Warfarin therapy guided by genotyping
HONG KONG, CHINA. The risks of bleeding complications and stroke are highest during the first 3 months of warfarin (Coumadin) therapy. It is also clear that the dosage necessary to achieve an INR of 2.0 to 3.0 varies considerably between patients. Studies have shown that patients who require relatively low daily doses have a considerably higher risk of major bleeding events than do people who need higher doses. Researcher at the Chinese University of Hong Kong now report that patients requiring lower doses are 6 times more likely to have a genetic abnormality (polymorphism) in the cytochrome P450 enzyme system involved in the metabolism of pharmaceutical drugs and herbs.
The researchers found that determining if patients had the abnormal gene prior to initiating warfarin therapy
could reduce the risk of major bleeding from about 8% to about 7% per year. Inasmuch as the cost of
genotyping (determining if variant genes are present) is about $100 US and the average cost of treating a major
bleeding event is $15,000 US, genotyping would appear to be a worthwhile investment, not only from the
patient's point of view, but also from the point of overall cost to the health care system. The researchers
emphasize, however, that patients with the variant gene may require closer INR monitoring.
ICD alleviates sleep apnea
KITAKYUSHU, JAPAN. Sleep apnea syndrome (SAS) has been associated with adverse effects on cardiovascular function, including hypertension, nocturnal angina, cardiac mechanical dysfunction, and bradyarrhythmias. Apnea is defined as the cessation of breathing during sleep for at least 10 seconds. Japanese medical doctors recently reported the case of a 75-year-old man whose SAS was markedly reduced by adjustment of his ICD (implanted cardioverter defibrillation). The patient had a history of chronic atrial fibrillation and 5 years earlier had had a single-chamber ICD implanted. He was admitted for evaluation and treatment of sleep disorder. At admission, the number of central type apnea incidents during an 11-hour sleep period was 104 and the number of obstructive type sleep apnea episodes was 62. The patient also experienced 280 episodes of reduced breathing (hypopnea). His total apnea-hypopnea index (combined number of apneas and hyponeas per hour of sleep) was 43.3. The doctors observed that the patient's mean heart rate during sleep was 55 beats/minute. The ICD was set to kick in if the heart rate dropped below 40 beats/minute.
Prior to the next night's sleep evaluation, the doctors adjusted the ICD so that it would maintain a minimum heart
rate of 70 bpm. This intervention caused a dramatic drop in both central type apnea events (from 192 to 136)
and in hypopnea events (from 280 to 121) resulting in a reduction in the apnea-hypopnea index from 43.3 to
24.6. The number of obstructive type apnea events was not affected by the intervention. The man was
subsequently treated with continuous nasal positive airway pressure and his daytime sleepiness resolved.
Editor's comment: Patients with ICDs and sleep apnea may benefit from having their ICD adjusted so as to initiate ventricular pacing if their heart rate falls below 70 bpm during the night.
Safety of antiarrhythmic drugs
CLEVELAND, OHIO. The AFFIRM trial involved 4060 AF patients with a mean age of 70 years. Seventy-one per cent had a history of hypertension, 38% had coronary artery disease, and 26% had impaired left ventricular function. Only 12% had lone AF. Half the patients were randomized to rate control plus anticoagulation, while the other half were randomized to rhythm control plus anticoagulation. After 5 years of follow-up, 21.3% of the patients in the rate control group had died as compared to 23.8% in the rhythm control group.
The researchers involved in the trial have now taken another look at the collected data for the 2033 patients assigned to the rhythm control group in order to determine if the use of antiarrhythmic drugs was an important factor in the occurrence of proarrhythmic events (sudden death due to arrhythmia, resuscitated cardiac arrest, sustained ventricular tachycardia, and torsade de pointes). Torsade de pointes is a variant of ventricular tachycardia involving an abnormally long QT interval (greater than 600 milliseconds). The QT interval is the period of ventricular contraction and relaxation.
A total of 96 arrhythmic events occurred over the 6-year follow-up period and 12 of these were classified as
torsade de pointes. The overall incidence of torsade de pointes was 0.6% at 5 years. The cumulative
incidence of all arrhythmic events at 6 years was 6% in women and 7% in men and two-thirds of these events
were fatal. Age above 65 years, congestive heart failure, and mitral regurgitation were associated with a
substantially increased risk. Dofetilide (Tikosyn) was associated with an 8.3% risk of torsade de pointes, while
the risk for sotalol and amiodarone was 0.5% and 0.4% respectively. The use of flecainide and propafenone
was not associated with an increased risk of torsade de pointes, but less than 23% of the group were using
these drugs. The researchers conclude that properly administered and monitored antiarrhythmic drugs are not a
major contributor to the overall mortality of patients with atrial fibrillation and underlying heart disease. However,
they do emphasize that drugs that prolong the QT interval (quinidine, procainamide, disopyramide, sotalol,
ibutilide, and dofetilide) should be used with caution, especially in patients with reduced left ventricular ejection
Editor's comment: Although the study only included 240 lone afibbers, the finding that flecainide and propafenone were not associated with an increased frequency of proarrhythmic events in this study is reassuring.
Pulmonary vein stenosis after RF ablation
CLEVELAND, OHIO. One of the more serious complications of pulmonary vein isolation by radiofrequency (RF) ablation is pulmonary vein stenosis. This involves the narrowing of one or more pulmonary veins due to scar tissue formation during the procedure. Severe stenosis (narrowing of a vein by more than 70%) can lead to serious respiratory symptoms and may necessitate the placement of a stent in the vein. The risk of pulmonary vein stenosis depends on the skill of the EP performing the ablation, the location (distal or ostial) of the ablation line, the temperature reached during ablation, and on the type of imaging system used to guide the ablation catheter.
Researchers at the Cleveland Clinic have compared stenosis rates for 5 different procedures.
Severe stenosis (narrowing of 70% or more in at least one vein) was detected in 15.5% of patients in group 1, 20% in group 2, 2.9% in group 3, 1.4% in group 4, and 0% in group 5. Moderate stenosis (50-69% narrowing) was observed in 4.4% of all patients, and mild stenosis (less than 50%) in 7.7% of all patients.
The researchers also found that it could take as much as 3 months after the procedure before stenosis showed
up in a spiral CT scan. About 8% of patients having a normal scan one month after the procedure showed some
stenosis 3 months after the procedure. None of the patients who had a normal scan at 3 months progressed to
stenosis at the 6- and 12-month scans. However, it is possible that even mild narrowing at the 3-month scan
can progress to severe stenosis, so it should not be ignored.
Editor's comment: The Cleveland researchers seem to have had a particularly bad experience with their initial evaluation of the CARTO system. Other laboratories, however, have reported excellent results with this system.
Pappone method explained
MILAN, ITALY. Dr. Carlo Pappone and his team at the San Raffaele University Hospital in Milan pioneered the circumferential radiofrequency (RF) pulmonary vein ablation technique in which the ablation lines are drawn so as to encircle the left pulmonary veins within one ring of scar tissue and the right veins within a separate ring � the two rings are connected with a line on the back wall of the left atrium.
The team at San Raffaele has been performing RF ablations since 1998 and has now treated about 4000 patients with paroxysmal or chronic atrial fibrillation. Dr. Pappone recently outlined the details of his procedure in an article published in the Journal of Cardiovascular Electrophysiology. Here are the highlights:
Pappone, C and Santinelli, V. The who, what, why, and how-to guide for circumferential pulmonary vein ablation. Journal of Cardiovascular Electrophysiology, Vol. 15, October 2004, pp. 1226-30
Editor's comment: I can highly recommend this article for anyone interested in the details of RF ablation. Professor Haissaguerre (Bordeaux) and Dr. Andrea Natale (Cleveland Clinic) are scheduled to present the details of their methods in upcoming issues of the Journal of Cardiovascular Electrophysiology.
Reversion of pulmonary vein stenosis
SYDNEY, AUSTRALIA. Pulmonary vein stenosis (narrowing of the pulmonary vein diameter) is a possible complication of pulmonary vein isolation. It is not clear whether the stenosis tends to worsen over time, regress on its own, or stay the same. Australian researchers now provide a preliminary answer to these questions, but, unfortunately, their sample size was quite small. The study involved 26 AF patients (22 lone afibbers) who underwent a second (touch-up) pulmonary vein isolation procedure an average of 129 days after the first procedure. Angiographic images before and after the procedures were obtained in order to compare the extent of stenosis.
Signs of stenosis were found in 14 of 87 targeted veins after the first procedure, but no new stenoses were
observed before the second procedure. During the average 129-day time interval between the first and second
procedures, the extent of stenosis remained the same in 8 veins, increased in 1 vein, improved in 2 veins, and
completely disappeared in 3 veins. New stenoses appeared in 6 of the 68 veins ablated in the second
procedure. None of the patients had symptoms that could be attributed to stenosis. The researchers conclude
that progression of stenosis is uncommon in the medium-term and that about one-third of all cases eventually
resolve themselves partially or completely.
ACE inhibitors and atrial fibrillation
MADRID, SPAIN. Numerous clinical trials have evaluated the effectiveness of angiotensin converting enzyme (ACE) inhibitors and angiotensin II type-1 receptor blockers (ARBs) in the treatment of cardiovascular disease. Some of these trials have provided tantalizing indications that ACE inhibitors and ARBs may also play a role in preventing atrial fibrillation. Researchers at the Alcala University recently scoured the medical literature for studies from which data could be extracted to prove or disprove this effect. They found 7 trials that fulfilled their selection criteria. These trials involved almost 25,000 patients with hypertension, heart failure, ischemic heart disease or diabetes. Four ACE inhibitors (enalapril, captopril, trandolapril and lisinopril) and two ARBs (irbesartan and valsartan) were evaluated for at least a 12-week period.
The researchers found that patients treated with ACE inhibitors or ARBs had about half the risk of being
classified as having atrial fibrillation by the end of the trial as did controls. The researchers point out that the
renin-angiotensin system is involved in many aspects of arrhythmias and cardiovascular disease. Angiotensin II
is known to contribute to atrial electrical remodeling and enalapril has been found to reduce remodeling and
atrial fibrosis. ACE inhibitors dampen the activity of the sympathetic branch of the autonomic nervous system
and enhance baroreflex sensitivity, thus enhancing vagal tone. Both ACE inhibitors and ARBs also have
potassium-sparing effects. The researchers conclude that ACE inhibitors and ARBs may be beneficial in the
prevention and recurrence of atrial fibrillation in cardiovascular disease patients. The beneficial effects are likely
to be more pronounced the more serious the disease and patients with just hypertension are likely to observe
the least benefit as far as atrial fibrillation prevention is concerned.
Editor's comment: These studies did not include any lone afibbers, so it is not possible to say whether ACE inhibitors or ARBs may benefit this category of afibbers. However, the fact that both classes of drugs increase vagal tone would make it unlikely that they would benefit vagal afibbers.
Evaluation of the CARTO system
LONDON, UNITED KINGDOM. Pulmonary vein isolation (PVI) involves creating lesions around the pulmonary veins, usually with an ablation catheter heated with radiofrequency energy. A catheter cooled with liquid nitrogen (cryotherapy) may also be used. Knowing exactly where in the atrium the catheter is located at any one time is a major challenge. Several approaches to dealing with this problem are commonly used.
Fluoroscopy is a technique for obtaining "live" x-ray images of a patient. An x-ray beam is transmitted periodically through the patient and strikes a fluorescent plate coupled to an image intensifier that, in turn, is coupled to a video camera which relays the picture to a video screen watched by the surgeon. It is clearly important to keep the fluoroscopy time as short as possible during the procedure so as to minimize radiation exposure to patient, surgeon and staff.
Electrical (activation) mapping makes use of a reference electrode (usually placed as a patch between the patient's shoulder blades) and a movable electrode. By measuring the impedance (resistance) between these two electrodes it is possible to obtain an image of the atrium based on electrical readings. The differences in impedance readings at various spots in the heart can be quite pronounced. Moving the catheter just inside a vein, for example, can produce a difference of 4 ohms in the reading as compared to when the catheter is just outside the vein (in the ostial area). This feature is clearly very useful when performing ostial ablation.
Electroanatomic mapping is a fairly new mapping and navigation system consisting of an external ultralow magnetic field emitter (location pad placed beneath the operating table), a miniature passive magnetic field sensor housed in the tip of a movable catheter, and a computer processing unit and video screen. The system, also known as the CARTO system, produces a 3-dimensional, real time image of the inside of the atrium without the use of fluoroscopy. Points obtained during activation mapping are overlaid on the CARTO map and used to guide the ablation probe.
Ultrasound imaging, also known as Intracardiac Echocardiography (ICE), is a new technique. It makes use of a rotating ultrasound probe housed in the tip of a special catheter. ICE is especially useful in determining just the correct amount of heat to be applied to a certain spot destined for ablation.
Researchers at St. Bartholomew's Hospital in London recently released the results of a study comparing the performance of conventional mapping (fluoroscopy + activation mapping) with that of electroanatomic (CARTO) mapping. The procedures were compared in a series of 102 patients undergoing ablation for atrial flutter, Wolff- Parkinson-White syndrome, focal atria tachycardia, ischemic ventricular tachycardia or right ventricular outflow tract tachycardia. Highlights of the results are:
The British researchers conclude that the use of the CARTO system markedly reduces radiation exposure
without sacrificing procedural success. They also predict that CARTO will prove even more superior in more
complicated procedures such as pulmonary vein ablation, especially once the learning period has been gone
Blessed Relief � At Least for Now!
After posting a personal update on my condition on the LAF Bulletin Board, Hans invited me to share my "success story". For those of you who are not aware of the online LAF forum (www.afibbers.com/forum/list.php?f=6), it is an incredible source of information and has been of great comfort to me personally. Through this portal of communication, I have come to know and respect many people who share my condition; we have both celebrated our victories together and commiserated our losses. Many of those veterans have experiences more fascinating and endearing than mine and I am humbled by their courage and strength. For me, the forums, and other resources at Hans' site, have been the BEST and most accurate sources of information available online and I strongly encourage everyone to take advantage of the many resources that are available there.
My journey has been long (although short compared to many of those suffering with this condition) and full of valleys and mountains. I could not have traversed it without my friends, family, caring local doctors and strong faith. If I can be an encouragement to anyone, then I am happy to write about my experience.
It has been well over eight months since I have had an atrial fibrillation attack. The ectopic beats have almost completely subsided and I feel more heart-healthy now than shortly before this journey began. As a matter of fact, the deep worry about a full-blown attack has finally gone away as well. I was diagnosed with lone atrial fibrillation on October 10th, 2002.
For those of you who don't know me, I am a college instructor/administrator, musician, and have been an active contributor to Hans' LAF forum for well over a year. I have personally visited or spoken with the foremost electrophysiologists in America to learn about my condition (you can find most of my discourse with them online at www.afibbers.org in the archived sections). After first deciding to have an ablation to correct my problem, I decided against the procedure, for various personal reasons, after a final consultation with Dr. Hugh Calkins at Johns Hopkins University. I am not contesting that there are those of you who have had fantastic results with these types of procedures, but after my studies, I decided that the PVA/PVI was not for me, at least not at that time.
Like many of you, my experience with atrial fibrillation, seemingly, came out of the blue. Fortunately for me when it happened, one of my friends, an Emergency Medical Technician (EMT), convinced me to go to the emergency room. At that time, I was studying to become an EMT as well. I don't know what would have been worse, not knowing what all the readings were on the machines in the ER, or knowingly staring in horror at the monitors watching my vitals jump around like a fast paced game of ping-pong. Either way, I surmise, it is not pleasant.
Everyone with this condition needs to know what they are dealing with. I have both a healthy respect for conventional medicine and "alternative" approaches. I firmly believe that true health wisdom can be obtained by marrying together both approaches and becoming a student interested in approaches that are best suited for your own health and particular situation. Modern medicine excels at diagnosing conditions and emergency medicine. I do not particularly like the modern medical approach to the treatment of all illnesses, but can respect their accomplishments with many of them. In a similar fashion, I believe that much good can be gleaned from nutritional and health-based approaches that have been proven to promote good health. Personally, I chose both venues and became a student of my condition, I wanted to know everything that would or could help me with my diagnosed condition of lone atrial fibrillation.
Finding out the mechanism behind your atrial fibrillation is of paramount importance. There are many things that are associated with atrial fibrillation that are very dangerous. Some of these aggravating conditions include an enlarged heart, problems with the heart valves, severe irregularities in blood pressure, problems with the endocrine system, coronary vasoconstrictions and plaque and even central nervous system problems. These problems are not to be trifled with. I strongly submit that being properly diagnosed by professional medical personnel is an absolute necessity and should not be glossed over. Finding out my diagnosis of paroxysmal lone atrial fibrillation was both a blessing and a cause for great consternation. The good news was that there was not a known cause for what I had; the bad news was that they didn't know what was causing it and could only confirm I had it. Now my educational journey as a student of atrial fibrillation began in earnest.
My fear started to subside as I began to know my enemy. Knowing the enemy started with research, research led me to consume volumes of information both by the medical establishment and accepted holistic-health alternatives. Eventually my research led me to the book Lone Atrial Fibrillation: Towards a Cure, by Hans Larsen and also to the www.afibbers.org forums.
I have as much respect for what is happening on the forums as I do for all that is happening in academic research about this subject. I can confirm that I have come to the same conclusion as other well-informed "afibbers" using the forum with regard to the information that is available there: the general consensus of those involved with this particular bulletin board is better than most of the general practitioners and even many electrophysiologists (particularly those not well informed about atrial fibrillation) who are consulting us about our own conditions! There are very few well-published electrophysiologists that I have come to respect. Some of the doctors I do admire are Pappone, Calkins, Tchou, Natale, Morady, Haissaguerre and, of course, the late Dr. Coumel. In addition, I respect Hans Larsen's research and publications as much as any of them.
I have found the LAF forums to be a strong light in the dark void of information (or mis-information). All of us have a story and we get to tell it there; it has been my best therapy. The opportunity to have discourse about our common foe is worth its weight in research papers about it!
What has worked for me, no doubt, will work for some of you. As many of you know who have had contact with others with our condition, each individual's condition is different and manifests itself in us all differently. For me, like many of you, I KNEW my atrial fibrillation was tied to my digestive system. Despite this I began with the normally prescribed route. After fighting with multiple types of prescription drugs (which I have determined were not good for me, some even detrimental!), trying to find the "secret" vitamin health formula, getting the right diet and health regimen, detoxifying my body, countless medical tests, pin-pointing triggers and changing my lifestyle, I have come up with this conclusion: My atrial fibrillation is linked to� INSERT TRUMPET FANFARE HERE� my digestive system!
What seemed so complex came down to this axiom: Controlling the stomach problems controls the atrial fibrillation. So this is my secret: fight GERD, fight indigestion, eat better foods, heal my stomach, reduce stress and stop taking excito-toxins and unnatural foods, especially sucralose (Splenda). Allow me to reiterate � especially sucralose.
Most nutritional consultants, dieticians or medical professionals "worth their salt" will tell you to stay away from aspartame, acesulfame-potassium, sucralose, trans-fats, and any other artificial thing and they would be right! But for me, sucralose put me into atrial fibrillation faster than any other single thing. Now as to why, I surmise it may be an allergy to the substituted chlorine molecules; they must irritate my stomach. Am I allergic to chlorine? � no, but my stomach must be! In addition, if I eat too much food at one time, have food too spicy, too cold, too acidic, too "whatever" my stomach becomes irritated. When my stomach is irritated, I get atrial fibrillation�a pretty simply syllogism.
The vagus nerve is intimately connected with your stomach and with your heart. It plays a major role in the parasympathetic functions and autonomic functions of the nervous system, which includes some of the electrical activity that controls the rhythmic processes of the heart. For me, when my stomach or upper digestive tract becomes irritated, whether "esophageally", "stomachally" or "whateverachlly", the electrical process that controls my heart rhythm is compromised and "sooner than later" I have atrial fibrillation. This is usually preceded by a number of "warning signs" that manifest themselves as ectopic beats, either pre-ventricular contractions (PVCs) or pre-atrial contractions (PACs).
I now control the entire process of lessening the stomach irritation by eating only bacterially enriched (acidophilus, bifidus, etc.) yogurt in the morning. In addition, I now take Acidaphex (a prescription proton pump inhibitor) in the morning. I try not to eat too big of a lunch and I don't eat too late. I try and avoid foods that I now know irritate my stomach. I would suggest making a list, to those researching their condition, of what is being consumed and whether or not a reaction is being produced. This would be similar to a food- allergy list.
In the beginning, after I really began to focus on my stomach being a major culprit, I would take bismuth (Pepto) if I felt an imminent atrial attack forming. Nine times out of ten this stopped it from occurring and further confirmed my suspicions about the origins of my attacks. That being said, bismuth subsalicylate has been found to be toxic in LARGE quantities and can cause delirium, psychosis, ataxia and myoclonus�but it sure worked! Paying attention to my stomach was the key to understanding how to avert triggering my condition. I rarely take the "Pepto" anymore, but would not hesitate to use it if I felt a batch of fibrillations heading my way. I have tried just about everything else, and this, again for me, was the most effective at preventing an imminent occurrence of atrial fibrillation.
Probably equally important for me was additional supplementation of magnesium, calcium and potassium in addition to the standard multivitamin regimen and increased water intake in my diet. Perhaps the additional potassium (potassium is regulated by the FDA and in large supplemental quantities has been known to be toxic as well) supplementation seemed more effective to me than the others. In my years of using these different supplements, all three minerals: potassium, magnesium and calcium seemed to have a positive effect on me and an alkalizing effect on my stomach. In addition, they all have electrolytic properties and are major players in controlling normal rhythms of the heart.
When choosing my supplements, I became acutely aware that not all brands of supplements are created equally. They may be of the same dosage but most of them use different chelating or binding agents that affect the body's ability to absorb them. The absorption properties of the supplement increase the amount of minerals available to your body (bioavailability). Once I determined apicolinate was better than acitrate and that everything is better absorbed than an oxide, the minerals/supplements began to have a better effect on me because I was choosing better supplements.
Once my stomach had a chance to recover from whatever it was that took the toll on it, the feelings of "riding on the edge" or even being close to the edge of an atrial fibrillation episode all but vanished. Honestly, I still will feel an ectopic beat from time to time but the majority of the major sensations are gone. Nonetheless, I remain ever vigilant and continue to watch my condition and evaluate my methods. I hope and pray for the best and continue to prepare for the worst. Fortunately for those of us who have been diagnosed with lone atrial fibrillation, compared to other major illnesses, the "worst" isn't all that bad.
|# in group|
|Total by group, %|
|Present age (mean)|
|Age at diagnosis (mean)|
|Age at ablation (mean)|
|Age at ablation (range)|
|Years of afib (mean)|
|Females in group, %|
|Underlying heart disease, %|
|Mitral valve prolapse, %|
|Success among women, %|
|Success among men, %|
None of the observed differences in Table 1 were statistically significant, although the difference between the success rate for paroxysmal vagal afibbers (69%) and that for mixed afibbers (40%) did come close to being so (p = 0.066).
The overall success rate of 51%, or 65% including afibbers still on drugs, is somewhat disappointing, but as we shall see further on, the success rate is highly dependent on when and where the procedure was performed.
There were 5 afibbers who had their ablation at age 70 years or older. Four (subjectively) considered their procedure a complete success, while one considered it a failure. Looking at the success rate using objective criteria shows that 2 afibbers were totally successful, 2 were partially successful, and 1 was a failure. Thus, based on this very small sample, ablations in elderly afibbers are not significantly less successful than those in younger ones.
There was a general trend for ablatees to judge the results of their ablation more favourably than would be the case if objective criteria were used. This indicates that any kind of improvement following an ablation is considered a blessing.
|# of episodes(1)|
|Episode duration, hrs(2)|
|Afib burden, hrs(3)|
(1) median number of episodes in 3 months prior to ablation
(2) median duration of episodes in hours
(3) number of episodes x duration of episodes
The differences observed in Table 2 were not statistically significant, thus providing no indication that the severity of paroxysmal afib prior to ablation has any effect on the outcome.
Year of Ablation
Technological advances in mapping technology and ablation protocols, as well as skills progression along a fairly steep learning curve, have improved the success rate for RF ablation substantially over the years.
It is clear that success rates have improved considerably between the period 1997-2000 and the present. The 40% difference in success rate between 1997-2000 and 2004 is statistically significant (p = 0.04).
The prevalence of repeat ablations (touch-ups) was 22% overall and 46% considering only initially unsuccessful ablations. Considering only the outcome of the most recent ablations (touch-ups included) improves success rates further. The success rate for touch-up procedures was not impressive. Only 10 of 26 procedures (38%) were fully successful, 15% were partially successful, and 42% were failures. The fate of one touch-up procedure was uncertain.
Five different procedures were used to perform the RF ablations.
|PVI + focal|
It is clear that the popularity of the various procedures has changed markedly over the years. The initial focal point procedure has gone from 62% in 1997-2000 to 9% in 2004, while the pulmonary vein isolation procedure (PVI) has gone from 0% in 1997-2000 to 60% in 2004. The circumferential PVI (Pappone method) is still relatively rare among the respondents to our survey.
The success rates of the various procedures are presented in Table 6.
|PVI + focal|
The success rate of purely focal ablation is clearly quite poor, while the success rate of pulmonary vein isolation (PVI) is substantially better at 66%. The difference is very significant in statistical terms (p = 0.003). Overall, based on our data, the PVI procedure is the best with a success + partial success rate of 80%. The circumferential PVI would also appear to have a reasonable success rate but, with only 3 afibbers so far having reported on this procedure, it is not possible to draw any conclusions.
Although the procedure used in the ablation is very important in determining the outcome, it is clear that the equipment, specific techniques, and the skill of the electrophysiologist play a major role as well.
Facility and Electrophysiologist
Although clearly arbitrary on my part, I believe the following facilities and electrophysiologists are among the top worldwide. I am sure Dr. Carlo Pappone's facility in Milan deserves inclusion as well, but I do not have any data from this facility. Here then are my top choices, in alphabetical order.
|Centinella Hospital, CA||Dr. Nademanee*|
|Cleveland Clinic, OH||Drs. Natale, Schweikert, Tchou, Saliba|
|Good Samaritan, LA||Dr. Bhandari|
|Good Samaritan, San Jose, CA||Dr. Coggins|
|Haut-Leveque, Bordeaux, FR||Drs. Haissaguerre, Jais|
|Johns Hopkins||Drs. Calkins, Berger|
|Marin General Hospital, CA||Dr. Natale**|
|University of Pennsylvania||Dr. Callans|
|University of South Carolina||Dr. Wharton|
|Utah Valley Hospital||Dr. Hwang|
These 8 facilities (Group A) performed 52% of the 106 ablations for which location and EP are known. A comparison of their performance with that of the remaining 48% (Group B) would thus be of interest.
|# in group|
|Age at first ablation (mean)|
|Age at first ablation (range)|
|Years of afib (mean)|
|Females in groups|
|Underlying heart disease|
Although there is no significant difference between the distribution of paroxysmal, persistent, and permanent afibbers among the two groups, there is a statistically significant (p = 0.02) difference between the percentage of mixed (39% versus 66%) and vagal afibbers (46% versus 25%) treated in the two groups. The success rate for vagal afibbers is generally higher than that for mixed afibbers.
There was no difference in gender distribution and neither the difference in the prevalence of underlying heart disease, nor the difference in afib severity were statistically significant. Thus, apart from a greater preponderance of vagal afibbers in Group A, there is no significant difference between patients in the two groups.
A comparison of the known success rates and touch-up utilization for the period 2001-2004 is presented in Table 9.
|# in sample|
|After initial ablation|
|After most recent ablation|
|Touch-up rate, overall|
|Touch-up rate, on failures|
|Touch-up success rate|
It is extremely clear from the above table that the most important variables in the success of an RF ablation are the facilities and the expertise and skill of the electrophysiologist. The differences in success rates are dramatic, so dramatic in fact that I re-checked them twice. Essentially, while the success rate in Group A is 68% for the initial ablation and 76% with a touch-up, the corresponding numbers for Group B are 21% and 29%. Even including partial successes (no afib, but still on antiarrhythmics) the differences are still startling:
The conclusion is pretty inescapable � there are still a lot of EPs out there on the steep part of the learning curve. Unless you can have your ablation performed in a Group A center or equivalent, you are better off postponing your procedure for a couple of years.
Stenosis (narrowing of diameter) of the pulmonary veins can occur during ablation, particularly if the ablation is performed inside the veins (PVA). Stenosis is defined as a narrowing of one or more veins by at least 50%, while severe stenosis is defined as narrowing by 70% or more. It is important to check for stenosis about 3 months after the procedure, particularly in the case of PVA. This is usually done via a spiral CT scan.
|# in sample|
It is clear that the practice of checking for stenosis is significantly less prevalent in Group B centers than in Group A and that the actual incidence of stenosis is substantially higher in Group B centers, particularly in the case of PVAs. At least one case of confirmed serious stenosis occurred in a Group B center.
Adverse effects related to the ablation procedure were reported by 8% of Group A ablatees and 19% of Group B ablatees (overall rate = 14%). The most common adverse effects were hematomas in the area of catheter insertion and bruising. More serious effects involved one case of severe damage to the mitral valve (necessitating replacement), development of atrial flutter (1 case), and penetration of the cardiac wall (tamponade) requiring open heart surgery (1 case). Forty per cent of the adverse events had resolved themselves at the time the survey was completed.
For successful ablations the median time to recovery of normal sinus rhythm and no more afib episodes was 1 month (range 0-12 months). The median time to recovery of full physical capacity was 2 months (range 0-11 months with an outlier of 48 months). There was no correlation between age at ablation and time to recovery. About 20% of all successful ablatees reported experiencing a significant number of PACs and PVCs at the time they completed the survey. The corresponding percentage for unsuccessful ablatees was 46%.
The majority of successful ablatees (71%) no longer needed to avoid any triggers and 14% only needed to avoid some previous triggers. Fifteen per cent stated that it was too early to tell whether trigger avoidance was still necessary.
There was no significant difference in median blood pressure before the ablation (120/70) and after the ablation (118/72). Twenty-one out of 63 respondents (33%) reported using blood pressure lowering medications before the ablation, while 17 out of 63 (27%) reported using them after the procedure.
Prior to ablation 22 of 62 respondents (35%) were classified as being hypertensive, either because they had a blood pressure exceeding 140/90 or because they were on anti-hypertensive drugs. After ablation 17 out of 58 respondents (29%) were classified as being hypertensive. This difference was not statistically significant.
Overall, there is no reason to suspect that blood pressure is affected by ablation.
Many afibbers have noticed an increase in pulse (heart) rate after the ablation. For most, the rate returns to normal after a few months, but for others, it remains elevated. It is not clear what causes the elevation, but one possible explanation is that vagal nerve endings are damaged during the procedure, thus diminishing the "restraining" influence of the parasympathetic branch of the autonomic nervous system. Heart rate changes are detailed in Table 11.
The median difference in heart rate increase was somewhat lower in the successful group than in the unsuccessful one (11 bpm versus 20 bpm), but this difference was not statistically significant. The range in increase was quite wide, 4-52 bpm for the unsuccessful group and 2-25 bpm for the successful group.
Table 12 summarizes the survey results concerning the use of antiarrhythmics, beta- and calcium channel blockers and warfarin before and after the ablation arranged according to the outcome of the procedure.
|Prior to procedure|
|Use of antiarrhythmics|
|Use of blockers|
|Use of warfarin|
|Months warfarin used|
|Use of antiarrhythmics|
|Use of blockers|
|Use of warfarin|
The use of statin drugs (Lipitor, atorvastatin) to control inflammation after the ablation was mainly confined to recent ablations carried out at the Cleveland Clinic. Group A centers used statin drugs in 47% of cases whereas Group B centers only used them in 17% of cases. Fourteen per cent of statin users experienced side effects, primarily muscle pain and weakness. Thirty-two per cent of statin takers were supplementing with coenzyme Q10 in order to counteract long-term adverse effects of Lipitor.
Change in Afib Burden
A question uppermost in the minds of afibbers contemplating ablation is will I be worse off if the ablation is unsuccessful? Fourteen afibbers who had undergone an unsuccessful ablation supplied data regarding their afib severity for a 3-month period prior to the ablation and for a 3-month period after. Results are tabulated in Table 13 (medians used in all cases).
|# of episodes|
|Duration of episodes|
It is clear that even though the unsuccessful ablations did not eliminate afib completely, they did reduce the number of episodes and overall burden (number of episodes x duration) and also reduced the need for medication. In no case did an afibber end up with more or longer episodes after the ablation.
Satisfaction with Procedure
The majority (89%) of afibbers who had undergone a RF ablation would recommend it with 7% responding that it would depend on the circumstances, but that it should probably only be done as a last resort; 4% did not recommend the procedure. Even among afibbers having undergone an unsuccessful procedure 82% would still recommend it, while 18% would not.
Permanence of Procedure
The first ablation included in our survey performed in 1997 was not successful. The first ablation that is known to have been successful was done in February 2000 � almost 5 years ago. Another one done in May 2000 is also known to be successful to date. Several ablations done in 2001 are known to be "still holding". I am not aware of any initially successful ablations that have "stopped working", but my data in this area is quite limited. Nevertheless, at this point in time, I have no evidence to suggest that successful ablations eventually allow afib to resurface.
The survey results regarding the maze procedure, cryoablation, ICD implantation, AV node ablation and flutter ablation will be presented in the next issue.
The AFIB Report is published 10 times a year by Hans R. Larsen MSc ChE
1320 Point Street, Victoria, BC, Canada V8S 1A5
Phone: (250) 384-2524
E-mail: [email protected]
Copyright © 2004 by Hans R. Larsen
The AFIB Report does not provide medical advice. Do not attempt self- diagnosis or self-medication based on our reports. Please consult your health-care provider if you wish to follow up on the information presented.