Atrial fibrillation is the most common heart rhythm abnormality. It increases in incidence as we age. Atrial fibrillation reduces the efficiency of the heart making patients feel fatigued, and causes swirling of the blood in the fibrillating heart chambers which can lead to blood clots and strokes. 75,000 new strokes occur each year due to atrial fibrillation and the risk increases with age. When stroke strikes, permanent damage, loss of function or death can occur. Statistically, if a person develops atrial fibrillation and is compared to their neighbor who never develops atrial fibrillation, the person with atrial fibrillation will be 2x more likely to die and have 5x the risk of suffering a stroke in their lifetime.
Medications to treat atrial fibrillation have limited ability to durably convert and keep patients with atrial fibrillation in normal sinus rhythm. Hence most patients are placed on rate controlling drugs and lifelong blood thinners such as Coumadin to make them feel more comfortable and help reduce their risk of stroke.
What causes atrial fibrillation?
It turns out that many of the electrical impulses that initiate and propagate atrial fibrillation emanate from either the pulmonary veins or the back wall of the left atrium. Cardiologists specially trained in arrhythmias of the heart are called electrophysiologists. Knowing that the pulmonary veins and the back wall of the left atrium can initiate and propagate atrial fibrillation, physicians for years have been working to better understand and treat atrial fibrillation. One well known highly effective surgical procedure is called the Cox-Maze procedure. In this procedure, which is performed through a 10 – 12 inch full sternotomy incision, the patient is put on a heart lung bypass machine, the heart is stopped, and essentially cut and sewn back together at defined lines of anatomy. By this act of extensively cutting and sewing the heart back together again at these well-defined anatomical lines, the aberrant electrical currents that initiate and propagate atrial fibrillation are interrupted. The cure rates for long standing persistent (chronic) atrial fibrillation with this surgical technique can approach 80% in long term studies and should usually be done at the same time in most patients undergoing heart surgery for any other reason. In addition to a high rate of getting patients back into normal sinus rhythm, patients receiving a Cox- Maze surgical procedure very rarely suffer a stroke in long term follow-up. Part of the Cox-Maze surgical procedure is ligation of the left atrial appendage. What relative role; ligating the left atrial appendage (which is known to be the location of most of the thrombi that form in the heart) vs. resuming normal sinus rhythm, in markedly reducing the risk of stroke in these patients is still undetermined.
Catheter ablation of Atrial Fibrillation:
Electrophysiologists have long attempted to recreate the clinical success of the Cox-Maze surgical procedure. To achieve the same results less invasively, they have tried snaking radiofrequency emitting catheters up the veins in the leg, across the interatrial septum of the heart, electrically mapping and then ablating the left atrium and pulmonary veins in a manner similar to the ablation lines described in the Cox-Maze surgical procedure. They ablate the tissue with a radiofrequency emitting catheter that heats the local tissue on contact up to as high as 50 degrees Celsius. Ablating electrophysiologists have to be concerned at all times with damaging nearby surrounding tissues like the esophagus which can lead to a rare but usually lethal complication like an atrial-esophageal fistula. The hope of catheter ablation is that it can attain the block to conduction that the Cox-Maze surgical procedure affords the patient and high resumption of normal sinus rhythm, without the trauma of open heart surgery. Unfortunately, even if catheter ablation is successful in restoring a patient to normal sinus rhythm, the left atrial appendage is almost never ligated. After decades of catheter ablation being performed, this recently published paper indicates the less than impressive results of catheter ablation in patients with long standing persistent (chronic) atrial fibrillation.
Objectives: This study describes the 5-year efficacy of catheter ablation for long-standing persistent atrial fibrillation (LS-AF). Background – Long-term outcome data after catheter ablation for LS-AF are limited.
Methods: Long-term follow-up of 56 months (range 49 to 67 months) was performed in 202 patients (age 61 + 9 years) who underwent the sequential ablation strategy for symptomatic LS-AF. Initial ablation strategy was circumferential pulmonary vein isolation (PVI). Additional ablation was performed only in acute PVI nonresponder, if direct current cardioversion failed after PVI.
Results: After the first ablation procedure, sinus rhythm was documented in 41 of 202 (20.3%) patients. After multiple procedures, sinus rhythm was maintained in 91 of 202 (45.0%) patients, including 24 patients receiving antiarrhythmic drugs. In 105 patients, PVI was the sole ablative therapy, 49 (46.7%) of those patients remained in sinus rhythm during follow-up. Patients with a total AF duration of < 2 years had a significantly higher ablation success rate than patients whose AF duration was > 2 years (76.5% vs. 42.2%, respectively; p = 0.033). Persistent AF duration (hazard ratio: 1.09 [95% confidence interval: 1.04 to 1.13]; p < 0.001) independently predicted arrhythmia recurrences, and acute PVI responders had a reduced risk of relapse (hazard ratio: 0.57 [95% confidence interval: 0.41 to 0.78]; p < 0.001) after the first ablation.
Conclusions: During 5-year follow-up, single- and multiple ablation procedure success was 20% and 45%, respectively, for patients with LS-AF. For patients with a total AF duration of < 2 years, the outcomes were favorable. (J Am Coll Cardiol 2012;60:1921–9).
In summary, this paper demonstrates that in patients with long standing persistent (chronic) atrial fibrillation, at 5 years, the success rate of catheter ablation was a disappointing 20% after one procedure and 45% after multiple procedures. (You can click here to download this article).
Is there a better way?
Robotic Hybrid Atrial Fibrillation Ablation:
Since the results of catheter based ablation alone can be so dismal and the Cox-Maze surgical procedures can be so invasive, might there be a better way? Why not learn from our success in robotic hybrid coronary revascularization and combine the best of both worlds of cardiac surgery and cardiology?
There exists a robotic assisted method for wrapping a long radiofrequency emitting catheter around the beating heart in a closed chest setting that can provide linear ablation lines similar to the Cox-Maze surgical procedure with no sternotomy and no use of cardiopulmonary bypass. Several years ago when I served as medical director of the Center for Atrial Fibrillation Treatment at Hawaii Medical Center, using a first generation radiofrequency emitting catheter, I performed over 70 of these procedures without a single mortality and average hospital length of stay of 1- 2 days. Since this personal series was performed, the technology has improved markedly and we now have available a 3rd generation radiofrequency catheter that promises even better rates of transmurality.
Read the articles here.
In addition, investigators have recently reported that a hybrid approach may be the best approach to treat long standing persistent (chronic) atrial fibrillation. In a hybrid approach, after a minimally invasive surgical ablation is performed, after 30 days, electrophysiologists performs a check of the ablation lines performed at surgery and “spot weld” ablates any areas not completely transmural. In addition, they usually add some additional ablation lesions that are not accessible to a minimally invasive surgical approach. In this manner, by combining the best of both the worlds of cardiac surgery and cardiology, investigators are reporting impressive clinical success!
Objectives: Electrophysiologic and surgical procedures to treat stand-alone atrial fibrillation (AF) have recently evolved, but disappointing results in patients with long-standing persistent (LSP) AF have challenged the durability of these procedures.
Methods: Lone AF patients (n = 36) with either LSP-AF (n = 28) or persistent AF (n = 8) were prospectively enrolled in the study and consecutively treated by thoracoscopic ablation followed by electrophysiologic evaluation 30 days afterward. Mean left atrial dimension was 50.3 + 5.5 mm, and average AF duration was 72.8 months (range, 7-240 months). The thoracoscopic procedure was a right monolateral approach to create a box lesion using a temperature-controlled radiofrequency device with suction adherence. A continuous rhythm monitoring device was implanted at the end of the operation.
Results: Thoracoscopic ablation was successfully completed without morbidity or mortality and without any intensive care unit stay. Intraoperative exit and entrance block was achieved in 100% and 88.8% (32/36) of patients, respectively. At 33+2 days after the operation, an electrophysiologic study confirmed entry–exit block in 83.3% (30/36) whereas pulmonary vein reconnections were observed in 16.7% (6/36) of patients. Additional transcatheter lesions were performed in 61.1% (22/36) of patients. At a mean follow-up of 30 months (range, 1-58 months), 91.6% (33/36) of patients are in sinus rhythm with 77.7% (28/36) of these patients off antiarrhythmic drugs and 88.8% (32/36) free of warfarin. Long-term incidence of left atrial flutter was 0%
Conclusions: The combination of a surgical box lesion and transcatheter ablation in a hybrid approach provided excellent durable clinical outcomes in patients with LSP-AF. (J Thorac Cardiovasc Surg 2012;-:1-6).
(You can click here to download this article).
Allied with our electrophysiologic colleagues, we have developed our own program of robotic hybrid minimally invasive surgical /EP cardiac ablation for medically refractory and symptomatic atrial fibrillation. In addition, for all our patients in this revolutionary and unique program, we perform left atrial appendage ligation. The left atrial appendage is known to be the primary site where blood clots form in atrial fibrillation. We feel that by adding left atrial appendage ligation to robotic hybrid minimally invasive surgical and EP ablation, we are reducing our patient’s future stroke risk significantly. Active clinical programs utilizing these approaches are currently underway at major academic centers like the University of Chicago and the University of North Carolina.
Picture of one of our robotic minimally invasive surgical ablation patients 2 weeks after surgery:
Video Clip of Robotic Atrial Fibrillation Ablation and Left Atrial Appendage Ligation:
KITV news coverage of one of my patients after Minimally Invasive Atrial Fibrillation Surgery
Dr.Lee’s Interview on Robotic Atrial Fibrillation Ablation
Dr.Lee’s Podcast Interview on Robotic Atrial Fibrillation Ablation