Modulation of cardiac ventricular conduction: Impact on QRS duration, amplitude and dispersion

Area of Science:

• Cardiology
• Electrophysiology
• Molecular Biology

Background:

• Assessing ventricular conduction is crucial in clinical and experimental settings.
• QRS duration is the current standard for evaluating global ventricular conduction time.
• QRS amplitude has also been proposed as a measure of ventricular conduction.

Purpose of the Study:

• To systematically investigate the relationship between QRS duration and QRS amplitude (RS-height) in murine ECGs.
• To explore these relationships in wild-type mice and mice lacking the transmembrane protein podoplanin (PDPN-/-).
• To assess the impact of flecainide, a sodium channel blocker, on these ECG parameters.

Main Methods:

• ECG recordings were performed on anesthetized wild-type and PDPN-/- mice.
• Flecainide was administered intraperitoneally at cumulative doses of 5 mg/kg and 10 mg/kg.
• Analysis focused on QRS duration, RS-height, and their ratio, including dispersion between genotypes.

Main Results:

• PDPN-/- mice exhibited shorter QRS duration and greater RS-height compared to wild-type mice.
• Flecainide administration caused dose-dependent increases in QRS duration and decreases in RS-height in both genotypes.
• Changes in RS-height were more pronounced than changes in QRS duration following flecainide treatment.
• Flecainide-induced changes in QRS duration and RS-height were significantly correlated.
• Dispersion of the QRS/RS-height ratio was significantly smaller in PDPN-/- mice.

Conclusions:

• QRS duration is inversely related to RS-height in the murine ECG.
• Both QRS duration and RS-height should be considered for a thorough analysis of ventricular conduction time in mice.
• Findings may have implications for understanding cardiac electrophysiology and developing novel diagnostic markers.