Response patterns of arterial pressure and heart period to Mueller manoeuvre and their comparison to those of Valsalva manoeuvre

Abstract

It has not been established if the Mueller manoeuvre (MM) induces characteristic arterial pressure (AP) and heart rate changes analogous to those observed during its respiratory strain opposite, the Valsalva manoeuvre (VM). Our aims were to explore, on a beat-by-beat basis, if MM evokes well-defined changes in AP and heart period (HP), and to compare these responses with those of VM. From the ECG and AP records of 24 healthy subjects who performed VM and MM in sitting position, RR intervals and AP series were computed. The series were ensemble-averaged, and the characteristic points that limit the phases were semi-automatically detected from each record. Our main findings were: (i) MM provoked consistent patterned responses in both AP and HP in the same four phases of VM; (ii) the AP and HP changes of MM were parallel to those of VM in phases II and IV, and opposite in direction in phases I and III; (iii) pooled data during the strain and poststrain and the mean characteristic points of AP and HP were smaller in MM than in VM (P< 0.001); (iv) MM presented two changes absent in VM, AP and HP rise immediately after phase I and hypotension in late phase IV; (v) systolic pressure and HP presented a strong positive correlation (r=0.87 ± 0.02) in late phase II of MM. Our study characterizes on a phase-by-phase basis the AP and RR interval responses to MM, documents their great similarity to those corresponding to VM and establishes that MM exerts a 50% smaller impact on the cardiovascular autonomic function than VM.