Primary cardiac valve tumours are rare. This is a case report of a 32-year-old non-smoker man with a history of stroke 1 year prior and no other cardiovascular risk factors. The patient was admitted to our acute stroke ward for recurrent left hemiparesis, slurring of speech, facial asymmetry and central retinal artery occlusion. Initial laboratory investigations and ECG were normal. An urgent CT brain showed a large hypodense area at the right frontal, parietal, temporal, occipital region with effaced sulci and right lateral ventricle with midline shift and cerebral oedema in keeping with acute infarction. We proceeded with CT angiography of the cerebral and carotid on the following day, which revealed no evidence of thrombosis, aneurysm or arteriovenous malformation. There were no abnormal beaded vessels to suggest vasculitis. Transthoracic echocardiography revealed a large mobile mass in the left atrium. Meanwhile, MRI cardiac confirmed a large ill-defined mobile solid mass attached to the mitral valve’s inferoseptal component suggestive of mitral valve myxoma. This case report highlights the significance of considering a cardiogenic source of emboli in patients with large cerebral infarcts and other cardiac embolic phenomena. Imaging modalities such as echocardiography and cardiac MRI will help detect treatable conditions, such as valvular myxoma and prevent further complications.

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Cascaded H-bridge multilevel inverter is among the most preferred topology in solar systems. While traditional asymmetric cascaded H-bridge multilevel inverter is easy to achieve higher number of output voltage levels compared to traditional symmetric cascaded H-bridge multilevel inverter, charge balancing between the voltage sources remains a challenge for asymmetric cascaded H-bridge multilevel inverter. This drawback results in unsteady DC voltage levels due to unbalanced power drawn from each voltage sources. Besides that, in battery powered applications, unbalanced power drawn results in unequal discharged in the batteries. In this paper, two three-phase asymmetric cascaded H-bridge multilevel inverter topologies are proposed which offer easier in terms of modularity while maintaining the ease in charge balancing control. The performance of these two proposed topologies with charge balance control has been evaluated using PSIM software.

Multilevel inverters are one of the preferred inverter choices for solar photovoltaic (PV) applications. While these inverters are capable of producing AC staircase output voltage waveform, the total harmonic distortion (THD) of the output voltage waveform can become worse if the switching angle of each voltage level is not carefully chosen. In this paper, four switching angle arrangement techniques are presented and the switching angles generated by these techniques are applied to a new single-phase boost multilevel (SPBM) inverter. The performance of 3-, 5-, 7-, 9-and 11-level SPBM inverter having four different sets of switching angles derived using the aforementioned techniques have been evaluated and compared using PSIM software. Simulation results show that one of the techniques is able to produce an output voltage waveform with the lowest THD, whilst the other generates an output voltage waveform with the highest fundamental voltage component.