To quantify heterogeneous tissue at the periphery of areas of fibrosis (gray zone) in patients with hypertrophic cardiomyopathy (HCM) with the use of two different techniques. Cardiac magnetic resonance with late gadolinium enhancement analysis was performed in 33 patients with HCM. Gray zone was evaluated with the use of two different techniques previously described in patients after myocardial infarction. LGE was present in 25 (78%) patients. There was no significant difference in total LGE mass at two different cut-off values [53.8 g (interquartile range, IQR 43.5-77.8 g) vs. 53.8 g (IQR 37.8-64.5 g), respectively, P = 0.49]. Significant difference in gray zone mass assessed with the use of two techniques was demonstrated (19.1 +/- 7.3 g vs. 50.8 +/- 47.8 g; P = 0.003). There was a strong correlation between total LGE and gray zone mass (r = 0.789, P = 0.0001 for first method and r = 0.951, P < 0.0001 for the second one, respectively). However, significant variability of gray zone mass (and extent expressed as % of left ventricular mass) in patients with similar LGE size/extent was observed. Moreover, LGE mass varied greatly in patients with similar gray zone size. Neither left ventricular mass, nor with maximal wall thickness correlated with extent of gray zone assessed with both methods. The studied techniques provided similar results with regard to total LGE but significant differences were observed in gray zone mass. Two patients may have similar extent (or absolute mass) of LGE, but strikingly discrepant gray zone size.

Parathyroid adenoma injection is an alternative method of treatment for some patients resistant to treatment by means of vitamin D3 pulses or intravenous administration of calcitriol. The success of treatment is to a great extent determined by proper selection of patients and the taking of decisions when the period of secondary hyperparathyroidism is not very advanced.

The interval between DPs after achievement of block in the CTI correlates with AFL CL. The DPs interval expressed as a percentage of AFL CL allows better distinguishing between complete and incomplete isthmus block compared to standard method based on milliseconds. The DPs interval below 40% of AFL CL indicates sites close to a gap in the ablation line.

Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) is a well-established method for the treatment of atrial fibrillation (AF). As a rule, cryoenergy delivery is preceded by demonstrating full pulmonary vein (PV) occlusion by injecting contrast. Research on CBA without the use of contrast is sparse. The aim of the study was to determine efficacy and safety of a simplified protocol for CBA performed without demonstrating PV occlusion by venography and compare achieved results with those observed in patients undergoing conventional CBA. Methods This was a dual-centre, prospective, nonrandomized study (NCT04344743). The study cohort consisted of consecutive patients with paroxysmal AF, with 4 separate pulmonary veins (PVs), undergoing a first-time CBA. All ablations were performed using a 28-mm cryoballoon catheter (Arctic Front Advance, Medtronic). In the non-contrast (NC) group CBA was performed using standardized protocol without demonstrating PV occlusion by venography prior cryoapplication. In the case of PV isolation failure after a total of 5 minutes of cryoenergy delivery further attempts to isolate the vein were preceded by venography. A similar protocol was used in the conventional contrast (CC) group, where ablations were performed after confirmation of complete vein occlusion by venography. In both groups PVI was confirmed by demonstrating entrance and exit block using a diagnostic circular catheter (Achieve, Medtronic). Results The NC and CC groups comprised 51 and 22 patients, respectively. There were no differences between the NC and CC groups regarding baseline demographic, clinical and echocardiographic data. In the NC group 184 (90%) out of 204 veins were isolated without previous venography. Isolation of all 4 PVs without venography was possible in 34 (67%) patients. There were no differences between the NC and CC groups in terms of procedure duration (89.7 ± 22.6 vs. 90.0 ± 20.6 min; p=0.7) , left atrium dwelling time (71.2 ±21.3 vs 69.9 ± 19.1 min; p=0.8), fluoroscopy time (15.3 ± 6.3 vs. 15 ± 4.5 min; p=0.8) and radiation dose exposure (815 ± 594 vs. 945 ± 529 cGy*cm ). In the NC group, the use of contrast was significantly lower compared to the CC group (4.9 ± 10.1 vs. 19.4 ± 8.6 ml, p<0.001). The time to isolation and the minimum temperature achieved were comparable between the NC and CC groups. There were no serious adverse events in both groups. A one year freedom from AF was achieved in 73.5% and 71.5% of patients from the NC group the CC group, respectively (p=1). Conclusions Cryoballoon ablation without demonstrating vein occlusion with contrast is feasible, safe and enables isolation of the vast majority of pulmonary veins. The acute and one-year results for non-contrast cryoballoon ablation are comparable to those obtained using the conventional protocol with contrast.