Atrial Fibrillation at medium /high ventricular response
Short Summary

72-year-old male with diagnosis of chronic or permanent atrial fibrillation. In 1995 he suffered a TIA and in 2005 he underwent two unsuccessful attempts of atrial fibrillation ablation. The main treatment strategy for his atrial fibrillation has consisted of rate control and oral anticoagulation. Despite several attempts of different medications (digoxin, beta-blockers) he has remained in atrial fibrillation with a relatively moderate to fast ventricular response.

Patient's Questions
1)         What do you think is the best treatment to suggest between beta-blocker and digoxigenin? Alternative pharmacological options to these two ones? Are there indications for a further attempt of transcatheter ablation?
2)         In the light of the Holter test results in 2002, 2004 and 2008 do you notice a worsening in the arrhythmia? If so, is it correct to use a stronger antiarrhythmic drug?
3)         Do you think that the physical activity of the patient is consistent with his pathology taking into consideration that from a basic heart rate of 100 bpm it goes up, in a short time, to 150 bpm under stress? The patient can understand he has reached his effort limit from the dyspnea appearance or from the following breathless sensation?  
Medical Background

72 years old, male.
Diagnosis: Atrial Fibrillation at medium/high ventricular response
Medical history: 
-           In 1995 TIA (Transitory Ischemic Attack) which the MRI showed to be an ischemic lesion in the left parietal-temporal-occipital area.
-           Since 1992 AF (Atrial Fibrillation) for which in 2005 two ablations in Left Atrium (LA) were performed both being ineffective; at the Holter test in 2002 pauses longer than 2 seconds in the night-time (max 2,96 sec. at 2,50), in 2004 Holter without pauses. These examinations are being attached with the latest Holter test performed in November, 2008.
Case history:
During medical tests performed in October, 2007 the diagnosis of chronic AF (Atrial Fibrillation) with a slight biatrial dilation was confirmed; partial control of ventricular rate (often at around 100 bpm at rest, 150-160 under stress) with digoxigenin at low dosage (digoxinemia 0,5-0,6 with Lanoxil 0,250 mg/daily), patient always in a good hemodynamic compensation; patient on OAT (Oral anticoagulant therapy) with usual INR around 3; no evidence of ischemia in myocardial scintigraphy under stress in 2002.
At the end of these medical tests the two following pharmacological therapeutic options were suggested:
-           to continue taking digoxigenin, increasing its dosage: Lanoxin 0,250 1 tablet + Lanoxin 0,125 1 tablet, monitoring the digoxinemia at regular intervals;
-           to pass to a beta-blocker, for example Atenolol, starting with 100 mg ½ tablet in the morning, adding, if necessary ¼ tablet in the evening, proceeding, afterwards, with 100 mg in the morning, if the drug will be tolerated after about ten days.
The patient chose the second option replacing the therapy with digoxigenin with the beta-blocker and, at present, the home therapy consists of:
-           Lopresor 100 mg ½ tablet twice daily (at first atenolol that, however, was not well tolerated by the patient);
-           Sintrom according to INR.
Since the patient has started taking the beta-blocker, he has noticed a vertigo sensation with a slight progressive reduction of his physical performances.
At present, anyway, the patient practises a moderate physical activity playing tennis three times a week besides working out.
At present, the heart rate at rest is generally around 90-100 bpm, while after playing a tennis match it increases to 160-170 bpm.
To define the present clinical condition the results of recent medical reports of the latest performed cardiac medical tests are reported, the pictures of which you will find in the enclosure:
Holter test performed on 11/2008:
-       Total Arrhythmia due to Atrial Fibrillation throughout the all the RV media recording (91 bpm, min 49 bpm, max 150 bpm)
-       Present 1 pause longer than 2 seconds (2.22 sec at 09:57 a.m.)
-       Occasional isolated VEB (82), 1 couple
-       Stable the alterations of the ST-Segment

Color doppler echocardiography on 11/2008:
“Examination performed on patient in AF at medium/high ventricular response.
-       Regular left ventricular cavity dimensions (Telediastolic diameter=49mm; Telesistolic diameter=27 mm; Telediastolic volume=80ml) with slightly increased (=12mm) intraventricular septum end systolic thickness; no considerable alterations of the systolic thickening on the segments of the ventricular profile; uncompromised global systolic function (EF>60%).
-       Right ventricular cavity with normal dimensions and kinesis.
-       Minimal mitral valvular regurgitation.
-       Slight biatrial dilation (antero-posterior left atrial diameter = 46 mm).
-       Within normal limits the dimensions of the aortic root (=36 mm) and of the proximal segment of the ascending aorta”.
In the end it is reported that the patient has decided, by himself, to double since 1 week the therapy with Lopresor (passing from ½ tablet twice daily to 1 tablet twice daily) without any influence on the heart rate that remained unchanged.

Expert's Opinion

It is not clear from the information available how limited the patient is by the atrial fibrillation even though he seems to be able to continue his normal life playing tennis 3 times a week.
Sometimes it is quite difficult to control the ventricular rate in patients with atrial fibrillation. There is no exact rate that we should aim for but generally we would like to see a resting heart rate in the 60 to 90 bpm and increasing slowly to 120 to 140 bpm with exercise.
There are 3 main types of medications used for "rate response" and they are: digoxin, beta-blockers and calcium channel blockers used as a single agent or in combination. In extreme cases (non-responders) we can consider the use of amiodarone or AV nodal ablation (which involves the use of a pacemaker).
The patient's case seems to be a relatively mild case from the medical point of view. There is no evidence of significant structural heart disease and his symptoms seem to be mild. He is taking sintrom which in my opinion is the most important medication and will avoid any future risk of thrombo-embolism. Regarding the ventricular rate so far the echocardiogram has not shown any evidence of tachycardia related cardiomyopathy, therefore it seems that the ventricular rate has had no significant influence on his medical condition. So we are left mainly with improving his symptoms which are significantly related to the ventricular rate even though atrial fibrillation itself may cause symptoms unrelated to the ventricular response. Usually one drug alone is not sufficient to control the heart rate (especially during exercise) and in this particular case if Lopressor alone will not do the job we can consider combining it with digoxin. Another possibility is the combination of verapamil and digoxin. In my opinion there is no indication for a third ablation and I believe that there has been no worsening of the arrhythmia considering the Holters and the clinical evolution.
Hopefully with a better rate control his functional class and symptomatology will improve without the need for other more complicated treatments.