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ECG and Anatomical Features in Patients of Left Coronary Cusp Ventricular Arrhythmias With R Wave in Lead I
Satoshi Hara1, Hitoshi Hachiya1, Naoyuki Miwa1
1Cardiovascular Center Tsuchiura Kyodo Hospital Tsuchiura Ibaraki Japan.
Insights
Ventricular arrhythmias (VAs) from the left coronary cusp (LCC) can present with an R wave in lead I, unlike typical right coronary cusp (RCC) VAs. A leftward QRS axis during sinus rhythm predicts LCC origin, guiding ablation strategies.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Imaging
Background:
- Ventricular arrhythmias (VAs) originating from the aortic cusps are a significant clinical concern.
- While VAs with an R wave in lead I often arise from the right coronary cusp (RCC), left coronary cusp (LCC) origins are occasionally observed.
Purpose of the Study:
- To differentiate the electrocardiographic (ECG) and anatomical characteristics of VAs originating from the LCC versus the RCC.
- To identify predictors for LCC-originating VAs presenting with an R wave in lead I.
Main Methods:
- Retrospective analysis of patients undergoing successful catheter ablation for VA originating from the LCC or RCC.
- Comparison of 12-lead ECGs during VA and sinus rhythm, focusing on the presence of an R wave in lead I.
- Measurement of the left ventricular anatomical axis using CT imaging in LCC cases.
Main Results:
- Only 22% of LCC VAs showed an R wave in lead I, compared to 100% of RCC VAs.
- A leftward QRS axis during sinus rhythm (<-26°) and a smaller anatomical axis on CT were significantly associated with LCC VAs exhibiting an R wave in lead I.
- A modest correlation was found between the electrocardiographic and anatomical axes in LCC patients.
Conclusions:
- The presence of an R wave in lead I during VA does not exclusively indicate RCC origin.
- A leftward QRS axis during sinus rhythm is a valuable indicator for suspecting LCC origin in VAs.
- These findings suggest extending electrophysiological mapping to the LCC when a leftward QRS axis is observed in VAs with an R wave in lead I.
Backgrounds:
Ventricular arrhythmias (VAs) originating from the coronary cusps with R wave in lead I typically originate specifically from the right coronary cusp (RCC), but are occasionally of left coronary cusp (LCC) origin.
Methods:
We retrospectively analyzed patients who underwent successful initial catheter ablation for VA in either the LCC (N = 41) or RCC (N = 14). Twelve-lead ECG during VA and during sinus rhythm were compared between LCC arrhythmia patients with an R wave in lead I during VA (R(I)-wave group) and those without (non-R(I)-wave group). In LCC cases in whom CT was available, we measured the anatomical axis of the left ventricle in the frontal plane.
Results:
Among the 41 LCC patients, 9 (22.0%) showed an R wave in lead I in contrast to 100% of the 18 RCC patients. CT imaging was available for 22 LCC patients (53.7%) and revealed a modest correlation between electrocardiographic and anatomical axis (r = 0.64, p = 0.0014). The R(I)-wave group had a significantly more leftward QRS axis during sinus rhythm (2.0° ± 29.6° vs 43.1° ± 31.1°, p = 0.001) and smaller anatomical axis on CT (14.4° ± 16.46° vs 35.8° ± 11.71°, p = 0.004). ROC analysis showed that a QRS axis < 26° best predicted R wave presence in LCC patients.
Conclusion:
In cases of VA suspected to originate from the aortic cusps with R wave in lead I, the presence of a leftward QRS axis during sinus rhythm suggests mapping should be extended to the LCC.
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