Introduction/Aim
Veno‐arterial extracorporeal membrane oxygenation (V‐A ECMO) support is increasingly used in refractory cardiogenic shock and cardiac arrest, but is characterized by a rise in ...afterload of the left ventricle (LV) which may ultimately either further impair or delay cardiac contractility improvement. The aim of this study was to provide a comprehensive overview regarding the different LV venting techniques and results currently available in the literature.
Methods
A systematic literature search was performed in the PubMed database: 207 articles published between 1993 and 2016 were included. Papers dealing with pre‐clinical studies, overlapping series, and association with other assist devices were excluded from the review, with 45 published papers finally selected. Heterogeneous indications for LV unloading were reported. The selected literature was divided into subgroups, according to the location or the performed procedure for LV venting.
Results
Case reports or case series accounted for 60% of the papers, while retrospective study represented 29% of them. Adult series were present in 67%, paediatric patients in 29%, and a mixed population in 4%. LV unloading was performed percutaneously in 84% of the cases. The most common locations of unloading was the left atrium (31%), followed by indirect unloading (intra‐aortic balloon pump) (27%), trans‐aortic (27%), LV (11%), and pulmonary artery (4%). Percutaneous trans‐septal approach was reported in 22%. Finally, the unloading was conducted surgically in 16%,with open chest surgery in 71%, and minimally invasive surgery in 29% of surgical cases.
Conclusion
Nowadays, only a few data are available about left heart unloading in V‐A ECMO support. Despite the well‐known controversy, IABP remains widely used in combination with V‐A ECMO. Percutaneous approaches utilizing unloading devices is becoming an increasingly used option. However, further studies are required to establish the optimal LV unloading method.
Cardiovascular disease is the major cause of death worldwide. The success of medication and other preventive measures introduced in the last century have not yet halted the epidemic of cardiovascular ...disease. Although the molecular mechanisms of the pathophysiology of the heart and vessels have been extensively studied, the burden of ischemic cardiovascular conditions has risen to become a top cause of morbidity and mortality. Calcium has important functions in the cardiovascular system. Calcium is involved in the mechanism of excitation-contraction coupling that regulates numerous events, ranging from the production of action potentials to the contraction of cardiomyocytes and vascular smooth muscle cells. Both in the heart and vessels, the rise of intracellular calcium is sensed by calmodulin, a protein that regulates and activates downstream kinases involved in regulating calcium signalling. Among them is the calcium calmodulin kinase family, which is involved in the regulation of cardiac functions. In this review, we present the current literature regarding the role of calcium/calmodulin pathways in the heart and vessels with the aim to summarize our mechanistic understanding of this process and to open novel avenues for research.
Atrial fibrillation (AF) is accompanied by progressive epicardial fibrosis, dissociation of electrical activity between the epicardial layer and the endocardial bundle network, and transmural ...conduction (breakthroughs). However, causal relationships between these phenomena have not been demonstrated yet. Our goal was to test the hypothesis that epicardial fibrosis suffices to increase endo-epicardial dissociation (EED) and breakthroughs (BT) during AF.
We simulated the effect of fibrosis in the epicardial layer on EED and BT in a detailed, high-resolution, three-dimensional model of the human atria with realistic electrophysiology. The model results were compared with simultaneous endo-epicardial mapping in human atria. The model geometry, specifically built for this study, was based on MR images and histo-anatomical studies. Clinical data were obtained in four patients with longstanding persistent AF (persAF) and three patients without a history of AF.
The AF cycle length (AFCL), conduction velocity (CV), and EED were comparable in the mapping studies and the simulations. EED increased from 24.1 ± 3.4 to 56.58 ± 6.2% (
< 0.05), and number of BTs per cycle from 0.89 ± 0.55 to 6.74 ± 2.11% (
< 0.05), in different degrees of fibrosis in the epicardial layer. In both mapping data and simulations, EED correlated with prevalence of BTs. Fibrosis also increased the number of fibrillation waves per cycle in the model.
A realistic 3D computer model of AF in which epicardial fibrosis was increased, in the absence of other pathological changes, showed increases in EED and epicardial BT comparable to those in longstanding persAF. Thus, epicardial fibrosis can explain both phenomena.
Background: Assessing frailty is important in treating surgical patients to predict peri- and postoperative events like complications or mortality. The current standard is not optimal; therefore, new ...prognostic markers are being evaluated to enrich the current frailty assessment. One of these new markers is fat degeneration of the psoas muscle (myosteatosis). This can be assessed by measuring the psoas muscle density (PMD) with computed tomography (CT). The aim of this review is to investigate PMD, and, thus, myosteatosis, as a prognostic marker for postoperative mortality in adult patients undergoing general surgery. Methods: An electronic search was performed in PubMed to identify relevant studies associating PMD with postoperative mortality. The looked-upon period for mortality to occur did not matter for this review. The looked-upon outcome measure for this review was the hazard ratio. Results: From 659 potential articles from PubMed, 12 were included, for a total of 4834 participants. Articles were excluded when not focused on PMD, if the type of intervention was not specified, and when imaging other than with CT on the level of the third vertebra was performed. The included articles were assessed for bias with the Newcastle–Ottawa Scale (NOS). PMD was, after multivariable analyses, identified as an independent significant prognostic marker for several surgical cardiovascular interventions when we looked at the 5-year mortality rate and for fenestrated branched endovascular aortic repair (F-BEVAR) a slight significant protective correlation between postoperative mortality and PMD (when divided by psoas muscle area (PMI)) when we looked at the 30-day and 3-year mortality. Also, PMD was identified as an independent significant prognostic marker for a variety of surgical gastrointestinal interventions when we looked at 30-day/90-day/1-year/3-year/5-year mortality. PMD was not identified as a significant prognostic marker in urologic surgery. Conclusion: Myosteatosis has the potential to be a valuable contribution to the current frailty assessment for patients undergoing cardiovascular, gastrointestinal, or urologic surgery. However, more research must be conducted to further strengthen the prognostic value of myosteatosis, with special attention to, e.g., gender- or age-specific interpretations of the results.
Postoperative atrial fibrillation (POAF) is considered to be a transient arrhythmia in the first week after cardiac surgery.
To determine the 30-day incidence and predictors of POAF and the value of ...postoperative overdrive biatrial pacing in the prevention of POAF.
Patients (n = 148) without a history of atrial fibrillation undergoing aortic valve replacement or coronary artery bypass graft (CABG) were randomized into a pacing group (n = 75) and a control group. Patients were treated with standardized sotalol postoperatively. Rhythm was continuously monitored for 30 days by a transtelephonic event recorder.
POAF occurred in 73 (49.3%) patients, of whom 60 (40.5%) patients showed POAF during postoperative days (PODs) 0-5 and 37 (25%) patients during PODs 6-30. Prolonged aortic cross-clamp time was an important univariate predictor of 30-day and of late POAF (PODs 6-30; P = .017 and P = .03, respectively). Best-fit model analysis using 15 predetermined risk factors for POAF showed different positive interactive effects for early POAF (ie, baseline C-reactive protein levels with a history of myocardial infarction or low body mass index) and late POAF (ie, high body mass index, diabetes mellitus, baseline C-reactive protein, early POAF, creatinine levels, type of operation, smoking, and male gender). Biatrial pacing reduced the late POAF incidence in patients with aortic cross-clamp time >50 minutes (P = .006).
POAF is not limited to the first week after cardiac surgery but also occurs frequently in the postoperative month. It is desirable to regularly follow patients with POAF for atrial fibrillation recurrences after discharge.
Purpose
To make an
in vitro
evaluation of the lesion size and depth produced in two different sets of radio frequency energy bipolar delivery: simultaneous biparietal bipolar (SBB) and simultaneous ...uniparietal bipolar (SUB).
Methods
Two separate prototypes have been built for our purpose: one to be used in SBB mode and the other to be used SUB mode. Forty left atrium samples were taken from the hearts of freshly slaughtered pigs. They were ablated into a simulator ABLABOX, where blood flow, temperature, and contact force were controlled. After being sliced into a cryotome, the samples were digitalized by a flatbed scanner, and the images were analyzed by a computer morphometric software.
Results
Transmural lesions were achieved in 18/20 samples (90%) in SBB, while SUB showed transmurality in 9/20 samples (45%). Overall maximum diameter (
D
MAX
) resulted larger in SUB than in SBB (2.43 ± 0.30 mm, 1.62 ± 0.14 mm, respectively;
p
< 0.05): Moreover, maximum epicardial and endocardial diameters (
D
EPI
and
D
ENDO
, respectively) were wider in SUB group than SBB group (2.28 ± 0.30 mm, 2.26 ± 0.40 and 1.60 ± 0.14 mm, 1.59 ± 0.15 mm, respectively;
p
< 0.05). We observed the same tendency in lesion depth: The total area and volume (
A
TOT
and
V
TOT
) were broader in SUB group than in SBB one (581.01 ± 65.38 mm/mm
2
, 58.10 ± 6.53 mm/mm
3
and 521.97 ± 73.05 mm/mm
2
, 52.19 ± 7.30 mm/mm
3
. respectively;
p
< 0.05).
Conclusions
In contrast with the smaller lesion sizes, the biparietal bipolar group showed a higher transmurality rate. These findings may suggest a better drive of the energy flow when compared with SUB lesions.
Atrial cardiomyopathy (atCM) is an emerging prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy, and capillary density are hallmarks of atCM. The contribution ...of etiological factors and atrial fibrillation (AF) to the development of differential atCM phenotypes has not been quantified. This study aimed to evaluate the association between histological features of atCM and the clinical phenotype.
We examined left atrial (LA, n=95) and right atrial (RA, n=76) appendages from a European cohort of patients undergoing cardiac surgery. Quantification of histological atCM features was performed following wheat germ agglutinin/CD31/vimentin staining. The contributions of AF, heart failure, sex, and age to histological characteristics were determined with multiple linear regression models. Persistent AF was associated with increased endomysial fibrosis (LA: +1.13±0.47 μm,
=0.038; RA: +0.94±0.38 μm,
=0.041), whereas total extracellular matrix content was not. Men had larger cardiomyocytes (LA: +1.92±0.72 μm,
<0.001), while women had more endomysial fibrosis (LA: +0.99±0.56 μm,
=0.003). Patients with heart failure showed more endomysial fibrosis (LA: +1.85±0.48 μm,
<0.001) and extracellular matrix content (LA: +3.07±1.29%,
=0.016), and a higher capillary density (LA: +0.13±0.06,
=0.007) and size (LA: +0.46±0.22 μm,
=0.044). Fuzzy k-means clustering of histological features identified 2 subtypes of atCM: 1 characterized by enhanced endomysial fibrosis (LA: +3.17 μm,
<0.001; RA: +2.86 μm,
<0.001), extracellular matrix content (LA: +3.53%,
<0.001; RA: +6.40%,
<0.001) and fibroblast density (LA: +4.38%,
<0.001), and 1 characterized by cardiomyocyte hypertrophy (LA: +1.16 μm,
=0.008; RA: +2.58 μm,
<0.001). Patients with fibrotic atCM were more frequently female (LA: odds ratio OR, 1.33,
=0.002; RA: OR, 1.54,
=0.004), with persistent AF (LA: OR, 1.22,
=0.036) or heart failure (LA: OR, 1.62,
<0.001). Hypertrophic features were more common in men (LA: OR=1.33,
=0.002; RA: OR, 1.54,
=0.004).
Fibrotic atCM is associated with female sex, persistent AF, and heart failure, while hypertrophic features are more common in men.
The pathophysiological relevance of complex fractionated atrial electrograms (CFAE) in atrial fibrillation (AF) remains poorly understood.
The aim of this study was to comprehensively investigate how ...bipolar CFAE correlates with unipolar electrogram fractionation and the underlying electrophysiological substrate of AF.
Ten-second unipolar AF electrograms were recorded using a high-density electrode from the left atrium of 20 patients with AF (10 with persistent AF and 10 with paroxysmal AF) undergoing cardiac surgery. Semiautomated bipolar CFAE algorithms: complex fractionated electrogram-mean, interval confidence interval, continuous electrical activity, average complex interval, and shortest complex interval were evaluated against AF substrate complexity measures following fibrillation wave reconstruction derived from local unipolar activation time. The effect of interelectrode spacing and electrode orientation on bipolar CFAE was also examined.
All 5 semiautomated bipolar CFAE algorithms showed poor correlation with each other and AF substrate complexity measures (conduction velocity, number of waves or breakthroughs per AF cycle, and electrical dissociation). Bipolar CFAE also correlated poorly with fractionation index derived from unipolar electrograms. Increased interelectrode spacing resulted in an increase in bipolar CFAE detected except for the interval confidence interval algorithm. CFAE appears unaffected by bipolar electrode orientation (vertical vs horizontal). By contrast, unipolar fractionation index correlated well with AF substrate complexity measures and can be regarded as a marker for conduction block.
The lack of pathophysiological relevance of bipolar CFAE analysis may in part contribute to the divergent and limited success rates of catheter ablation strategies targeting CFAE.
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