Valsalva Maneuver and Strain-Related ECG Changes

Area of Science:

• Physiology
• Cardiology
• Medical Diagnostics

Background:

• The Valsalva maneuver (VM) involves distinct physiological changes across its four phases.
• While ECG manifestations of VM are documented, the strain phase's specific ECG alterations alongside hemodynamic and biochemical changes require further investigation.

Purpose of the Study:

• To investigate electrocardiogram (ECG) changes specifically during the strain phase of the Valsalva maneuver (VM).

Main Methods:

• A descriptive, self-controlled study involving 20 healthy male college students.
• Standardized VM protocol: 15-second expiratory pressure at 40 mmHg with an open glottis.
• Continuous ECG recording at rest and during the VM strain phase, with analysis of successive heartbeats.

Main Results:

• Significant alterations observed in RR and PR intervals, corrected QT interval (QTc), P wave duration and amplitude, T wave amplitude, and T/R amplitude ratio.
• No significant changes were noted in QRS duration or R wave amplitude.

Conclusions:

• The VM strain phase induces notable temporal and voltage modifications in specific ECG waves.
• Potential contributing factors include changes in cardiac/pulmonary volume, electrode interface, and autonomic nervous system activity.