A governing equation for rotor and wavelet number in human clinical ventricular fibrillation: Implications for sudden cardiac death.

BACKGROUND: Ventricular fibrillation (VF) is characterized by multiple wavelets and rotors. No equation to predict the number of rotors and wavelets observed during fibrillation has been validated in human VF. OBJECTIVE: The purpose of this study was to test the hypothesis that a single equation derived from a Markov M/M/∞ birth-death process could predict the number of rotors and wavelets occurring in human clinical VF. METHODS: Epicardial induced VF (256-electrode) recordings obtained from patients undergoing cardiac surgery were studied (12 patients; 62 epochs). Rate constants for phase singularity (PS) (which occur at the pivot points of rotors) and wavefront (WF) formation and destruction were derived by fitting distributions to PS and WF interformation and lifetimes. These rate constants were combined in an M/M/∞ governing equation to predict the number of PS and WF in VF episodes. Observed distributions were compared to those predicted by the M/M/∞ equation. RESULTS: The M/M/∞ equation accurately predicted average PS and WF number and population distribution, demonstrated in all epochs. Self-terminating episodes of VF were distinguished from VF episodes requiring termination by a trend toward slower PS destruction, slower rates of PS formation, and a slower mixing rate of the VF process, indicated by larger values of the second largest eigenvalue modulus of the M/M/∞ birth-death matrix. The longest-lasting PS (associated with rotors) had shorter interactivation time intervals compared to shorter-lasting PS lasting <150 ms (∼1 PS rotation in human VF). CONCLUSION: The M/M/∞ equation explains the number of wavelets and rotors observed, supporting a paradigm of VF based on statistical fibrillatory dynamics.

Maintaining safe lung cancer surgery during the COVID-19 pandemic in a global city.

BACKGROUND: SARS-CoV-2 has challenged health service provision worldwide. This work evaluates safe surgical pathways and standard operating procedures implemented in the high volume, global city of London during the first wave of SARS-CoV-2 infection. We also assess the safety of minimally invasive surgery(MIS) for anatomical lung resection. METHODS: This multicentre cohort study was conducted across all London thoracic surgical units, covering a catchment area of approximately 14.8 Million. A Pan-London Collaborative was created for data sharing and dissemination of protocols. All patients undergoing anatomical lung resection 1st March-1st June 2020 were included. Primary outcomes were SARS-CoV-2 infection, access to minimally invasive surgery, post-operative complication, length of intensive care and hospital stay (LOS), and death during follow up. FINDINGS: 352 patients underwent anatomical lung resection with a median age of 69 (IQR: 35-86) years. Self-isolation and pre-operative screening were implemented following the UK national lockdown. Pre-operative SARS-CoV-2 swabs were performed in 63.1% and CT imaging in 54.8%. 61.7% of cases were performed minimally invasively (MIS), compared to 59.9% pre pandemic. Median LOS was 6 days with a 30-day survival of 98.3% (comparable to a median LOS of 6 days and 30-day survival of 98.4% pre-pandemic). Significant complications developed in 7.3% of patients (Clavien-Dindo Grade 3-4) and 12 there were re-admissions(3.4%). Seven patients(2.0%) were diagnosed with SARS-CoV-2 infection, two of whom died (28.5%). INTERPRETATION: SARS-CoV-2 infection significantly increases morbidity and mortality in patients undergoing elective anatomical pulmonary resection. However, surgery can be safely undertaken via open and MIS approaches at the peak of a viral pandemic if precautionary measures are implemented. High volume surgery should continue during further viral peaks to minimise health service burden and potential harm to cancer patients. FUNDING: This work did not receive funding.

A cohort study of 30 day mortality after NON-EMERGENCY surgery in a COVID-19 cold site.

BACKGROUND: Two million non-emergency surgeries are being cancelled globally every week due to the COVID-19 pandemic, which will have a major impact on patients and healthcare systems. METHODS: During the peak of the pandemic in the United Kingdom, we set up a multicentre cancer network amongst 14 National Health Service institutions, performing urological, thoracic, gynaecological and general surgical urgent and cancer operations at a central COVID-19 cold site. This is a cohort study of 500 consecutive patients undergoing surgery in this network. The primary outcome was 30-day mortality from COVID-19. Secondary outcomes included all-cause mortality and post-operative complications at 30-days. RESULTS: 500 patients underwent surgery with median age 62.5 (IQR 51-71). 65% were male, 60% had a known diagnosis of cancer and 61% of surgeries were considered complex or major. No patient died from COVID-19 at 30-days. 30-day all-cause mortality was 3/500 (1%). 10 (2%) patients were diagnosed with COVID-19, 4 (1%) with confirmed laboratory diagnosis and 6 (1%) with probable COVID-19. 33/500 (7%) of patients developed Clavien-Dindo grade 3 or higher complications, with 1/33 (3%) occurring in a patient with COVID-19. CONCLUSION: It is safe to continue cancer and urgent surgery during the COVID-19 pandemic with appropriate service reconfiguration.

The insidious presentation and challenging management of esophageal perforation following diagnostic and therapeutic interventions.

Diagnostic and therapeutic interventions on the esophagus or adjacent organs are responsible for nearly half of all esophageal perforations. If not recognized at the time of the injury, iatrogenic esophageal perforations can present insidiously and lead to delay in diagnosis, thereby increasing morbidity and mortality. Acute clinical awareness is vital for prompt diagnosis, which is usually confirmed with contrast esophagography and contrast-enhanced computed tomography. After establishment of diagnosis, treatment should be promptly initiated and include fluid-volume resuscitation, cessation of oral intake, nasogastric tube insertion, broad-spectrum antibiotics and analgesia. Primary repair, when feasible, is the treatment of choice. Additional procedures beyond primary repair, such as relief of concomitant obstruction, may be necessary if there is underlying esophageal pathology. Drainage alone can be performed for perforations of the cervical esophagus that cannot be visualized. Esophageal T-tube placement or exclusion and diversion techniques are appropriate in clinically unstable patients and in cases where primary repair is precluded either due to preexisting esophageal disease or extensive esophageal damage. Esophagectomy should be performed in patients with malignancy, end-stage benign esophageal disease or extensive esophageal damage that precludes repair. Endoscopic techniques, including stenting, clipping or vacuum therapy, can be used in select cases. Finally, nonoperative management should be reserved for patients with contained esophageal perforations, limited extraluminal soilage and no evidence of systemic inflammation.

Carcinoma of unknown primary abuts left clavicle: Case report and review of the literature.

INTRODUCTION: Carcinoma of unknown primary is a well-recognized clinical syndrome which accounts for the 3-5% of all the malignancies. Patients with carcinoma of unknown primary usually present with late stage disease without having identified the primary source of the tumour despite an extensive diagnostic work-up. PRESENTATION OF CASE: A 60 years old male presented to the clinic complaining of a neck mass to the left lateral neck. Patient's history was unremarkable without evidence of any malignant disease. Clinical and radiological examination revealed a cystic mass extending from the lower one third of the neck to the left clavicle causing periostal reaction. Mass biopsy and PET-CT was unspecific for the primary origin of the mass. However in the context of tumour immunohistochemistry, HPV status, neck location and basaloid cell differentiation, the tumour mass was considered as carcinoma of unknown primary with possible oropharyngeal primary location. The patient underwent surgical resection of the mass, left clavicle and the first rib. One year after the operation the patient is disease free. DISCUSSION: Although CUP usually presents with cervical lyphadenopathy, in our case there was no evidence of lymph node tissue infiltration in the neck region. Surgical resection of the mass showed that the location was extending within the cervical soft tissues and upper thorax. Taking into consideration the absence of lymphadenopathy this is an uncommon location of carcinoma of unknown primary in the neck. CONCLUSION: This is an uncommon location of CUP with possible implications in survival and management.

Mechanistic insights from targeted molecular profiling of repolarization alternans in the intact human heart.

AIMS: Action potential duration (APD) alternans is an established precursor or arrhythmia and sudden cardiac death. Important differences in fundamental electrophysiological properties relevant to arrhythmia exist between experimental models and the diseased in vivo human heart. To investigate mechanisms of APD alternans using a novel approach combining intact heart and cellular cardiac electrophysiology in human in vivo. METHODS AND RESULTS: We developed a novel approach combining intact heart electrophysiological mapping during cardiac surgery with rapid on-site data analysis to guide myocardial biopsies for laboratory analysis, thereby linking repolarization dynamics observed at the organ level with underlying ion channel expression. Alternans-susceptible and alternans-resistant regions were identified by an incremental pacing protocol. Biopsies from these sites (n = 13) demonstrated greater RNA expression in Calsequestrin (CSQN) and Ryanodine (RyR) and ion channels underlying IK1 and Ito at alternans-susceptible sites. Electrical restitution properties (n = 7) showed no difference between alternans-susceptible and resistant sites, whereas spatial gradients of repolarization were greater in alternans-susceptible than in alternans-resistant sites (P = 0.001). The degree of histological fibrosis between alternans-susceptible and resistant sites was equivalent. Mathematical modelling of these changes indicated that both CSQN and RyR up-regulation are key determinants of APD alternans. CONCLUSION: Combined intact heart and cellular electrophysiology show that regions of myocardium in the in vivo human heart exhibiting APD alternans are associated with greater expression of CSQN and RyR and show no difference in restitution properties compared to non-alternans regions. In silico modelling identifies up-regulation and interaction of CSQN with RyR as a major mechanism underlying APD alternans.

The surgical management of non-malignant aerodigestive fistula.

BACKGROUND: Acquired aerodigestive fistula (ADF) are rare, but associated with significant morbidity. Surgery affords the best prospect of cure. We present our experience of the surgical management of ADFs at a specialist unit, highlighting operative techniques, challenges and assess clinical outcomes following intervention. We also illustrate findings of a Hospital Episodes Statistics search for ADFs. METHODS: A prospectively-maintained database was searched to identify all patients diagnosed with an ADF who were managed at our institution. Of 48 patients with an ADF, eight underwent surgical intervention. RESULTS: Four patients underwent an exploration of the ADF with primary repair of the defect. Two of these patients had proximal ADFs, amenable to repair through a neck incision, and two required a thoracotomy. Two patients suffered fistulae secondary to endoscopic therapy and underwent oesophageal exclusion surgery, with subsequent staged reconstruction. Two patients with previous Tuberculosis had a lung segmentectomy and lobectomy respectively, and a further patient in remission after treatment for lymphoma underwent oesophageal resection with synchronous reconstruction. Three patients suffered a complication, with one post-operative mortality. The remaining seven patients all achieved normal oral alimentation, with no evidence of ADF recurrence at a median follow-up of 32 months. CONCLUSIONS: Surgery to manage ADFs is effective in restoring normal alimentation and alleviates soiling of the airway, with a very low risk of recurrence. Several operative techniques can be utilised dependent on the features of the ADF. Early referral to specialist units is advocated, where the expertise to facilitate the complete management of patients is present, within a multi-disciplinary setting.

Spatio-temporal Organization During Ventricular Fibrillation in the Human Heart.

In this paper, we present a novel approach to quantify the spatio-temporal organization of electrical activation during human ventricular fibrillation (VF). We propose three different methods based on correlation analysis, graph theoretical measures and hierarchical clustering. Using the proposed approach, we quantified the level of spatio-temporal organization during three episodes of VF in ten patients, recorded using multi-electrode epicardial recordings with 30 s coronary perfusion, 150 s global myocardial ischaemia and 30 s reflow. Our findings show a steady decline in spatio-temporal organization from the onset of VF with coronary perfusion. We observed transient increases in spatio-temporal organization during global myocardial ischaemia. However, the decline in spatio-temporal organization continued during reflow. Our results were consistent across all patients, and were consistent with the numbers of phase singularities. Our findings show that the complex spatio-temporal patterns can be studied using complex network analysis.

Corrigendum: Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

This corrects the article DOI: 10.1038/nature22364.

The role of sympathectomy in long QT syndrome.

Long QT syndrome (LQTS) is an uncommon and potentially fatal cardiac channelopathy. Treatment options can be medical with ß-blockers or surgical with implantable cardioverter defibrillator (ICD) implantations and left cardiac sympathetic denervation (LCSD). Purpose of this paper is through a literature review to identify the management algorithm and the role of sympathectomy in LQTS.

Arterial Thoracic Outlet Syndrome Treated Successfully with Totally Endoscopic First Rib Resection.

Thoracic outlet syndrome (TOS) is a constellation of signs and symptoms caused by compression of the neurovascular structures in the thoracic outlet. TOS may be classified as either neurogenic TOS (NTOS) or vascular TOS: venous TOS (VTOS) or arterial TOS (ATOS), depending on the specific structure being affected. The basis for the surgical treatment of TOS is resection of the first rib, and it may be combined with scalenectomy or cervical rib resection. Herein, we describe a case of arterial thoracic outlet syndrome which was successfully treated with totally endoscopic video-assisted thoracoscopic surgery (VATS) first rib resection.

An unusual late onset of pulmonary alveolar microlithiasis: A case report and literature review.

Pulmonary alveolar microlithiasis (PAM) is an uncommon genetic disorder associated with alveolar cell injury. This injury is caused in most cases by inactivating mutations in SLC34A2 gene, which is responsible for the production of a sodium-dependent phosphate co-transporter. The dysfunction or deficiency of this transporter leads to the aggregation of local phosphate intra-alveolarly and formation of microliths. Most of the patients are asymptomatic at the time of the diagnosis but as the disease progress it leads to fatal respiratory or cardiac failure. We describe a case of a 63-year-old man referred to our department for a surgical lung biopsy. He has been symptomatic for one year with progressive shortness of breath and deteriorating exercise tolerance. The imaging was suggestive of extensive interstitial bilateral lung disease. Histological findings after the lung biopsy by video-assisted thoracic surgery (VATS) established the diagnosis of pulmonary alveolar microlithiasis. His sister suffered from the same disease and passed away at the age of 54. It is remarkably rare for PAM to have such a late onset with a previous normal X-ray and only a few cases have been reported worldwide.

Mediastinal hemangioendothelioma: Case report and review of the literature.

BACKGROUND: Epithelioid haemangioendothelioma (EHE) is a rare low-grade vascular neoplasm that can arise in the lung, liver, soft tissues or, less commonly, bone. Due to its low prevalence of less than one in a million and its non-specific clinical features, EHE is often misdiagnosed and managed inappropriately. Here we discuss the case of a 58 year-old gentleman with mediastinal EHE and review existing literature on pulmonary EHE (PEH). CASE HISTORY: A 58 year-old gentleman presented to our outpatient Clinic with chest discomfort and palpitations. A whole-body FDG-CT-PET showed an FDG-avid single 6.3cm nodule in the superior anterior mediastinum which was fully excised by robotic approach. Histology showed a nodular structure with clusters of epithelioid and spindled cells with a low proliferative index and mitotic count, suspended in a sclerotic stroma. Immunohistochemistry staining was positive for CD3 and CD34, confirming endothelial lineage, and SMA, identifying smooth muscle clusters. DISCUSSION: PEH typically presents in young Caucasian women, either incidentally as multiple small pulmonary nodules on CT or with respiratory symptoms that include cough, dyspnoea, chest pain and occasionally pleural effusions. Aetiology and prognosis remain unclear, although indicators of poor prognosis include the presence of respiratory symptoms, male gender, older age and multi-organ disease. Diagnosis is difficult and PEH is often misidentified as chronic granulomatous disease, amyloidosis or other malignancy of the lung. Histological features suggestive of PEH include nodules of hypocellular sclerotic stroma containing spindle-shaped tumour cells with abundant eosinophilic cytoplasm, vacuoles containing erythrocytes and low mitotic counts. CD31, CD34 and Fli-1 positive immunohistochemistry is strongly indicative of epithelioid lineage. There is no standard treatment for PEH but curative resection is the preferred treatment option where possible, with chemotherapy being used as adjuvant treatment or in widespread inoperable disease. CONCLUSION: This case report outlines the clinicopathological features that are characteristic of EHE with the hope of facilitating correct and early diagnosis in the future.

Tracking the Evolution of Non-Small-Cell Lung Cancer.

BACKGROUND: Among patients with non-small-cell lung cancer (NSCLC), data on intratumor heterogeneity and cancer genome evolution have been limited to small retrospective cohorts. We wanted to prospectively investigate intratumor heterogeneity in relation to clinical outcome and to determine the clonal nature of driver events and evolutionary processes in early-stage NSCLC. METHODS: In this prospective cohort study, we performed multiregion whole-exome sequencing on 100 early-stage NSCLC tumors that had been resected before systemic therapy. We sequenced and analyzed 327 tumor regions to define evolutionary histories, obtain a census of clonal and subclonal events, and assess the relationship between intratumor heterogeneity and recurrence-free survival. RESULTS: We observed widespread intratumor heterogeneity for both somatic copy-number alterations and mutations. Driver mutations in EGFR, MET, BRAF, and TP53 were almost always clonal. However, heterogeneous driver alterations that occurred later in evolution were found in more than 75% of the tumors and were common in PIK3CA and NF1 and in genes that are involved in chromatin modification and DNA damage response and repair. Genome doubling and ongoing dynamic chromosomal instability were associated with intratumor heterogeneity and resulted in parallel evolution of driver somatic copy-number alterations, including amplifications in CDK4, FOXA1, and BCL11A. Elevated copy-number heterogeneity was associated with an increased risk of recurrence or death (hazard ratio, 4.9; P=4.4×10-4), which remained significant in multivariate analysis. CONCLUSIONS: Intratumor heterogeneity mediated through chromosome instability was associated with an increased risk of recurrence or death, a finding that supports the potential value of chromosome instability as a prognostic predictor. (Funded by Cancer Research UK and others; TRACERx ClinicalTrials.gov number, NCT01888601 .).

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies.

IgG4 related lung disease extending to the thoracic vertebrae.

IgG4-related disease (IgG4-RD) is a fibroinflammatory condition that can affect practically every organ. Although it was first identified in pancreas and salivary glands, major organs like liver, biliary tree, kidney, thyroid glands and lungs are commonly involved, sometimes resulting in organ failure. We describe a case of an 41-year-old man presented with back pain after a rotator cuff injury. A Computed Tomography (CT) revealed incidentally a right lower lobe paravertebral lesion extending across the T5 and T6 vertebral levels and invading into the adjacent pleural surface. The laboratory findings and the CT guided biopsy were inconclusive. Morphological and immunohistochemical findings after a lung biopsy by video-assisted thoracic surgery (VATS) were suggestive to IgG4-related lung disease (IgG4-RLD), which was confirmed with high serum levels of IgG4. This represents the first case of a IgG4-RLD lesion located in the mediastinum and extending to the adjacent pleural surface and vertebrae and should be included in the differential diagnosis of posterior mediastinal masses.

Interactions between Activation and Repolarization Restitution Properties in the Intact Human Heart: In-Vivo Whole-Heart Data and Mathematical Description.

BACKGROUND: The restitution of the action potential duration (APDR) and conduction velocity (CVR) are mechanisms whereby cardiac excitation and repolarization adapt to changes in heart rate. They modulate the vulnerability to dangerous arrhythmia, but the mechanistic link between restitution and arrhythmogenesis remains only partially understood. METHODS: This paper provides an experimental and theoretical study of repolarization and excitation restitution properties and their interactions in the intact human epicardium. The interdependence between excitation and repolarization dynamic is studied in 8 patients (14 restitution protocols, 1722 restitution curves) undergoing global epicardial mapping with multi-electrode socks before open heart surgery. A mathematical description of the contribution of both repolarization and conduction dynamics to the steepness of the APDR slope is proposed. RESULTS: This study demonstrates that the APDR slope is a function of both activation and repolarization dynamics. At short cycle length, conduction delay significantly increases the APDR slope by interacting with the diastolic interval. As predicted by the proposed mathematical formulation, the APDR slope was more sensitive to activation time prolongation than to the simultaneous shortening of repolarization time. A steep APDR slope was frequently identified, with 61% of all cardiac sites exhibiting an APDR slope > 1, suggesting that a slope > 1 may not necessarily promote electrical instability in the human epicardium. APDR slope did not change for different activation or repolarization times, and it was not a function of local baseline APD. However, it was affected by the spatial organization of electrical excitation, suggesting that in tissue APDR is not a unique function of local electrophysiological properties. Spatial heterogeneity in both activation and repolarization restitution contributed to the increase in the modulated dispersion of repolarization, which for short cycle length was as high as 250 ms. Heterogeneity in conduction velocity restitution can translate into both activation and repolarization dispersion and increase cardiac instability. The proposed mathematical formulation shows an excellent agreement with the experimental data (correlation coefficient r = 0.94) and provides a useful tool for the understanding of the complex interactions between activation and repolarization restitution properties as well as between their measurements.

Sclerosing hemangioma of the lung showing strong FDG avidity on PET scan: Case report and review of the current literature.

Sclerosing Hemangioma is a rare lung tumor with polymorphic histologic features that usually occurs in middle aged women. Based on many immunohistochemical and ultrastructural studies, it is most probably derived from undifferentiated respiratory epithelial cells. Symptoms are usually due to enlargement of the tumor and compression of the surrounding tissues. Occurrence of multiple lesions or metastasis is extremely rare although some authors consider sclerosing hemangioma as a potentially low grade malignancy tumor. It usually presents with low to moderate uptake on FDG PET imaging. We present a case of sclerosing hemangioma with strong FDG avidity on PET scan in a 41 year old lady with history of haemoptysis. A full review of the literature on this topic was performed.

Key Features in the Management of Pulmonary Carcinosarcoma.

Pulmonary carcinosarcoma represents a category of extremely rare tumours accounting for 0.1% of all lung malignancies. It is defined as a poorly differentiated non-small-cell carcinoma that contains a component of sarcoma or sarcoma-like elements. These biphasic tumours typically have a poor prognosis due to late diagnosis and early metastases. Preoperative tissue diagnosis is usually difficult due to the heterogeneity of the tumour, with biopsies often just reflecting one element of the tumour. By means of a case illustration and review of the literature, we discuss the optimal management of patients with pulmonary carcinosarcoma.