We would like to thank Dr Flury for his letter raising some issues regarding our article "Reliability of an ECG algorithm for identification of the infarct-related artery in inferior myocardial infarction in clinical practice". Indeed, we were considering most of these issues when the idea to perform our study came up.
Our analysis was based on data from another study that were collected during the years 2006–2013. Thus, we are fully aware of the limitations associated with a retrospective analysis. Given the retospective design and the fact that right precordial leads (V3R, V4R) were and are, indeed, not routinely used at the Kantonsspital Graubünden (as well as in many other hospitals), we were not able to provide appropriate data. However, we strongly believe that, based on the available data, we were able to pinpoint the limitations of the algorithm proposed by Zimetbaum et al. [1].
In the original algorithm and in line with current European Guidelines [2, 3] lead V4R (and/or lead V1) is reported to be useful in differentiating right coronary artery (RCA) occlusion with right ventricular infarction from RCA occlusion without right ventricular infarction. However, the use of right precordial leads is not mandatory in the first step of the algorithm proposed by Zimetbaum et al., which aims for identification of the infarct-related artery (RCA vs left circumflex [LCX]). Our study was limited to this first crucial step of the algorithm and, therefore, right precordial leads were not needed to draw our conclusions.
We absolutely agree that primary therapy of patients with myocardial infarction before their admission to tertiary care hospitals providing interventional therapy is crucial to improve the outcome of patients with ST-elevation myocardial infarction (STEMI). However, in our opinion and given the results of our study, initial therapy of patients with acute inferior STEMI should not be guided by transient and rather unreliable ECG findings, but rather by the clinical picture (e.g., hypotension in combination with jugular vein congestion suggesting right ventricular infarction and indicating the need for volume administration). Moreover, the use of nitrates in patients with acute STEMI – though still frequent – is not supported by current European guidelines anymore [2].
In summary, for the reasons mentioned above and in our manuscript we would not recommend the use of the proposed algorithm in order to guide the therapeutic strategy of patients with acute inferior STEMI. However, of course, we would leave it to the discretion of every single physician to still use the algorithm.
Beate Buchmann, Piero O. Bonetti
References
Beate Buchman, MD
Herman-Burchard Strasse 1
CH-7265 Davos Wolfgang
beate.buchmann[at]gmx.de
