22. Atrioventricular Optimization by Transthoracic Echocardiography in a Patient with Interatrial Delay

Published on 02/03/2015 by admin

Filed under Cardiovascular

Last modified 22/04/2025

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History

The patient had a history of acute myocardial infarction with triple vessel disease and underwent coronary artery bypass surgery.

Comments

This patient had congestive heart failure with an ischemic cause.

Current Medications

The patient was taking aspirin 80 mg daily, candesartan 8 mg daily, furosemide 40 mg daily, metoprolol 50 mg twice daily, and simvastatin 20 mg daily.

Comments

This patient was on optimal medical therapy.

Current Symptoms

The patient exhibited mild shortness of breath on exertion.

Comments

This patient was in New York Health Association class II.

Physical Examination

Laboratory Data

Electrocardiogram

Findings

Bifid P wave was shown on the electrocardiogram (Figure 22-1) and nearly disappeared after AV optimization (Figure 22-2)

Comments

The electrocardiogram showed an enlarged atrium and interatrial delay before atrioventricular optimization and improvement after atrioventricular optimization.

Echocardiogram

Findings

When atrioventricular delay was set up as 30 ms, a truncated mitral valve A wave, with QA of 50 ms, was seen. (Figure 22-3)
image

FIGURE 22-1 

image

FIGURE 22-2 

Comments

The atrioventricular delay was too short.

Findings

When atrioventricular delay was set up as 270 ms, mitral inflow E and A waves were merged, with QA of −20 ms. (Figure 22-4)

Comments

The atrioventricular delay was too long.

Findings

In this patient, the optomized atrioventricular delay was 200 ms with the Ritter Method. (Figure 22-5)

Comments

Atrioventricular delay in this patient was longer than in most other patients.
image

FIGURE 22-3 

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FIGURE 22-4 

Findings

The mitral regurgitation method showed that when atrioventricular delay is set to a very long value, there is a time interval between the end of the mitral inflow A wave and onset of the systolic component of mitral regurgitation (δt). The optimized AV delay is AVlong − δt. (Figure 22-6)

Comments

With this method, we can use a single beat to perform atrioventricular optimization. However, it can be used only in patients with significant mitral regurgitation.

Focused Clinical Questions and Discussion Points

Question

Why should we optimize atrioventricular delay even in patients with successful implantation of CRT?
image

FIGURE 22-5 

image

FIGURE 22-6 

Discussion

Although out-of-box setting is possible for atrioventricular delay, in the real world the optimal atrioventricular delay differs widely and optimization should be performed individually. Optimization of the atrioventricular interval will ensure atrioventricular synchrony, maintaining the coordination between atria and ventricles. If the delay is too short, the mitral inflow A wave will be truncated. On the other hand, when delay is programmed too long, even with biventricular capture, diastolic mitral regurgitation may be present. Therefore atrioventricular optimization after CRT will decrease presystolic time, eliminate presystolic mitral regurgitation, improve left ventricular filling, and increase cardiac output.2,6

Question

What methods are usually used for atrioventricular optimization with transthoracic echocardiography?

Discussion

Several methods are used to optimize atrioventricular delay in CRT, usually based on the pulse wave mitral inflow acquired with transthoracic echocardiography.

Ritter Method

With the Ritter Method, the atrioventricular interval should be programmed short first and QA short is measured in the interval between the ventricular contraction spike and the end of the A wave.4 Then the atrioventricular interval is programmed long and the QA long is determined. Optimized AV delay = AVshort + ([AVlong + QAlong] − [AVshort + QAshort]).

Mitral Regurgitation Method

Atrioventricular delay is programmed longest with biventricular capture, and the interval between the end of the A wave and onset of the systolic component of mitral regurgitation can be obtained subsequently (δ t).5 Optimized AV delay = AVlong – δt.

The Iterative Method

Atrioventricular delay is programmed slightly shorter than the intrinsic atrioventricular interval.1 Then atrioventricular delay is gradually shortened by 20 ms every time until the mitral A wave is truncated. The next step is to prolong 10 ms until the truncated A wave disappears and the optimal AV delay is determined.

Question

What is the effect of interatrial delay on atrioventricular interval?

Discussion

When the patient has significant intraatrial conduction delay before implantation, the optimal atrioventricular delay will be longer than those without to allow adequate time for the electrical signal to travel to the left atrium. To ensure optimization of CRT, the atrial lead should be implanted in the atrial septum.
In this case, we showed that in a patient with interatrial delay, as detected with ECG, the optimized atrioventricular delay was approximately 200 ms, as assessed by Ritter Method, which was longer than the 100 to 130 ms in most patients. Published data also have demonstrated that patients with interatrial conduction delays benefit most by prolonging the delays during atrioventricular optimization.3

Final Diagnosis

The final diagnosis in this patient is CRT implantation with interatrial delay.

Plan of Action

The plan for this patient was to prolonged atrioventricular delay during the optimization.

Intervention

The atrioventricular delay was programmed to be longer.

Selected References

1. Cleland J.G., Daubert J.C., Erdmann E. et al. The CARE-HF study (CArdiac REsynchronisation in Heart Failure study): rationale, design and end-points. Eur J Heart Fail.. 2001;3:481–489.

2. Heydari B., Jerosch-Herold M., Kwong R.Y. et al. Imaging for planning of cardiac resynchronization therapy. JACC Cardiovasc Imaging. 2012;5:93–110.

3. Gorcsan 3rd. J., Abraham T., Agler D.A. et al. Echocardiography for cardiac resynchronization therapy: recommendations for performance and reporting. Report from the American Society of Echocardiography Dyssynchrony Writing Group endorsed by the Heart Rhythm Society. J Am Soc Echocardiogr. 2008;21:191–213.

4. Ritter P., Dib J.C., Lelievre T. et al. Quick determination of the optimal AV delay at rest in patients paced in DDD mode for complete AV block. (abstract). Eur J CPE. 1994;4:A163.

5. Meluzín J., Spinarová L., Bakala J. et al. Pulsed Doppler tissue imaging of the velocity of tricuspid annular systolic motion: a new, rapid, and non-invasive method of evaluating right ventricular systolic function. Eur Heart J. 2001;22:340–348.

6. Zhang Q., Fung J.W., Chan Y.S. et al. The role of repeating optimization of atrioventricular interval during interim and long-term follow-up after cardiac resynchronization therapy. Int J Cardiol. 2008;124:211–217.

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