Association of postoperative atrial fibrillation with higher dosing ratios of protamine-to-heparin.

Background: Postoperative atrial fibrillation (POAF) is defined as new-onset AF in the immediate postoperative period. The relatively high incidence of POAF after cardiac surgery is well described, but pathophysiological mechanisms underlying the initiation, maintenance, and progression of POAF may be multifactorial and have not yet been comprehensively characterized. One of the mechanisms includes altered Ca2+ kinetics. Accumulating evidence has suggested that altered atrial cytosolic calcium handling contributes to the development of POAF, protamine reversibly modulates the calcium release channel/ryanodine receptor 2 (RyR2) and voltage-dependent cardiac RyR2. However, it is currently unknown whether such abnormalities contribute to the arrhythmogenic substrate predisposing patients to the development of POAF. Methods: We have retrospectively analyzed 147 patients who underwent cardiac surgery with cardiopulmonary bypass support. Of these, 40 patients were excluded from the analysis because of pre-existing AF. All patients received heparin followed by protamine at different dosing ratios of protamine-to-heparin, depending on the periods studied. Results: The dosing ratio of protamine-to-heparin = 1.0 was compared with higher dosing ratios of protamine-to-heparin >1.0 up to 1.7. POAF developed in 15 patients (15/107 = 14%), of these, 5 out of 57 patients (33.3%) in the dosing ratio of protamine-to-heparin = 1.0 and 10 out of 35 patients (66.7%) in the higher dosing ratios of protamine-to-heparin. Statistical significance was observed in patients with higher dosing ratios of protamine-to-heparin, compared with the dosing ratio of protamine-to-heparin = 1.0 (odds ratio = 3.890, 95% CI = 1.130-13.300, p-value = 0.031). When types of diseases were analyzed in terms of higher dosing ratios of protamine-to-heparin, only valvular disorders were significantly associated with POAF (p = 0.04). Conclusions: Protamine is clinically utilized to reverse heparin overdose and has been shown to display immunological and inflammatory alterations. However, its association with POAF has not been reported. Our results provide evidence that higher dosing ratios of protamine-to-heparin may increase the incidence of POAF.

[Constrictive Pericarditis with Multiple Organ Failure after Coronary Artery Bypass Grafting].

A 67-year-old male patient, who had undergone coronary artery bypass grafting (CABG) 16 years before, developed congestive heart failure 5 years after surgery. Three years later, he developed repeated heart failure, sepsis by methicillin-resistant Staphylococcus aureus (MRSA), renal failure, repeated thrombophlebitis on his right leg and atrial fibrillation. He also suffered from clouding of consciousness and flapping tremor caused by hyperammonemia. The three bypass grafts showed normal flow, but the pericardium was severely thickened. Therefore, pericardiotomy was performed via median sternotomy with additional left thoracotomy without using cardiopulmonary bypass. Although, he developed MRSA mediastinitis after surgery, he recovered after a month of continuous negative pressure wound therapy. His liver function and septic conditions gradually recovered. No recurrence of heart failure has been observed for 8 years since his second surgery.

[Cardiac perforation with a passive fixation lead penetrating ventricular septum; report of a case].

A 81-year-old female developed diaphragm twitching 2 days after the intravenous implantation of pacemaker (DDD mode) with passive fixation leads. A computed tomography (CT) and fluoroscopy revealed the lead perforating the interventricular septum and the ventricular wall without any sign of pericardial effusion. Surgical procedure through median sternotomy was performed, and the penetrated lead was removed. The injured myocardium was repaired with a U stitch reinforced by Teflon-feltstrips. New epicardial leads were fixed on the right atrial wall and on the inferior wall of the right ventricle. The patient had been doing well until 86-year-old, when she died of myelodysplastic syndrome.

Delayed cardiac tamponade caused by self-inserted needles.

A 47-year-old female intentionally inserted needles through her chest wall, resulting in cardiac trauma. One week later, cardiac tamponade occurred. The needles were detected and removed successfully by thoracotomy. During the operation, fluoroscopy was used to locate the needles and greatly facilitated their successful removal.

Successful surgical treatment of mitral regurgitation for complete rupture of the anterior papillary muscle after acute myocardial infarction.

Papillary muscle rupture complicating acute myocardial infarction leads to mitral regurgitation and is associated with significant mortality. We experienced a case involving massive mitral regurgitation caused by complete anterior papillary muscle rupture following acute lateral myocardial infarction. A 75-year-old woman developed heart failure shortly after her admission, and the diagnosis was confirmed by echocardiography and cardiac catheterization. Under intra-aortic balloon pumping, the patient underwent emergency mitral valve replacement and coronary revascularization. Her postoperative course was uneventful, and she was discharged on the 40th postoperative day. We believe that prompt surgical treatment should be performed even in stable patients with ischemic mitral regurgitation, given that deterioration may be sudden and unpredictable especially in cases involving complete papillary muscle rupture.

Two cases of a free-floating ball thrombus in the left atrium.

A free-floating ball thrombus in the left atrium is an unusual occurrence that may cause fatal systemic emboli or left ventricular inflow obstruction, often resulting in sudden death. The first of 2 cases was a 59-year-old female with mitral stenosis and chronic atrial fibrillation who presented with severe dyspnea. Transthoracic echocardiography revealed a free-floating ball thrombus and emergency thrombectomy and mitral valve replacement were performed successfully. A second thrombus, which was not found at preoperative examination, was attached to the anterior mitral leaflet and may have been the source of the free-floating ball thrombus. The second case was a 79-year-old female with chronic renal failure who underwent mitral valve replacement 11 years prior to admission. She had been dependent on hemodialysis for 10 years, and had suffered several recent transient cerebral ischemic attacks. Computed tomography showed a ring-shaped, high-density area in the left atrium and transthoracic echocardiography revealed a floating ball thrombus in the left atrium. Thrombectomy was performed, but the patient died as a result of postoperative pneumonia 2 months later. Case 2 appears to be the first reported case of a ball thrombus in a hemodialysis patient who had previously undergone mitral valve replacement.