Sebastian Schnaubelt

The “Pectoral-Gap Phenomenon”: A Hypothesis on Origin and Mechanism

Against a background of increasing interest and vivid discussion in the sports community including various social media, a ‘‘phenomenon’’ has come to the clinician’s attention that has not specifically been addressed in a scientific way before. Emerging from a report on an American wrestling champion, the so-called ‘‘pectoral-gap phenomenon’’ raises questions. The athlete’s pectoral muscles seem to drift apart over the course of several years’ time, leaving a central space in the sternal region, as depicted in Fig. 1. In addition to this high-profile case involving an American wrestling champion, reports of an increasing number of athletes suffering from the same condition can be found in the social media. There it is hypothesized that recurrent micro trauma of muscle and surrounding tissue structures related to long-term body building, weight lifting, and wrestling might result in shrinking and symmetric lateral displacement of the medial portions of the pectoralis major muscle. The incidence of pectoralis injuries is increasing in the overall population, partly due to the increasing popularity of workouts such as bench pressing [1], although the risk of injuries in the pectoral region is highest in military personnel or athletes [2]. There are various pathologies of the pectoral region, such as rupture of the pectoralis muscle tendon [2, 3]; congenital Poland’s syndrome accompanied by a mostly unilateral pectoral morphologic anomaly and hand deformity [4, 5]; thoracic outlet syndrome, a controversial clinical entity presenting as constrictions in the thoracic region resulting in compression of the brachial plexus and/or the subclavian vessels [6]; cervical radiculopathy; tumor of the spinal cord or brachial plexus; amyotrophic lateral sclerosis; and Parsonage–Turner syndrome resulting in muscular atrophy [7]. However, none of these entities results in the ‘‘pectoral-gap phenomenon.’’ Reviewing the region’s anatomy, the medial pectoral nerve in most individuals penetrates through the pectoralis minor muscle in order to innervate the pectoralis major, which acts as an adductor and internal rotator of the shoulder joint [1]. The lateral pectoral nerve lies in the fascia on the lower side of the pectoralis major muscle [8], with both nerves emerging from the brachial plexus. The medial pectoral nerve supplies the pectoralis minor muscle and the distal segment of the pectoralis major muscle, and the lateral pectoral nerve supplies the upper/proximal portion of the pectoralis major muscle [9]. Anatomic studies have shown that the lateral pectoral nerve is larger than its medial counterpart, indicating a greater importance with regard to innervation. Doubleor single-nerve neuropraxia has been described to induce varying degrees of & Patrick Sulzgruber patrick.sulzgruber@meduniwien.ac.at

CD4+CD28null T Lymphocytes are Associated with the Development of Atrial Fibrillation after Elective Cardiac Surgery

Post-operative atrial fibrillation (POAF) is postulated as a complex interaction of different pathogenic factors, suggesting inflammatory processes as a main trigger of this particular type of atrial fibrillation. Therefore, the study sought to assess the impact of cellular immunity on the development of POAF. Comparing patients developing POAF to individuals free of POAF the fraction of CD4+CD28null T Lymphocytes was significantly higher in individuals developing POAF (11.1% [POAF] vs. 1.9% [non-POAF]; pu2009<u20090.001). CD4+CD28null cells were independently associated with the development of POAF with an adjusted odds ratio per one standard deviation of 4.89 (95% CI: 2.68–8.97; pu2009<u20090.001). Compared to N-terminal Pro-Brain Natriuretic Peptide, the fraction of CD4+CD28null cells demonstrated an increased discriminatory power for the development of POAF (NRI: 87.9%, pu2009<u20090.001; IDI: 30.9%, pu2009<u20090.001). Interestingly, a pre-operative statin-therapy was associated with a lower fraction of CD4+CD28null cells (pu2009<u20090.001) and showed an inverse association with POAF (pu2009<u20090.001). CD4+CD28null cells proved to be predictive for the development of POAF after cardiac surgery. Our results potentially indicate an auto-immune impact of this preexisting, highly cytotoxic T cell subset in the pathogenesis of POAF, which might be modified via the anti-inflammatory potential of a pre-operative statin-therapy.

Regional cerebral oxygen saturation during cardiopulmonary resuscitation as a predictor of return of spontaneous circulation and favourable neurological outcome – A review of the current literature

INTRODUCTIONnRegional cerebral oxygen saturation (rSO2) can be measured non-invasively even at no- or low-flow states. It thus allows assessment of brain oxygenation during CPR. Certain rSO2 values had been associated with return of spontaneous circulation (ROSC) and neurological outcome in the past. Clear-cut thresholds for the prediction of beneficial outcome, however, are still lacking.nnnMETHODSnWe conducted a database search to extract all available investigations on rSO2 measurement during CPR. Mean, median, and ΔrSO2 values were either taken from the studies or calculated. Thresholds for the outcome ROSC and neurological outcome were sought.nnnRESULTSnWe retrieved 26 publications for the final review. The averaged mean rSO2 for patients achieving ROSC was 41u202f±u202f12% vs. 30u202f±u202f12% for non-ROSC (pu202f=u202f.009). ROSC was not observed when mean rSO2 remained <26%. In ROSC patients, ΔrSO2 was 22u202f±u202f16% vs. 7u202f±u202f10% in non-ROSC patients (pu202f=u202f.009). A rSO2 threshold of 36% predicted ROSC with a sensitivity of 67% and specificity of 69% while ΔrSO2 of 7% showed a sensitivity of 100% and a specificity of 86% (AUCu202f=u202f0.733 and 0.893, respectively). Mean rSO2 of 47u202f±u202f11% was associated with favourable and 38u202f±u202f12% with poor neurological outcome. There was, however, a great overlap between groups due to scarce data.nnnCONCLUSIONnHigher rSO2 consistently correlated with increased rates of ROSC. The discriminatory power of rSO2 to prognosticate favourable neurological outcome remains unclear. Measuring rSO2 during CPR could potentially facilitate clinical decision-making.

Gender and age-specific aspects of awareness and knowledge in basic life support

Background The ‘chain of survival’—including early call for help, early cardiopulmonary resuscitation (CPR) and early defibrillation—represents the most beneficial approach for favourable patient outcome after out-of-hospital cardiac arrest (OHCA). Despite increasing numbers of publicly accessible automated external defibrillators (AED) and interventions to increase public awareness for basic life support (BLS), the number of their use in real-life emergency situations remains low. Methods In this prospective population-based cross-sectional study, a total of 501 registered inhabitants of Vienna (Austria) were randomly approached via telephone calls between 08/2014 and 09/2014 and invited to answer a standardized questionnaire in order to identify public knowledge and awareness of BLS and AED-use. Results We found that more than 52 percent of participants would presume OHCA correctly and would properly initiate BLS attempts. Of alarming importance, only 33 percent reported that they would be willing to perform CPR and 50 percent would use an AED device. There was a significantly lower willingness to initiate BLS attempts (male: 40% vs. female: 25%; OR: 2.03 [95%CI: 1.39–2.98]; p<0.001) and to use an AED device (male: 58% vs. female: 44%; OR: 1.76 [95%CI: 1.26–2.53]; p = 0.002) in questioned female individuals compared to their male counterparts. Interestingly, we observed a strongly decreasing level of knowledge and willingness for BLS attempts (-14%; OR: 0.72 [95%CI: 0.57–0.92]; p = 0.027) and AED-use (-19%; OR: 0.68 [95%CI: 0.54–0.85]; p = 0.001) with increasing age. Conclusion We found an overall poor knowledge and awareness concerning BLS and the use of AEDs among the Viennese population. Both female and elderly participants reported the lowest willingness to perform BLS and use an AED in case of OHCA. Specially tailored programs to increase awareness and willingness among both the female and elderly community need to be considered for future educational interventions.

Oxygenation in post-resuscitation care—how much is too much?

Despite continuous advances in patient care, both neurologic and psychologic disability after cardiac arrest (CA) still remain dismal with hypoxic brain injury as the main determinant [primary cause of death in 68% of in-hospital CA and 23% of out-of-hospital CA (OHCA)] (1).

Cardiac arrest as an age-dependent prognosticator for long-term mortality after acute myocardial infarction: the potential impact of infarction size

Background: The development of cardiac arrhythmias resulting in cardiac arrest represents a severe complication in patients with acute myocardial infarction. While the worsening of the prognosis in this vulnerable patient collective is well known, less attention has been paid to its age-specific relevance from a long-term perspective. Methods: Based on a clinical acute myocardial infarction registry we analysed 832 patients with acute myocardial infarction within the current analysis. Patients were stratified into equal groups (n=208 per group) according to age in less than 45 years, 45–64 years, 65–84 years and 85 years and older via propensity score matching. Multivariate Cox regression analysis was used to assess the age-dependent influence of cardiac arrest on mortality. Results: The total number of cardiac arrests differed significantly between age groups, demonstrating the highest incidence in the youngest population with 18.8% (n=39), and a significantly lower incidence by increasing age (−11.6%; P=0.01). After a mean follow-up time of 8 years, a total of 264 patients (31.7%) died due to cardiovascular causes. While cardiac arrest was a strong and independent predictor for mortality within the total study population with an adjusted hazard ratio of 3.21 (95% confidence interval 2.23–4.61; P<0.001), there was no significant association with mortality independently in very young patients (<45 years; adjusted hazard ratio of 1.73, 95% confidence interval 0.55–5.53; P=0.35). Conclusion: We found that arrhythmias resulting in cardiac arrest are more common in very young acute myocardial infarction patients (<45 years) compared to their older counterparts, and were able to demonstrate that the prognostic value of cardiac arrest on long-term mortality in patients with acute myocardial infarction is clearly age dependent.