To the Editor We read with interest the case report by Dr Scheffer and colleagues. 1 However, we find it necessary to make some comments about the report, including the interpretation of the electrocardiogram (ECG) findings.The P-wave duration is extremely long at 220 milliseconds (ms), with a biphasic pattern in leads III and aVF, while the final part of the P wave is isodiphasic in lead II. These changes are compatible with type I atypical advanced interatrial block, which predisposes to atrial fibrillation. 2 We found that the changes in the precordial leads fulfill all the criteria for left septal fascicular block according to the 2022 Brazilian Guidelines: qR complex from V 1 to V 4 , increasing R-wave amplitude (maximum ≥15 mm) from V 1 to V 2 , decreasing QRS complex amplitude from V 4 to V 6 , and partly negative T waves in the right precordial leads. These criteria are valid in the absence of right ventricular hypertrophy, septal hypertrophy, and old lateral myocardial infarction. 3 In addition, there is an increased R wave peak time (80 ms) in lead V 2 . 4 The coexistence of first-degree atrioventricular block, left anterior fascicular block (LAFB), left septal fascicular block, and right bundle-branch block means that the patient has incomplete left posterior fascicular block. We consider this ECG case to be tetrafascicular intraventricular block, which has never been published before, to our knowledge. Compared with patients with typical bifascicular block, patients with tri-and tetrafascicular block have more extensive fibrosis and degeneration of the left bundle pathways.Dr Scheffer and colleagues 1 consider the left axis deviation with absence of S waves in leads I and aVL to be a pattern of left bundle-branch block in the extremity leads. However, the ECG findings of this patient fulfill the criteria for LAFB: SIII greater than SII, frontal plane QRS complex axis of −75°, qR in lead aVR and aVL, and R wave peak time of 45 ms or greater. Because this is not typical bifascicular block with LAFB and right bundlebranch block, there are no S waves in leads I and aVL.Regarding the authors' definition of the ECG diagnosis of masquerading bundle-branch block, 1 we want to add that the ECG tracing of this patient shows an RS pattern in leads V 5 and V 6 . When discussing diseases associated with masquerading bundle-branch blocks, it is important to mention the progressive cardiac conduction defect (Lenègre disease). Finally, we want to point out that the terms posterior or posterolateral myocardial infarction should be replaced by the term lateral myocardial infarction. 5
