Passive Control in a Continuous Beam under a Traveling Heavy Mass: Dynamic Response and Experimental Verification.

The motion of a heavy mass on a bridge span causes vibrations whose magnitude and frequency content depend on the mechanical properties of the structural system, including the magnitude of that mass and its speed of traverse. In order to limit vibrations that could potentially cause damage, a simple passive device configuration, namely the tuned mass damper (TMD), is introduced and its effect on the beam vibrations analyzed. Specifically, a TMD in the form of a single-degree-of-freedom (SDOF) unit comprising a mass and a spring is placed on the span to act as a secondary system for absorbing vibrations from the primary system, i.e., the bridge itself. A Lagrangian energy balance formulation is used to derive the governing equations of motion, followed by an analytical solution using the Laplace transform to investigate the transmission of vibratory energy between primary and secondary systems. Results are given in terms of time histories, Fourier spectra and spectrograms, where the influence of the TMD in reducing vibratory energy is demonstrated. The TMD is placed in the region where the beam's transverse motion is at a maximum, while its mechanical properties are sub-optimal, in the sense that there is no separate damper present and minimal damping is provided by the spring element itself. In parallel with the analysis, a series of experiments involving a simply supported model steel bridge span traversed by a heavy mass are conducted to first gauge the analytical solution and then to confirm the validity of the proposed passive scheme.

Cardiorenal multimorbidity in hospitalized cardiology patients: The Hellenic Cardiorenal Morbidity Snapshot (HECMOS) study.

PURPOSE: Cardiovascular disease is commonly accompanied by renal dysfunction. Multimorbidity in hospitalized patients impacts unfavorably on prognosis and hospital stay. We aimed to illustrate the contemporary burden of cardiorenal morbidity across inpatient cardiology care in Greece. METHODS: The Hellenic Cardiorenal Morbidity Snapshot (HECMOS) used an electronic platform to collect demographic and clinically relevant information about all patients hospitalized on March 3, 2022, in Greece. The participating institutions covered all levels of inpatient cardiology care and most of the country's territories to collect a real-world, nation representative sample. RESULTS: A total of 923 patients (men 68.4%, median age 73 ± 14.8 years) were admitted to 55 different cardiology departments. 57.7% of the participants were aged >70 years. Hypertension was highly prevalent and present in 66% of the cases. History of chronic HF, diabetes mellitus, atrial fibrillation, and chronic kidney disease was present in 38%, 31.8%, 30%, and 26%, respectively. Furthermore, 64.1% of the sample exhibited at least one of these 4 entities. Accordingly, a combination of ≥2 of these morbid conditions was recorded in 38.7%, of ≥3 in 18.2%, whereas 4.3% of the sample combined all 4 in their medical history. The most common combination was the coexistence of heart failure-atrial fibrillation accounting for 20.6% of the sample. Nine of 10 nonelectively admitted patients were hospitalized due to acute HF (39.9%), acute coronary syndrome (33.5%), or tachyarrhythmias (13.2%). CONCLUSION: HECMOS participants carried a remarkable burden of cardio-reno-metabolic disease. HF in conjunction with atrial fibrillation was found to be the most prevalent combination among the studied cardiorenal nexus of morbidities in the whole study population.

Delayed identification of high-degree atrioventricular block with prolonged asystole revealed after the removal of an implantable loop recorder owing to battery depletion.

There is a need for prolonged monitoring and close follow-up in cases of recurrent unexplained syncope and no diagnosis at the time of ILR explanation. Also, a second ILR should be implanted in cases with no clear diagnosis of syncope that probably has a cardiac origin.

Atrial fibrillation induced by appropriate ventricular antitachycardia pacing in an ICD recipient.

In this short communication we briefly describe a 69-year-old man with dilated cardiomyopathy and an implantable cardioverter defibrillator who suffered a prolonged episode of palpitations. The interrogation of the device revealed an episode of ventricular tachycardia successfully treated with antitachycardia pacing. However, just before ventricular tachycardia termination, atrial fibrillation ensued. This specific proarrhythmic effect of antitachycardia pacing is concisely discussed. Retrograde conduction from the ventricles to the atria causing increased atrial pressures and mechano-electrical feedback, in the presence of a vulnerable atrial substrate, seems to be the most plausible mechanism. .

Pseudo-polymorphic Ventricular Tachycardia in a 12-lead Holter Recording.

We present an image of pseudo-polymorphic ventricular tachycardia recording on a 12-lead surface ECG Holter. Although at first glance the appearance of the recording resembled polymorphic ventricular tachycardia, careful investigation revealed normal electrocardiographic findings.