RESUMO
BACKGROUND: Myocardial mechano-energetic efficiency (MEE) is the capability of the left ventricle (LV) to convert the chemical energy obtained from the cardiac oxidative metabolism into mechanical work. The aim of present study was to establish normal non-invasive MEE and MEEi reference values. METHODS: In total, 1168 healthy subjects underwent physical examinations, clinical assessment, and standardized transthoracic echocardiographic (TTE) examination. MEE was obtained by TTE as the ratio between stroke volume (SV) and heart rate (HR): MEE = SV/HR [HR expressed in seconds (HR/60)]. Because MEE is highly related to left ventricular mass (LVM), MEE was then divided by LVM with the purpose of obtaining an estimate of energetic expenditure per unit of myocardial mass (i.e., indexed MEE, MEEi, mL/s/g). RESULTS: The mean values of MEE and MEEi in the overall population were 61.09 ± 18.19 mL/s; 0.45 ± 0.14, respectively. In a multivariable analysis, gender, body surface area (BSA), diastolic blood pressure, left atrial volume indexed to BSA, E/e' and tricuspid annular plane systolic excursion (TAPSE) were the independent variables associated with MEE, while age, gender, BSA and TAPSE were the independent variables associated with MEEi. CONCLUSIONS: The knowledge of age- and gender-based MEE and MEEi normal values may improve the global assessment of LV cardiac mechanics and serve as a reference to identify phenotypes at high risk of cardiovascular events.
RESUMO
BACKGROUND: The standard approach to subcutaneous defibrillator (S-ICD) implantation often requires general anesthesia or anesthesiologist-delivered deep sedation. Ultrasound-guided serratus anterior plane block (SAPB) combined with parasternal block (PSB) has been proposed in order to provide anesthesia/analgesia and to reduce the need for sedation during S-ICD implantation. In this pilot study, we compared the double-block approach (SAPB + PSB) with the single-block approach (SAPB only) and with the standard approach involving local anesthesia and sedation. METHODS: We prospectively enrolled 22 patients undergoing S-ICD implantation: in 10, the single-block approach was adopted; in 12, the double-block approach. As a control group, we retrospectively enrolled 14 consecutive patients who had undergone S-ICD implantation under standard local anesthesia and sedation in the previous 6 months. Intra- and postprocedural data, including patient-reported pain intensity, were collected and compared in the three study groups. RESULTS: The double-block approach was associated with a shorter procedure duration than the single-block and standard approaches (63.3 ± 7.9 vs 70.1 ± 6.8 vs 76.9 ± 7.8 min; P < .05) and with a lower dose of local an aesthetic for infiltration (18.9 ± 1.7 vs 27.5 ± 4.6 vs 44.6 ± 4.0 cc; P < .001). Both the double- and single-block approaches were associated with lower pain intensity at the device pocket and the lateral tunneling site (P < .05). The double-block approach proved superior to the other two approaches in controlling intraoperative pain at the parasternal tunneling site (P < .05). CONCLUSIONS: In our study, SAPB combined with PSB was superior to SAPB alone and to the standard approach in controlling intraoperative pain during S-ICD implantation. In addition, this approach resulted in shorter procedure durations.
