Stereotactic radiosurgery for ablation of ventricular tachycardia.

AIMS: Stereotactic body radiotherapy (SBRT) for ventricular tachycardias (VTs) could be an option after failed catheter ablation. In this study, we analysed the long-term efficacy and toxicity of SBRT applied as a bail-out procedure. METHODS AND RESULTS: Patients with structural heart disease and unsuccessful catheter ablations for VTs underwent SBRT. The planning target volume (PTV) was accurately delineated using exported 3D electroanatomical maps with the delineated critical part of re-entry circuits. This was defined by detailed electroanatomic mapping and by pacing manoeuvres during the procedure. Using the implantable cardioverter-defibrillator lead as a surrogate contrast marker for respiratory movement compensation, 25 Gy was delivered to the PTV using CyberKnife. We evaluated occurrences of sustained VT, electrical storm, antitachycardia pacing, and shock; time to death; and radiation-induced events. From 2014 until March 2017, 10 patients underwent radiosurgical ablation (mean PTV, 22.15 mL; treatment duration, 68 min). After radiosurgery, four patients experienced nausea and one patient presented gradual progression of mitral regurgitation. During the follow-up (median 28 months), VT burden was reduced by 87.5% compared with baseline (P = 0.012) and three patients suffered non-arrhythmic deaths. After the blanking period, VT recurred in eight of 10 patients. The mean time to first antitachycardia pacing and shock were 6.5 and 21 months, respectively. CONCLUSION: Stereotactic body radiotherapy appears to show long-term safety and effectiveness for VT ablation in structural heart disease inaccessible to catheter ablation. We report one possible radiation-related toxicity and promising overall survival, warranting evaluation in a prospective multicentre clinical trial.

Color Doppler Ultrasound in the pre-histological determination of the biological character of major salivary gland tumors.

OBJECTIVES: The aim of the study was to assess the use of color Doppler ultrasound in the pre-histological determination of the biological features of salivary gland tumors. MATERIAL AND METHODS: Ninety-six patients with major salivary gland tumors of unknown histology were examined and operated on in our clinics. They were pre-operatively examined using ultrasound imaging with color Doppler. Peak systolic velocity (PSV) was measured and pulsatility index (PI) and resistive index (RI) were calculated on the pulsed wave traces. The Doppler flow parameters were correlated with clinical stage and tumour type (benign/carcinoma) as confirmed by final histological diagnosis. For the correlations, the tumors were categorized into 3: benign (group I), malignant stages I+II (group II), malignant stages III+IV (group III). RESULTS: The average PSV value was 22.15 cm/s for benign and 32.74 cm/s for all malignant tumors. The average RI value was 0.77 for benign and 0.86 for all malignant tumors. The average PI value for benign tumors was 2.85 and 3.14 for all malignant tumors. No significant differences between benign and malignant tumors in terms of SV and PI values were found. The RI values for benign tumors differed significantly from those of malignant ones (P=0.021). There were no significant differences in average PSV, PI and RI values in relation to salivary gland tumor group - I, II, III. There was no confirmation of the reported applicability of PSV and PI values in differenting benign from malignant tumors. CONCLUSION: We were not able to demonstrate significant differences in Doppler flow parameters PSV and PI between benign tumors and carcinomas. Only the RI could be used to differentiate them. There were also no significant differences in PSV, PI and RI values between low (I+II) and high (III+IV) clinical tumour stage.