title: The slope of the initial temperature drop predicts acute pulmonary vein isolation using the second-generation cryoballoon.
abstract: OBJECTIVE
  There is no objective, early indicator of occlusion quality, and efficacy of cryoballoon pulmonary vein isolation. As previous experience suggests that the initial cooling rate correlates with these parameters, we investigated the slope of the initial temperature drop as an objective measure.
  
  
  RESULTS
  A systematic evaluation of 523 cryoapplications in 105 patients using a serial ROC-AUC analysis was performed. We found the slope of a linear regression of the temperature-time function to be a good predictor (PPV 0.9, specificity 0.72, sensitivity 0.71, and ROC-AUC 0.75) of acute isolation. It also correlated with nadir temperatures (P< 0.001, adjusted R2= 0.43), predicted very low nadir temperatures, and varied according to visual occlusion grades (ANOVA P< 0.001).
  
  
  CONCLUSIONS
  About 25 s after freeze initiation, the temperature-time slope predicts important key characteristics of a cryoablation, such as nadir temperature. The slope is the only reported predictor to actually precede acute isolation and thus to support decisions about pull-down manoeuvres or aborting a cryoablation early on. It is also predictive of very low nadir temperatures and phrenic nerve palsy and thus may add to patient safety.
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Nikolas
authors.initials: N
authors.lastname: Deubner
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Greiss
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Ersan
authors.initials: E
authors.lastname: Akkaya
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Sergey
authors.initials: S
authors.lastname: Zaltsberg
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hain
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Berkowitsch
authors.affiliation: Armed Services Central Hospital, Koblenz, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Güttler
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Kuniss
authors.affiliation: Kerckhoff Heart Center, Bad Nauheim, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Neumann
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D062906:Cardiac Catheters / Q000009:adverse effects; D016009:Chi-Square Distribution; D003080:Cold Temperature / Q000009:adverse effects; D003452:Cryosurgery / Q000009:adverse effects / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D061214:Patient Safety; D059348:Peripheral Nerve Injuries / Q000209:etiology / Q000503:physiopathology; D010791:Phrenic Nerve / Q000293:injuries / Q000503:physiopathology; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery*; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Arrhythmias; Atrial fibrillation; Catheter ablation; Cryoballoon