Improper TimingIt appears at first glance that the larger wave is the diastolic, but it is deceiving. A line drawn through the R wave will only intersect some part of the preceding diastolic wave. It cannot touch any part of a systolic wave due to the electromechanical delay involved with measuring the finger plethysmogram. Even the Peak and Area measurements from the device are inaccurate due to the timing being so far off.

Troubleshooting ECG TriggeringAnytime the R wave amplitude drops by 25% or more, sensing of that beat may be dropped. If this is occurring frequently, try an alternate lead placement and use new electrodes.

Troubleshooting ECG trigger issuesLead placement not displaying a prominent enough QRS complex. This leads to intermittent signal disruption. Trying other lead placements and increase signal amplitude.

Troubleshooting ECG triggering problems: Device is double counting heart rate from two trigger signals per beat. This put the sensed heart rate level past the 125 beats per minute upper threshold and does not allow counterpulsation to begin. Change lead placement for less

prominent T wave or in some cases P wave.

Troubleshooting ECG triggering

Device paused, intrinsic rhythm, HR 76Shortly after starting EECP, HR climbs to 113 as PM rate response activated

Troubleshooting ECG triggering: effects of a rate responsive pacemaker increases HR and makes it more challenging to identify the systolic versus diastolic waves. Notice the late

deflation. Using the 1:2 trigger allows for easier identification of the systolic and diastolic waves

1:1 Trigger 1:2 Trigger

Trouble Shooting ECG triggeringCompetitive pacing or intrinsic breakthrough beats will interfere with consistent R wave triggering. It is best if a patient is 100% paced or 100% intrinsic beats. Otherwise there will be frequent stops and starts to counterpulsation. Sometime pacemaker device setting need to be adjusted to allow for a lower demand pacing threshold or to setting the pacing rate slightly higher to overcome occasion intrinsic beats.

Troubleshooting ECG triggering

Wide negative deflection QRS triggers from one point later on QRS

Other times it triggers earlier on the QRS

Troubleshooting ECG triggering issuesSolve this issue with switching the ECG polarity, swap black and white lead placement to demonstrate upward QRS complex. This makes triggering easier for device.

Troubleshooting ECG triggeringA negative deflection or biphasic QRS complex can cause intermittent counterpulsation triggering irregularities as the device triggers from one point of the QRS one beat and another point on another beat This leads to slightly irregular cuff inflation durations despite having a regular heart beat even. Choose a lead placement with a prominent upright R wave to help relieve this.

Troubleshooting ECG triggeringCompetitive pacing versus intrinsic beats causing interruption in counterpulsation.

Troubleshooting ECGAnother example of HR double counting. This time also triggering from the T wave. HR registers as 172, beyond the upper limits of HR parameters. No counterpulsation can begin.

Try different lead placement that provide positive QRS complex. Use 12 lead ECG to help determine which leads might be helpful.

Atrial FibrillationDevice triggering is based on analysis of several previous R-R intervals, so inflation duration can be estimated for future beats. Atrial fibrillation confounds this and leads to long periods of no cuff inflation on long beats. Inflation timing can still be adjusted with accuracy while the deflation marker will fluctuate significantly. The treatment will generally be better tolerated in patients with good rate control while in atrial fibrillation.