Myocardial hypertrophy is not a prerequisite for changes in early gene expression in left ventricular volume overload

Currently it is not certain whether hypertrophy or the underlying disease is the primary trigger of the alterations in early gene expression in the progression of cardiac disease to end-stage heart failure. In this study, we tested the notion that in left ventricular overload disorders, the changes in early gene expression in the progression to heart failure is independent of the manifestation of cardiac hypertrophy. We compared the expression of the early genes c-fos, c-myc, and c-jun in six dilated cardiomyopathic hearts (DCM) and 15 patients with left ventricular volume overload (VOL) resulting from mitral/aortic regurgitation and no significant stenosis or hypertrophic manifestations, using eight healthy donor hearts as controls. In VOL, c-myc was elevated by 88% (P < 0.01) in the left ventricle, 46% in the right ventricle, onefold (P < 0.01) in the left atrium, and 54% (P < 0.05) in the right atrium, while in DCM, it was increased by 71% (P < 0.02), 55%, 48% (P < 0.05) and 91% (P < 0.05), respectively. Similarly, c-jun was elevated by 41% (P < 0.01) in the left ventricle, 39% (P < 0.05) in the right ventricle, 83% (P < 0.02) in the left atrium and 21% in the right atrium in VOL, while in DCM it was elevated by 13% in the left ventricle, 29% in the left atrium, and 41% in the right atrium, but decreased by 13% in the right ventricle. In contrast, c-fos was slightly decreased in the left ventricle and atrium of both DCM and VOL, and in left atrium of the VOL group, but remained unchanged in the other myocardial chambers. These results show that, in the human myocardium, the three early genes are regulated differently, possibly in disease- and chamber-specific fashions, and manifestation of left ventricular hypertrophy is not a prerequisite for the elevation in their expression in left ventricular overload disorders.     

Implantation of a Dual Chamber Pacing and Sensing Single Pass Defibrillation Lead

GRADAUS, R., et al. : Implantation of a Dual Chamber Pacing and Sensing Single Pass Defibrillation Lead. Dual-chamber ICDs are increasingly used to avoid inappropriate shocks due to supraventricular tachycardias. Additionally, many ICD patients will probably benefit from dual chamber pacing. The purpose of this pilot study was to evaluate the intraoperative performance and short-term follow-up of an innovative single pass right ventricular defibrillation lead capable of bipolar sensing and pacing in the right atrium and ventricle. Implantation of this single pass right ventricular defibrillation lead was successful in all 13 patients (  age 63 ± 8 years  ; LVEF  0.44 ± 0.16  ; New York Heart Association [NYHA]  2.4 ± 0.4  , previous open heart surgery in all patients). The operation time was  79 ± 29  minutes, the fluoroscopy time  4.7 ± 3.1  minutes. No perioperative complications occurred. The intraoperative atrial sensing was  1.7 ± 0.5 mV  , the atrial pacing threshold product was  0.20 ± 0.14 V/ms  (  range 0.03–0.50 V/ms  ). The defibrillation threshold was  8.8 ± 2.7 J  . At prehospital discharge and at 1-month and 3-month follow-up, atrial sensing was  1.9 ± 0.9, 2.1 ± 0.5, and 2.7 ± 0.6 mV  , respectively, (  P = NS, P < 0.05, P < 0.05  to implant, respectively), the mean atrial threshold product  0.79, 1.65, and 1.29 V/ms  , respectively. In two patients, an intermittent exit block occurred in different body postures. All spontaneous and induced ventricular arrhythmias were detected and terminated appropriately. Thus, in a highly selected patient group, atrial and ventricular sensing and pacing with a single lead is possible under consideration of an atrial pacing dysfunction in 17% of patients.     

Myocardial β-adrenergic reactivity in volume overload-induced cardiac hypertrophy in the rat

Summary— The purpose of this study was to evaluate the changes in myocardial β-adrenergic reactivity in animals undergoing a 4 week cardiac volume overload. Aortocaval shunt (ACS) or sham operation (sham) were performed in male Wistar rats, and 4 weeks later, isoproterenol dose-effects (chronotropic, inotropic and lusitropic properties) were studied after pithing. Noradrenaline (NA) and adrenaline (A) concentrations and NA turn-over index were evaluated in plasma and heart ventricles, while β-adrenoceptor characteristics in ventricle homogenates and slices with [¹²⁵I]iodocyanopindolol, and the β(1)/β(2)-adrenoceptor ratio were estimated. Four weeks of cardiac volume overload resulted in a 55% increase in ventricle weight/body weight ratio (from 2.5 ± 0.1 to 3.9 ± 0.1 mg/g in sham and ACS rats, respectively) and a 20% increase in protein contents (from 11.3 ± 0.7 to 13.8 ± 1.1 mg/100 mg ventricles in sham and ACS rats, respectively). Furthermore, NA and A concentrations and NA turn-over index were increased in ACS rats (14, 40 and 80% versus sham, respectively). A shift to the right of the responses in heart rate, left ventricular systolic pressure, +d P /d t _max and -d/ P /d t _max responses following increasing doses of isoproterenol was observed, without change in the dose inducing maximum effect. Total β-adrenoceptor characteristics and β(1)/β(2) ratio were unchanged. However, β(1)-adrenoceptor density increased in epicardium while decreasing in endocardium of left ventricle from ACS rats. Rightward shift at lower doses of isoproterenol-induced cardiac responses in volume-overloaded rats are not likely due to overall β-adrenoceptor density changes.     

Assessment of right ventricular function in recipient twin of twin to twin transfusion syndrome with speckle tracking echocardiography

This study was undertaken to evaluate the right ventricular myocardial systolic function and its relation to the fetal volume and pressure overload in recipient twin of twin to twin transfusion syndrome with speckle tracking echocardiography. Longitudinal peak systolic strains of the right ventricle were measured by speckle tracking echocardiography in 17 patients with twin-to-twin transfusion syndrome (TTTS) and 19 normal monochorionic diamniotic pregnancies. The right ventricular free wall thickness in recipient twin (0.43 ± 0.14 cm) was significantly larger than that in the donor (0.21 ± 0.04 cm, p < 0.05) and the control group (0.18 ± 0.03 cm, p < 0.05 for larger twin and 0.17 ± 0.02 cm, p < 0.05 for smaller twin). Although there were no significant differences in the right ventricular fractional shortening and cavity area percent change among control and the TTTS groups, the absolute value of peak systolic strains of ventricular septum, right ventricular free wall and global right ventricle in recipients were all significantly lower than those of the donors and the control group. Besides, the global right ventricular peak systolic strain correlated well with gestational age adjusted right ventricular free wall thickness (r = 0.65, p = 0.04) but not with gestational age adjusted right ventricular end-diastolic dimension (r = 0.38, p = 0.28) and cavity area percent change (r = 0.33, p = 0.35). Right ventricular systolic dysfunction measured with decreased right ventricular peak systolic longitudinal strain exists despite the absence of diminished fractional shortening and cavity area percent change and this reduced systolic function correlates with the right ventricular pressure overload as shown by increased right ventricular free wall thickness.     

Compression of the Left Ventricular Outflow Tract During Cardiopulmonary Resuscitation

Objectives:  This prospective observational study was performed to investigate if the hand position used for external chest compressions is in an optimal position for compressing the ventricles during standard cardiopulmonary resuscitation (CPR).
Methods:  Transesophageal echocardiography (TEE) was performed during standard CPR in 34 patients with nontraumatic cardiac arrest (24 males, mean ± standard deviation [SD] age = 56 ± 12 years). On the recorded image of TEE, an area of maximal compression (AMC) was identified, and the degree of compression at the AMC and the left ventricular stroke volume was calculated.
Results:  A significant narrowing of the left ventricular outflow tract (LVOT) or the aorta was noted in all patients, with the degree of compression at the AMC ranging from 19% to 83% (mean ± SD = 49 ± 19%). The AMC was found at the aorta in 20 patients (59%) and at the LVOT in 14 patients (41%). A significant narrowing of more than 50% of the diameter at the end of the relaxation phase occurred in 15 patients (44%). On linear regression, the left ventricular stroke volume was correlated with the location of the AMC (R² = 0.165, p = 0.017).
Conclusions:  The outflow of the left ventricle is affected during standard CPR, resulting in varying degrees of narrowing in the LVOT and/or the aortic root.     

Effects of topiramate on migraine frequency and cortical excitability in patients with frequent migraine

We studied the excitability of the visual and motor cortex in 36 patients with frequent migraine without aura (30 women, mean age 38.6 ± 10.0 years) before and after treatment with topiramate (100 mg/day) using transcranial magnetic stimulation. Treatment with topiramate resulted in reduction of both headache frequency (12.0 ± 1.3 to 5.8 ± 3.2 migraine days per month; P  = 0.004) and cortical excitability: motor cortex thresholds increased on the right side from 43.8 ± 7.5% to 47.7 ± 9.2% ( P  = 0.049) and on the left side from 43.4 ± 7.0% to 47.2 ± 9.6% ( P  = 0.047), and phosphene thresholds increased from 58.9 ± 11.1% to 71.2 ± 11.2% ( P  = 0.0001). Reduction of headache frequency correlated inversely with an increase of visual thresholds and did not correlate with motor thresholds. The effect of topiramate in migraine prevention is complex and can not be explained simply by inhibition of cortical excitability.     

Predictive Value of Left Ventricular Remodeling by Area Strain Based on Three-Dimensional Wall-Motion Tracking After PCI in Patients with Recent NSTEMI

We aimed to explore whether a novel left ventricular performance index, area strain (AS), based on three-dimensional wall-motion tracking (3-D-WMT) done before and after percutaneous coronary intervention (PCI) could predict left ventricular (LV) remodeling in patients with recent non-ST elevation myocardial infarction (NSTEMI). Sixty-one patients (53.6 ± 8.8 years) with recent NSTEMI were enrolled. Coronary angiography and PCI were undertaken for reperfusion. Parameters of myocardial deformation (including LV end-diastolic volume, LV end-systolic volume, LV ejection fraction, LV global and regional peak area strain) were measured by 3-D-WMT before and 1 week after reperfusion therapy. Six months after reperfusion, LV negative remodeling was defined as lack of improvement in LV function, with increase in LV end-diastolic volume ≥15%. Patients were subdivided into remodeled group (n = 25) and non-remodeled group (n = 36) at follow-up. Patients with negative LV remodeling had significantly higher cardiac troponin I (cTnI) levels at baseline (21.21 ± 12.22 vs. 15.56 ± 8.91 ng/mL; p = 0.0357), higher B-type natriuretic peptide (BNP) level (247.56 ± 177.39 vs. 170.53 ± 97.89 pg/mL; p = 0.0336) and reduced global AS (−27.9 ± 4.6% vs. −31.9 ± 4.3%; p = 0.001) than those without remodeling. Global AS at baseline had a significantly close correlation with cTnI level 36 h after MI (r = 0.71, p < 0.001). Moreover, a weak relationship was found between LV global AS at baseline and BNP level 24 h after myocardial infarction (r = 0.423, p < 0.001). By multivariate logistic regression analysis, lack of improvement of global AS 1 week after PCI was found to be a powerful independent predictor of negative LV remodeling at follow-up (OR = 1.41, 95% CI 1.28–3.27, p = 0.003). In particular, a global AS ≤32% (absolute value) showed a sensitivity and a specificity of 86.1% and 68.0% in predicting negative LV remodeling. These data suggest that AS could be used to assess myocardial global and regional LV function with good feasibility and repeatability. Global AS 1 week after PCI is a good independent predictor of negative LV remodeling after 6-month follow-up.     

Endocardial Electrogram Analysis after Intramyocardial Injection of Mesenchymal Stem Cells in the Chronic Ischemic Myocardium

Background: Cell injection therapies have been introduced for the treatment of patients with coronary heart disease. However, intramyocardial injection of bone marrow (BM)-derived cells may generate proarrhythmogenicity.
Methods: Two weeks after the placement of a circumflex artery-ameroid constrictor, 21 pigs received mesenchymal stem cells (MSC, n = 9), mononuclear (BM)-derived stem cells (MNC, n = 6), and placebo (n = 6) using a electromechanical mapping (EMM)-guided percutaneous transendocardial injection catheter. At week 6, EMM was repeated and the injected areas were analyzed in detail to evaluate local bipolar electrogram fragmentation, duration, and amplitude. Myocardial fibrosis was evaluated by a quantitative histological analysis.
Results: At week 6, the injection of MSC or MNC did not increase local electrogram fragmentation (MSC group: 1.4 ± 0.3 vs. 1.3 ± 0.2; MNC group: 1.4 ± 0.2 vs. 1.3 ± 0.2; P = NS), prolong electrogram duration (MSC group: 27.1 ± 7.8 ms vs. 23.7 ± 2.0 ms; MNC group: 27.8 ± 3.5 ms vs. 26.8 ± 5.6 ms; P = NS), or decrease bipolar voltages (MSC group 2.7 ± 0.9 mV vs. 2.8 ± 1.0 mV; MNC group 2.0 ± 1.0 mV vs. 1.7 ± 0.4 mV). From week 2 to week 6, mean left ventricular ejection fraction increased in the MSC group (37.9 ± 4.2% vs. 45.9 ± 2.2%; P = 0.039) only. Histological analysis of the ischemic regions revealed 17.6 ± 5% myocardial fibrosis in the MNC group vs. 13.6 ± 3.4% MSC vs. 28.7 ± 8.7% in the control group (P = 0.038 and P = 0.013). No death occurred in any animal after the injection procedure.
Conclusion: Intramyocardial injection of MSC or MNC do not increase fragmentation and duration of endocardial electrograms in the injected ischemic myocardium but attenuate ischemic damage and therefore may not create an electrophysiological substrate for reentry tachycardias     

容量超负荷诱导心力衰竭研究进展

容量超负荷动物模型制作通常分为低压力型和高压力型两类。低压力型通常采用二尖瓣反流模型;高压力型通常采用主动脉反流和主动脉腔静脉瘘模型。容量超负荷和细胞外基质相关,会引起左室细胞外基质重构,进而导致进展性的结构和功能性的左室重构,引发细胞外基质的降解与更新的不平衡。肥大细胞、心肌纤维化细胞及活性氧自由基和容量超负荷诱导心力衰竭的过程中发挥着重要的作用。本文总结了容量超负荷和压力超负荷诱导心力衰竭在机制方面的差异,揭示了肥大相关信号在两类超负荷心脏重构中的差异,并初步提出了钙调神经磷酸酶(CaN)和蛋白激酶B(Akt)信号通路可能分别是针对两类超负荷精准化治疗的靶点。未来对其上下游调控因子在两类超负荷心脏重构中的调控差异,尚需进行更深入的研究。     

Emergency guide wire pacing: new methods for rapid conversion of a cardiac catheter into a pacemaker

We developed a new electrode to convert rapidly a previously inserted pulmonary artery or left ventricular catheter into a pacemaker. One method of doing this is by withdrawal of the pulmonary artery catheter from the pulmonary artery to the right ventricle by pressure control, and a Teflon-coated guide wire, stripped of 5 mm of insulation at its tip, is advanced through the catheter to contact the endocardium. In the second method, the pacing electrode is advanced through the distal lumen of the catheter while it is positioned within the pulmonary artery and withdrawn into the right ventricle while pacing. Finally, a third Method involves advancement of the guide wire electrode into the left ventricle through a pigtail catheter. To pace, the guide wire electrode is connected to the cathode of a pacemaker referenced to a skin electrode. We paced 10 of 10 right heart cardiac catheterization, intra- and postoperative surgery patients by methods 1 and 2, and 4 of 4 left heart catheterization patients by method 3. Thresholds (mean ± SEM) for guide wire pacing were: right ventricle 1.52 ± 0.4 mA; left ventricle 1.33 ± 0.1 mA. Guide wire pacing is rapid, reliable, and requires little operator skill. Our indications for guide wire pacing are: 1) emergency right ventricular pacing in operative or intensive care unit patients with unexpected bradyarrhythmias who have an indwelling pulmonary artery catheter; and 2) emergency left ventricular pacing in left heart cardiac catheterization patients with contrast-induced bradyarrhythmias.     

Acute Hemodynamic Effects of Atrioventricular Pacing at Differing Sites in the Right Ventricle Individually and Simultaneously

We hypothesized that pacing, which provided a rapid uniform contraction of the ventricles with a narrower QRS, would produce a better stroke volume and cardiac output (CO). We sought to study whether pacing simultaneously at two sites in the right ventricle (right ventricular apex and outflow tract) would provide a narrower QRS and improved CO in 11 patients undergoing elective electrophysiology studies. Patients were studied by transthoracic echocardiography measurement of CO using the Doppler flow velocity method in normal sinus rhythm, AOO pacing (rate 80), DOO pacing in the right ventricular apex (AV delay 100 ms). DOO pacing in the right ventricular outflow tract, and DOO pacing at both right ventricular sites simultaneously in random order. The COs were 5.42 ± 1.83, 5.61 ± 1.97. 5.67 ± 1.6. 5.84 ± 1.68. and 5.86 ± 1.52 L/min, respectively (no significant difference by repeated measures analysis of variance [ANOVA]). The QRS durations were 0.09 ± 0.02, 0.09 ± 0.02. 0.13 ± 0.027, 0.13 ± 0.03, and 0.11 ± 0.03 sees respectively. Repeated measures ANOVA showed that the QRS duration significantly increased with right ventricular apex or right ventricluar outflow tract pacing compared to sinus rhythm and AOO pacing (P < 0.001) but then diminished with pacing at both sites (P < 0.01). QRS duration was not correlated with CO, however the change in QRS duration correlated significantly with the change in CO when pacing was performed at the two right ventricular sites simultaneoasly. In conclusion, during DOO pacing, there was a trend for pacing in the right ventricular outflow tract or both sites to improve the CO compared to the right ventricular apex. With simultaneous pacing at both ventricular sites, the QRS narrowed. Further studies will be required to see if this approach has value in patients with poor left ventricular function or congestive heart failure.     

Magnetocardiographic Intra-QRS Fragmentation Analysis in the Identification of Patients with Sustained Ventricular Tachycardia after Myocardial Infarction

KORHONEN, P., et al. : Magnetocardiographic Intra-QRS Fragmentation Analysis in the Identification of Patients with Sustained Ventricular Tachycardia after Myocardial Infarction. The aim of this study was to investigate if magnetocardiographic (MCG) analysis of cardiac micropotentials within the QRS complex can identity patients prone to ventricular arrhythmias, and to compare it to MCG time-domain, late-field analysis. The study population consisted of 136 patients with remote MI, 53 with and 83 without a history of VT. After averaging and high pass filtering of multichannel MCG signals, time-domain parameters describing the end-QRS activity and fragmentation index M and score S describing the whole QRS complex were computed. Fragmentation and time-domain parameters differed between the VT and control groups: fragmentation index M was  12 ± 3  versus  9 ± 2  (  P < 0.001  ), fragmentation score S was  83 ± 42  versus  56 ± 21  (  P < 0.001  ), and filtered QRS duration was  144 ± 32  versus  114 ± 19 ms  (  P < 0.001  ) in VT and control groups, respectively. A combination of fragmentation parameters yielded 87% sensitivity and 61% specificity in VT identification. Corresponding figures for a time-domain parameter combination were 81% and 72%. Sensitivity of time-domain analysis was 88% and specificity was 75% in a subgroup with anterior MI. In multivariate analysis, fragmentation and time-domain analyses discriminated VT patients from controls independently of the extent of coronary artery disease or left ventricular dysfunction. MCG in postinfarction patients reveals pathology associated with propensity to ventricular arrhythmias inside and not only at the end of the QRS complex. MCG seems most accurate in the anterior infarct location.     

Effects of Septal Pacing on P Wave Characteristics: The Value of Three-Dimensional Echocardiography

SZILI-TOROK, T., et al .: Effects of Septal Pacing on P Wave Characteristics: The Value of Three-Dimensional Echocardiography. Interatrial septum (IAS) pacing has been proposed for the prevention of paroxysmal atrial fibrillation. IAS pacing is usually guided by fluoroscopy and P wave analysis. The authors have developed a new approach for IAS pacing using intracardiac echocardiography (ICE), and examined its effects on P wave characteristics. Cross-sectional images are acquired during pullback of the ICE transducer from the superior vena cava into the inferior vena cava by an electrocardiogram- and respiration-gated technique. The right atrium and IAS are then three-dimensionally reconstructed, and the desired pacing site is selected. After lead placement and electrical testing, another three-dimensional reconstruction is performed to verify the final lead position. The study included 14 patients. IAS pacing was achieved at seven suprafossal (SF) and seven infrafossal (IF) lead locations, all confirmed by three-dimensional imaging. IAS pacing resulted in a significant reduction of P wave duration as compared to sinus rhythm (   99.7 ± 18.7   vs   140.4 ± 8.8  ms; P < 0.01   ). SF pacing was associated with a greater reduction of P wave duration than IF pacing (   56.1 ± 9.9   vs   30.2 ± 13.6  ms; P < 0.01   ). P wave dispersion remained unchanged during septal pacing as compared to sinus rhythm (   21.4 ± 16.1   vs   13.5 ± 13.9  ms; NS   ). Three-dimensional intracardiac echocardiography can be used to guide IAS pacing. SF pacing was associated with a greater decrease in P wave duration, suggesting that it is a preferable location to decrease interatrial conduction delay. (PACE 2003; 26[Pt. II]:253–256)     

Spatial Resolution of Body Surface Potential and Laplacian Pace Mapping

LI, G., et al. : Spatial Resolution of Body Surface Potential and Laplacian Pace Mapping. The spatial resolution (SR) of the body surface Laplacian map (BSLM) was assessed using a three-dimensional, realistically shaped, heart-torso model. The BSLMs were estimated from the body surface potential maps (BSPMs) generated by pacing different sites of the ventricle of a three-dimensional computer heart model using a novel three-dimensional spline Laplacian algorithm. Pacing was performed at a total of 88 myocardial units in five regions of the AV ring (anterior, left wall, posterior, right wall, and septum) and three regions adjacent to the AV ring in the middle anterior and posterior of the ventricles. The SR of the BSPMs and BSLMs were investigated by means of the correlation coefficient (CC) of maps. When 5 μV and 10 μV Gaussian white noises were added into the simulated BSPMs, the SR, at 36 ms after the onset of pacing, was about  5.0 ± 1.2 mm  and  5.4 ± 1.3 mm  for the BSPMs, and  3.3 ± 0.8 mm  and  4.0 ± 0.9 mm  for the BSLMs, respectively. The results of the present simulation study suggest that the BSLM has higher SR and may provide a more accurate means than the BSPMs for differentiating between the accessory pathways or the sites of other ectopic cardiac beats along the AV ring and in its neighboring regions.     

二维斑点追踪成像技术对超重及肥胖女性孕中晚期胎儿心室构型变化的评估

目的应用二维斑点追踪成像（2D-STI）评价孕前超重及肥胖女性孕中晚期胎儿心室构型变化。 方法回顾性选取2019年6月至2020年3月于空军军医大学唐都医院进行胎儿超声心动图检查的孕妇80例,根据孕前体质量指数（BMI）将其分为正常对照组30例、超重组27例和肥胖组23例。应用胎儿超声心动图获得常规胎儿心脏形态学指标,采用2D-STI技术并利用Fetal HQ软件获得孕24周及孕32周胎儿双侧心室24节段舒张末期横径及球形指数（SI）,3组间进行单因素方差分析,并采用LSD-t检验进一步行组间两两比较。 结果常规方法测量肥胖组、超重组与正常对照组孕妇胎儿的左、右心室舒张末期横径,左、右心室舒张末期长径,心胸面积比及左心室每搏输出量,3组间差异均无统计学意义（P均＞0.05）。孕中期（孕24周）肥胖组室间隔厚度较正常对照组增厚［（2.10±0.41）mm vs（1.85±0.33）mm］,孕晚期（孕32周）肥胖组室间隔厚度较正常对照组及超重组均增厚［（3.10±0.65）mm vs（2.46±0.52）mm、（2.55±0.53）mm］,差异均有统计学意义（P均＜0.05）。2D-STI测得肥胖组左心室横径孕24周第6~12节段及孕32周第7~12节段分别较同孕龄正常对照组明显增宽,肥胖组左心室SI孕32周第4~12节段较正常对照组明显降低（P均＜0.05）。2D-STI测得肥胖组右心室横径孕24周第3~10节段及孕32周第1~8节段分别较同孕龄正常对照组明显增宽,肥胖组右心室SI孕32周第1~9节段较正常对照组明显降低（P均＜0.05）。 结论孕前肥胖的孕妇胎儿左心室中间段、右心室基底段节段性横径增宽,与正常对照者相比更接近球形,提示测量左心室中间段及右心室基底段横径可更敏感地反映孕前肥胖孕妇胎儿心室形态的改变。     

A prospective, double-blind, randomized clinical feasibility trial of controlling the storage age of red blood cells for transfusion in cardiac surgical patients

BACKGROUND: Recent evidence demonstrates an association between duration of storage of red blood cells (RBC) and morbidity and mortality after cardiac surgery. We studied the feasibility of two different schemes for categorizing and randomizing age of RBC units transfused in cardiac surgical patients.
STUDY DESIGN AND METHODS: In Phase 1, 20 subjects were randomly assigned to standard of care (SOC) versus no RBCs with more than 21 days' storage duration. In Phase 2, 23 subjects were randomized to RBCs of 7 ± 4 versus 21 ± 4 days' storage duration. The age of study RBC units was masked.
RESULTS: In Phase 1, no patients received RBCs 31 days or older in SOC, and there was overlap in storage age shared in both arms so the predefined feasibility criteria were not met. In Phase 2, it was feasible to deliver specified age RBCs to the 7-day arm (achieved in 100% of subjects), but feasibility was not demonstrated for the 21-day arm (only 50% of subjects transfused with target age RBCs). Significant differences, however, were observed between the 7 ± 4- and 21 ± 4-day arms with respect to age of all RBC units (6 ± 2 vs. 18 ± 7, p = 0.0002) and maximum age (7 ± 2 vs. 20 ± 7, p < 0.0001).
CONCLUSION: Given the current storage age distribution of available RBC inventory, use of a SOC arm in future studies is unlikely to result in a large exposure to "old" blood. It is feasible to randomize patients to "younger" RBCs (3-11 days) but design strategies are needed to provide "intermediate-aged" or "old" blood as a comparator.     

Angiographic Anatomy of the Coronary Sinus and Its Tributaries

Permanent left ventricular pacing has been shown to imporve the hemodynamic and clinical status of patients with severe heart failure. To pace the left ventricle, the electrode is implanted in tributaries of the coronary sinus (CS). However, the anatomy of cardiac veins with this purpose in mind has not been described in detail. Methods: One hundred consecutive patients admitted for coronary angiography had a simultaneous coronary venography performed after the injection of 8 to 10 mL of contrast material into the left coronary artery. Cardiac veins were analyzed in antero-posterior, left anterior oblique 60±, and right anterior oblique 30± views by three different observers. The number, dimension, angulation, and position of the coronary sinus and of its tributaries were studied. Results: Two veins are consistently present: the middle cardiac vein (mean diameter 2.62 ± 1.26 mm) and the great cardiac vein (mean diameter 3.55 ± 1.24 mm). The left posterior vein(s) (LPV) (mean diameter 2.25 ± 1.2 mm) is (are) variable in number (ranging from 0 to 3), size, and angulation. The absence of LPV limits the ability to pace the left ventricle endovenously. The diameter of the vein (< 2 mm) and its angulation may also complicate the insertion of the lead. Conclusion: Angiographic analysis of dimensions, tortuosity, number, and angulation of venous tributaries of the CS seems to allow the insertion of commercially available pacing leads in approximately 85% of cases. An increase in this percentage hinges on the development of new, dedicated leads.     

Abnormal Cardiac Innervation in Patients with Idiopathic Ventricular Fibrillation

BIFFI, M., et al .: Abnormal Cardiac Innervation in Patients with Idiopathic Ventricular Fibrillation. Idiopathic ventricular fibrillation (VF) is diagnosed in up to nearly 10% of survivors of out-of-hospital cardiac arrest. The arrhythmogenic substrate is unknown. This study examined the role of cardiac innervation as a possible contributor to this arrhythmia. Eight patients with idiopathic VF were compared with eight normal subjects (controls) by [¹²³] I metaiodobenzylguanidine SPECT (MIBG), measuring peak uptake, late uptake, and clearance of the nuclear tracer. The left ventricle was divided in 13 segments in the bull's-eye target plot. Peak and late MIBG uptake was increased in the anterolateral segments (2,3,7,8) compared to the inferoposterior and septal segments, in controls and in patients. No difference was observed between controls and patients in the inferoposterior and septal segments. In contrast, a significantly higher MIBG uptake was observed in patients compared to controls in the anterolateral segments (   94 ± 4%   vs   81 ± 11%, P < 0.03   for peak uptake;   94 ± 5%   vs   79 ± 12%, P < 0.01   for late uptake). No difference was observed in MIBG clearance in any segment in either study group. Cardiac sympathetic innervation is highly heterogeneous, though predominant in anterolateral segments in normal subjects. Patients with idiopathic VF exhibit the same distribution, though have a significantly greater density of sympathetic terminals in the anterolateral segments than controls, which may promote ventricular arrhythmias. (PACE 2003; 26[Pt. II]:357–360)     

Flight-associated headaches-prevalence and characteristics

Environmental factors in airplanes may precipitate headaches. We conducted a questionnaire-based study among consecutive travellers to determine the rate, severity and duration of flight-associated headaches (FAHA). Of the 906 eligible travellers (mean age 33.3 ± 13.8 years), 22.3% reported headaches at least once per month. FAHA occurred in 52 travellers (5.7%), of whom 34 were women ( P  = 0.0023 vs. none FAHA). The duration of pain was 4.0 ± 10.2 h after takeoff and continued for 5.7 ± 14.2 h after landing. Migraine was diagnosed in 19.2% of those with FAHA. The magnitude of headache was 6 ± 2 (on a scale of 1–10). Among those who suffer from FAHA, 45.4% reported that their pain was unilateral, in contrast to 72.7% among those with 'non-flight' headaches ( P  = 0.019). Nine travellers had headaches when descending to −400 m below sea level, and nine upon climbing to high altitude. This preliminary observation indicates that FAHA is not uncommon and should be further investigated.