The diagnostic role of T wave morphology biomarkers in congenital and acquired long QT syndrome: A systematic review.

INTRODUCTION: QTc prolongation is key in diagnosing long QT syndrome (LQTS), however 25%-50% with congenital LQTS (cLQTS) demonstrate a normal resting QTc. T wave morphology (TWM) can distinguish cLQTS subtypes but its role in acquired LQTS (aLQTS) is unclear. METHODS: Electronic databases were searched using the terms "LQTS," "long QT syndrome," "QTc prolongation," "prolonged QT," and "T wave," "T wave morphology," "T wave pattern," "T wave biomarkers." Whole text articles assessing TWM, independent of QTc, were included. RESULTS: Seventeen studies met criteria. TWM measurements included T-wave amplitude, duration, magnitude, Tpeak-Tend, QTpeak, left and right slope, center of gravity (COG), sigmoidal and polynomial classifiers, repolarizing integral, morphology combination score (MCS) and principal component analysis (PCA); and vectorcardiographic biomarkers. cLQTS were distinguished from controls by sigmoidal and polynomial classifiers, MCS, QTpeak, Tpeak-Tend, left slope; and COG x axis. MCS detected aLQTS more significantly than QTc. Flatness, asymmetry and notching, J-Tpeak; and Tpeak-Tend correlated with QTc in aLQTS. Multichannel block in aLQTS was identified by early repolarization (ERD30% ) and late repolarization (LRD30% ), with ERD reflecting hERG-specific blockade. Cardiac events were predicted in cLQTS by T wave flatness, notching, and inversion in leads II and V5 , left slope in lead V6 ; and COG last 25% in lead I. T wave right slope in lead I and T-roundness achieved this in aLQTS. CONCLUSION: Numerous TWM biomarkers which supplement QTc assessment were identified. Their diagnostic capabilities include differentiation of genotypes, identification of concealed LQTS, differentiating aLQTS from cLQTS; and determining multichannel versus hERG channel blockade.

Rotator cuff muscles perform different functional roles during shoulder external rotation exercises.

The aim of this study was to compare activity in shoulder muscles during an external rotation task under conditions of increasing arm support to investigate whether changing support requirements would influence muscle recruitment levels, particularly in the rotator cuff (RC) muscles. Electromyographic recordings were collected from seven shoulder muscles using surface and indwelling electrodes. The dominant shoulder of 14 healthy participants were examined during dynamic shoulder external rotation performed at 90° abduction with the arm fully supported, partially supported, and unsupported. Linear regressions between arm support load and the averaged muscle activity across participants for each muscle showed infraspinatus predominantly contributing to rotating the shoulder whilst supraspinatus, deltoid, upper trapezius, and serratus anterior were predominantly functioning in support/stabilization roles. During dynamic shoulder external rotation in mid-range abduction, the RC muscles perform different functional roles. Infraspinatus is responsible for producing external rotation torque, supraspinatus is playing a larger joint stabilizer role, and subscapularis is contributing minimally to joint stability. The results also indicate that increasing support load requirements during an external rotation task may be a functionally specific way to retrain the stabilization function of axioscapular muscles. Manipulating joint stabilization requirements while maintaining constant rotational load is a novel method of investigating the differential contribution of muscles to joint movement and stabilization during a given task.

Safety and efficacy of aerobic exercise commenced early after cardiac surgery: A systematic review and meta-analysis.

BACKGROUND: Aerobic exercise is a critical component of cardiac rehabilitation following cardiac surgery. Aerobic exercise is traditionally commenced 2-6 weeks following hospital discharge and most commonly includes stationary cycling or treadmill walking. The initiation of aerobic exercise within this early postoperative period not only introduces the benefits associated with aerobic activity sooner, but also ameliorates the negative effects of immobilization associated with the early postoperative period. METHODS: A systematic review identified all studies reporting safety and efficacy outcomes of aerobic exercise commenced within two weeks of cardiac surgery. A meta-analysis was performed comparing functional, aerobic and safety outcomes in patients receiving early postoperative aerobic exercise compared with usual postoperative care. RESULTS: Six-minute walk test distance at hospital discharge was 419 ± 88 m in early aerobic exercise patients versus 341 ± 81 m in those receiving usual care (mean difference 69.5 m, 95% confidence interval (CI) 39.2-99.7 m, p < 0.00001). Peak aerobic power was 18.6 ± 3.8 ml·kg-1·min-1 in those receiving early exercise versus 15.0 ± 2.1 ml·kg-1·min-1 in usual care (mean difference 3.20 ml·kg-1·min-1, 95% CI 1.45-4.95, p = 0.0003). There was no significant difference in adverse events rates between the two groups (odds ratio 0.41, 95% CI 0.12-1.42, p = 0.16). CONCLUSION: Aerobic exercise commenced early after cardiac surgery significantly improves functional and aerobic capacity following cardiac surgery. While adverse event rates did not differ significantly, patients included were very low risk. Further studies are required to adequately assess safety outcomes of aerobic exercise commenced early after cardiac surgery.

Anatomical variations of the renal arterial vasculature: An Australian perspective.

INTRODUCTION: Variations of the renal arteries have been studied and published across various population groups, but similar information for the ethnically diverse nation of Australia is lacking. This study describes the pattern of renal artery anomalies in a section of the Australian population based on computed tomography (CT) angiograms of the abdomen and cadaveric dissection. METHODS: The renal arterial vasculature of 594 kidneys from 300 subjects (28 cadavers, 272 CT) was studied. The number and pattern of renal arteries were categorised on the basis of laterality, point of origin and termination in the kidney (superior pole, hilum and inferior pole), symmetry and sex. RESULTS: Multiple renal arteries were discovered in 22% of subjects and 12.12% of kidneys. The most common pattern observed was the presence of one variant renal artery (93.1%), compared to the finding of two (5.6%) and three (1.4%) multiple arteries. The aorta was the most frequent site of origin for anomalous vessels, while the hilum was the predominant point of entry. No significant difference was established between left- and right-sided kidneys (13.8% vs. 12.5%; P = 0.627); however, unilateral distribution was more common than bilateral additional renal arteries (16.7% vs. 3.4%; P < 0.01), and variations among males were more than females (27.2% vs. 15.2%; P < 0.05). A higher rate of multiple renal arteries was noted in cadaveric dissections compared to CT images (46.4% vs. 19.5%; P < 0.01). CONCLUSION: These findings provide application of an evidence-based teaching tool that facilitates education regarding renal arterial variations in Australia.