[Estimation of ventricular activation by scintigraphic phase image analysis].

Area of Science:

• Cardiology
• Nuclear Medicine
• Medical Imaging

Background:

• Ventricular activation sequence analysis is crucial for understanding cardiac electrophysiology.
• Scintigraphic phase imaging offers a non-invasive method to assess cardiac function.

Purpose of the Study:

• To evaluate the accuracy of scintigraphic phase imaging in identifying the site of ventricular activation onset.
• To compare phase imaging findings with electrocardiogram (ECG) predictions in various cardiac conditions.

Main Methods:

• ECG-gated equilibrium cardiac blood pool scintigraphy was performed in 29 subjects (controls, bundle branch blocks, Wolff-Parkinson-White syndrome, pacemakers).
• Phase image analysis utilized Fourier transform to determine the earliest phase angle.
• Standard 12-lead ECGs were recorded for comparison.

Main Results:

• Phase imaging accurately identified ventricular activation sites in Wolff-Parkinson-White syndrome and pacemaker patients.
• In normal subjects and complete right bundle branch block (CRBBB) patients, phase imaging showed discrepancies with predicted activation sites.
• Similar discrepancies were observed in complete left bundle branch block (CLBBB) patients, potentially due to interventricular septum paradoxical motion.

Conclusions:

• Scintigraphic phase imaging is useful for determining ventricular activation sites in specific conditions like WPW syndrome and with pacemakers.
• Caution is advised when interpreting phase imaging for activation onset in normal subjects and bundle branch block patients due to motion artifacts.
• Phase imaging effectively reflects the overall ventricular activation sequence direction in most cases.