Hormones Causing Arrythmia?

[dcmom]

I have been having PAC's since 12/01.  They began while I was taking Allegra-D, but did not stop when the medication was stopped after only about 8 pills.  I have seen my PCP and a Cardiologist who did blood tests for anemia,electrolytes and thyroid - all were normal.  A 24 hr. Holter monitor and an echocardiogram documented the PAC's at 1100+ per 24 hrs, plus a few PVC's, but showed no other abnormality.  I do not smoke or drink alcohol, and have cut out caffeine with no effect.  I also have some chest discomfort akin to muscle soreness that the drs. do not feel is heart related (it is not affected by exertion/rest).  Absent any other cause, the drs. attribute the PAC's to hormonal changes of pre-menopause.  My OB/GYN put me on birth control pills (Mircette) to regulate hormone levels, also with no effect so far.  Can hormones really cause PAC's?  How about lack of sleep?  I fall asleep fine, but have been unable to stay asleep through the night for several years, and this is the only other cause I can think of.  I am an otherwise healthy 40 year old woman with no family history of heart problems of any kind.  What else can I do to determine the cause and fix my PAC's?  Thank you for your help.

[CCF-M.D.-CRC]

Dear dcmom,
Premature atrial contractions (PACs) are early atrial beats that originate from cells (foci) in atrium other than the pacemaker cells.  Recently it has been demonstrated that these foci are generally around the pulmonary veins.  They may be increased by pseudoephedrine which is in Allegra-D but that effect should stop after the drug wears off.  It is unknown if menopause increases PACs but it may be possible.  Stress (perhaps from lack of sleep) and caffeine do tend to increase PACs and PVCs.

The good news is that PACs are in general benign.  For some people however they are very troublesome and treatment is required.  The first line therapy is of course avoidance of triggers such as caffeine and lack of sleep.  If there are still significant problems then medications such as beta-blockers can be tried.  If these fail antiarrhythmic drugs such as flecanide may be effective.  Finally if drugs fail then an ablation procedure may be considered.  This is an outpatient procedure done by an cardiologist who specializes in heart rhythms (an electrophysiologist) and is effective in stopping PACs in the majority of cases.