Factors underlying clinical tolerance and hemodynamical consequences during monomorphic sustained ventricular tachycardia (VT) are poorly known and need to be clarified.

To study hemodynamical consequences of VT and to evaluate clinical potential predictable factors of poor tolerance.

Patients admitted for VT ablation with invasive blood pressure measurement have been retrospectively included. Intra-arterial pressures (IAP) were collected during VT and correlated to clinical, ECG and baseline echocardiographic parameters.

Fifty-three consecutive patients with 100 VT were included (66±12years old, 83% ischemic cardiomyopathy, LVEF 33±14%). Fifty-five VT were untolerated needing immediate termination. On the 100 VT, resynchronization therapy, VT rate, a concordant VT and presence of diuretics were significantly associated with untolerated VT in multivariate analysis. Untolerated VT were significantly associated to a lower IAP and drop in IAP.

Two different patterns of hemodynamic profiles during VT could be observed: a preserved regular 1:1 relationship between QRS and IAP and some dissociation between QRS and IAP. VT with the second pattern were more often untolerated compared to the first pattern (71% vs. 24%, P<0.001).

A lower LVEF and the less frequent presence of diabetes was present in patients with only untolerated VT versus patients with only well-tolerated VT.

In patients with both well-tolerated and untolerated VT, the latter were significantly faster and had shorter QRS durations (Fig. 1).

This study about hemodynamic during sustained monomorphic VT helps to explain the large variability in clinical tolerance, which is clearly related to IAP during VT. VT tolerance may be linked to resynchronization therapy, LVEF, presence of diabetes and diuretics, baseline QRS duration, VT rate, QRS duration during VT, presence of concordant VT and pattern of hemodynamical profile.