Electrocardiogram and TAVR
Any insight for mortality?
Understanding which patients with aortic stenosis should evolve better than others is essential in stratification to avoid indications of futile treatment in this group of patients. In the current guidelines, interventional treatment is only recommended in cases of predicted survival greater than 1 year.
Several previous studies have brought prognostic information on the presence of myocardial fibrosis in patients with aortic stenosis, but all were performed using magnetic resonance or tomography, expensive tests and not available in much of the Brazilian territory. In addition to the unavailability, they are not exempt from complications, either by infusing gadolinium in the elderly with reduced creatinine clearance, or by infusing iodinated contrast and radiation by tomography.
With a 1% increase in the amount of ventricular fibrosis, patients with aortic stenosis had an increase of up to 11% in the risk of mortality and 8% of cardiovascular mortality in 1 year.
Fibrosis arises at the moment when the concentric hypertrophy compensation mechanism becomes unbalanced, with areas of relative ischemia. Two types of fibrosis are formed, cicatricial, which resembles fibrosis that originates in infarction and diffuse interstitial, both with negative prognostic impact. This diffuse fibrosis has a more recent description and it is still uncertain whether traditional imaging methods would be able to adequately analyze this tissue replacement.
Since the 70s, North American researchers led by Selvester showed that it was possible, through the electrocardiogram, to estimate the amount of fibrosis in patients with ischemic cardiomyopathy. An update of a score from the same group was recently published, validating the use for patients with any cardiomyopathy and even in the presence of conduction blocks.
Our research group at the Instituto Dante Pazzanese de Cardiologia conducted an interesting study on the use of this score that predicts fibrosis as a predictor of mortality in patients with aortic stenosis and who underwent TAVR. It was found that the presence of a score that estimated more than 9% of LV fibrosis was a stronger predictor of mortality than the traditional drop in ejection fraction or presence of pulmonary hypertension over 1 year.
This corroborates the findings of other publications that addressed other imaging tests, when the reference was fibrosis burden and mortality, but the innovation of this work is to bring the same information using a low-cost, harmless and universally distributed test.
In an analysis that does not exceed 5 minutes, any doctor trained in electrocardiogram would be able to estimate the amount of fibrosis. When knowing the burden of fibrosis, the cardiologist has in his hands a tool that can help him find the right moment to indicate the procedure and even to question whether the interventional treatment of an elderly patient, full of comorbidities and on top of that with high ventricular fibrosis would be beneficial.
One of the criticisms of these considerations is the fact that we are guided by the presence or absence of fibrosis for the taking of conducts and the process already points to an advanced stage of the disease. The presence of scar fibrosis already brings comorbidities, even with the proper treatment, being necessary to find the patient in an earlier stage.
1 – Musa TA, Treibel TA, Vassiliou VS, et al. Myocardial Scar and Mortality in Severe Aortic Stenosis. Circulation. 2018; 138 (18): 1935-1947.
2 – Bignoto TC, Le Bihan D, by Mattos Barretto RB, et al. Predictive role of Selvester QRS score in patients undergoing transcatheter aortic valve replacement [published online ahead of print, 2020 Apr 16]. Catheter Cardiovasc Interv. 2020