BACKGROUND Recent advances have enabled noninvasive mapping of cardiac arrhythmias with electrocardiographic imaging and noninvasive delivery of precise ablative radiation with stereotactic body radiation therapy (SBRT). We combined these techniques to perform catheter-free, electrophysiology-guided, noninvasive cardiac radioablation for ventricular tachycardia. METHODS We targeted arrhythmogenic scar regions by combining anatomical imaging with noninvasive electrocardiographic imaging during ventricular tachycardia that was induced by means of an implantable cardioverter–defibrillator (ICD). SBRT simulation, planning, and treatments were performed with the use of standard techniques. Patients were treated with a single fraction of 25 Gy while awake. Efficacy was assessed by counting episodes of ventricular tachycardia, as recorded by ICDs. Safety was assessed by means of serial cardiac and thoracic imaging. RESULTS From April through November 2015, five patients with high-risk, refractory ventricular tachycardia underwent treatment. The mean noninvasive ablation time was 14 minutes (range, 11 to 18). During the 3 months before treatment, the patients had a combined history of 6577 episodes of ventricular tachycardia. During a 6-week postablation “blanking period” (when arrhythmias may occur owing to postablation inflammation), there were 680 episodes of ventricular tachycardia. After the 6-week blanking period, there were 4 episodes of ventricular tachycardia over the next 46 patient-months, for a reduction from baseline of 99.9%. A reduction in episodes of ventricular tachycardia occurred in all five patients. The mean left ventricular ejection fraction did not decrease with treatment. At 3 months, adjacent lung showed opacities consistent with mild inflammatory changes, which had resolved by 1 year. CONCLUSIONS In five patients with refractory ventricular tachycardia, noninvasive treatment with electrophysiology-guided cardiac radioablation markedly reduced the burden of ventricular tachycardia. (Funded by Barnes–Jewish Hospital Foundation and others.)

There is a paucity of data regarding the use of direct thrombin inhibitors such as bivalirudin for children on extracorporeal life support (ECLS). We sought to compare the outcomes of children on ECLS anticoagulated with bivalirudin versus heparin. Patients transitioned from heparin to bivalirudin were treated as a separate group. A single‐institution, retrospective review of all consecutive children (neonate to 18 years) placed on ECLS in the cardiac or pediatric intensive care units was performed (June 2018‐December 2019). Data collected included demographics, anticoagulation strategy, number of circuit interventions, blood product use on ECLS, survival to decannulation, and survival to discharge. Fifty‐four children were placed on ECLS for a total of 56 runs. Demographics and venovenous versus venoarterial ECLS were similar. The bivalirudin group had longer median duration of support compared to the heparin group––11.0 days [IQR 6.2, 23.1] versus 3.3 days [2.1, 6.2], P < .001. Patients switched from heparin to bivalirudin had a similar duration of support (10.3 days [8.3, 18.3]) as those on bilvalirudin alone. However, there was no difference in red blood cell, fresh frozen plasma, or platelet transfusions. There was no difference in the number of circuit interventions, survival to decannulation or discharge. The freedom to first circuit intervention was longer with bivalirudin compared to heparin. Our data suggest that even with longer pediatric ECLS runs on bivalirudin, there were no differences in the outcomes between the heparin and bivalirudin groups, with longer freedom from first circuit intervention with bivalirudin. While this is the largest reported series comparing children on ECLS anticoagulated with heparin versus bivalirudin, larger studies are needed to determine the optimal anticoagulation strategy for this diverse and complicated group of children.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and the treatment options include medical treatment and catheter-based or surgical interventions. AF is a major cause of stroke, and its prevalence is increasing. The surgical treatment of AF has been revolutionized over the past 2 decades through surgical innovation and improvements in endoscopic imaging, ablation technology and surgical instrumentation. The Cox-maze (CM) procedure, which was developed by James Cox and introduced clinically in 1987, is a procedure in which multiple incisions are created in both the left and the right atria to eliminate AF while allowing the sinus impulse to reach the atrioventricular node. This procedure became the gold standard for the surgical treatment of AF. Its latest iteration is termed the CM IV and was introduced in 2002. The CM IV replaced the previous cut-and-sew method (CM III) by replacing most of the incisions with a combination of bipolar radiofrequency and cryoablation. The use of ablation technologies, made the CM IV technically easier, faster and more amenable to minimally invasive approaches. The aims of this article are to review the indications and preoperative planning for the CM IV, to describe the operative technique and to review the literature including comparisons of the CM IV with the previous cut-and-sew method. Finally, this review explores future directions for the surgical treatment of patients with AF.

For selected patients with a history of AF undergoing cardiac surgery, concomitant CM4 did not add significantly to postoperative morbidity or mortality and was associated with improved late survival compared with patients with untreated AF and a similar survival to patients without a history of AF.

Introduction Despite a lack of demonstrated efficacy, potassium and magnesium supplementation are commonly thought to prevent postoperative atrial fibrillation (POAF) after cardiac surgery. Our aim was to evaluate the natural time course of electrolyte level changes after cardiac surgery and their relationship to POAF occurrence. Methods Data were reviewed from 2041 adult patients without preoperative AF who underwent CABG and/or valve surgery between 2009 and 2013. In patients with postoperative AF, the plasma potassium and magnesium levels nearest to the first AF onset time were compared to time-matched electrolyte levels in patients without AF. Results POAF occurred in 752 patients (36.8%). At the time of AF onset or the matched time point, patients with POAF had higher potassium (4.30 vs. 4.21 mmol/L, p<0.001) and magnesium (2.33 vs. 2.16 mg/dL, p<0.001) levels than controls. A stepwise increase in AF risk occurred with increasing potassium or magnesium quintile (p<0.001). On multivariate logistic regression analysis, magnesium level was an independent predictor of POAF (OR 4.26, p<0.001), in addition to age, Caucasian race, preoperative beta blocker use, valve surgery, and postoperative pneumonia. Prophylactic potassium supplementation did not reduce the POAF rate (37 vs. 37%, p=0.813), while magnesium supplementation was associated with increased POAF (47 vs. 36%, p=0.005). Conclusion Higher serum potassium and magnesium levels were associated with increased risk for POAF after cardiac surgery. Potassium supplementation was not protective against POAF, while magnesium supplementation was even associated with increased POAF risk. These findings help explain the poor efficacy of electrolyte supplementation in POAF prophylaxis.

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Objectives Most patients with atrial fibrillation (AF) undergoing cardiac surgery do not receive concomitant ablation. This study reviewed outcomes of patients with AF undergoing Cox-Maze IV (CMIV) with radiofrequency and cryoablation and CABG at our institution. Methods Between the introduction of radiofrequency ablation in 2002 and 2015, 135 patients underwent left- or bi-atrial CMIV with CABG. Patients undergoing other cardiac procedures, except mitral valve repair, or who had emergent, reoperative or off-pump procedures were excluded. Eighty-three patients remained in the study group after exclusion criteria were applied. Freedom from atrial tachyarrhythmias (ATA) was ascertained using EKG, Holter monitor, or pacemaker interrogation at 1 to 5 years postoperatively. Results Operative mortality was 3%. Freedom from ATA at 1 year in the CMIV group was 98%, with 88% off antiarrhythmic drugs; freedom from ATA and antiarrhythmic drugs was 70% at 5 years. Conclusions The addition of CMIV to CABG resulted in excellent freedom from ATA at one-to-five years. These patients are at increased risk for nonfatal complications compared with others undergoing concomitant surgical ablation.

Objective-The Cox-Maze IV procedure has been shown to be an effective treatment for atrial fibrillation when performed concomitantly with other operations either via median sternotomy or right minithoracotomy. Few studies have compared these approaches in patients with lone atrial fibrillation. This study examined outcomes with sternotomy versus minithoracotomy in standalone Cox-Maze IV procedures at our institution. Methods-Between 2002 and 2015, 195 patients underwent stand-alone biatrial Cox-Maze IV. Minithoracotomy was used in 75 patients, sternotomy in 120. Freedom from atrial tachyarrhythmias was ascertained using EKG, Holter, or pacemaker interrogation at 3-60 months. Predictors of recurrence were determined using logistic regression. Results-Of 23 preoperative variables, the only differences between groups were that minithoracotomy patients had a higher rate of NYHA 3/4 symptoms and a lower rate of prior stroke. Minithoracotomy and sternotomy patients had similar atrial fibrillation duration and type. Minithoracotomy patients had a smaller LA diameter (4.5 vs. 4.8 cm, p=0.03). More minithoracotomy patients received a box lesion (73/75 vs. 100/120, p=0.002). Minithoracotomy patients had a shorter hospital stay (7 vs. 8 days, p=0.009) and a similar rate of major complications (3/75 (4%) vs. 7/120 (6%), p=0.74). There were no differences in mortality or freedom from atrial tachyarrhythmias. Predictors of atrial fibrillation recurrence included a preoperative pacemaker, omission of the left atrial roof line, and NYHA 3/4 symptoms. Conclusions-Stand-alone Cox-Maze IV via minithoracotomy was as effective as via sternotomy with a shorter hospital stay. A minimally invasive approach is our procedure of choice.