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Inadequacy of fluoroscopy and electrocardiogram in predicting septal position in RVOT pacing - Validation with
Gautam Sharma1, Salman Salahuddin2, Prashanthan Sanders3
1Professor and Head, Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029, India.
Insights
Conventional electrocardiogram (ECG) and fluoroscopy methods are unreliable for confirming right ventricular outflow tract (RVOT) lead placement. Cardiac computed tomographic angiography (CTA) reveals the lateral fluoroscopic view is more accurate for septal lead positioning.
Area of Science:
- Cardiology
- Medical Imaging
- Electrophysiology
Background:
- Electrocardiographic (ECG) and fluoroscopic criteria are traditionally used to guide right ventricular outflow tract (RVOT) lead placement.
- Validation of these criteria for confirming true septal RVOT lead position is limited.
Purpose of the Study:
- To validate conventional ECG and fluoroscopic methods against cardiac computed tomographic angiography (CTA) for determining RVOT lead position.
- To assess the accuracy of different fluoroscopic views in identifying septal lead placement.
Main Methods:
- Forty-four patients with permanent pacemaker leads in the RVOT underwent CTA.
- Lead positions were classified as anterior, free wall, or septal using CTA.
- Fluoroscopic images were analyzed for correlation with CTA findings.
Main Results:
- Only 43% of patients had leads in the true septal RVOT position confirmed by CTA; 57% had anterior placement.
- The standard fluoroscopic LAO view showed poor specificity (16%) for predicting septal lead position.
- The lateral fluoroscopic view demonstrated higher accuracy, with 73.7% sensitivity and 80% specificity for septal lead placement.
Conclusions:
- Conventional ECG and fluoroscopy are inaccurate for differentiating septal from anterior RVOT pacing.
- CTA-guided analysis indicates the lateral fluoroscopic view is more reliable than the LAO view for predicting septal lead placement.
Background:
Electrocardiographic (ECG) and fluoroscopic criteria, which are the only available guides to achieve a true septal position during right ventricular outflow tract (RVOT) pacing, have been infrequently validated. We sought to validate these using cardiac computed tomographic angiography (CTA) to confirm lead position within the RVOT septum.
Methods:
Forty-four patients with permanent pacemaker leads in the RVOT position underwent CTA. Lead positions in RVOT were classified as anterior, free wall, or septal location. Fluoroscopic images were obtained in 4 standard views.
Results:
Only 19 (43%) patients had lead in true septal position within the RVOT in CTA while 25 patients (57%) were found to have an anterior lead location. Mean QRS axis, QRS duration, negative QRS in lead I, and notching in inferior leads were not significantly different between the two groups. The standard fluoroscopic LAO view showed a rightward-directed lead not only in all 19 patients with septal location, but also in 14/25 patients in the anterior location (p=0.22), and thus had a sensitivity of 100% but specificity of only 16% in predicting true septal position. The posteriorly directed lead in left lateral view was more accurate in predicting true septal position with good sensitivity (73.7%) and excellent specificity (80%).
Conclusions:
This study, using validation with CTA, showed that conventional ECG criteria and fluoroscopy are inaccurate in differentiating septal from anterior RVOT pacing. The fluoroscopic lateral view, as corroborated by CTA, is more reliable than the LAO view in predicting septal lead placement.
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