RESUMO
Ventricular arrhythmias (VA) can be life-threatening arrhythmias that result in significant morbidity and mortality. Catheter ablation (CA) is an invasive treatment modality that can be effective in the treatment of VA where medications fail. Recurrence occurs commonly following CA due to an inability to deliver lesions of adequate depth to cauterise the electrical circuits that drive VA or reach areas of scar responsible for VA. Stereotactic body radiotherapy is a non-invasive treatment modality that allows volumetric delivery of energy to treat circuits that cannot be reached by CA. It overcomes the weaknesses of CA and has been successfully utilised in small clinical trials to treat refractory VA. This article summarises the current evidence for this novel treatment modality and the steps that will be required to bring it to the forefront of VA treatment.
RESUMO
The past decade has seen considerable growth in therapeutics and device technologies to treat patients with hypertension and other cardiovascular disease states. Uncoupling ventriculo-arterial interactions in these patients, however, is often complex and not adequately accounted for by arterial pressure or vascular resistance measurement alone. In reality, the global vascular load presented to the left ventricle (LV) includes both steady-state and pulsatile components. Whereas steady-state load is best represented by the vascular resistance, pulsatile load, which incorporates wave reflections and arterial stiffness, may oscillate during various phases of the cardiac cycle and is best determined by the vascular impedance (Z). In recent years, measurement of Z has become more readily accessible through an array of simultaneous applanation tonometry, echocardiography and cardiac magnetic resonance (CMR) techniques. In the following review, we evaluate existing and newer methods to assess Z so as to better understand the pulsatile characteristics of the human circulation in hypertension and other cardiovascular disease states.
