The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output

Giraffes – the tallest extant animals on Earth – are renowned for their high central arterial blood pressure, which is necessary to secure brain perfusion. The pressure which may exceed 300 mmHg has historically been attributed to an exceptionally large heart. Recently, this has been refuted by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It remains enigmatic, however, how the normal-sized giraffe heart generates such massive arterial pressures. We hypothesized that giraffe hearts have a small intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min−1, respectively. End-diastolic and end-systolic volumes were 521±61 ml and 228±42 ml, yielding an ejection fraction of 56±4%, and a stroke volume of 0.59 ml kg−1. Left ventricular circumferential wall stress was 7.83±1.76 kPa. We conclude that, relative to body mass, a small left ventricular cavity and a low stroke volume characterizes the giraffe heart. The adaptations result in typical mammalian left ventricular wall tensions, but results in lowered cardiac output.</jats:p

STereotactic Arrhythmia Radioablation (STAR): the Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary consortium (STOPSTORM.eu) and review of current patterns of STAR practice in Europe

The EU Horizon 2020 Framework-funded Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) consortium has been established as a large research network for investigating STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia (VT). The aim is to provide a pooled treatment database to evaluate patterns of practice and outcomes of STAR and finally to harmonize STAR within Europe. The consortium comprises 31 clinical and research institutions. The project is divided into nine work packages (WPs): (i) observational cohort; (ii) standardization and harmonization of target delineation; (iii) harmonized prospective cohort; (iv) quality assurance (QA); (v) analysis and evaluation; (vi, ix) ethics and regulations; and (vii, viii) project coordination and dissemination. To provide a review of current clinical STAR practice in Europe, a comprehensive questionnaire was performed at project start. The STOPSTORM Institutions' experience in VT catheter ablation (83% ≥ 20 ann.) and stereotactic body radiotherapy (59% > 200 ann.) was adequate, and 84 STAR treatments were performed until project launch, while 8/22 centres already recruited VT patients in national clinical trials. The majority currently base their target definition on mapping during VT (96%) and/or pace mapping (75%), reduced voltage areas (63%), or late ventricular potentials (75%) during sinus rhythm. The majority currently apply a single-fraction dose of 25 Gy while planning techniques and dose prescription methods vary greatly. The current clinical STAR practice in the STOPSTORM consortium highlights potential areas of optimization and harmonization for substrate mapping, target delineation, motion management, dosimetry, and QA, which will be addressed in the various WPs

Validation of the national Danish ablation database: a retrospective, registry-based validation study

Aim.To validate the National Danish Ablation Database (NDAD) by investigating to what extent data in NDAD correspond to medical records. Type of study. Non-blinded, registry-based, retrospective, validation study. Material and methods. A sample of patients who underwent ablation for atrial fibrillation in Denmark between 1 January 2016 and 31 December 2016 were included. By utilizing medical records as gold standard, positive predictive (PPV) and negative predictive values (NPV) for NDAD were assessed and presented as five main categories: arrhythmia characteristics, demographics, cardiac history, complications, and medication. PPV’s and NPV’s exceeding 90% were considered as high agreement. Results. 597 patients (71.0% males) were included in the study. Median age was 63.1 (IQR: 54.9–68.4) years. The median PPV and NPV estimates across all variables were respectively 90.4% (95% CI: 68%–95.2%) (PPV) and 99.4% (95% CI: 98.4%–99.8%) (NPV) at baseline, and 91.7% (95% CI: 67.4%–95.4%) (PPV) and 99.3% (98.2%–99.3%) (NPV) at follow-up. Conclusion. The data registered in NDAD agrees to a great extent with the patients’ medical records, suggesting NDAD is a database with high validity. As a result of low complication rate, the PPV- and NPV-estimates among complication variables were prone to somewhat greater uncertainty compared to the rest

STereotactic Arrhythmia Radioablation (STAR): the Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary consortium (STOPSTORM.eu) and review of current patterns of STAR practice in Europe.

The EU Horizon 2020 Framework-funded Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) consortium has been established as a large research network for investigating STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia (VT). The aim is to provide a pooled treatment database to evaluate patterns of practice and outcomes of STAR and finally to harmonize STAR within Europe. The consortium comprises 31 clinical and research institutions. The project is divided into nine work packages (WPs): (i) observational cohort; (ii) standardization and harmonization of target delineation; (iii) harmonized prospective cohort; (iv) quality assurance (QA); (v) analysis and evaluation; (vi, ix) ethics and regulations; and (vii, viii) project coordination and dissemination. To provide a review of current clinical STAR practice in Europe, a comprehensive questionnaire was performed at project start. The STOPSTORM Institutions' experience in VT catheter ablation (83% ≥ 20 ann.) and stereotactic body radiotherapy (59% > 200 ann.) was adequate, and 84 STAR treatments were performed until project launch, while 8/22 centres already recruited VT patients in national clinical trials. The majority currently base their target definition on mapping during VT (96%) and/or pace mapping (75%), reduced voltage areas (63%), or late ventricular potentials (75%) during sinus rhythm. The majority currently apply a single-fraction dose of 25 Gy while planning techniques and dose prescription methods vary greatly. The current clinical STAR practice in the STOPSTORM consortium highlights potential areas of optimization and harmonization for substrate mapping, target delineation, motion management, dosimetry, and QA, which will be addressed in the various WPs