Timo Weimar

The cox-maze procedure for lone atrial fibrillation: a single-center experience over 2 decades.

Background— The Cox-Maze procedure (CMP) has achieved high success rates in the therapy of atrial fibrillation (AF) while becoming progressively less invasive. This report evaluates our experience with the CMP in the treatment of lone AF over 2 decades and compares the original cut-and-sew CMP-III to the ablation-assisted CMP-IV, which uses bipolar radiofrequency and cryoenergy to create the original lesion pattern. Methods and Results— Data were collected prospectively on 212 consecutive patients (mean age, 53.5±10.4 years; 78% male) who underwent a stand-alone CMP from 1992 through 2010. The median duration of preoperative AF was 6 (interquartile range, 2.9–11.5) years, with 48% paroxysmal and 52% persistent or long-standing persistent AF. Univariate analysis with preoperative and perioperative variables used as covariates for the CMP-III (n=112) and the CMP-IV (n=100) was performed. Overall, 30-day mortality was 1.4%, with no intraoperative deaths. Freedom from AF was 93%, and freedom from AF off antiarrhythmics was 82%, at a mean follow-up time of 3.6±3.1 years. Freedom from symptomatic AF at 10 years was 85%. Only 1 late stroke occurred, with 80% of patients not receiving anticoagulation therapy. The less invasive CMP-IV had significantly shorter cross-clamp times (41±13 versus 92±26 minutes; P<0.001) while achieving high success rates, with 90% freedom from AF and 84% freedom from AF off antiarrhythmics at 2 years. Conclusions— The CMP, although simplified and shortened by alternative energy sources, has excellent results, even with improved follow-up and stricter definition of failure.Background— The Cox-Maze procedure (CMP) has achieved high success rates in the therapy of atrial fibrillation (AF) while becoming progressively less invasive. This report evaluates our experience with the CMP in the treatment of lone AF over 2 decades and compares the original cut-and-sew CMP-III to the ablation-assisted CMP-IV, which uses bipolar radiofrequency and cryoenergy to create the original lesion pattern. Methods and Results— Data were collected prospectively on 212 consecutive patients (mean age, 53.5±10.4 years; 78% male) who underwent a stand-alone CMP from 1992 through 2010. The median duration of preoperative AF was 6 (interquartile range, 2.9–11.5) years, with 48% paroxysmal and 52% persistent or long-standing persistent AF. Univariate analysis with preoperative and perioperative variables used as covariates for the CMP-III (n=112) and the CMP-IV (n=100) was performed. Overall, 30-day mortality was 1.4%, with no intraoperative deaths. Freedom from AF was 93%, and freedom from AF off antiarrhythmics was 82%, at a mean follow-up time of 3.6±3.1 years. Freedom from symptomatic AF at 10 years was 85%. Only 1 late stroke occurred, with 80% of patients not receiving anticoagulation therapy. The less invasive CMP-IV had significantly shorter cross-clamp times (41±13 versus 92±26 minutes; P <0.001) while achieving high success rates, with 90% freedom from AF and 84% freedom from AF off antiarrhythmics at 2 years. Conclusions— The CMP, although simplified and shortened by alternative energy sources, has excellent results, even with improved follow-up and stricter definition of failure.

Approaching a Paradigm Shift: Endoscopic Ablation of Lone Atrial Fibrillation on the Beating Heart

BACKGROUND Percutaneous catheter ablation has been the preferred treatment strategy for many patients with symptomatic drug-refractory atrial fibrillation (AF). However, incomplete ablation lines and varying success rates remain a problem in certain subgroups. This article evaluates the feasibility and efficacy of endoscopically performed left atrial ablation in patients with lone AF. METHODS Epicardial bipolar radiofrequency ablation was performed on the beating heart through a bilateral endoscopic approach in 89 consecutive patients with lone AF. This included isolation of the pulmonary veins using a clamp; isolation of the posterior left atrial wall, including a trigonal line to the aortic noncoronary sinus using a linear ablation device; and resection of the left atrial appendage (LAA). Preoperative, perioperative, and postoperative data were collected prospectively and included questionnaires and 24-hour Holter monitoring at 6 and 12 months and annually thereafter. RESULTS Mean follow-up was 12±6 months (range, 4-28 months). No patients were lost to follow-up. Mean duration of AF was 6.4±5.7 years, with 35% paroxysmal AF and 65% persistent or long-standing persistent AF. Mean operation time was 180±43 minutes. There were no deaths, no conversion to sternotomy, and no early or late stroke. Freedom from AF was 88%, 90%, and 90% at 6, 12, and 24 months, respectively. Freedom from AF without antiarrhythmic drugs was 71%, 82%, and 90% at 6, 12, and 24 months, respectively. CONCLUSIONS Endoscopic radiofrequency ablation on the beating heart reveals high success rates with low procedure-related morbidity. For improvement of future treatment strategies, a randomized trial is advisable to compare this procedure with catheter ablation in certain patient subgroups.

The David Procedure in Different Valve Pathologies: A Single-Center Experience in 236 Patients

BACKGROUND Reports of the long-term outcome after the David procedure in different valve pathologies are limited. We compared our results in patients with tricuspid and bicuspid aortic valves, including those who required additional cusp repair. METHODS Between 1997 and 2011, 236 patients (76% males; mean age, 56 ± 15; range, 12 to 79 years) underwent valve-sparing aortic root replacement (David procedure) for aortic regurgitation and were prospectively followed up clinically and echocardiographically. RESULTS The follow-up was 94% complete. Cumulative follow-up time was 896 patient-years (mean follow-up time, 4.5 ± 2.7; range, 0.6 to 13.7 years). The 30-day mortality was 1.7% (4 of 236), and late mortality was 4% (10 of 232), with one cardiac-related death due to aortic valve regurgitation. Overall freedom from valve replacement was 94% and 87% at 5 and 10 years, respectively. In 201 patients with tricuspid aortic valves, freedom from reoperation was 94% and 90% at 5 and 10 years, respectively. This was comparable to the 53 patients with bicuspid aortic valves, with a freedom from reoperation of 97% at 5 years (p = 0.632). Forty-two patients (18%) required additional cusp repair and had a 100% freedom from reoperation at 5 years. Overall, 10 patients (4%) required reoperation, with a mean interval of 11.5 ± 10.7 months. Reasons for reoperation were recurrent aortic valve regurgitation grade II (n = 6), aortic stenosis (n = 2), endocarditis (n = 1), and a ruptured central plication (n = 1). CONCLUSIONS The David procedure revealed excellent long-term outcomes independently from the valve morphology. Rates of reoperations and valve-related morbidity were acceptably low. Additional cusp repair was no predictor for failure of this procedure.

Quo Vadis Pulmonary Autograft—The Ross Procedure in Its Second Decade: A Single-Center Experience in 645 Patients

BACKGROUND The enthusiasm about the advantages of a viable autologous transplant faded with recent reports of autograft deterioration and associated reoperations after the Ross procedure. This report evaluates predictors for autograft failure and outcomes extending into the second decade after a Ross procedure. METHODS From 1995 through 2012, 645 consecutive patients (mean age, 42.3 ± 14.2 years; 76% males) underwent a Ross operation using mainly the root replacement technique (98%). They were prospectively followed up with clinical and echocardiographic evaluations. Total follow-up was 5,349 patient-years and was 96% complete. Mean follow-up duration was 8.4 ± 4.6 years (range, 0 to 17.4 years). RESULTS Early mortality was 0.9% (n = 6). Cumulative survival at 15 years was 92.7% (95% confidence interval, 90.1% to 95.3%) and did not differ from the general German population (p = 0.261). Freedom from reoperation on the autograft or the pulmonary allograft at 12 years was 91.6% (95% confidence interval, 88.5% to 94.9%) and 95.0% (95% confidence interval, 92.8% to 97.2%), respectively. Sixty-five patients (10.1%) required a total of 78 valve-related reoperations after a Ross procedure (1.5%/patient-year) with a reoperative hospital mortality of 3.8% (n = 3). Forty-seven autograft reoperations were observed in 44 patients (0.87%/patient-year); 22 of them (47%) could be performed as a valve-sparing procedure. Preoperative aortic valve regurgitation and an aortic annulus of at least 26 mm were identified as predictors for autograft failure. CONCLUSIONS In this large series, the Ross procedure resulted in excellent long-term survival rates with a low risk of valve-related morbidity and a considerably low rate of reoperations in young and middle-aged patients and should be considered as an important treatment option in this cohort.

Differential impact of short periods of rapid atrial pacing on left and right atrial mechanical function

Current techniques to describe atrial function are limited by their load dependency and hence do not accurately reflect intrinsic mechanical properties. To assess the impact of atrial fibrillation on atrial function, combined pressure-volume relationships (PVR) measured by conductance catheters were used to evaluate the right (RA) and left (LA) atrium in 12 isoflurane-anesthetized pigs. Biatrial PVR were recorded over a wide range of volumes during transient caval occlusion at baseline sinus rhythm (SR), after onset of rapid atrial pacing (RAP), after 1 h of RAP, after conversion to SR, and after 1 h of recovery. Cardiac output decreased by 16% (P = 0.008) with onset of RAP. Mean LA and RA pressures increased by 21 and 40% (P < 0.001), respectively, and remained elevated during the entire recovery period. RA reservoir function increased from 51 to 58% and significantly dropped to 43% after resumption of SR (P = 0.017). Immediately after RAP, a right shift of LA end-systolic PVR-intercept for end-systolic volume required to generate an atrial end-systolic pressure of 10 mmHg (24.4 ± 4.9 to 28.1 ± 5.2 ml, P = 0.005) indicated impaired contractility compared with baseline. Active LA emptying fraction dropped from 17.6 ± 7.5 to 11.7 ± 3.7% (P < 0.001), LA stroke volume and ΔP/Δt(max)/P declined by 22% (P = 0.038 and 0.026, respectively), while there was only a trend to impaired RA systolic function. Stiffness quantified by the ratio of pressure to volume at end-diastole was increased immediately after RAP only in the RA (P = 0.020), but end-diastolic PVR shifted rightward in both atria (P = 0.011 LA, P = 0.045 RA). These data suggest that even short periods of RAP have a differential impact on RA and LA function, which was sustained for 1 h after conversion to SR.

Impact of differential right-to-left shunting on systemic perfusion in pulmonary arterial hypertension

This study aimed at identifying the ideal right‐to‐left shunt‐fraction to improve cardiac output (CO) and systemic perfusion in pulmonary arterial hypertension (PHT).

Evaluation of a novel cryoablation system: in vivo testing in a chronic porcine model.

ObjectiveCryoablation is commonly used at present in the surgical treatment of atrial fibrillation (AF). However, there have been few studies examining the efficacy of the commonly used ablation devices. This report compares the efficacy of two cryoprobes in creating transmural endocardial lesions on the beating heart in a porcine model for chronic AF. MethodsIn six Hanford miniature swine, the right atrial appendage and the inferior vena cava were isolated using a bipolar radiofrequency clamp to create areas of known conduction block. A connecting ablation line was performed endocardially via a purse string with the novel malleable 10-cm Cryo1 probe for 2 minutes at −40°C. Additional ablation lines were created with the Cryo1 and the 3.5-cm 3011 Maze Linear probe on the right and the left atrial wall. Epicardial activation mapping was performed before and immediately after ablation as well as 14 days postoperatively. Histologic examination was performed 14 days postoperatively. ResultsTransmural lesions were confirmed in 83/84 cross-sections (99%) for the Cryo1 probe and in 40/41 cross-sections (98%) for the 3011 Maze Linear probe. There was no difference between the devices in lesion width (mean ± SD, Cryo1, 10.7 ± 3.5 mm; 3011, 10.0 ± 3.9 mm; P = 0.31), lesion depth (Cryo1, 4.5 ± 1.7 mm; 3011, 4.6 ± 1.5 mm; P = 0.74), or atrial wall thickness (Cryo1, 4.5 ± 1.8 mm; 3011, 4.7 ± 1.7 mm; P = 0.74). There was a conduction delay across the right atrial ablation line (20 ± 2 milliseconds vs 51 ± 8 milliseconds, P < 0.001) that remained unchanged at 14 days (51 ± 8 milliseconds vs 52 ± 10 milliseconds, P = 0.88). ConclusionsThe Cryo1 probe created transmural lesions on the beating heart, resulting in sustained conduction delay. Both probes had a similar performance in lesion geometry in this chronic animal model.

Safeguards and pitfalls in minimally invasive mitral valve surgery

Minimally invasive mitral valve surgery has been established in many institutions worldwide. Appropriate indications and patient selection for this procedure must be based on a thorough understanding of its limitations and specific pitfalls. Particular risks can be minimized with careful attention to detail when planning and performing the surgery. The following chapter offers a stepwise description of the procedure; we point out particular advantages, discuss our rationale for certain steps, as well as focus on potential dangers of minimally invasive mitral valve surgery. Several graphics have also been provided to illustrate our approach and demonstrate important structural and anatomical concepts of the mitral valve apparatus.

Epicardial Ablation Performance of a Novel Radiofrequency Device on the Beating Heart in Pigs

PURPOSE Only bipolar clamps create reliable transmural lesions on the beating heart. This study evaluated the performance of a new radiofrequency (RF) device on the beating heart in an acute porcine model. DESCRIPTION Six domestic pigs were ablated with a novel bipolar RF linear device on the beating heart (ablation time of 40 s, 3 each on right and left atria and 1 each on superior and inferior vena cavae). The heart was stained with 2, 3, 5-triphenyl-tetrazolium chloride, and each lesion was cross-sectioned for lesion depth and transmurality. EVALUATION Transmurality was documented in 89% of the cross-sections. Sixty-three percent of lesions were transmural along the entire lesion length. Overall, 85% of the nontransmural cross-sections were located on the right atrium, and half of the nontransmural sections were in the superior or inferior vena cavae lesions. CONCLUSIONS This novel device was able to create transmural lesions on the beating heart, more effectively in the left atrium than in the right atrium.

The Impact of Previous Catheter-Based Ablation on the Efficacy of the Cox-Maze IV Procedure

BACKGROUND Failed catheter-based ablation for the treatment of atrial fibrillation is an indication for the Cox-maze procedure. Many patients are referred for the Cox-maze IV procedure with recurrent atrial fibrillation after a previous catheter-based ablation, but the efficacy and safety of surgical management in these patients remains unclear. METHODS Data were collected prospectively on 129 consecutive patients who underwent a stand-alone Cox-maze IV procedure. Patients were grouped by the presence (n=61; 47%) or absence (n=68; 53%) of previous catheter ablation history. Follow-up was conducted at 3, 6, and 12 months (94% complete, mean 15.1±15.6 months) with electrocardiograms and 24-hour Holter monitoring. RESULTS In patients with no ablation history compared with those with, freedom from atrial tachyarrhythmias and antiarrhythmic drugs were similar at 3 months (73% versus 67%), 6 months (85% versus 83%), and 12 months (81% versus 87%; p<0.05 for all). Those who had failed previous catheter ablation had significantly smaller left atria and longer durations of atrial fibrillation, and were more likely to have persistent atrial fibrillation compared with the group without prior ablation history. All analyzed baseline patient characteristics and comorbidities were similar between the groups. No differences were found in complication rates or surrogate measures of operative difficulty. CONCLUSIONS The Cox-maze IV procedure is safe and effective in treating recurrent atrial fibrillation regardless of previous catheter ablation history. Surgical management should be considered in patients who have failed catheter ablation for the treatment of their atrial fibrillation.