Differences of two cryoballoon generations: insights from the prospective multicentre, multinational FREEZE Cohort Substudy.

AIMS: Cryoballoon (CB) ablation with the second-generation cryoballoon (CBG2) seems to be more effective than its predecessor [first-generation cryoballoon (CBG1)], but phrenic nerve palsies were observed more frequently. The aim of this study was to compare the safety and efficacy of CBG1 and CBG2 in a substudy of the prospective multicentre, multinational FREEZE Cohort Study. METHODS AND RESULTS: Periprocedural data were analysed, and a total of 532 patients with paroxysmal atrial fibrillation (AF) were examined (n = 224 for CBG1 and n = 308 for CBG2). Procedure time decreased significantly from 149 to 130 min when comparing CBG1 with CBG2 (P < 0.0001), and pulmonary vein isolation (PVI) was achieved in 97.8 and 97.6% of PVs with CBG1 and CBG2 (P = 0.77), respectively. The need for dual-balloon usage within a procedure dropped (20.1 vs. 9.0%, P < 0.001), and the fluoroscopy time was reduced when operating the CBG2. Atrial fibrillation recurrence rates until discharge were similar (5.0 vs. 5.8%, P = 0.69). Comparable low rates of major complications were observed with both CBs, and there was a non-significant trend for more phrenic nerve palsies. CONCLUSION: Second-generation cryoballoon demonstrated a high rate of acute PVI in a significant faster procedure, which also utilized less radiation exposure and less dual-balloon usage during an average procedure. The safety profile remains favourable with a non-significant trend for more phrenic nerve palsies. If the enhancements lead to a higher clinical benefit has to be determined. The 1-year outcome data from the ongoing FREEZE Cohort Study comparing radiofrequency and CB ablation will shed some light on that issue. CLINICAL TRIALS GOV IDENTIFIER: NCT01360008.

Left ventricular noncompaction syndrome masquerading or misdiagnosed as congenital long QT syndrome: remember QT prolongation does not equal long QT syndrome.

Distinguishing congenital long QT syndrome from QT prolongation caused by drugs or a different underlying disease process is essential for selecting the proper treatment. Herein, we present a case of a patient referred for left cardiac sympathetic denervation as a last resort treatment option for her 19-year standing diagnosis of long QT syndrome with malignant ventricular fibrillation. However, based on her atypical clinical course and additional imaging studies, a diagnosis of left ventricular noncompaction, rather than long QT syndrome, was made. She left the clinic with a drastically different treatment plan and an improved quality of life. Because many cardiac and noncardiac diseases can demonstrate QT prolongation on electrocardiogram, all possible diagnoses should be considered before diagnosing a patient with congenital long QT syndrome especially with regard to the profound treatment implications and genetic follow-up in family members.