Benign emergence of pathological Q waves following minimally invasive direct coronary artery bypass surgery: a case series

Figures

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  Figure 1. Primary axis and their changes following MIDCAB. Given a more rightward primary axis in group 2 (>60°), the QRS axis remained positive even after significant axis changes, thereby reducing the likelihood of new Q waves. However, the primary axis in group 1 was less positive (0°–60°), leading to the presence of new Q waves following significantly leftward axis alterations. All patients without significant RCA stenosis were in group 3, characterized by the absence of both new Q waves and significant QRS axis changes (red lines). Notably, among the three remaining patients in group 3 with significant RCA stenosis, a primary axis < 0° was observed. MIDCAB, minimally invasive direct coronary artery bypass; RCA, right coronary artery.

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  Figure 2. ECG changes in a patient with new Q waves after MIDCAB. (Upper panel) Prior to MIDCAB, the primary QRS axis ranged between 0° and 60°. (Mid panel) Following MIDCAB, enhanced blood flow strengthened anterior wall activation, resulting in a pronounced leftward axis shift to generate new Q waves in leads III and aVF. (Lower panel) Following PCI in the RCA, the QRS axis and amplitude reverted to pre-MIDCAB levels, attributing to increased blood flow in the inferior wall. ECG, electrocardiogram; MIDCAB, minimally invasive direct coronary artery bypass; PCI, percutaneous coronary intervention; RCA, right coronary artery.

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  Figure 3. ECG changes in a patient with significant QRS axis alteration after MIDCAB. (Upper panel) Prior to MIDCAB, the primary QRS axis exceeded 60°, indicating relatively stronger inferior activation. (Mid panel) Following MIDCAB, enhanced blood flow led to strengthened anterior wall activation, resulting in a marked leftward axis shift, heightened QRS amplitude in lead aVL, and diminished QRS amplitude in leads III and aVF. (Lower panel) Subsequent to PCI in the RCA, the QRS axis and amplitude reverted to pre-MIDCAB levels, attributed to increased blood flow in the inferior wall. Abbreviations as in Fig. 2.