Cardiovascular response to static handgrip in trained and untrained men

Dynamic handgrip exercise for the evaluation of mitral valve regurgitation: an echocardiographic study to identify exertion induced severe mitral regurgitation

Handgrip exercise (HG) has been occasionally used as a stress test in echocardiography. The effect of HG on mitral regurgitation (MR) is not well known. This study aims to evaluate this effect and the possible role of HG in the echocardiographic evaluation of MR. 722 patients with MR were included (18% primary, 82% secondary disease). We calculated effective regurgitant orifice area (EROA) and regurgitant volume (RVOL) at rest and during dynamic HG. Increase in MR was defined as any increase in EROA or RVOL. We analyzed the data to identify possible associations between clinical or echocardiographic parameters and the effect of HG on MR. MR increased during dynamic HG in 390 of 722 patients (54%) (∆EROA = 25%, ∆RVOL = 27%). Increase of regurgitation occurred in 66 of 132 patients with primary MR (50%) and in 324 of 580 patients with secondary MR (55%). This increase was associated with larger baseline EROA and RVOL, but it was independent from other clinical or echocardiographic parameters. In secondary MR, dynamic HG led to a reclassification of regurgitation severity from non-severe at rest to severe MR during HG in 104 of 375 patients (28%). There was a significant association between this upgrade in MR classification and higher New York Heart Association (NYHA) class (OR 1.486, 95%-CI 1.138-1.940, p = 0.004). Dynamic HG exercise increases MR in about half of patients independent of the etiology. Dynamic HG may be used to identify symptomatic patients with non-severe secondary MR at rest but severe MR during exercise.

Cardiac responses to maximal anisotonic isometric contractions during handgrip and leg extension

A group of 14-healthy men performed anisotonic isometric contractions (AIC), for 60 s, at an intensity of 100% maximal voluntary contraction force (MVC) during handgrip (HG) and leg extension (LE). Heart rate (fc), stroke volume index (SVI) and cardiac output index (QcI) were measured during the last 10 s of both AIC by an impedance reography method. Force (F) exerted by the subjects was recorded continuously and reported as a relative force (Fr) (% MVC). The F generated during MVC was greater for LE than for HG (502.1 N compared to 374.6 N, P < 0.001). The rate of decrease in Fr was significantly slower for LE than HG for the first 25 s of the exercise (phase 1 of AIC). The Fr developed by the subjects at the end of AIC was 40% MVC for both LE and HG. The increase in fc was greater for LE (63 beats.min-1) than for HG (52 beats.min-1), P < 0.01. The SVI decreased significantly from the resting level by 17.0 ml.m-2 and by 18.2 ml.m-2 for LE and HG, respectively. The QcI increased insignificantly for HG by 0.09 l.min-1.m-2 and significantly for LE by 0.56 l.min-1.m-2 (P < 0.001). It was concluded that although both AIC caused a significant decrease in SVI, greater increases in fc and Qc were observed for LE than for HG. The greater fc and Qc reported during LE was probably related to the greater relative force exerted by LE during phase 1 of AIC. It seems, therefore that central command might have dominated for phase 1 of AIC but that the muscle reflex also contributed significantly to the control of the cardiac response to the high intensity AIC.