From the Guidelines
Isometric handgrip actually increases the intensity of the murmur in a patient with a Ventricular Septal Defect (VSD) with right-to-left shunting, as stated in the guidelines 1. This occurs because isometric handgrip increases systemic vascular resistance, which can affect the pressure gradient across the ventricular septum. According to the guidelines, murmurs of MR, VSD, and AR also increase with handgrip exercise 1. Some key points to consider include:
- Respiration: Right-sided murmurs generally increase with inspiration, while left-sided murmurs usually are louder during expiration 1.
- Valsalva maneuver: Most murmurs decrease in length and intensity, but there are exceptions for certain conditions like HCM and MVP 1.
- Exercise: Murmurs caused by blood flow across normal or obstructed valves become louder with both isotonic and isometric exercise, including handgrip 1. It's essential to consider the patient's overall cardiovascular function and potential risks when performing isometric handgrip maneuvers, especially in those with compromised function or conditions like Eisenmenger syndrome 1.
From the Research
Isometric Hand Grip and VSD with Right-to-Left Shunt
- Isometric hand grip can increase systemic vascular resistance (SVR) due to the increased muscle tension [no direct evidence from provided studies].
- In a patient with a Ventricular Septal Defect (VSD) and a right-to-left shunt, an increase in SVR could potentially decrease the right-to-left shunt flow by increasing the pressure gradient between the left and right ventricles [no direct evidence from provided studies].
- However, the provided studies do not directly address the effect of isometric hand grip on the murmur in patients with VSD and right-to-left shunt.
- Studies have shown that reducing pulmonary vascular resistance (PVR) can improve oxygenation and reduce right-to-left shunt flow in patients with VSD and pulmonary hypertension 2.
- Surgical interventions, such as unidirectional valved patch closure, can also be effective in reducing right-to-left shunt flow and improving oxygenation in patients with VSD and severe pulmonary arterial hypertension 3.
- Other studies have reported cases of VSD with coexisting conditions, such as coronary sinus atrial septal defect 4 or chronic constrictive pericarditis 5, which can affect the hemodynamics of the defect.
- The hemodynamic effects of vasodilator agents have been studied in experimental VSD models, showing that reduction of systemic vascular resistance can decrease the ratio of pulmonary to systemic flow 6.
Murmur Characteristics
- The murmur associated with VSD is typically a holosystolic or pansystolic murmur, best heard at the left lower sternal border.
- The intensity of the murmur can vary depending on the size of the defect and the presence of any obstructive lesions.
- In patients with right-to-left shunt, the murmur may be less intense or even absent due to the reduced flow across the defect.