Presentation_ChronotropicIncompetence

Chronotropic Incompetence & Adaptive Rate Pacing : 

Chronotropic Incompetence & Adaptive Rate Pacing Frank W Meissner, MD FACP, FACC, FCCP, FASNC, CPHIMS, CCDS February 18, 1009

Slide 2: 

Greatest Equations of All Time 1+1=2 C=2pr a2=b2+C2 a/b=c/d eip+1=0 F=mad S=0 PV=nRT I=V/R 1+1=2 C=2pr a2=b2+C2 a/b=c/d eip+1=0 F=mad S=0 PV=nRT I=V/R i?·d?=m? E=h? ?=H0d S = k(logW) C=Blog2(1+S/N) E=mc2

Greatest Equations of All Time : 

Greatest Equations of All Time 1+1=2 C=2pr a2=b2+C2 a/b=c/d eip+1=0 F=mad S=0 PV=nRT I=V/R i?·d?=m? E=h? ?=H0d S = k(logW) C=Blog2(1+S/N) E=mc2 CO=SV·HR

Slide 4: 

4

Chronotropic Incompetence: A Mathematical Definition : 

Chronotropic Incompetence: A Mathematical Definition CO=SV·HR

Chronotropic Incompetence : 

6 Chronotropic Incompetence Clinical Definition of Chronotropic Incompetence: The inability of the heart to regulate its rate appropriately in response to physiologic stress1 Generally recognized types of Chronotropic Incompetence (CI) 2 : Failure to achieve Max Heart Rate (MHR) A delay in achieving MHR Inadequate sub-maximal and recovering heart rate Rate instability during exercise 1. Chronotropic incompetence as defined by H. Weston Moses, in “A Practical Guide to Cardiac Pacing.” 2. Lukl, J. et al. “Incidence and Significance of Chronotropic Incompetence in Patients Indicated for Primary Pacemaker Implantation of Pacemaker Replacement.” PACE September 1999, Vol 22 (p.1284-1291)

Why is Chronotropic Incompetence a Problem? : 

7 Why is Chronotropic Incompetence a Problem? Generally recognized symptoms of chronotropic incompetence:3 Failure to achieve maximum heart rate (MHR) A delay in achieving MHR Inadequate sub-maximal and recovering heart rate Rate instability during exercise Chronotropic incompetence is a Class I indication4 2 Chronotropic incompetence as defined by H. Weston Moses, in A Practical Guide to Cardiac Pacing. 3 Lukl J, Doupal V, Sovava E, et al. Incidence and significance of chronotropic incompetence in patients indicated for primary pacemaker implantation or pacemaker replacement. PACE. 1999;22:1284-1291. 4 ACC/AHA/NASPE 2002 Guideline Update for Implantation of Pacemakers and Antiarrhythmia Devices. See http://www.acc.org/clinical/guidelines/pacemaker/pacemaker.pdf for full ACC/AHA/NASPE 2002 guidelines.

Clinical Clues Suggesting CI : 

8 Clinical Clues Suggesting CI What complaints do you hear from Chronotropically Incompetent patients who aren’t properly treated? “I’m just getting older” “I frequently feel fatigued” “I can’t do the things I used to do” “I have to cut my yard on two different days” “When I’m active I feel lightheaded” You may hear these complaints from: Patients with pacemakers who do not have optimized therapy Patients without pacemakers

Slide 9: 

9 5 Lukl J, Doupal V, Sovava E, et al. Incidence and significance of chronotropic incompetence in patients with indications for primary pacemaker implantation or pacemaker replacement. PACE. 1999;22:1284-1291. What is the prevalence of chronotropic incompetence (CI) in the pacemaker population? Chronotropic Incompetence Prevalence

CI is a Progressive Disease : 

10 It is important to monitor all of your patients, even your chronotropically competent patients CI is progressive and worsens over a short period of time Sub analysis6 Pacemaker less than 2 yrs: 53% Pacemaker more than 4 yrs: 70% n=38 6 Gwinn N, Leman R, et al. Chronotropic incompetence: A common and progressive finding in pacemaker patients. Am Heart J. 1992;123:1216-1219. CI is a Progressive Disease

The Ability to Generate Elevated Heart Rates Benefits All Age Groups : 

11 The Ability to Generate Elevated Heart Rates Benefits All Age Groups How many times a day does the average person under age 65 raise his or her heart rate above 90 beats per minute? 7 Mianulli M, Birchfield D, Yakimow K, et al. Do elderly pacemaker patients need rate adaptation – implications of daily heart rate behavior in normal adults. PACE.1996;19(pt II):681(abstract). All patients benefit from the ability to raise their heart rates! 178 times per day7 151 times per day7 How many times a day does the average person over age 65 raise his or her heart rate above 90 beats per minute?

What should their heart rate be? : 

12 What should their heart rate be? Chronotropic Assessment Exercise Protocol (CAEP)

Wilkoff Mathematical Model of the Cardiac Chronotropic Response to Exercise : 

Wilkoff Mathematical Model of the Cardiac Chronotropic Response to Exercise Normal predicted heart rate for an individual at a submaximal stage of exercise: Wilkoff et al. J Electrophysiol 3:176-180, 1989

Slide 14: 

Exercise Heart Rate Response and Mortality Lauer et al. JAMA 1999;281:524-529

CI & Cardiac Death : 

CI & Cardiac Death Lauer et al., JAMA.1999:281:524-529

Physiologic Responses and Rate-Adaptation : 

Physiologic Responses and Rate-Adaptation

Physiologic Responses and Rate-Adaptation : 

Physiologic Responses and Rate-Adaptation

Characteristics of an Ideal Sensor for Rate-Responsive Pacing : 

Characteristics of an Ideal Sensor for Rate-Responsive Pacing

Characteristics of an Ideal Sensor for Rate-Responsive Pacing : 

Characteristics of an Ideal Sensor for Rate-Responsive Pacing Reliable Consistent Durable Efficient Easily implanted Physiologically appropriate

Activity Sensors : 

Activity Sensors Piezoelectric crystals bonded to the inside of the pulse generator housing – sense vibration, causing a minute change in the shape of the crystals’ structure and a voltage proportional to the force is generated Accelerometer – monitors body motion in the anteroposterior direction which converts the change in velocity or direction of motion to electrical signals

Activity Sensors : 

Activity Sensors

Accelerometer : 

22 Accelerometer Signal Processing Accelerometers sense the electrical signal generated from body motion to deliver a proportional pacing response

Accelerometer : 

23 Accelerometer MSR LRL Pacing rate (ppm) End activity RECOVERY RESPONSE Start activity THRESHOLD REACTION Summary

Activity Sensors : 

Activity Sensors Disadvantages: PE crystals are sensitive to pressure (lying face-down or turning on box spring mattress can lead to inappropriate increase in heart rate) PE crystal-based devices fail to increase HR appropriately as treadmill incline or grade is increased while the speed of walking is constant (Accelerometer does better) PE crystal–based devices show a more dramatic increase in HR when walking down stairs than climbing stairs (accelerometer is better in this situation) Both sensors are more responsive to lower body than upper body exercises PE crystal devices in unipolar mode can lead to sensor-mediated pacemaker tachycardia if generator flipped in pocket (pocket stimulation) Both sensors fail to respond appropriately to emotional stress, swimming, isometric exercises, stationary bicycle riding

Minute Ventilation : 

25 Minute Ventilation Should this man’s heart rate be the same for both levels of activity? Minute Ventilation Sensor

Review of Minute Ventilation : 

26 Tidal Volume Respiration Period Review of Minute Ventilation Minute ventilation is the product of respiratory rate (breaths/minute) and tidal volume VE = true minute ventilation MV = minute ventilation using impedance measurement

Minute Ventilation Sensor : 

Minute Ventilation Sensor An excitation signal is sent between the can and ventricular ring electrode (the largest electrodes) The waveform is designed to minimize interaction with monitoring equipment by: Having an amplitude 1/3 the size of that used by competitive MV devices (320 µA vs. 1000 µA) Providing a balanced waveform (less polarization artifact) 320 uA 50mS 80 uS

Minute Ventilation : 

28 Minute Ventilation Transthoracic Impedance Measurements Ohm’s Law R=V/I Indifferent Electrode Minute Ventilation

Slide 29: 

29 .60 1.0 .92 Minute Ventilation Blended Sensor Restores Chronotropic Competence10 10 Chronotropic competence is defined by: Wilkoff BL, Corey J, Blackburn G. A mathematical model of cardiac chronotropic response to exercise. J Electrophysio. 1989;3(3):176–180. Refer to Physician’s System Guide for more information on adaptive-rate therapy. Additional clinical performance was assessed using INSIGNIA Ultra clinical data with the AutoLifestyle feature programmed On. Data on file. 11 Wilkoff BL, Corey J, Blackburn G. A mathematical model of cardiac chronotropic response to exercise. J Electrophysio. 1989;3(3):176–180. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Accelerometer Sensors only do 60% of the job of restoring competence.

Slide 30: 

30 There is a BIG difference in how sensors work Example: Patient Playing Golf

Let’s look at a simple example : 

31 Let’s look at a simple example An accelerometer and an MV pacemaker that are pacing at 60 ppm will deliver the same baseline cardiac output.

Slide 32: 

32 An accelerometer and an MV pacemaker that are pacing at 60 ppm will deliver the same baseline cardiac output. Upon exercise, the two pacers will produce two different heart rates (90 and 106 ppm). Both pacers will produce incremental CO for the patient. Let’s look at a simple example

Small difference in HR means a big difference in CO : 

33 Small difference in HR means a big difference in CO An accelerometer and an MV pacemaker that are pacing at 60 ppm will deliver the same baseline cardiac output. Upon exercise, the two pacers will produce two different heart rates (90 and 106 ppm). Both pacers will produce incremental CO for the patient. In this example, at a pacemaker rate of 106 ppm there will be an incremental CO that is 53% higher than the incremental CO produced by the pacemaker going at 90 ppm. This is a simple outcome of: CO = HR x SV 53%

Is 53% more Oxygen a big deal? : 

34 Is 53% more Oxygen a big deal? Denver Houston

Pacemaker Indications – Class I : 

35 Pacemaker Indications – Class I Sinus node dysfunction with documented symptomatic bradycardia, including frequent sinus pauses that include symptoms Symptomatic chronotropic incompetence Symptomatic sinus bradycardia that results from required drug therapy for medical conditions.

Slide 36: 

36

Slide 37: 

37

Questions : 

Questions