Heart Rhythm Parameters

The difference in ectopic beats per day was statistically significant when comparing mixed to vagal afibbers on a bad day and on an average day. No other differences between the various afib types or between male and female afibbers were statistically significant. However, there was clearly a significant difference between a good day and a bad day for all afibbers.

Forty-seven afibbers (3 adrenergic, 17 mixed and 27 vagal) had Holter monitor recordings which showed the distribution between PACs and PVCs during a 24-hour period.

PACs are clearly the predominant form of ectopics, particularly for vagal afibbers. There was no indication that the type of ectopic beat experienced was associated with the number of ectopics on a bad or average day.

One hundred and twenty-one afibbers (14 adrenergic, 43 mixed and 64 vagal) had observed the nature of their ectopic beats, i.e. whether they were single or came in runs of 2, 3 or more.

Ectopic beats in runs were the predominant form for all afibbers and the most frequent number of beats in a run was 2-3 (experienced by 30 afibbers) followed by 3-4 or more (experienced by 9 afibbers). Seventy-one afibbers (67% of adrenergic, 79% of mixed and 67% of vagal) associated a run of ectopic beats with the initiation of an episode while 28 afibbers had observed no such association.

One hundred and eleven afibbers (10 adrenergic, 37 mixed and 64 vagal) had observed the frequency of their ectopic beats prior to an episode. Most (53%) had not observed any change, but 42% had noted an increase and 5% had noted a decrease.

Ninety-one afibbers responded to the question as to whether they had observed any change in frequency in ectopic beats with changes in position, stress, rest, etc.

*time of day

A change in position was associated with an increase in ectopic beats by 25% of all afibbers (29% among vagal afibbers). An increase in ectopic beats was also significantly associated with time of day (20% of all afibbers) and exposure to stress (19% of all afibbers), but 23% of all afibbers reported that their ectopics were evenly spread throughout the day and not influenced by anything they were aware of.

The finding that almost 80% of all afibbers have noticed a connection between increased ectopy and an event involving a change in autonomic nervous system balance clearly underscores the important role of the ANS in the etiology of afib.

There was a significant association between episode frequency and the number of ectopic beats experienced in an average day (r=0.23, p=0.03). The association was particularly strong (r=0.4815, p=0.02) in afibbers who had been diagnosed on a Holter monitor as having predominantly PACs (premature atrial complexes). An association between PVC-type ectopic beats and episode frequency was not observed, possibly due to the small number of afibbers diagnosed with PVCs as the predominant ectopy (N=7) or because PVCs do not affect episode frequency. The finding that a higher number of PACs on an average day correlates with more frequent episodes is certainly not surprising, as PACs are believed to initiate the episodes. However, it does point out the importance of avoiding PAC-generating activities as much as possible.

Atrial Flutter

The prevalence of atrial flutter was 25% among adrenergic afibbers, 28% among mixed, 18% among vagal, and 29% among permanent. The observed differences in prevalence were not statistically significant.

There were no differences in average age (55 years) or gender distribution (20% women) among afibbers with flutter and those without, nor were there any differences in afib episode frequency or duration. There was no difference in drug use between afibbers with flutter and those without; however, afibbers with flutter were significantly more likely to have hypoglycemia (idiopathic postprandial syndrome) then were those without flutter (39% versus 17%). It is tempting to speculate that an over-enthusiastic insulin response might play a role in atrial flutter and that those suffering from this condition could improve their situation by eating frequently, emphasizing low glycemic index foods, and ensuring protein in every meal and snack.

Only two afibbers, both vagal, had undergone the maze procedure and in both cases the procedure was a success. One adrenergic and one vagal afibber had had an ICD (implantable cardioverter defibrillator) installed and both were successful in eliminating episodes. None of the respondents had undergone AV node ablation and subsequent implantation of a pacemaker. Considering that 166 afibbers responded to this part of the survey it would appear that the maze procedure, ICD implantation, and AV node ablation are not widely used in the treatment of lone atrial fibrillation.

The majority of the 59 respondents (83%) had the paroxysmal form of LAF, 10% had the permanent form, and the remaining 7% (all vagal) had persistent afib prior to their ablation. Among the paroxysmal afibbers 3 (6%) were adrenergic, 28 (57%) were mixed, and 18 (37%) were vagal. These percentages are somewhat different from the overall make-up of our current database of 341 afibbers (14% adrenergic, 37% mixed, and 49% vagal). This may reflect the fact that mixed LAF generally responds poorly to pharmacological treatment.

The average age of the respondents was 54 years with a range of 33 to 76 years. The average age at diagnosis was 46 years with a range of 23 to 75 years. Thus the average number of years that LAF had been present was 8 years with a range of 1 to 30 years. These numbers are not significantly different from the averages obtained by considering all the entries in our main database, so there is no reason to believe that the respondents to the ablation survey were either younger or older than the general population of afibbers.

Twenty-seven per cent of respondents were female, again not significantly different from the proportion in our total database.

The most common procedure was pulmonary vein ablation (PVA) performed on 37 afibbers (63%) followed by focal point ablation on 16 (27%), and a combination of both performed on the remaining 6 (10%). The overall success rate for the PVA procedure was 62%, for the focal point ablation 25%, and for the combined procedure 83%. It should be pointed out that the success rate was dependent on how recently the procedure had been performed. For the 38 procedures performed in 2002 or 2003 the overall success rate was 66% and the success rate for PVA, focal point and combined was 68%, 40%, and 100% (only 2 procedures) respectively. The overall success rate of 66% and the 68% success rate for PVA procedures performed during 2002-2003 found in our survey is well within the range reported in the literature of 47% to 80%[1]. These success rates include 20-40% of patients still taking antiarrhythmic drugs and 10-30% requiring a second procedure[1]. In our survey 10 out of 59 respondents (17%) had undergone more than one ablation procedure. The repeat procedure rate was particularly high (25%) in the unsuccessful group. One afibber in the successful group later developed left atrial flutter.

There was a highly significant correlation between success rate and the year in which the procedure was performed (r=0.43, p=0.0008) with success steadily improving since 1999 to the present. This improvement is no doubt due to a combination of improved technology and equipment and greater surgeon skills.

Eighteen or 75% of 24 respondents who knew their ablation site had undergone PV ablation in the area of the atrium adjoining the pulmonary veins (ostial ablation) while the remaining 6 (25%) had their ablation inside the veins. The success rates for the ostial ablation were 67% as compared to 33% for the vein ablation.

Sixteen ablated afibbers submitted information regarding the catheter size used in their procedure. An 8 mm catheter was used in 8 cases, a 4 mm in 7 cases, and a 5 mm in 1 case. The success rate with the 8 mm catheter was 75%. (NOTE: All but one of these procedures were performed at the Cleveland Clinic). The success rate with the 4 mm catheter was 57%, but neither rate should be considered definitive due to the small sample size (8 and 7 respondents respectively).

Even successful ablations were not always instantly successful. The average time span from ablation to full return to continuous sinus rhythm was about 7 weeks with a range of 1 day to 3 months. Afibbers who had been successfully ablated were significantly less likely to be on antiarrhythmics or blockers than were non-successful ones (12% versus 85%) and their use of antiarrhythmics was often short-term - just post ablation. The majority (56%) of afibbers in the unsuccessful group were on warfarin (Coumadin) as compared to 23% in the successful group. Most of the warfarin users in the successful group had undergone their ablation very recently so the warfarin use is likely to be a temporary measure only.

Only 3 of the 8 afibbers (38%) who had an ablation inside the pulmonary veins had been checked for stenosis and none was found. Thirty-eight per cent of those undergoing ostial ablation had also been checked for stenosis and none had shown any sign of it. While stenosis should not be a factor in ostial ablation it could be in vein ablation. Of the 22 afibbers who did not specify the area ablated 9 or 41% had been checked for stenosis and 3 (33%) had shown signs of it.

Effect of Supplementation and Diet

It is conceivable that supplementation, especially with vitamin C or vitamin E could affect the healing process of the ablation scars and thus alter the outcome of an ablation. Fifty-one per cent of respondents supplemented with vitamin C (average daily intake of 1425 mg) and 53% with vitamin E (average daily intake of 475 IU) in the time period before and after the ablation.

Most (74%) of the 38 respondents who specified their diet consumed a standard American diet, while 14% ate a vegetarian or partly vegetarian diet.

Atrial fibrillation episodes release copious amounts of atrial natriuretic peptide (ANP) as a result of the rapid movement of the walls of the atria. ANP is a powerful diuretic and helps lower blood pressure by suppressing the release of aldosterone. It is conceivable that eliminating the periodic release of ANP through a successful ablation could affect blood pressure. Three afibbers reported a slightly lower pressure after the ablation while 2 reported a slight increase. However, 88% reported no change. Average blood pressure for afibbers in the successful group was 116/73 as compared to 117/72 for those in the unsuccessful group.

Sequel to Unsuccessful Ablation

A question uppermost in the minds of afibbers considering an ablation is, "Will I be worse off if the ablation fails?" Fifteen afibbers who had undergone an unsuccessful ablation reported on their episode severity after the ablation. Twelve (80%) felt that their episode severity was the same or less than before the procedure, two felt the situation had gotten worse, and one felt it had gotten much worse. The median number of episodes for 24 non-successes was 24 over a 6-month period and the median duration of these episodes was 8 hours. The number of episodes reported is substantially higher than that observed in the general afib population (median of 6 over a 6-month period), but may not represent a worsening for the specific afibbers who underwent an unsuccessful ablation. It should also be kept in mind that a group of "heavy hitter" paroxysmal afibbers experienced a median of 84 episodes over a 6-month period. Thus it is not clear whether one is better or worse off after an unsuccessful ablation, but the majority of afibbers actually experiencing a failed ablation did not feel they were worse off.

Rhythm Parameters

*on Holter monitor recording

The response rate regarding rhythm parameters was too low to draw meaningful conclusions. There was some indication that respondents who underwent both successful and unsuccessful ablations continued to experience ectopic beats after the procedure, but very few considered them a major nuisance. PACs (prior to ablation) were predominant in the successful group and atrial runs (during Holter monitoring) were common in both groups.

Perhaps the most interesting observation was that an increase in pulse rate following the ablation was quite common. Ten out of 19 respondents reported an increase in rate, eight reported no change, and one reported a decrease. The average (mean) increase was 12 bpm with a range of 7 to 29 bpm. Three respondents reported that their pulse rate reverted to normal after about a year, but another 4 had experienced no reversal after a year or longer. The remaining 3 were too close time-wise to their ablation to conclude whether their pulse rate would return to normal. I have been unable to find any studies that have investigated the possible long-term consequences of an increased heart rate subsequent to ablation therapy.

Successful Ablations

The 32 successful ablations were performed by 20 different electrophysiologists (EPs) at 15 different institutions.