinical outcomes with continuous right ventric-

Figure

lar pacing. The Second Multicenter Automatic Defibrilla- r

or Implantation Trial II (MADIT-II) showed a trend ofore frequent hospitalization in the implantable cardio-

erter defibrillator (ICD) group (19.9 vs 14.9, p � 0.09), butt was unclear if this effect was because of longer life spans,hock-related admissions, or right ventricular pacing.4 Theual Chamber and VVI Implantable Defibrillator (DAVID)

rial enrolled 506 patients with ICD indications but with noacemaker indications. Devices were implanted and ran-omized to ventricular backup pacing only at a rate of 40eats per minute (VVI-40) or dual-chamber pacing rate-

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esponsive pacing with a low rate of 70 beats per minute

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DDDR-70) with forced right ventricular pacing. Patients inhe VVI-40 group had fewer primary end point eventsdeath or heart failure hospitalizations) when compared withhe DDR-70 group (hazard ratio [HR], 1.61; p �0.03). Inarticular, those patients with right ventricular pacing40% had worse event-free rates (p � 0.09).5 Study of theode Selection Trial in Sinus Node Dysfunction (MOST)

opulation evaluated complications of heart failure associ-ted with right ventricular pacing. Pacing �40% in DDDRode was associated with an increased risk of heart failure–

elated hospitalizations (HR, 2.99). Furthermore, there waslinear relation between percent cumulative right ventric-

lar pacing and the development of atrial fibrillation.6

ewer devices with managed ventricular pacing algorithmsay be beneficial in avoiding these adverse outcomes.

Patient activity: Patient activity can be plotted as activeours during the day. Studies have documented that patientctivity decreases as a patient approaches hospitalization188 min/day down to 164 min/day, p � 0.028).3 Patientctivity level is also useful in patient education. We oftenhow the patient activity report to our patients to discusshanges in their physical activity and to encourage in-reased activity.

Intrathoracic impedance: Newer and more heart fail-re–specific device-based markers have been and are beingeveloped. For example, intrathoracic impedance can beollowed in some newer devices via a derived fluid index,he OptiVol fluid index (Medtronic, Inc.). Impedance isnversely proportional to pulmonary capillary wedge pres-ures. Pilot studies on this concept documented changesefore heart failure exacerbation requiring hospitalization.7

ngoing studies will determine the prospective validity ofhis concept.

Other measurements and devices: A new implantableemodynamic monitoring system, Chronicle (Medtronic,nc.), which provides continuous intracardiac hemodynamicata about the patient, is currently awaiting regulatory ap-roval. The data have been shown to be reproducible, botht rest and with activity, over time.8 This device is specif-cally designed to provide information on the managementf heart failure and will provide additional information onhe clinical status of the patient when not in the office. Thisemodynamic monitor is only the first in a number of heartailure management devices currently being developed.

Some implantable devices have been paired to externalevices, such as a weight scale and blood pressure cuffhat can be accessed over the Internet. An example is theatitude patient management system (Boston Scientific,t. Paul, MN). These data along with arrhythmia and heartate variability data can be transmitted and monitored overhe Internet with physician notification via e-mail in thevent of significant changes. These data can also be printedrom the Internet database and placed on the patient’s chart

efore a clinic visit. i

hich Patients Should Be Monitored?

or physicians taking care of patients with heart failure, these of device data is not limited to a diagnostic “spot check”f thresholds and impedance data. These data can alsorovide insight into what is happening with patients whenhey are not in the office. Ideally, reports should be collectedt every patient encounter. Otherwise, the clinical utility ofhe information is significantly reduced. Many conditionsonitored by devices are relatively asymptomatic. A patientho developed atrial fibrillation in the last 24 hours may notevelop symptoms of heart failure for a few weeks. Evenignificant episodes of nonsustained ventricular tachycardiaay not be perceptible to the patient. Thus, in our practice,e follow up all patients with compatible devices at the

ime of their clinic visit and at least bimonthly. Lesstable patients or those with recurrent decompensationan be monitored more closely, with checks as frequentlys once or twice per week.

emote Monitoring Using the Internet

he ability to manage device data via Internet sites is a newnd growing field with great promise. Most of the implant-ble cardiac device companies currently offer the ability toiew information over the Internet. However, only certainevices from each company are supported by Internet mon-toring systems. Patients can download device data the nightefore a clinic visit, so the information can be accesseduickly, immediately before the visit. Another useful prac-ice is to monitor the patient between office visits. If theownload shows a problem, the patient can be contacted,nd clinical treatment can be instituted. In some instances,reatment can occur without the patient having to leave theomfort of his or her home. We have found that this capa-ility sometimes allows us to identify the need for a labo-atory test or other test before the patient’s visit with us.emote transmission has also allowed us to monitor patientsho live a great distance from the clinic.Internet access of data also provides many other potential

pportunities for the prevention of heart failure hospitaliza-ion. Our clinic has asked patients who have devices witholume monitoring capability to download device data onceweek to proactively identify clinical problems. Althoughe are awaiting the results of several upcoming trials, it isoped that these data may allow less frequent clinic visits orore information between clinic visits. Additionally, pa-

ients have responded very favorably. They feel they areeing “watched over.” The frequency of downloads mayepend on both the clinic and the severity of the disease. Aatient with New York Heart Association (NYHA) func-ional class II heart failure who has never been hospitalizeday not benefit from frequent examinations of intrathoracic

mpedance, whereas we may request that an NYHA class IV

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15GGermany and Murray/Device Diagnostics in Outpatient Management of Heart Failure

atient transmit information several times a week to facili-ate care.

ollow-Up Evaluation

mong the best uses of technology allowing remote trans-ission of device data is to decrease the need for such

requent follow-up. Often, patients with heart failure arelderly, cannot drive, or live a significant distance from theanaging clinic. For stable patients, the use of the technol-

gy allows the number of follow-up visits to be decreased.ther patients can then be filtered into the clinic. Follow-up

requency may be determined by specific results found inhe device data. Data points, such as heart rate variability,ave been proposed to help determine the frequency athich patients should be seen.9

Protocols using the data can be extremely helpful asell. We have devised protocols for the use of impedanceonitoring data during a clinic visit (Figure 2) and afterscheduled download from the patient’s home (Figure

igure 2. Use of devices in the office. BNP � B-type natriuretic peptide;xam � examination; HF � heart failure; labs � laboratory tests.

). These protocols provide standardization and utiliza- d

ion for physician extenders as well as those less com-ortable using the information. However, further studiesre needed to determine the utility of such information toitrate drugs remotely and to reduce healthcare utiliza-ion.

eimbursement

lthough the time it takes to access these data is decreas-ng, this extra time may adversely affect a busy clinic.hallenges remain in determining the types of reimburse-ent available for this tailored medical care. A potential

trategy may be to include time and/or complexity of theisit. By looking at rhythm disturbances and volume data,he visit becomes more complex and time consuming. Ifhe data are accessed remotely as part of the routine EPvaluation of the device, this would appropriately bencluded in the normal interrogation charge.

Currently, the physician managing the day-to-day care isot reimbursed for the complex issues associated with HF

Figure 3. Use of device information in the outpatient setting.

isease management. Medicare has recently approved reim-

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ursement for remote integration of the device, includingnalysis of the device functioning and thresholds. Specificilling codes, such as those now used for device interroga-ions by EP practices, are still needed for the isolated anal-sis of heart failure device data.

To add to the complexity of reimbursement in the out-atient setting, workflow patterns have to be established. Aseen in the protocol, patients with abnormal volume infor-ation are contacted. If the physician calls the patient di-

ectly, this is coded as a telephone contact. However, a moreractical approach is to have a nurse or physician extenderontact the patient, although this is not reimbursed.

onclusion

echnology has developed incredible ways to help us treatatients. Increasing numbers of patients with heart failureave implantable cardiac devices that can provide us withignificant insights into their management and care. Byapping into this information, we can more effectively treatur patients. However, without creation of easy and simpleays to access and use these data, opportunities to better

erve our patients may be lost. More complex and fascinat-ng devices are on the horizon. Determining ways to incor-orate this into daily clinical practice now will help ease theransition when these devices become standard of careithin the next few years.

. La Rovere MT, Pinna GD, Maestri R, Mortara A, Capomolla S, Febo O,Ferrari R, Franchini M, Gnemmi M, Opasich C, et al. Short-term heartrate variability strongly predicts sudden cardiac death in chronic heart

failure patients. Circulation 2003;107:565–570.

. Adamson PB, Kleckner K, VanHout WL, Srinivasan S, Abraham WT.Cardiac resynchronization therapy improves heart rate variability inpatients with symptomatic heart failure. Circulation 2003;108:266–269.

. Adamson PB, Smith AL, Abraham WT, Kleckner KJ, Stadler RW, ShihA, Rhodes MM, on behalf of the InSync III Model 8042 and AttainOTW Lead Model 4193 Clinical Trial Investigators. Continuous auto-nomic assessment in patients with symptomatic heart failure: prognosticvalue of heart rate variability measured by an implanted cardiac resyn-chronization device. Circulation 2004;110:2389–2394.

. Moss AJ, Zareba W, Hall WJ, Klein H, Wilber DJ, Cannom DS,Daubert JP, Higgins SL, Brown MW, Andrews ML, for the MulticenterAutomatic Defibrillator Implantation Trial II Investigators. Prophylacticimplantation of a defibrillator in patients with myocardial infarction andreduced ejection fraction. N Engl J Med 2002;346:877–883.

. Wilkoff BL, Cook JR, Epstein AE, Greene HL, Hallstrom AP, Hsia H,Kutalek SP, Sharma A, for the Dual Chamber and VVI ImplantableDefibrillator Trial Investigators. Dual-chamber pacing or ventricularbackup pacing in patients with an implantable defibrillator: the DualChamber and VVI Implantable Defibrillator (DAVID) trial. JAMA2002;288:3115–3123.

. Sweeney MO, Hellkamp AS, Ellenbogen KA, Greenspon AJ, FreedmanRA, Lee KL, Lamas GA, for the Mode Selection Trial (MOST) Inves-tigators. Adverse effect of ventricular pacing on heart failure and atrialfibrillation among patients with normal baseline QRS duration in aclinical trial of pacemaker therapy for sinus node dysfunction. Circu-lation 2003;107:2932–2937.

. Yu CM, Wang L, Chau E, Chan RH, Kong SL, Tang MO, ChristensenJ, Stadler RW, Lau CP. Intrathoracic impedance monitoring in patientswith heart failure: correlation with fluid status and feasibility of earlywarning preceding hospitalization. Circulation 2005;112:841–848.

. Magalski A, Adamson P, Gadler F, Böehm M, Steinhaus D, ReynoldsD, Vlach K, Linde C, Cremers B, Sparks B, Bennett T. Continuousambulatory right heart measurements with an implantable hemody-namic monitor. J Card Fail 2002;8:63–70.

. Adamson PB. Continuous heart rate variability from an implanteddevice: a practical guide for clinical use. Congest Heart Fail 2005;11:

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