Termination of dobutamine infusion causes transient rebound left heart diastolic dysfunction in healthy elderly women but not in men: a cardiac magnetic resonance study

The Effects of Dobutamine in Septic Shock: An Updated Narrative Review of Clinical and Experimental Studies

The key objective in the hemodynamic treatment of septic shock is the optimization of tissue perfusion and oxygenation. This is usually achieved by the utilization of fluids, vasopressors, and inotropes. Dobutamine is the inotrope most commonly recommended and used for this purpose. Despite the fact that dobutamine was introduced almost half a century ago in the treatment of septic shock, and there is widespread use of the drug, several aspects of its pharmacodynamics remain poorly understood. In normal subjects, dobutamine increases contractility and lacks a direct effect on vascular tone. This results in augmented cardiac output and blood pressure, with reflex reduction in systemic vascular resistance. In septic shock, some experimental and clinical research suggest beneficial effects on systemic and regional perfusion. Nevertheless, other studies found heterogeneous and unpredictable effects with frequent side effects. In this narrative review, we discuss the pharmacodynamic characteristics of dobutamine and its physiologic actions in different settings, with special reference to septic shock. We discuss studies showing that dobutamine frequently induces tachycardia and vasodilation, without positive actions on contractility. Since untoward effects are often found and therapeutic benefits are occasional, its profile of efficacy and safety seems low. Therefore, we recommend that the use of dobutamine in septic shock should be cautious. Before a final decision about its prescription, efficacy, and tolerance should be evaluated throughout a short period with narrow monitoring of its wanted and side effects.

Reproducibility of peak filling and peak emptying rate determined by cardiovascular magnetic resonance imaging for assessment of biventricular systolic and diastolic dysfunction in patients with pulmonary arterial hypertension

Right ventricular (RV) and left ventricular (LV) diastolic stiffness may be independent contributors to disease progression in pulmonary arterial hypertension (PAH). The aims of this study are to assess reproducibility of peak emptying rate (PER) and early diastolic peak filling rate (PFR) for both the RV and the LV in PAH and study their relationship to stroke volume (SV). Triple weekly repetition of 20 (totalling 60) cardiovascular magnetic resonance (CMR) scans, were done on 10 patients with PAH and 10 healthy controls. RV and LV volumes were measured over the full cardiac cycle. PER and PFR were calculated as the first derivative of the time-volume relationship in both the RV and the LV and indexed to body surface area. Reproducibility and the relation to SV were studied in a mixed model. PFR was lower in PAH in both the RV (PAH = 170 mL/m²/s, controls = 236 mL/m²/s [p < 0.01]) and in the LV (PAH = 209 mL/m²/s, controls = 311 mL/m²/s [p < 0.01]). PERs were not significantly different between patients and controls. Reproducibility of PER and PFR was high. A trial targeting normalization of PFR requires a total sample size of < 20. PER and PFR in both ventricles were strongly associated with stroke volume (all four: p < 0.01). Biventricular diastolic dysfunctions are strongly associated with stroke volume, and CMR can quantify them with high reproducibility, enabling small sample sizes for trials of therapies targeting diastolic dysfunction to increase survival.

Takotsubo cardiomyopathy, a two-stage recovery of left ventricular systolic and diastolic function as determined by cardiac magnetic resonance imaging

AIMS

Takotsubo cardiomyopathy (TTC) is an entity mimicking acute myocardial infarction, characterized by transient severe systolic heart failure. Echocardiographic studies suggest that diastolic dysfunction is present in TTC at presentation; however, no reports exist regarding the time course of left ventricular (LV) recovery. This study describes the recovery of LV systolic and diastolic function in TTC. We hypothesized that, in TTC, there is diastolic dysfunction at admission, and that recovery is delayed compared with systolic function.

METHODS AND RESULTS

We enrolled (consecutively 2010-12) 16 patients (mean age 66, range 39-84 years) diagnosed with TTC and 20 healthy matched controls. We performed cardiac magnetic resonance imaging (CMR) at admission, pre-discharge, and 3-month follow-up. Diastolic function was assessed by LV peak filling rate (LVPFR) and left atrial (LA) emptying volumes. At admission, LV ejection fraction was low, increased at pre-discharge (37 ± 6 vs. 58 ± 6%, P < 0.001), and normalized at follow-up (to 65 ± 5%, P = 0.01). LVPFR did not increase during hospitalization (80 ± 3 vs. 89 ± 4 mL/s/m(2), P = 0.21), but was normalized at follow-up (to 206 ± 19, P < 0.001; controls, 214 ± 13, P = 0.23). During hospitalization, LA passive emptying volume remained low (6 ± 2 vs. 8 ± 3 mL/m(2), P = 0.05) and LA active emptying volume remained high (17 ± 3 vs. 16 ± 3 mL/m(2), P = 0.71), whereas LA conduit volume increased (7 ± 3 vs. 23 ± 4 mL/m(2), P < 0.001). T2-weighted imaging demonstrated non-coronary distributed apical oedema without contrast enhancement.

CONCLUSION

Patients with TTC undergo fast systolic recovery. However, at discharge, profound diastolic dysfunction is demonstrated by CMR. At follow-up, both LV systolic and diastolic function is normalized in patients with recovered TTC.