Texas Heart Institute journal
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Case Reports
Dual atrioventricular-nodal physiology, elicited by pacing and leading to a reversible cardiomyopathy.
Atrioventricular nodal re-entry tachycardia is the most common form of regular paroxysmal tachycardia in the adult population. This tachycardia is a re-entrant rhythm that uses the anatomic location of the atrioventricular node and its surrounding perinodal atrial tissue. The simplest concept regarding the atrioventricular nodal physiology that allows re-entry is founded upon the postulated existence of 2 atrioventricular nodal pathways with different conduction velocities and refractory periods. ⋯ He developed a tachycardia-induced cardiomyopathy with a perpetual dual response to the pacemaker stimulus. The tachycardia displayed characteristic dual atrioventricular-nodal physiology that was suppressed by amiodarone therapy, leading to a reversal of the cardiomyopathy. We discuss the mechanisms that surround such phenomena.
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We sought to determine, retrospectively, whether obesity was associated with adverse renal outcomes in 17,630 patients who underwent cardiac surgery from January 1995 through December 2006. Obesity was defined as a body mass index > or = 30 kg/m2. The primary outcome was any episode of postoperative renal insufficiency (requiring or not requiring dialysis) before hospital discharge. ⋯ Obesity was associated with an increased risk of postoperative renal insufficiency in patients undergoing isolated CABG (OR, 1.38; 95% CI, 1.18-1.61), isolated valve surgeries (OR, 1.39; 95% CI, 1.05-1.85), and combined CABG and valve surgeries (OR, 1.35; 95% CI, 0.99-1.83; statistically nonsignificant). Development of postoperative renal insufficiency was associated with a significantly higher mortality rate (P <0.0001) and with a significantly longer hospital stay (23 vs 10.5 days; P <0.0001). We conclude that obesity is associated with a significant increase in postoperative renal insufficiency in cardiac surgery patients, an effect that we attribute to an increase in postoperative renal failure that does not require dialysis.
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Case Reports
Pericardial tamponade consequent to a dynamite explosion: blast overpressure injury without penetrating trauma.
Acute cardiac tamponade is a life-threatening emergency that requires prompt treatment by either percutaneous or surgical pericardiocentesis. It may occur after penetrating or blunt chest trauma. ⋯ Physicians should be aware of the possibility of pericardial tamponade in victims of barotraumatic events such as dynamite or bomb explosions, even in the absence of penetrating trauma. Cardiac tamponade, although life-threatening, is easy to treat when recognized.
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The aim of this retrospective study was to determine the prevalence and predictors of electrical storm in 227 patients who had received implantable cardioverter-defibrillators (ICDs) and had been monitored for 31.7 +/- 15.6 months. Of these, 174 (77%) were men. The mean age was 55.8 +/- 15.5 years (range, 20-85 yr), and the mean left ventricular ejection fraction (LVEF) was 0.30 +/- 0.14. ⋯ Clinical variables with the most significant association with electrical storm were low LVEF (P = 0.04; hazard ratio of 0.261, and 95% confidence interval of 0.08-0.86) and higher use of class IA antiarrhythmic drugs (P = 0.018, hazard ratio of 3.84, and 95% confidence interval of 1.47-10.05). Amiodarone treatment and use of beta-blockers were not significant predictors when subjected to multivariate analysis. We conclude that electrical storm is most likely to occur in patients with lower LVEF and that the use of Class IA antiarrhythmic drugs is a risk factor.
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Case Reports
Acute aortic dissection early after off-pump coronary surgery: true frequency underestimated?
Since the adoption of off-pump coronary artery bypass surgery (OPCAB), numerous investigators have compared its short- and long-term results with those of on-pump coronary bypass surgery. Some reports of OPCAB were quite favorable, whereas others were critical, claiming that it resulted in incomplete revascularization and reduced venous graft patency. A potentially serious complication of OPCAB, not heretofore sufficiently confronted, is the increased incidence of early postoperative acute aortic dissection, in comparison with the more familiar intraoperative and late-occurring aortic dissection after conventional on-pump bypass surgery. ⋯ Prevention lies in the strict control of systolic blood pressure during the performance of proximal anastomoses; avoidance of aortic clamping through the use of sequential all-arterial grafts or new-generation mechanical connectors; and, at times, aggressive replacement of the aorta with a prosthetic graft. Herein, we present the cases of 4 patients who sustained acute aortic dissection early after OPCAB. We review the pertinent medical literature.