Central cannulation by Seldinger technique: a reliable method in ascending aorta and aortic arch replacement.

BACKGROUND: Extensive type A aortic dissections that involve peripheral great vessels can complicate the choice of a cannulation site for cardiopulmonary bypass. We started to employ direct cannulation of the true lumen on the concavity of the aortic arch by Seldinger technique and evaluated the efficacy of this access technique as an alternative arterial inflow target in aortic surgery. MATERIAL/METHODS: Twenty-four consecutive patients (mean age: 59±14 years) underwent type A aortic dissection repair using selective antegrade cerebral perfusion. Direct aortic cannulation was used in 14 cases, subclavian access in 6 patients, and femoral entry in 4 patients. Perioperative factors were evaluated to identify the reliability and eventual benefits of direct cannulation method at the aortic arch. RESULTS: There were no operative deaths and cumulative 30-day mortality rate was 25% (6). Permanent neurological deficits were not observed; in 1 patient transient changes occurred (4%). Time to reach circulatory arrest was the shortest in the direct access group, with mean 27±11 (CI: 20.6-33.3) min vs. 43±22 (28.0-78.0) min (p=0.058) and 32±8 (23.6-40.4) min (p=0.34) by femoral cannulation and subclavian entry, respectively. Direct arch cannulation resulted in the best renal function in the first 72 h after surgery and similar characteristics were observed in lactic acid levels. CONCLUSIONS: Ultrasound-guided direct cannulation on the concavity of the aortic arch using a Seldinger technique is a reliable method in dissection repairs. Prompt antegrade perfusion provides not only cerebral but also peripheral organ and tissue protection, which is an advantage in this high-risk group of patients.

Staged hybrid ablation in left atrial appendage aneurysm a rare cause of refractory atrial tachyarrhythmia-a case report.

Background: Left atrial appendage aneurysm (LAAA) is a rare cardiac anomaly, which can be congenital or acquired in origin. Because most cases are asymptomatic, it is typically diagnosed incidentally in the second to third decades of life. We present a case of a 28-year-old male with refractory atrial tachyarrhythmias and significantly reduced exercise tolerance. The informed consent was given by patient for this manuscript. Case summary: We present a case of a 28-year-old male with refractory atrial tachyarrhythmias and significantly reduced exercise tolerance after an episode of COVID respiratory infection. He was referred by primary care physician for management of atrial fibrillation (AF) with CHA2DS2Vasc score zero. He had documented AF and atrial flutter (AFL) resistant to both chemical and electrical cardioversions. Initial portable focused transthoracic echocardiography documented borderline reduced left ventricular ejection fraction in context of AFL. Electrophysiological study confirmed the diagnosis of typical AFL. Successful radiofrequency ablation of cavo-tricuspid isthmus resulted in bidirectional isthmus conduction block. However, patient developed AF, which was electrically cardioverted at the end of procedure. Patient was discharged on bisoprolol, ramipril, and apixaban, and outpatient cardiac MRI was organized to look for post-COVID myocardial scarring. Patient had recurrence of symptoms, and this time it was due to AF. Multimodal imaging led to discovery of LAAA, in which after discussion in multidisciplinary meeting, he was accepted for and managed with surgical resection of LAAA with concomitant Cox-Maze IV procedure. On 9 months post-operative follow up, patient is maintaining sinus rhythm and has completely returned to baseline activities. Discussion: A young patient with refractory atrial arrhythmia should be referred for multimodal cardiovascular imaging to rule out any structural heart disease. Left atrial appendage aneurysm is rare and can be managed conservatively, but surgical excision is most reported and appears to favour arrhythmia-free survival.

Continuous in vivo blood pressure measurements using a fully implantable wireless SAW sensor.

In this paper, the development of a fully implantable wireless sensor able to provide continuous real-time accurate pressure measurements is presented. Surface Acoustic Wave (SAW) technology was used to deposit resonators on crystalline quartz wafers; the wafers were then assembled to produce a pressure sensitive device. Excitation and reading via a miniature antenna attached to the pressure sensor enables continuous external interrogation. The main advantages of such a configuration are the long term stability of quartz and the low power necessary for the interrogation, which allows 24/7 interrogation by means of a hand-held, battery powered device. Such data are of vital importance to clinicians monitoring and treating the effects of hypertension and heart failure. A prototype was designed and tested using both a bio-phantom test rig and an animal model. The pressure traces for both compare very well with a commercially available catheter tip pressure transducer. The work presented in this paper is the first known wireless pressure data from the left ventricle of the heart of a living swine.

Heterotopic abdominal heart transplantation in rats for functional studies of ventricular unloading.

INTRODUCTION: Chronic changes in mechanical load regulate long-term cardiac function. Chronic overload of the ventricle results in myocardial failure. Clinical use of ventricular assist devices shows that chronic reduction in load has a number of different consequences on the myocardium, including beneficial reverse remodeling as well as undesired remodeling (e.g., myocardial atrophy and fibrosis, both of which could have negative functional implications). The complex response to mechanical unloading necessitates reproducible animal models of mechanical unloading for use in the laboratory. This article aims to describe the operative technique of two animal models of mechanical unloading in detail, to enable the reproducible use of these animal models. METHODS: In 1964, Abbott et al first described the heterotopic abdominal heart transplantation technique as a means to study the biology of transplanted cardiac grafts. This involves an aorto-aortic anastomosis and a pulmonary artery to inferior vena cava anastomosis. In this model, the left ventricle is virtually completely volume unloaded, receiving only thebesian venous return, and substantially but not entirely pressure unloaded. In this report we describe two refined techniques for mechanical unloading of healthy or failing hearts based on experience with over 500 operations. RESULTS: We describe an operative technique, including cardioprotective strategies, that provides a model of mechanical unloading with no immunological rejection and allows measurements of parameters of myocardial structure and function for many months. We describe a refined technique that achieves a lesser degree of left ventricular volume unloading, involving transplantation of both heart and lungs via a single aorto-aortic anastomosis. CONCLUSIONS: This article is the first to describe these two techniques in sufficient detail to enable novices to attempt and understand these operations and the differences between them. The technique we describe provides an effective and reproducible model of complete and partial mechanical unloading.

Impact of concomitant coronary artery bypass grafting on in-hospital outcome in octogenarians undergoing aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: Abundant data are available reporting excellent in-hospital outcomes after surgical aortic valve replacement (AVR) in octogenarians. However, there is a paucity of studies reporting the in-hospital outcome of concomitant AVR and coronary artery bypass grafting (CABG) in this group of patients. Hence, a comparison was made of the impact of concomitant AVR and CABG versus isolated AVR on in-hospital outcome in octogenarians. METHODS: Between January 2001 and October 2011, a total of 114 consecutive octogenarians undergoing combined AVR and CABG were compared with a control group of octogenarians (n = 68) undergoing isolated AVR. A retrospective analysis was performed of a prospectively collected cardiac surgery database. In addition, the medical notes and charts of all study patients were reviewed. RESULTS: The two groups had a similar mean age (AVR 82.3 +/- 2.4 years versus AVR + CABG 82.6 +/- 2.1 years; p = 0.91), demographics and EuroSCORE (AVR 11.4 versus AVR + CABG 13.2; p = 0.12). The aortic cross-clamp and cardiopulmonary bypass times were longer for AVR + CABG patients (p < 0.001). In-hospital mortality (7.4% after isolated AVR, 9.6% after AVR + CABG; p = 0.35 between groups) and major clinical outcomes for the two groups were found to be similar except for an increased need for hemofiltration in AVR + CABG patients (p = 0.02). CONCLUSION: In-hospital outcomes for concomitant AVR and CABG in octogenarians are comparable to those of isolated AVR, justifying the performance of combined AVR and CABG in this high-risk group of carefully selected patients.

In-hospital outcomes of pedicled bilateral internal mammary artery use in diabetic and nondiabetic patients undergoing off-pump coronary artery bypass grafting: single-surgeon, single-center experience.

OBJECTIVE: A common perception is that use of pedicled bilateral internal mammary arteries (BIMA) increases the risk of sternal wound complications in diabetic patients undergoing coronary artery bypass grafting (CABG). The purpose of this study was to compare the in-hospital outcomes of CABG using pedicled BIMA in diabetic and nondiabetic patients. METHODS: From September 1998 to September 2010, 390 consecutive diabetic patients and 519 nondiabetic patients underwent isolated off-pump CABG using pedicled BIMA. The 2 groups had comparable preoperative demographics except for a higher prevalence of acute myocardial infarction (18.9% versus 6.1%, P = .01), peripheral vascular disease (17.2% versus 2.7%, P = .001), an ejection fraction <30% (17.7% versus 8.5%, P = .02), and chronic renal failure (4.5% versus 0.9%, P = .01) in the diabetic patients. RESULTS: The operative mortality rate of the diabetic patients was comparable to that of the nondiabetic patients (2.8% versus 2.1%, P = .87). The in-hospital outcomes, including occurrence of superficial and deep sternal wound infections, were similar except for an increased occurrence of wound infection at the vein harvest site (6.6% versus 1.1%, P = .04) and a need for hemofiltration (11.8% versus 2.1%, P = .02) in the diabetic patients. CONCLUSIONS: Pedicled BIMA use is associated with comparable incidences of sternal wound complications and other outcomes in diabetic patients and nondiabetic patients. Strict perioperative glycemic control, adherence to meticulous closure technique, and postoperative management of surgical wounds can make pedicled BIMA use a default strategy for diabetic patients.

Concomitant off-pump coronary artery bypass grafting results in improved in-hospital outcomes for patients with ischemic mitral regurgitation undergoing surgery.

OBJECTIVE: Surgical management of ischemic mitral regurgitation (IMR) has primarily consisted of revascularization with or without the addition of mitral valve repair or replacement. We hypothesize that performing off-pump coronary artery bypass (OPCAB) grafting before fixing MR improves in-hospital outcomes for patients with IMR undergoing surgery. METHODS: From January 2000 through December 2010, a total of 96 consecutive patients with moderate or severe IMR, as determined by preoperative echocardiography, underwent on-pump coronary artery bypass grafting (CABG) (n = 66) or OPCAB (n = 30) revascularization with concomitant mitral valve repair or replacement. A retrospective analysis of a prospectively collected cardiac surgery database (PATS; Dendrite Clinical Systems, Oxford, UK) was performed. In addition, medical notes and charts were reviewed for all study patients. RESULTS: The 2 groups had similar preoperative demographic and EuroSCORE risk-stratification characteristics. The operative mortality rate for the entire cohort was 9.4%. Patients who underwent OPCAB grafting had a lower operative mortality than those who underwent CABG (3.3% versus 12.1%; P = .006). The mean ±SD cardiopulmonary bypass time (82.7 ± 34.7 minutes versus 160.7 ± 45.2 minutes; P < .001) and cross-clamp time (49.0 ± 22.4 minutes versus 103.4 ± 39.5 minutes; P < .001) were significantly shorter in the off-pump group than in the on-pump group. The OPCAB group also had significantly less in-hospital morbidity and shorter stays in the intensive care unit and the hospital. CONCLUSION: Our analysis shows that OPCAB grafting (compared with conventional CABG) before repairing MR is associated with favorable in-hospital outcomes for patients undergoing surgery for IMR.

Cardiomyocyte Ca2+ handling and structure is regulated by degree and duration of mechanical load variation.

Cardiac transverse (t)-tubules are altered during disease and may be regulated by stretch-sensitive molecules. The relationship between variations in the degree and duration of load and t-tubule structure remains unknown, as well as its implications for local Ca(2+)-induced Ca(2+) release (CICR). Rat hearts were studied after 4 or 8 weeks of moderate mechanical unloading [using heterotopic abdominal heart-lung transplantation (HAHLT)] and 6 or 10 weeks of pressure overloading using thoracic aortic constriction. CICR, cell and t-tubule structure were assessed using confocal-microscopy, patch-clamping and scanning ion conductance microscopy. Moderate unloading was compared with severe unloading [using heart-only transplantation (HAHT)]. Mechanical unloading reduced cardiomyocyte volume in a time-dependent manner. Ca(2+) release synchronicity was reduced at 8 weeks moderate unloading only. Ca(2+) sparks increased in frequency and duration at 8 weeks of moderate unloading, which also induced t-tubule disorganization. Overloading increased cardiomyocyte volume and disrupted t-tubule morphology at 10 weeks but not 6 weeks. Moderate mechanical unloading for 4 weeks had milder effects compared with severe mechanical unloading (37% reduction in cell volume at 4 weeks compared to 56% reduction after severe mechanical unloading) and did not cause depression and delay of the Ca(2+) transient, increased Ca(2+) spark frequency or impaired t-tubule and cell surface structure. These data suggest that variations in chronic mechanical load influence local CICR and t-tubule structure in a time- and degree-dependent manner, and that physiological states of increased and reduced cell size, without pathological changes are possible.

Ten-year outcome analysis of off-pump sequential grafting: single surgeon, single center experience.

OBJECTIVES: Despite increasing recognition that off-pump coronary artery bypass surgery and sequential grafting strategy individually are associated with improved outcomes, concerns persist regarding the safety and efficacy of combining these 2 techniques. We compared in-hospital and midterm outcomes for off-pump multivessel sequential and conventional coronary artery bypass grafting. METHODS: From September 1998 to September 2008, 689 consecutive patients received off-pump multivessel sequential coronary artery bypass grafting performed by a single surgeon. These patients were propensity matched to 689 patients who underwent off-pump coronary artery bypass grafting without sequential anastomoses. A retrospective analysis of prospectively collected perioperative data was performed. In addition, medical notes and charts of all the study patients were reviewed. The mean duration of follow-up was 5.1 ± 2.0 years. RESULTS: The major in-hospital clinical outcomes in the sequential and control groups were found to be similar. After adjusting for clinical covariates, sequential grafting was not an independent predictor of in-hospital adverse events (odds ratio [OR], 1.18; 95% confidence interval [CI], 0.86-1.50; P = .31), medium-term mortality (hazard ratio [HR], 1.26; 95% CI, 1.06-1.32; P = .92), and readmission to hospital (HR, 1.12; 95% CI, 0.96-1.20; P = .80). Sequential grafting was an independent predictor of receiving more than 3 distal anastomoses (OR, 7.46; 95% CI, 4.27-11.45; P < .0001). Risk-adjusted survival was 89% for sequential grafting patients and 88% for conventional grafting patients (P = .96) during the medium-term follow-up. CONCLUSION: Our analysis confirms the short- and midterm safety and efficacy of off-pump sequential coronary artery bypass grafting.

Prolonged mechanical unloading affects cardiomyocyte excitation-contraction coupling, transverse-tubule structure, and the cell surface.

Prolonged mechanical unloading (UN) of the heart is associated with detrimental changes to the structure and function of cardiomyocytes. The mechanisms underlying these changes are unknown. In this study, we report the influence of UN on excitation-contraction coupling, Ca(2+)-induced Ca(2+) release (CICR) in particular, and transverse (t)-tubule structure. UN was induced in male Lewis rat hearts by heterotopic abdominal heart transplantation. Left ventricular cardiomyocytes were isolated from the transplanted hearts after 4 wk and studied using whole-cell patch clamping, confocal microscopy, and scanning ion conductance microscopy (SICM). Recipient hearts were used as control (C). UN reduced the volume of cardiomyocytes by 56.5% compared with C (UN, n=90; C, n=59; P<0.001). The variance of time-to-peak of the Ca(2+) transients was significantly increased in unloaded cardiomyocytes (UN 227.4+/-24.9 ms(2), n=42 vs. C 157.8+/-18.0 ms(2), n=40; P<0.05). UN did not alter the action potential morphology or whole-cell L-type Ca(2+) current compared with C, but caused a significantly higher Ca(2+) spark frequency (UN 3.718+/-0.85 events/100 mum/s, n=47 vs. C 0.908+/-0.186 events/100 microm/s, n=45; P<0.05). Confocal studies showed irregular distribution of the t tubules (power of the normal t-tubule frequency: UN 8.13+/-1.12x10(5), n=57 vs. C 20.60+/- 3.174x10(5), n=56; P<0.001) and SICM studies revealed a profound disruption to the openings of the t tubules and the cell surface in unloaded cardiomyocytes. We show that UN leads to a functional uncoupling of the CICR process and identify disruption of the t-tubule-sarcoplasmic reticulum interaction as a possible mechanism.

Mini-sternotomy aortic valve replacement: is it safe and effective? Comparison with standard techniques.

BACKGROUND AND AIM OF THE STUDY: Mini-sternotomy aortic valve replacement (MSAVR) has been increasingly performed at the authors' institution since October 2003. The study aim was to compare results obtained with MSAVR to those following AVR with conventional sternotomy (SAVR). METHODS: Between 1998 and 2008, a total of 143 consecutive patients (mean age: 67 +/- 12.5 years) underwent AVR at the authors' institution. Of these patients, 82 underwent SAVR, and 61 underwent MSAVR performed through a reversed-L-shaped median sternotomy with a transverse limb at the right fourth intercostal space. Ascending aortic and right atrial cannulation through the mini-sternotomy were employed for cardiopulmonary bypass (CPB). RESULTS: Typically, the MSAVR patients were slightly younger than SAVR patients (mean age: 67 +/- 16 years and 70 +/- 15 years, respectively; p = 0.037), had a lower incidence of diabetes (3% versus 18%, p = 0.008), and a slightly higher left ventricular ejection fraction (74.5 +/- 12% versus 71 +/- 12%, p = 0.019). There were no other inter-group preoperative differences. As expected, MSAVR required a slightly longer aortic cross-clamp time (49 +/- 19 min) compared to SAVR (44.5 +/- 16 min; p = 0.019), and longer CPB times (77 +/- 31 min versus 60 +/- 26 min; p <0.0001), though the overall operating times were similar (p = 0.38). Postoperatively, MSAVR patients were extubated at 3 +/- 5 h, similar to SAVR patients (4 +/- 5 h) (p = 0.13). The median intensive therapy unit stay was 1 +/- 1 days in both groups. The median hospital stay was comparable between groups (MSAVR, 7 +/- 5 days; SAVR, 8 +/- 4 days; p = 0.48). The MSAVR patients had a higher incidence of delayed pericardial effusions requiring pericardiocentesis (n = 4; p = 0.031), but this did not affect survival. The 30-day mortality was similar in both groups (MSAVR group, n = 1 (1.6%); SAVR group, n = 3 (3.7%); p = 0.64). At five years after surgery, freedom from cardiac-related death was 96 +/- 2.6% in MSAVR patients, and 89 +/- 4.9% in SAVR patients (p = 0.32). CONCLUSION: Mini-sternotomy AVR is technically challenging with longer CPB and aortic cross-clamp times. However, with increasing surgical experience, it offers results comparable to those achieved with conventional AVR, and with acceptable cosmetic results.

Chylothorax and chylopericardium following mitral and tricuspid valve repairs and radiofrequency maze procedure.

Surgical radiofrequency Maze procedure is a well-developed technology with an established safety profile. Clinical complications, albeit rare, have been described secondary to usage of unipolar radiofrequency devices. Bipolar radiofrequency devices have virtually eliminated the complications associated with unipolar devices, thereby combining safety with efficacy. We report a case of chylopericardial tamponade and chylothorax following radiofrequency Maze procedure using a bipolar device.

Transcatheter aortic valve implantation in low-risk patients: A case of rational over exuberance. The time is not now.

BACKGROUND: Review of evidence and concerns, relating to extension of transcatheter aortic valve implantation usage to low-risk patients. METHODS: Comprehensive literature review was conducted identifying articles relating to transcatheter aortic valve implantation. RESULTS: Transcatheter aortic valve implantation is effective in patients with aortic stenosis. Currently, long-term durability and cost-effectiveness are unproven, anticoagulation requirement undefined, permanent pacemaker implantation and paravalvular leak rates higher than following surgical aortic valve replacement. CONCLUSIONS: Current evidence supporting transcatheter aortic valve implantation usage in low-risk patients is insufficient. Extending use now, to this large young patient population is premature, and should be delayed.

Impact of minimal access valve surgery on clinical outcomes: current best available evidence.

UNLABELLED: Recent years have seen a surge in the enthusiasm to perform minimal access valve surgery to reduce morbidity and improve clinical outcomes. Despite tremendous enthusiasm on the part of proponents of minimal access valve surgery, skepticism still exists about the actual impact of minimal access valve surgery in reducing postoperative morbidity. This review article attempts to evaluate the current best available evidence on the impact of minimal access valve surgery on postoperative clinical outcomes. METHODS: The English language scientific literature was reviewed primarily by searching Medline from 1966 through February 2008 using PubMed interface. All blinded or unblinded randomized clinical trials, comparing minimal access valve surgery with conventional valve surgery through a full sternotomy, recruiting adult human patients undergoing valve repair, or replacement and reporting impact of these two approaches on at least 1 pertinent clinical or economic outcome, were included. RESULTS: Current best available evidence from randomized clinical trials (Grade A, Level 1b) does not show any significant quantitative differences between minimal access valve surgery and conventional valve surgery for perioperative mortality or other primary outcome events of stroke, renal failure, or respiratory failure. There are small but statistically significant benefits for minimal access valve surgery for surrogate outcomes of ventilation time, intensive care unit stay, and total length of stay. CONCLUSION: The published evidence is thin and a large multicenter randomized clinical trial with preferably standardization of minimal access valve surgery techniques and long term follow-up is required to validate the safety and efficacy of minimal access valve surgery.

Does surgical sympathectomy improve clinical outcomes in patients with refractory angina pectoris?

A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was: In patients with angina pectoris refractory to medical therapy, does surgical sympathectomy improve clinical outcomes? A total of 528 papers were identified using the search protocol described, of which 6 represented the best evidence to answer the clinical question. There were 5 case series and 1 prospective cohort study. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All 5 of the case series demonstrated an improvement in symptoms, exercise tolerance or quality of life in patients undergoing surgical sympathectomy. An early case series investigating an open approach had a high morbidity and mortality rate, but the 4 other series used a minimally invasive technique and had low morbidity and zero perioperative mortality rates. The cohort study compared surgical sympathectomy with transmyocardial laser revascularization (TMR) and concluded TMR to be superior. However, this study looked only at unilateral sympathectomy, whereas all 5 case series focused on bilateral surgery. We conclude that the best currently available evidence does suggest that patients report an improvement in their symptoms and quality of life following surgical sympathectomy, but the low level of this evidence does not allow for a statistically proved recommendation.

Impact of combined clenbuterol and metoprolol therapy on reverse remodelling during mechanical unloading.

BACKGROUND: Clenbuterol (Cl), a ß2 agonist, is associated with enhanced myocardial recovery during left ventricular assist device (LVAD) support, and exerts beneficial remodelling effects during mechanical unloading (MU) in rodent heart failure (HF). However, the specific effects of combined Cl+ß1 blockade during MU are unknown. METHODS AND RESULTS: We studied the chronic effects (4 weeks) of ß2-adrenoceptor (AR) stimulation via Cl (2 mg/kg/day) alone, and in combination with ß1-AR blockade using metoprolol ((Met), 250 mg/kg/day), on whole heart/cell structure, function and excitation-contraction (EC) coupling in failing (induced by left coronary artery (LCA) ligation), and unloaded (induced by heterotopic abdominal heart transplantation (HATx)) failing rat hearts. Combined Cl+Met therapy displayed favourable effects in HF: Met enhanced Cl's improvement in ejection fraction (EF) whilst preventing Cl-induced hypertrophy and tachycardia. During MU combined therapy was less beneficial than either mono-therapy. Met, not Cl, prevented MU-induced myocardial atrophy, with increased atrophy occurring during combined therapy. MU-induced recovery of Ca2+ transient amplitude, speed of Ca2+ release and sarcoplasmic reticulum Ca2+ content was enhanced equally by Cl or Met mono-therapy, but these benefits, together with Cl's enhancement of sarcomeric contraction speed, and MU-induced recovery of Ca2+ spark frequency, disappeared during combined therapy. CONCLUSIONS: Combined Cl+Met therapy shows superior functional effects to mono-therapy in rodent HF, but appears inferior to either mono-therapy in enhancing MU-induced recovery of EC coupling. These results suggest that combined ß2-AR simulation +ß1-AR blockade therapy is likely to be a safe and beneficial therapeutic HF strategy, but is not as effective as mono-therapy in enhancing myocardial recovery during LVAD support.

RF communication with implantable wireless device: effects of beating heart on performance of miniature antenna.

The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable antennas are presented (two different geometries) along with which are placed within the heart of living swine the dynamic reflection coefficients. These antennas are designed to operate in the short range devices frequency band (863-870 MHz) and are compatible with a deeply implanted cardiovascular pressure sensor. The measurements recorded over 27 seconds capture the effects of the beating heart on the frequency tuning of the implantable antennas. When looked at in the time domain, these effects are clearly physiological and a combination of numerical study and posthumous autopsy proves this to be the case, while retrospective simulation confirms this hypothesis. The impact of pulsating anatomy on antenna design and the need for wideband implantable antennas is highlighted.

Outcomes and predictors of mortality and stroke after on-pump and off-pump coronary artery bypass surgery in octogenarians.

OBJECTIVE: Octogenarians, as the fastest growing stratum of the population and with the highest prevalence of coronary artery disease, are being increasingly referred for coronary artery bypass grafting (CABG). The general perception is that the presence of comorbidities and the propensity for neurological injury expose them to a higher risk for mortality and morbidity after conventional on-pump CABG, and therefore, off-pump CABG should be preferentially offered to octogenarians to improve outcomes. This study evaluates the in-hospital outcomes and predictors of mortality and stroke in octogenarians undergoing on- and off-pump CABG at our institution. METHODS: From January 2000 to December 2010, a total of 290 octogenarians underwent off-pump (n = 217) and on-pump (n = 73) CABG. Their data were prospectively entered into the cardiac surgery database (Patients Analysis & Tracking System; Dendrite Clinical Systems, Ltd, Oxford, England, United Kingdom) and analyzed retrospectively. Outcome measures included in-hospital mortality, major complications, and length of stay. Multivariate analysis was performed to identify predictors of combined outcome of in-hospital mortality and stroke. RESULTS: The mean ± SD age of the patients was 82 ± 2.0 years. Preoperative demographics were similar for the on-pump and off-pump groups. The patients who underwent off-pump CABG had a lower number of distal anastomoses performed compared with the patients who underwent on-pump CABG [mean difference, 0.2; 95% confidence interval (CI), 0.02-0.4; P = 0.03]. However, the ratio of grafts (received/needed) was the same in both groups. In-hospital mortality for the entire cohort was 7.2%, with no significant difference between the groups for death (6.0% vs 11.0%; P = 0.08), stroke (2.8% vs 2.8%; P = 1.0), other major complications, and length of hospital stay. Independent predictors of combined outcome identified from the multiple logistic model included heart failure [odds ratio (OR), 4.4; 95% CI, 1.5-13.0; P = 0.008], diabetes (OR, 2.6; 95% CI, 1.0-6.0; P = 0.046), nitrate infusion (OR, 2.9; 95% CI, 1.1-8.0; P = 0.04), postoperative renal failure requiring hemofiltration (OR, 8.6; 95% CI, 3.5-21.1; P < 0.001), and postoperative ventricular arrhythmias (OR, 7.3; 95% CI, 1.9-27.8; P = 0.009). CONCLUSIONS: Both on-pump and off-pump CABG are reasonable revascularization strategies in octogenarians. Careful patient selection and individualized treatment decisions can minimize postoperative mortality and morbidity in octogenarians undergoing on- and off-pump CABG.

The effect of SN-6, a novel sodium-calcium exchange inhibitor, on contractility and calcium handling in isolated failing rat ventricular myocytes.

BACKGROUND AND PURPOSE: Specific Na(+) /Ca(2+) exchanger (NCX) inhibition is a potential strategy to correct reduced contractility and depleted sarcoplasmic reticulum (SR) Ca(2+) content in heart failure (HF). SN-6, a benzyloxyphenyl derivative and proposed selective NCX inhibitor, could be used for this purpose. This study aimed to evaluate the effects of SN-6 on contractility and Ca(2+) handling in normal and failing rat cardiomyocytes. EXPERIMENTAL APPROACH: HF was induced in rats by coronary artery ligation. Left ventricular myocytes were isolated and superfused with increasing concentrations of SN-6. KEY RESULTS: Sarcomere shortening, induced by field-stimulation, was reduced in amplitude with increasing concentrations of SN-6 compared with control solution. This effect was greater in failing cells. Kinetics of contractility (time to 90% peak and time to 50% relaxation) were significantly faster. Despite this, intracellular Ca(2+) transients demonstrated no change in the peak amplitude at low concentrations of SN-6, suggesting that SN-6 may affect myofilament sensitivity to Ca(2+) . Ten micro molar SN-6 significantly reduced peak Ca(2+) amplitude by 61.57% and 64.73% in normal and failing cells, respectively. Diastolic Ca(2+) was significantly increased at 1 µM SN-6. SR Ca(2+) content, assessed by rapid application of caffeine, was reduced in failing cells with 1 µM SN-6. Peak ICa , measured by whole-cell patch clamping, was significantly reduced in normal and failing myocytes at 1 µM SN-6. CONCLUSIONS AND IMPLICATIONS: Our data suggest that SN-6 is not a selective inhibitor of NCX and impairs contractility and Ca(2+) handling. Its use, together with similar putative NCX blockers, in correcting the contractile abnormalities of heart failure requires further studies.

Influence of ivabradine on reverse remodelling during mechanical unloading.

AIMS: Ivabradine (Iva) has shown beneficial structural and functional effects in clinical and experimental heart failure (HF), but its action in combination with mechanical unloading (MU), such as during treatment with left ventricular assist devices (LVAD), is unknown. The aim of this study was to investigate the effects of Iva during MU, in a rodent model of HF. METHODS AND RESULTS: We studied the chronic effects (4 weeks) of Iva (10 mg/kg/day) alone and in combination with MU [induced by heterotopic abdominal heart transplantation (HATx)] on whole-heart and cellular structure, function, and excitation-contraction (E-C) coupling in a rodent (rat) model of HF, 12 weeks post-left coronary artery (LCA) ligation. Effects of Iva were compared with those of ß-blockade using metoprolol [(Met), 250 mg/kg/day]. Iva, but not Met, reversed myocardial fibrosis, alone and in combination with MU. MU-induced restoration of deranged E-C coupling was enhanced by Iva to a greater extent than Met: both Iva and Met enhanced the recovery of the Ca(2+) transient amplitude and the sarcoplasmic reticulum (SR) Ca(2+) content, but Iva alone maintained MU-induced normalization of L-type Ca(2+) current and t-tubule abnormalities. Met prevented MU-induced reduction in the myocardial size (myocardial atrophy); Iva had no effect on this parameter. CONCLUSION: Iva shows beneficial structural and E-C coupling effects during MU: Iva reverses myocardial fibrosis and enhances the restoration of deranged E-C coupling, displaying more beneficial effects than that of Met. These results suggest that Iva may prove effective in enhancing functional recovery in heart failure patients receiving LVAD therapy.