AV Node Ablation

Some questions to ask

by Gemita - 2024-04-07 05:24:02

MegZ, firstly, I know shortness of breath is difficult to deal with but try to stay as calm as you can to help to relieve your symptoms.  It must be frustrating to be having symptoms after a potentially curative procedure for Atrial Fibrillation and to be pushed from one consultant to another after presumably being told that no cause for your symptoms can be found?  I am assuming you have had investigations to try to get to the bottom of this and that you do not have any significant lung disease, like COPD that might be getting worse, since I see you have sleep apnea?  I see you are living at a fairly high altitude.  Do you experience these symptoms at lower levels too??  

In the absence of a lung or heart cause, some possible causes come to mind following an AV Node ablation.   As background, I considered an AV node ablation years ago too, but eventually decided not to go ahead because once I got my pacemaker, my AF symptoms and episodes seemed much improved.  I learnt the following however from my consultant:

1. Although rare, Phrenic nerve injury, normally a benign complication, could occur during a catheter ablation procedure. The phrenic nerve is more sensitive to damage from heat than the myocardium because it tends to have insulator properties that retain heat. The average effect of nerve paralysis due to AV Node ablation is usually transitory with most patients having a complete resolution of symptoms between 6 and 28 months post-ablation.  I would respectfully ask whether the pulmonologist or cardiologist could consider checking whether your Phrenic nerve could have been damaged during the AV Node procedure?  I was told by my consultant that damage to heart nerves and veins could occur in some patients causing breathlessness and that these could be difficult to treat in the short term.

2. Ask your cardiologist whether your ablation has been completely effective?  Although 100% effective most of the time, like all ablation procedures, an AV Node ablation can sometimes “rarely” fail.  If the procedure is letting through any fast rhythms from AF, you will feel breathless again, although I note you feel better overall.  A touch up procedure would be as fast as the original procedure if needed.

3. What is your base rate set at, maybe ask if it could be set a little higher to help?  After an AV Node ablation they usually set it slightly higher anyway to compensate for the loss of atrial kick following the severing of the AV node and also to help prevent a dangerous ventricular arrhythmia from occurring following this procedure.  Atrial kick occurs as the atria contract prior to ventricular contraction.  Atrial kick contributes up to 35% to the volume of blood in the ventricle. This extra volume in turn increases cardiac output by a similar amount.  Although we can live without the atrial kick following an AV Node ablation (which prevents atrial signals reaching the ventricles), loss of atrial kick can adversely affect our ability to exercise and cause some breathlessness. 

4. Finally and importantly, if you are now pacing 100% in the Right Ventricle, there is the risk of developing pacing induced cardiomyopathy from dyssynchrony of the ventricles, leading to heart failure symptoms which could include breathlessness.  I would respectfully go back to your doctors and ask all these questions for your own peace of mind and safety.  If you are developing difficult symptoms from right ventricular pacing (and I was told by my consultant this could happen), your doctors may want to consider an upgrade of your pacemaker to a cardiac resynchronization therapy (CRT) device.   They would normally request an echocardiogram first to look for signs of a significant drop in your ejection fraction.  Has this by chance already been done?

Good luck and please try to stay calm.  I am sure there is an explanation 

AVNode Ablation

by MegZ - 2024-04-11 00:06:40

Thank you, Gemita, A very thoughtful and helpful reply.   I'll read it several times to make sure I understand what I need to ask my cardiologist at our next meeting.    I really appreciate your comments.

MegZ