[SCD-FORUM] 157S consultation Dr. Rondon

[SCD Symposium]

Answer for Dr. Perez Soliz:

I dare answer you about the case of your 51-year-old chagasic patient, with permanent pacemaker, and current evidence of mild AF with FC II-III and echo that is normal. 

This population has indication of anticoagulation to prevent, as you know well, the risk of 4 to 1 of stroke. 

Now, in this population, if EF is normal and there is no evidence of spontaneous echo or thrombi in the left atrium, they have a better prognosis than those with low EF and sign of "smoke" in the atrium or ventricle. 

The ACUTE protocol demands 4 to 6 weeks of anticoagulation, maintaining INR between 2 to 2.5 with new echo before the cardioversion procedure, and if it is the same as before, programmed cardioversion can be conducted. A single effective shock is preferable. This has been reported in several works: the greater the load, the possibility of the first load to be effective is approximately within the following range of effectiveness:

            100 J  = 70 - 75 %
            200 J =  78 - 80 %
            250 J =  85 %
            300 J =  92 % 

If you use defibrillator with biphasic power, you may try 150 to 170 J with a percentage close to 95% of effectiveness in the first shock. 

Please, remember placing the blades so that the pacemaker is not included within them, to prevent damaging the circuit, so it is suggested to place removable blades with anterior-posterior positioning. 

I recommend to sedate her with Diprivan (Propofol) 0.3 to 0.5 mg/Kg, slow impregnation and once the sedative effect is achieved, synchronize the load and apply cardioversion. 

Then, maintain anticoagulation for another 4 weeks, due to the electric stunning effect and atrial remodeling. Electrical activity and poor mechanic activity may be observed, so the left appendage should be seen again, and pulse doppler flow should be measured in the neck of the appendage. This should be greater than 30 – 35 cm/sec, to know if there is low risk of thrombogenesis. 

I think that the management is appropriate in this way, and if reversion to SR is not achieved, then you should consider electrophysiological study, check fragmented atrial potentials and with a color 3D mapping system (Ensite System) the possibility of pulmonary vein isolation, if this is the origin of the AF. 

You still have many options with your patient, even though I don't deny how discouraging AF is in chagasic patients. 

Dr Mauricio Rondón 
Hospital Universitario de Caracas 
Venezuela