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Noninvasive recording of the His bundle electrogram: value of supplementary verapamil
Abstract:
We obtained noninvasive recordings of the His bundle electrogram using the Marquette high resolution MAC unit in 65 patients and 5 normal subjects. Overlap of atrial activity prevented identification of a His potential in 25 subjects, in 23 of whom the PR interval was equal to or less than 160 ms. After intravenous verapamil (10 mg) the AH interval was lengthened, with an increase in the PR interval of 10-60 (mean 20) ms. A characteristic His bundle electrogram was recorded in 48 of the 70; in 8 there was persistent atrial activity and in 4 electrical interference could have obscured a His potential. In 10 patients the absence of a His complex despite a clear "window" of at least 70 ms between the end of atrial activity and the onset of ventricular depolarization suggested that its vector was outside the plane of the electrode arrangement, or that there was a prolonged H-V interval; the latter has been confirmed in 2 patients. Intracardiac His bundle recordings in 25 subjects who had characteristic surface electrical activity of the His bundle disclosed good correlation between invasive and noninvasive measurements of the H-V interval. This noninvasive technique using portable equipment, which permits serial evaluation of the His bundle electrogram, may facilitate prospective studies in patients with conduction disease.
Insights
This study demonstrates a noninvasive His bundle electrogram technique for evaluating cardiac conduction. The method shows promise for serial assessments in patients with conduction system disease.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Accurate assessment of cardiac conduction is crucial for diagnosing and managing heart rhythm disorders.
- Invasive His bundle electrogram recordings provide valuable diagnostic information but carry inherent risks.
- Development of noninvasive techniques is essential for safer and more accessible cardiac electrophysiological evaluation.
Purpose of the Study:
- To evaluate the efficacy of a noninvasive His bundle electrogram recording technique.
- To assess the correlation between noninvasive and invasive measurements of cardiac conduction intervals.
- To determine the potential of this noninvasive method for serial patient evaluation.
Main Methods:
- Noninvasive His bundle electrogram recordings were obtained using the Marquette high-resolution MAC unit in 70 subjects (65 patients, 5 normal).
- Intracardiac His bundle recordings were performed in 25 subjects for comparative analysis.
- Verapamil was administered intravenously to assess its effect on cardiac conduction intervals.
Main Results:
- A characteristic His bundle electrogram was successfully recorded noninvasively in 48 of 70 subjects.
- Noninvasive and invasive measurements of the H-V interval showed good correlation.
- The noninvasive technique allowed for serial evaluation and identified potential conduction abnormalities.
Conclusions:
- The noninvasive His bundle electrogram technique is a feasible method for assessing cardiac conduction.
- This portable, noninvasive approach may facilitate prospective studies in patients with conduction disease.
- Further research can leverage this technique for improved diagnosis and management of cardiac arrhythmias.