Electrophysiological and Histopathological Characteristics of Ventricular Tachycardia Associated With Primary Cardiac Tumors.

BACKGROUND: Ventricular tachycardia (VT) associated with primary cardiac tumors (PCTs) originating from the ventricles is rare, but lethal, in young patients. OBJECTIVES: This study aimed to clarify the mechanisms underlying primary cardiac tumor-related ventricular tachycardia (PCT-VT) and establish a therapeutic strategy for this form of VT. METHODS: Among 67 patients who underwent surgery for VT at our institute between 1981 and 2020, 4 patients aged 1 to 34 years, including 3 males, showed PCT-VT (fibroma, 2; lipoma, 1; and hamartoma, 1), which was investigated using a combination of intraoperative electroanatomical mapping and histopathological studies. RESULTS: All 4 patients developed electrical storms of sustained VTs refractory to multiple drugs and repetitive endocardial ablations. The VT mechanism was re-entry, and intraoperative electroanatomical mapping showed a centrifugal activation pattern originating from the border between the tumor and healthy myocardium, where fractionated potentials were detected during sinus rhythm. Histopathological studies of serial sections of specimens acquired from these areas revealed tumor infiltration into the surrounding myocardium with cell disorganization, exhibiting myocardial disarray. Several myocardia entrapped in the tumor edges contributed to the development and sustainment of re-entrant VT activation. In the 2 patients in whom complete resection was unfeasible, encircling cryoablation to entirely isolate the unresectable tumor was effective in suppressing VT occurrence. CONCLUSIONS: The mechanism underlying PCT-VT involves re-entry localized at the tumor edges. Myocardial disarray associated with tumor infiltration is a substrate for this form of VT. Cryoablation along the border between the tumor and myocardium is a promising therapeutic option for unresectable PCT-VT.

Surgery for ventricular tachycardia originating from the left ventricular summit.

OBJECTIVES: Ventricular tachycardia (VT) originating from the left ventricular summit region, the most superior region of the left ventricle surrounded by the major coronary arteries and veins, is frequently refractory to pharmacological therapies and endocardial and epicardial catheter ablation. METHODS: Eleven patients with an age from 31 to 79 (median 56) years old, underwent map-guided surgery for left ventricular summit VT. All patients had undergone 1-5 unsuccessful sessions of catheter ablation for incessant VT, preoperatively. Five patients had suffered VT storm and 1 had a history of cardiopulmonary resuscitation. Four patients had implanted with a defibrillator. Epicardium to endocardium transmural cryothermia was applied at the VT origin determined by intraoperative epicardial mapping with electro-anatomical mapping system. Harmonic scalpel was used to remove the epicardial fat and cryothermia was applied directly to the myocardium, avoiding thermal or mechanical injuries to the coronary vessels. Additional endocardial cryothermia at the VT origin was performed by a cryoprobe introduced into the left ventricular cavity through an aortotomy. RESULTS: There was no surgical mortality or long-term mortality related to VT during a median follow-up period of 60 months (interquartile range: 34-82). Five-year freedom from preoperatively documented left ventricular summit VT and non-documented VT was 91% and 73%, respectively. All the patients with postoperative VT underwent successful catheter ablation. Other patients were free from VT during the follow-up period. CONCLUSIONS: Epicardial to endocardial transmural cryothermia at the VT origin guided by intraoperative electro-anatomical mapping with a close collaboration with electrophysiologists was crucial in successful surgery for left ventricular summit VT.

Multicenter Study of Surgical Ablation for Atrial Fibrillation in Aortic Valve Replacement.

There is controversy regarding appropriate surgical ablation procedures concomitant with nonmitral valve surgery. We retrospectively investigated the impact of surgical ablation for atrial fibrillation during aortic valve replacement between 2010 and 2015 in 16 institutions registered through the Japanese Society for Arrhythmia Surgery. Clinical data of 171 patients with paroxysmal and nonparoxysmal atrial fibrillation undergoing aortic valve replacement were collected and classified into full maze operation (n = 79), pulmonary vein isolation (PVI) (n = 56), and no surgical ablation (n = 36) groups. All patients were followed up and electrocardiograms were recorded in 68% at 2 years. The myocardial ischemia time was significantly longer in the maze group than the others during isolated aortic valve replacement (p ≤ 0.01), but there were no significant differences in 30-day or 2-year mortality rates between groups. The ratios of sinus rhythm at 2 years in paroxysmal and nonparoxysmal atrial fibrillation in the maze group versus PVI group were 87% versus 97%, respectively (p = 0.24) and 53% versus 42%, respectively (p = 0.47). No patients with nonparoxysmal atrial fibrillation in the no surgical ablation group maintained sinus rhythm at 2 years. In conclusion, both maze and PVI during aortic valve replacement are valuable strategies to restore sinus rhythm at 2 years and result in favorable early and midterm survival rates.

Shunt and pace: a novel experimental model of atrial fibrillation with a volume-loaded left atrium.

BACKGROUND: Atrial fibrillation (AF) is frequently seen in patients with a volume-loaded left atrium (LA) such as mitral valve regurgitation (MR). Previous animal models have incomplete relevance to human AF associated with MR. METHODS: A novel experimental model with a combination of volume loading of LA by creating a shunt from the subclavian artery to pulmonary artery and electrical remodeling induced by continuous rapid LA pacing was designed and the electrophysiological effects were examined in 10 canines. Five weeks after the shunt surgery, the entire atrial epicardium was mapped during sustained AF with form-fitted electrode patches with 246 bipolar electrodes and a three-dimensional dynamic mapping system to characterize the induced AF. RESULTS: Three animals died of severe heart failure and pacing failure occurred in one. Remaining six animals were subjected to the analysis. The LA diameter increased progressively after the shunt surgery. Sustained AF was induced after 3 weeks of continuous rapid LA pacing in all animals. The activation maps revealed repetitive focal activations arising from the pulmonary veins, right or left atrial regions, and reentrant activations in the RA, which patterns of atrial activations are the same as those seen in human AF. CONCLUSION: The animal model with a combination of LA volume load and electrical remodeling was relevant to human AF associated with LA volume load. Studies using the present model may provide further knowledges of AF and may be useful in examining the effects of pharmacological and non-pharmacological therapies.

Surgical Ablation of Ventricular Tachycardia.

Surgery for ventricular tachycardia (VT) is indicated in patients in whom pharmacotherapy or catheter ablation is ineffective or frequent VT attacks are not suppressed or with frequent activation of implantable cardioverter defibrillator. In ischemic VT, resection of fibrous endocardium combined with encircling cryothermia at the border between the infarcted and normal myocardium is performed. In surgery for VT associated with cardiomyopathy, close collaboration between the physician and surgeon is important and intraoperative mapping using electro-anatomic mapping system is helpful. In VT associated with cardiac tumors, cryothermia of the thinned subepicardial myocardium at the edge of the tumor is recommended in addition to resection of tumors.

Older Patients and Patients with Severe Arteriosclerosis Are Less Likely to Develop Keloids and Hypertrophic Scars after Thoracic Midline Incision: A Survey-Based Analysis of 328 Cases.

BACKGROUND: Surgery is a well-known trigger of keloid and hypertrophic scarring. Sternotomy scars are subject to high skin tension, which is known to promote pathologic scarring. This suggests that sternotomies in adults are associated with high pathologic scarring rates, which aligns with the authors' anecdotal experience. However, this notion has never been examined formally. Therefore, the authors conducted a survey-based cohort study of patients who had undergone a sternotomy. METHODS: All consecutive Japanese adults (18 years of age or older) who underwent cardiovascular surgery with sternotomy in 2014 to 2017 were identified in 2019 by chart review and sent a questionnaire. Respondents formed the study cohort. The questionnaire presented randomly ordered photographs of representative mature, keloid, and hypertrophic scars and asked the patients to choose the image that best resembled their midline scar when it was particularly noticeable. The incidence of self-reported pathologic scarring (keloids and hypertrophic scars were grouped together) and the patient demographic (age and sex) and clinical characteristics (intima-media thickness of the left and right common and internal carotid arteries) that were associated with pathologic scarring were determined. RESULTS: Of the 548 patients who underwent sternotomy, 328 responded for a 60 percent response rate. The mean patient age was 67 years, and 68.0 percent were male. Of these patients, 195 (59.5 percent) reported they had a pathologic scar. Compared with patients who had a mature scar, patients who had a pathologic scar had younger mean age (65 versus 69 years; p = 0.0002) and lower intima-media thickness (0.92 versus 1.05 mm; p = 0.028). CONCLUSIONS: Sternotomy was associated with a high rate of pathologic scarring. Older age and arteriosclerosis were associated with less pathologic scarring. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Multicenter randomized study evaluating the outcome of ganglionated plexi ablation in maze procedure.

OBJECTIVE: The benefit of adding ganglionated plexi ablation to the maze procedure remains controversial. This study aims to compare the outcomes of the maze procedure with and without ganglionated plexi ablation. METHODS: This multicenter randomized study included 74 patients with atrial fibrillation associated with structural heart disease. Patients were randomly allocated to the ganglionated plexi ablation group (maze with ganglionated plexi ablation) or the maze group (maze without ganglionated plexi ablation). The lesion sets in the maze procedure were unified in all patients. High-frequency stimulation was applied to clearly identify and perform ganglionated plexi ablation. Patients were followed up for at least 6 months. The primary endpoint was a recurrence of atrial fibrillation. RESULTS: The intention-to-treat analysis included 69 patients (34 in the ganglionated plexi ablation group and 35 in the maze group). No surgical mortality was observed in either group. After a mean follow-up period of 16.3 ± 7.9 months, 86.8% of patients in the ganglionated plexi ablation group and 91.4% of those in the maze group did not experience atrial fibrillation recurrence. Kaplan-Meier atrial fibrillation-free curves showed no significant difference between the two groups (P = .685). Cox proportional hazards regression analysis indicated that left atrial dimension was the only risk factor for atrial fibrillation recurrence (hazard ratio: 1.106, 95% confidence interval 1.017-1.024, P = .019). CONCLUSION: The addition of ganglionated plexi ablation to the maze procedure does not improve early outcome when treating atrial fibrillation associated with structural heart disease.

Recanalized saphenous vein graft once occluded in postoperative acute period.

A 69-year-old female with diabetes mellitus underwent off-pump coronary artery bypass grafting for old myocardial infarction and unstable angina with reduced left ventricular wall motion due to triple vessel disease. Although the saphenous vein graft was confirmed to be patent during surgery, it developed occlusion at the distal anastomotic site on postoperative first day. However, recanalization was achieved for this saphenous vein graft following the administration of direct oral anticoagulants in addition to antiplatelet therapy. Anticoagulant therapy, in addition to antiplatelet therapy, should be considered for preventing and dissolving thrombus in postoperative acute period, especially in high-risk patients for thrombotic graft occlusion.

Outcomes of abdominal aortic aneurysm repairs: Endovascular vs open surgical repairs.

BACKGROUND: Operative mortality after endovascular aneurysm repair (EVAR) has been reported as lower than open surgical repair (OSR) for abdominal aortic aneurysm (AAA) in randomized controlled trials. However, many cohort studies have demonstrated similar mortality rates for both procedures. We compared operative mortality between EVAR and OSR, at our institution. METHODS: All AAA operations from 2012 to 2017 were reviewed, and baseline characteristics were collected. Outcomes included 30-day mortality, operative data, complications, length of hospital stay (LOS), costs, re-intervention, and survival rates were compared. A multivariable analysis with unbalanced characteristics was performed. RESULTS: We had a total of 162 patients, 100 having OSR and 62 for EVAR. The EVAR group was older, with higher ASA classification. Thirty-day mortality rate did not significantly differ (0/100 for OSR and 2/62 (3%) for EVAR; p = 0.145), while the EVAR group had less blood loss, shorter operative times, and LOS, but higher re-intervention rates (adjusted hazard ratio 6.4 (95%CI: 1.4, 26.8)). Survival rates did not significantly differ between the groups. EVAR cost approximately 1-million yen more. CONCLUSIONS: OSR had low 30-day mortality rate in selected low-risk patients whereas EVAR had less blood loss, shorter operative times, LOS and could be done in high-risk patients with low 30-day mortality but with higher re-intervention rate.

Evaluation of a sludge-treatment process comprising lipid extraction and drying using liquefied dimethyl ether.

Liquefied dimethyl ether (DME) was used to extract lipids from sewage sludge. Factorial experimental analyses were used to evaluate the influence of different variables on raw lipid extraction and sludge drying. The DME method was compared with the Bligh and Dyer (B&D) method for three undigested and two anaerobically digested dewatered sludges. The results indicate that although the raw lipid yield of the B&D method was 5% higher than that of the DME method, the proportion of fatty acid methyl esters (FAMEs) in raw lipids extracted by the DME method was 14.1-33.4%, almost twice that of the B&D method. The FAME composition varied according to sludge type, and the dewatered undigested sludges contained more unsaturated fatty acids (e.g. C18:1, C18:2). The lower heating value (LHV) of product by the DME method ranged from 3.74 to 5.70 MJ/kg compared with 1.21-0.39 MJ/kg for the B&D method. Also, DME could be reused at least five times without significantly reducing the lipid yield and drying efficiency. Finally, an economic analysis of the DME, the conventional solvent extraction, and the heat-drying methods was conducted.

Saphenous vein characteristics evaluated using three-dimensional contrastless computed tomography before coronary artery bypass grafting.

OBJECTIVE: Saphenous vein (SV) grafts are occasionally unsuitable for grafting owing to anatomic variants. However, there is some concern regarding preoperative SV evaluation. We used contrastless 3D-CT to investigate the anatomical SV characteristics before CABG. METHODS: Contrastless 3D-CT was used to preoperatively evaluate the SV anatomy in 102 consecutive patients undergoing elective first-time CABG. The external diameter of the SV was measured at the mid-level of the thigh and calf segments on both sides. Abnormal branches of the SV were classified into three categories; (1) partial duplication, which was defined as double SVs; (2) large accessory SVs, which were larger than the great SV; and (3) complicated branches of the SV, which resulted in the great SV being undetected. The existence of varicose veins was assessed. RESULTS: The size distribution of the SV (< 3 mm/3-5 mm/5 mm <) was 9/142/53 and 17/154/33 in the thigh and calf segments, respectively. Abnormal branches of the SV were found in 47 patients (46%): (1) partial duplication was noted in 40 patients; (2) large accessory SV was observed in eight patients; and (3) complicated branches were identified in five patients. Varicose veins were detected in 15 patients. SV was harvested in 74 patients, and no additional skin incision was required. CONCLUSIONS: Contrastless 3D-CT is an objective, less time-consuming modality to preoperatively evaluate the SV, and may be less invasive in terms of avoiding unnecessary skin incision. This technique is useful for defining atypical anatomical variations, such as partial duplications, large accessory SVs, and varicose veins.

Repetitive aortic dissection in a patient with giant cell arteritis.

Giant cell arteritis is reportedly associated with thoracic aortic aneurysm and acute aortic dissection. We encountered a patient with giant cell arteritis who suffered acute aortic dissection three times within a short period. A pathological specimen of the ascending aorta taken at surgery for type A acute aortic dissection revealed the typical features of giant cell arteritis. Giant cell arteritis patients might be at greater risk of acute aortic dissection than healthy individuals.

The safety and feasibility of laparoscopic gastrectomy for gastric cancer in very elderly patients: short-and long-term outcomes.

PURPOSE: It remains unclear whether laparoscopic gastrectomy (LG) for gastric cancer is a suitable treatment for very elderly (VE) patients. We aimed to assess the safety and feasibility of LG for gastric cancer in VE patients. METHODS: We reviewed 226 consecutive patients who underwent LG between January 2010 and December 2016. We compared VE patients (age ≥ 80, n = 38) with non-elderly patients (age ≤ 79, n = 188). RESULTS: An ASA-PS score ≥ 2 was more common in VE group (86.8 vs. 48.9%; P < 0.01). There were no significant differences in the operating time, blood loss, postoperative hospital stay, or postoperative morbidity between the groups. The 3-year survival rate and 3-year disease-specific survival rate were lower in the VE group (53.7 vs. 85.6%; P < 0.0001, 78.5 vs. 92.4%; P = 0.0116). A univariate analysis showed that PS scores ≥ 2, Charlson comorbidity index ≥ 4, and pN stage were independent predictors of decreased overall survival rates in the VE group. A multivariate analysis showed total gastrectomy, a Charlson comorbidity index ≥ 4, and the pN stage to be independent predictors in the VE group. CONCLUSION: LG for gastric cancer is, thus, considered to be safe for patients aged 80 years or older. Total gastrectomy, a Charlson comorbidity index ≥ 4, and the pN stage were independent risk factors for a poor prognosis in these patients.

What is a precise anatomic resection of the liver? Proposal of a new evaluation method in the era of fluorescence navigation surgery.

BACKGROUND/PURPOSE: Indocyanine green (ICG) fluorescence navigation has been adapted for anatomic liver resection (AR) but an objective method for evaluation of its validity is required. This pilot study aimed to propose a new method to evaluate the accuracy of parenchymal division along the plane between hepatic segments and estimate the real-time navigation efficacy for AR by the Medical Imaging Projection System (MIPS), which continuously demonstrates the transection plane using projection mapping with ICG fluorescence. METHODS: Ten patients who underwent open AR using liver segmentation with ICG fluorescence technique between August 2016 and July 2019 were included: six patients under MIPS guidance (MIPS group), while four using only conventional ICG fluorescence technique before parenchymal resection (non-MIPS group). Densitometry of the captured fluorescence image was performed to evaluate the fluorescence area ratio of each transection plane. The accurate fluorescence area ratio was calculated by subtracting the fluorescence area rate on the resected side from that on the remnant side. RESULTS: The accurate fluorescence area ratio of the MIPS group and the non-MIPS group was 23.0 ± 12.6% and 5.6 ± 9.5%, respectively (P = .038). CONCLUSIONS: Based on the results of our new method, real-time navigation using the MIPS may facilitate performing AR along the plane between hepatic segments.

Computational fluid dynamics simulations of flow distribution and graft designs in apicoaortic bypass.

OBJECTIVE: Apicoaortic bypass has double outlets and its graft design is similar to that of a left ventricular assist device (LVAD). The left ventricular apex to the descending aorta (LV-DsAo) bypass is widely used in apicoaortic bypass. In contrast, the left ventricular apex to the ascending aorta (LV-AsAo) bypass is standard in LVAD surgery. This study aimed to evaluate the graft designs of apicoaortic bypass and their effects on flow distribution and energy loss (EL). METHODS: A simulation study using computational fluid dynamics was performed on the geometry and hemodynamics data obtained from a 30-year-old patient who underwent a LV-DsAo bypass. The ratio of the cardiac output (CO) through the ascending aorta (AsAo) and apicoaortic conduit was set at 50:50, 30:70, and 10:90. Regional blood flow (RBF) and EL were calculated for the different distribution ratios. As an alternative to the LV-DsAo bypass, a virtual LV-AsAo bypass surgery was performed, and each parameter was compared with that of the LV-DsAo bypass. RESULTS: At a distribution ratio of 50:50, the RBF to the head and EL were 16.4% of the total CO and 62.0 mW in the LV-DsAo bypass, and 32.3% and 81.5 mW in the LV-AsAo bypass, respectively. The RBF to the head decreased with the CO through the AsAo in the LV-DsAo bypass, but it was constant in the LV-AsAo bypass. The EL increased inversely with the CO through the AsAo in both graft designs. CONCLUSION: The regional blood flow distribution was different, but the trend of the EL which increased inversely with the CO through the AsAo was similar between the LV-DsAo and LV-AsAo bypasses.

The Effect of Continuous Field Block through Intercostal Muscles after Atrial Septal Defect Closure via a Mini-Right Thoracotomy in Pediatric Patients.

BACKGROUND: Postoperative pain management in thoracotomy patients often is difficult. Furthermore, pediatric patients present more challenges because of their inability to effectively communicate their pain intensity. The purpose of this study was to evaluate the use of continuous field block through intercostal muscles as postoperative pain management in pediatric thoracotomy. METHODS: Between 2014 and 2018, 11 patients underwent an ASD closure using a cardiopulmonary bypass via a mini-right thoracotomy through the fourth intercostal space. At the time of chest closure, a single-shot field block via the fourth intercostal muscles was performed with levobupivacaine (0.6 mg/kg). The first five patients were only given the single-shot field block (Single group). The remaining six patients were given levobupivacaine continuously (0.1 mg/kg/hr) through an indwelling catheter until the chest tube removal (Continuous group). The groups' vital signs, total amounts of acetaminophen used, postoperative courses were compared. RESULTS: Although the heart rate did not differ between the groups, the respiratory rate was significantly higher in the Single group versus the Continuous group at 16 and 32 hr post-surgery (35.6 ± 9.7/min vs. 18.5 ± 4.7/min; p=0.007, 43.0 ± 10.4 vs. 25.3 ± 3.1; p=0.042, respectively). The accumulated dosage of acetaminophen given by postoperative day 2 was significantly higher in the Single group versus the Continuous group (55.3 ± 22.1 mg/kg vs. 7.8 ± 17.4 mg/kg; p=0.012). CONCLUSIONS: Continuous field block via intercostal muscles after ASD closure via a mini-right thoracotomy in children was effective to stabilize the vital signs and reduce the analgesic medication use.

Histological properties of oscillating intracardiac masses associated with cardiac implantable electric devices.

BACKGROUND: There have been a few cases of echogenic cardiac implantable electric device (CIED) lead-associated oscillating intracardiac masses (ICMs) in leads imaged by echocardiography. The histological properties of ICMs could help clarify the etiological diagnosis. Although there is extensive literature on mass size, the histological properties of such masses have not been characterized. The aim of this research was to clarify the histological features of oscillating ICMs in CIED patients. METHODS: Preoperative echocardiography was performed in all candidates for CIED removal. In the patients with ICMs, specimens were obtained by 3 methods: direct tissue collection during open-heart surgery; tissue collection together with the CIED lead during transvenous extraction; and tissue collection by catheter vacuum during transvenous CIED removal. A standard histopathological examination of ICM tissue was performed. RESULTS: A total of 106 patients underwent lead removal in our institute (April 2009-March 2018); 14 patients had an ICM (13.2%), and 7 specimens were obtained in patients with CIED lead-related ICM. Following histological examination, 2 types of ICM were identified: one mainly composed of thickened endocardium (EN type; 3 patients), and the other mainly an aggregate of inflammatory cells as a neutrophil cell (NC type; 4 patients). CONCLUSIONS: Two histological types of intracardiac masses, including a thickened endocardium type and a neutrophil cell type, were identified. These classifications might help make an accurate histological diagnosis of lead-associated intracardiac masses.