Right ventricle dysfunction and echocardiographic parameters in the first 24h following resuscitation in the post-cardiac arrest patient: A retrospective cohort study.

OBJECTIVES: To describe the echocardiographic parameters of the right ventricle (RV) in first 24h post-cardiac arrest (CA) in humans; to determine if the etiology of arrest predicts RV dysfunction; to quantify parameters of the right ventricle in the first 24h post-CA. DESIGN: Retrospective cohort study. Arrests were categorized by as circulatory, respiratory, or arrhythmia. RV fractional area change (RVFAC), longitudinal strain (LS), tricuspid annular plane systolic excursion (TAPSE), and right ventricular dimensions were evaluated. We defined RV dysfunction as the presence of an abnormal RVFAC, TAPSE or LS based on the latest echocardiographic guidelines. Structural abnormalities were defined as the presence of abnormal longitudinal strain, RV mid-diameter, basal diameter and RV end diastole/systole. SETTING: Two academic inpatient facilities between 2010 and 2013. PATIENTS: All patients with successful resuscitation following CA with a technically adequate echocardiogram within 24h. MEASUREMENTS AND MAIN RESULTS: Fifty-nine patients met inclusion criteria. Nineteen subjects had CA from a circulatory etiology, 23 from arrhythmias, and 17 from respiratory causes. Fifty-two of 59 patients met criteria for having functional anomalies of the RV. There was no statistical difference between the etiology of CA and the presence of RV dysfunction (p=0.106). Fifty-seven of 59 patients had evidence of structural abnormalities. CONCLUSIONS: RV dysfunction is present in the majority of post-CA patient regardless of the etiology of arrest. Further studies are needed to investigate if there are relationships between echocardiographic findings and survival and to assess temporal findings of RV function post-CA.

Stroke volume obtained by electrical interrogation of the brachial artery: transbrachial electrical bioimpedance velocimetry.

The goal of this study is to measure left ventricular stroke volume (SV) from the brachial artery (BA) using electrical bioimpedance. Doppler-derived SV was used for comparison. Twenty-nine healthy adults were recruited for study. Doppler echocardiographic-derived SV was obtained from the product of distal left ventricular outflow tract cross-sectional area and systolic velocity integral. SV from the BA was obtained by transbrachial electrical bioimpedance velocimetry (TBEV). Application of a current field across the left brachium was effected by injection of a constant magnitude, high frequency, low amperage, alternating current. Therein, a static voltage (U(0)) and pulsatile voltage change (ΔU(t)) were measured and converted to their corresponding impedances, Z(0) and ΔZ(t). TBEV-derived SV was obtained by multiplying a square root value of the normalized, acceleration-based, peak first time derivative of ΔZ(t) by a volume conductor and systolic flow time. Inter-method agreement was determined by the Bland-Altman method. To assess the contribution of blood resistivity variations to ΔZ(t), BA diameters were measured at end-diastole and peak systolic expansion. Results indicate that since the BA demonstrates parabolic, laminar flow, with minimal diameter changes, blood resistivity variations are likely responsible for the derived impedance changes. Bland-Altman analysis shows that SV is obtainable by TBEV from healthy humans at rest.

Usefulness of compensatory hyperkinesis in the noninfarcted left ventricular wall in separating single from multivessel coronary artery disease in patients with initial ST-elevation acute myocardial infarction.

We assessed the contractility of the contralateral wall on 2-dimensional echocardiography in 50 patients with an initial ST-elevation acute myocardial infarction who underwent coronary angiography. Compensatory hyperkinesis, which we defined as a fractional thickening of >/=60% in the contralateral wall, was a strong predictor of single-vessel coronary artery disease, with a positive predictive value of 85%.