ABC | Volume 112, Nº6, June 2019

Case Report Riera et al Atrial and ventricular infarction: P-loop shape Arq Bras Cardiol. 2019; 112(6):803-806 Figure 2 – Comparison between normal P loops and the present case. Frontal plane: In the present case, the maximal vector voltage is > 0.2 mV, and the morphology is broad with a notch in the middle portion (arrows). Right sagittal plane: The maximal anterior forces are ≥ 0.06 mV and maximal posterior forces are > 0.04 mV: biatrial enlargement. Horizontal plane: the normal P loop maximal vector location is located between +50° and -45°, maximal vector voltage is < 0.1 mV, maximal anterior forces are up to 0.06 mV and maximal posterior forces are up to 0.04 mV. In the present case, anterior and posterior forces exceed these values. Conclusion: biatrial enlargement and suspicion of AI by notched P loop in the frontal and right sagittal plane. RA: right atrium; LA: left atrium. 1. Lazar EJ, Goldberger J, PeledH, ShermanM, FrishmanWH. Atrial infarction: diagnosis and management. AmHeart J. 1988;116(4):1058-63. 2. Cunningham KS, Chan KL, Veinot JP. Pathology of isolated atrial infarction: case report and review of the literature. Cardiovasc Pathol. 2008;17(3):183-5. 3. Cler ALR. Infarctus auricularis: Tachyarrhythmie terminale. Bull Med Soc Hop Paris. 1925;41:1603-7. 4. Langendorf R. Elektrokardiogram bei vorhof-infarkt. Acta Med Stand. 1939;100:136-49. 5. Hellerstein HK. Atrial infarction with diagnostic electrocardiographic findings. AmHeart J. 1948;36(3):422-30. 6. Tranchesi J, Adelardi V, deOJ. Atrial repolarization--its importance in clinical electrocardiography. Circulation. 1960 Oct;22:635-44. 7. Liu CK, GreenspanG, Piccirillo RT. Atrial infarction of the heart. Circulation. 1961 Mar;23:331-8. 8. LuML, De Venecia T, Patnaik S, Figueredo VM. Atrial myocardial infarction: A tale of the forgotten chamber. Int J Cardiol. 2016 Jan 1;202:904-9. References marginal, or diagonal coronary arteries. 11 In the present case, the coronary obstruction occurred in the proximal portion of the LAD, consequently also the diagonals that can irrigate the LA causing AI in this structure. 3. The branches of LCX. These branches provide irrigation for the LA. 12 Conclusion Though AI was first reported 89 years ago, its recognition remains elusive. AI should be suspected in any patient who presents with typical chest pain, elevated cardiac biomarkers and ECG changes consistent with AI: PR-segment deviations (elevation and depression), the presence of abnormal P-wave shape (M-shaped, W-shaped, irregular or notched) and/or presence of supraventricular tachyarrhythmias. P loop VCG analysis appears to be a valuable diagnostic tool. Author contributions Conception and design of the research, Writing of the manuscript and Critical revision of the manuscript for intellectual content: Riera ARP, Barros RB, Silva e Sousa Neto AF, Raimundo RD, Abreu LC, Nikus K; Analysis and interpretation of the data: Riera ARP, Nikus K. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. 805