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- 1. Use of Cardiac Pacing for HF and AF Don W. Wallick, PhD
- 3. Coupled Pacing –Rate Control 1 st Pacing Paradigm
- 4. Concept of Coupled Pacing during AF Electrically Activating the Ventricles after a Specific Delay Atrium Ventricle AV Node Created by Yamada used in Yanulis et al. Ann. Thor. Surg. 86: 984-8, 2008 Atrium Ventricle AV Node
- 6. Animal Preparation for Acute AF Conductance/ pressure catheter to produce PV loops Ao Pressure catheter RA electrode- used to induce AF RV electrode Sense RV activation then apply CP LA Pressure catheter Epicardial Echocardiography
- 7. Representative P-V loops during Acute AF AF + CP 0 20 40 60 80 100 120 140 160 0 10 20 30 40 AF 0 20 40 60 80 100 120 140 160 0 10 20 30 40 LV volume (ml) LV volume (ml) LV pressure (ml) Modified from Yamada et al. Am. J. Physiol. 285: H2630-8, 2003
- 10. Effect of Altering the time delay for CP application
- 11. Representative Responses Modified from Yamada et al. Heart Rhythm 3: 722-7, 2006
- 12. Summary Concerning Possible Arrhythmias Coupled pacing is still effective in rate reduction and pump function even after longer time delays (220ms) compared to the shorter delays (180ms). An established embolization model (diffuse infarction) was used to test whether the therapy can be safely applied in post-infarcted state. Coupled pacing may be safer than previously believed.
- 15. Paired Pacing vs Coupled Pacing P P P P P P P’ P P’ P P’ P P’ P P’ Paired Stimulation S S S S S S S S S Coupled Pacing P P’ P P’ Art Press Art Press P’ P’ P’ P’
- 17. Acute Cardiac Energetics Study
- 18. Animal preparation Aortic pressure catheter LA pressure catheter LV pressure catheter Aortic flow probe Coronary flow probe Coronary Sinus RA electrode RV electrode
- 19. Acute Study Protocol α - chloralose anesthesia Stage 1: Baseline Sinus Rhythm Stage 2: Atrial Fibrillation Stage 3: Acute Heart Failure Stage 4: Acute Heart Failure/ Atrial Fibrillation SR AF HF HF/AF Rapid Atrial Pacing +3-5% Isoflurane CP Modified from Yamada et al. Am. J. Physiol. 287: H2016-22, 2004
- 20. Effects of CP External Cardiac Work Myocardial Oxygen Consumption (ml/min) (J/min) 12 0 5 10 15 20 25 30 0 2 4 6 8 10 NS NS NS NS p<0.001 p<0.01 NS p<0.001 SR AF HF HF/AF SR AF HF HF/AF Coupled Pacing Modified from Yamada et al. Am. J. Physiol. 287: H2016-22, 2004 Off On Off On Off On Off On Off On Off On Off On Off On
- 21. Myocardial Efficiency (%) 0 5 10 15 20 25 30 SR AF HF HF/AF Coupled Pacing Effects of CP Modified from Yamada et al. Am. J. Physiol. 287: H2016-22, 2004 NS p<0.01 p<0.01 p<0.05 Off On Off On Off On Off On
- 25. Experimental Setup Modified from Yanulis et al .Ann. Thor. Surg. 86: 984-8, 2008
- 27. Effects of Chronic AF and Coupled Pacing on Cardiac Volumes (Echocardiographic measurements) Modified from Yanulis et al. Ann. Thor. Surg. 86: 984-8, 2008
- 28. Modified from Yanulis et al. Ann. Thor. Surg. 86: 984-8, 2008
- 30. CRT + CP Pacing 2 nd Pacing Paradigm
- 35. Animal preparation RA electrode RV electrode Epicardial Echocardiography LV electrode Vagal electrode
- 36. Right atrium Right ventricle VS Left ventricle VS RR 127 ±17 cpm 70 ±13 ms Baseline N=6 Sinus Rhythm Step 1 VRMC QRS duration Experimental protocol Atrial Fibrillation Step 2 Step 3 Step 4 Step 5 116±17 cpm 65 ±11 ms CRT+ CP N=6 103 ±14 cpm 76 ±10 ms CRT-VS N=3 232 ±15 cpm 61 ±9 ms CRT N=6 219 ±39 cpm 110 ±23 ms RV pacing N=6 213±32 cpm 63 ±19 ms Atrial pacing N=6 CP CRT
Notas del editor
- This schema shows the concept of bigeminal pacing. 1
- 8 healthy dogs were studied. After anesthetizing an animal, mid strontomy was done, and the heart was cradled. Millar catheters were inserted to LV and LA, Electrodes were sutured on RA appendage and RV apex. Transesophageal echocardiography were used to obtain the transmitral flow velocities.
- These are the representative pressure-volume loops during AF. Bigeminal pacing decreases the variability in pulse pressure and strake volume.
- In conclusion, the reduction of ventricular mechanical contraction rate can be achieved using Bigeminal pacing method. LV contractility and stroke work improved with bigeminal pacing during both AT and AF at least on a short-term basis. Bigeminal pacing may be a feasible clinical strategy to control heart rate in patients with AT and AF.
- We studied 7 anesthetized open chest dogs. Epicardial electrodes were sutures to the right atrium and ventricle. A conductance/pressure catheter was placed in left ventricle to obtain left ventricular pressure and volume. A Miller catheter was inserted from a pulmonary vein and the tip was placed in left atrium. Bigeminal pacing was applied by a Bloom stimulator. We used the stimulator to sense the ventricular activation and apply a pace beat to the right ventricular apex. While monitoring the left ventricular pressure, we progressively decreased the coupling delay form 250 ms until we obtained the maximal slowing of the ventricular activation with minimal contraction of the ventricle.
- The experiments consisted of 4 stages, sinus rhythm, AF, HF and HF/AF. AF was induced and maintained by rapid RA pacing. HF was created by by excessive isoflurane inhalation. Each stages lasted at least 10 minutes and was into 2 periods; before and during the coupled pacing.
- This slide shows effect of coupled pacing on external cardiac work and oxygen consumption. Couple pacing increased External cardiac work in all stages expect sinus rhythm. Myocardial oxygen consumption tended to be increased by coupled pacing in all stage, however this trend was not significant.
- Because coupled pacing increased external cardiac work to much greater degree than myocardial oxygen consumption, this pacing increased myocardial efficiency in all stages except sinus rhythm.
- In conclusions, Coupled pacing increased myocardial efficiency during either acute heart failure or AF as well as concurrent AF and heart failure in our canine model This therapy may be a novel, viable strategy for ventricular rate control and improving cardiac function during chronic AF, especially in patients with concurrent heart failure.
- 8 healthy dogs were studied. After anesthetizing an animal, mid strontomy was done, and the heart was cradled. Millar catheters were inserted to LV and LA, Electrodes were sutured on RA appendage and RV apex. Transesophageal echocardiography were used to obtain the transmitral flow velocities.