Blocked Pac

[mdxchick]

Hello,
I thought I would try to post here also since I posted and paid on the doctors form and still have not recieved a post back. I know these doctors are very busy and they do this out of the kindness of their heart but it's sometimes hard to sit and wait when you are anxious.
I am a 35 year old female with a history of mild aortic vlave disease, mitral valve insufficiency, papiations and I am currently being treated for hypokalemia (3.1). I do also suffer anxiety. I recently wore a event monitor for episodes of a racing heart. A week prior to wearing the monitor I was taken to the hospital for a heart rate of 160 and what the EMT said was SVT. I was giving a shot of adenosine which only brought my  heart rate back down to 123. At the emergency department doctor looked over the ecg he said I was not in SVT and it was just sinus tachycardia. The doctor believed it was do to dehydration. I went to my cardiologists for the monitor and wore it for 2 weeks the findings where sinus tachycardia, and a pause of 2.8sec. while awake. The doctor called this a blocked pac and said it didn't reach the ventricles ,said it was normal and if I would start to pass out or it would reach a 5 sec pause I would need a pacemaker. Getting a possible pacemaker doesn't sound normal. He made it sound as if it was not a big deal. My question is this something I should worry about? I have young children and don't want to be in a car and pass out and hurt them or someone else. He did refer me to a cardiologist that specializes in heart rhythms but I will not see him for 3 months. I always seem to have tons of questions when I leave but I am going crazy having to wait that long and I can't seem to find any information on this, the olny thing I found is that it is called a nonconducted pac and that it usually happens during sleep. Is  a 2.8 sec pause not a big deal?
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[mdxchick]

Thank you so much for your answer. It has really but my mind at rest. I have been doing well with my heart rate being in the normal range and not racing. I have started to make sure I am drinking 8 glasses of water a day and I think this has helped greatly. I did go and see a ep and he would like to do a mapping if the heart. I plan on having it done in the next month or so.

[CCFHeart MD23]

Dear mdxchick,

I can understand why you’re concerned about your symptoms and potential risks for your and your children. Fortunately you have age on your side which means that you’re in a better position to tolerate changes in heart beat, whether that be due to sinus tachycardia or another forms of arrhythmia such as supraventricular tachycardia (SVT).

Perhaps let’s start by understanding your risk of a dangerous event such as collapse, syncope, or a cardiac arrest. Firstly your age puts you in a lower risk category. You have also experience a rapid heart rate without loss of consciousness, again lowering your risk of collapse in future. If your valve disease is rated as mild and you have normal ventricular function - that again puts you in a lower risk category. If the rhythm they detected in the emergency department was indeed a sinus tachycardia that again puts you in a low risk category. Do you have a family history of cardiac arrest? If the answer is no, give yourself another tick in the low risk category. I recommend that you also have a plan for future palpitations so that you can activate it and be confident in your ability to manage the situation. Your plan should include stopping any work that includes mechanical equipment (including driving by pulling over to the side of the road), informing someone nearby, lying down in a safe place with your knees bent, and taking 5 deep breaths to see if your symptoms pass. If your symptoms persist or are associated with feeling unwell (including dizziness, shortness of breath, chest pain, or nausea), call an ambulance.

Pauses are common on Holter monitors, particularly in the presence of electrolyte disturbances such as hypokalemia (for which you are being treated). My first question here is why do you have hypokalemia? This can be caused by vomiting, diarrhea, laxatives, diuretics (fluid pills), kidney disease, and a hormonal imbalance called primary aldosteronism. Are you taking any medications that lower the heart rate? If so these should be stopped following discussion with your doctor. Before considering any intervention for arrhythmia or palpitations, the underlying issue (i.e. hypokalemia and whatever is causing it) needs to be treated first. Patients with mitral valve insufficiency (particularly ‘mitral valve prolapse’) do have an increased chance of having supraventricular arrhythmia.

Moving on to your question about the pacemaker….Sometimes we doctors find it challenging getting the balance right when it comes to providing information to our patients. Sometimes we explain too little. At other times we explain too much. In this case I think your doctor may have been outlining a range of possibilities but unfortunately scared you with the mention of pacemakers. You are right – this is not required in the majority of young patients we see with palpitations. The American Heart Association Guidelines list a range of indications for permanent pacemaker insertion, including a period of asystole lasting more than 3.0 seconds. Does your 2.8 second pause warrant pacemaker insertion? Once again, this should only be considered in patients without an underlying reversible cause such as hypokalemia or pauses occurring in the presence of SVT. A repeat Holter following correction of your hypokalemia will be important.

I hope this information helps. Remember your warning symptoms, feel confident activating your palpitation plan, and remember to write a list of top 5 questions for when you see your heart specialist.