Ann Thorac Surg 1996;62:1202-1203
© 1996 The Society of Thoracic Surgeons
Case Report
Successful Surgical Repair of Aortic Dissection Presenting With Complete Heart Block
Michael E. Jessen, MD,
Vernon P. H. Horn, MD,
David E. Weaver, MD,
James D. Boehrer, MD,
W. Steves Ring, MD
Department of Surgery, St. Paul Medical Center, Dallas, Texas
Accepted for publication April 26, 1996.
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Abstract
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Acute dissection of the ascending aorta can present with complete heart block if the dissecting hematoma involves the interatrial septum near the atrioventricular node. We report a case of acute type A dissection presenting with complete heart block treated with emergency grafting of the ascending aorta, aortic valve replacement, and coronary artery bypass grafting. The patient survived, although complete heart block persisted requiring permanent pacemaker implantation.
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Introduction
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Complete heart block is a rare presenting feature of acute dissection of the ascending aorta, but carries a dismal prognosis. We describe a case of acute type A aortic dissection presenting with pain, hypertension, and complete heart block that was successfully treated with emergency surgical repair.
A 58-year-old woman was in her usual state of good health when she experienced the sudden onset of neck and chest discomfort. She noted no dyspnea, diaphoresis, or back pain. She presented to the emergency room, where she was noted to have a heart rate of 35 beats/min, a blood pressure of 164/84 mm Hg, clear lung fields, and a murmur of aortic insufficiency. She was a former smoker but had no other risk factors for cardiovascular disease. No prior episodes of bradycardia were documented. An electrocardiogram revealed complete heart block with a ventricular rate of 35 beats/min. Initial creatine kinase values were normal. A chest roentgenogram revealed a cardiac silhouette within normal limits, mild tortuosity of the aorta, and normal lung fields. She was taken to the angiography suite, where a temporary transvenous pacemaker was placed. Cardiac catheterization was performed, revealing 3+ aortic insufficiency, a moderately dilated left ventricle with preserved wall motion, a normal left main coronary artery, and 90% stenoses of the proximal left anterior descending and proximal circumflex coronary arteries. The right coronary artery was normal. Contrast in the ascending aorta suggested an aortic dissection. Subsequently, a transesophageal echocardiogram was performed (Fig 1
), which demonstrated a dissection of the ascending aorta without involvement of the aortic arch or descending aorta. Moderately severe aortic insufficiency was noted, as well as a small pericardial effusion. She was taken immediately to operation.
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Fig 1. . Transesophageal echocardiogram in the transverse plane demonstrating a dissection of the ascending aorta. The smaller, crescent-shaped false lumen appears near the noncoronary sinus.
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At operation, a median sternotomy was performed and the pericardium was opened. Approximately 100 mL of fresh blood was evacuated from the pericardial space, and the ascending aorta was noted to contain a hematoma confined to the proximal segment extending distally to within 2 cm of the origin of the innominate artery. Some hematoma was noted on the epicardial surface of the heart near the right coronary artery. The aortic arch and right atrium were cannulated for cardiopulmonary bypass, and a cross-clamp was applied above the dissection in the distal ascending aorta. No period of circulatory arrest was required. Myocardial protection was achieved with cold blood cardioplegia delivered via the coronary sinus. The proximal ascending aorta was opened, and a transverse tear on the posterior aspect above the sinotubular ridge was noted. The aorta was resected from an area above the coronary arteries to the distal extent of the dissection, and the layers of the aortic wall were reapposed between two layers of Teflon felt. The aortic valve was bicuspid, with changes consistent with chronic degeneration. The valve was removed and replaced with a no. 25 St. Jude Medical (St. Paul, MN) mechanical prosthesis using a supraannular pledgeted suture technique. The segment of ascending aorta was replaced with a 30-mm Hemashield tube graft (Meadox Medicals, Oakland, NJ), and coronary bypass grafts were constructed with saphenous vein to the obtuse marginal branch of the circumflex coronary artery and with the left internal thoracic artery to the left anterior descending coronary artery. The heart was deaired, temporary atrial and ventricular pacing wires were attached, and the patient was rewarmed and separated from bypass without difficulty.
The postoperative course was notable for mediastinal bleeding that necessitated reexploration. No surgical bleeding site was identified. The patient was extubated the day after operation and remained in complete heart block. A permanent DDD pacemaker was inserted under local anesthesia on postoperative day 6. She was discharged home 3 days later and remains in good health at 6-month follow-up.
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Comment
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Acute dissections of the ascending aorta can have varied presentations, but clinical and electrographic evidence of complete heart block as an initial feature is rare. Large series often describe no instance of this phenomenon [1], and reported cases of the combination are infrequent [2–4]. When complete heart block occurs, the mechanism has been described as rupture of a dissecting hematoma into the aortoatrial space. The hematoma then extends through the interstitial tissue of the atrial myocardium and progresses down the interatrial septum to an area near the central fibrous body of the heart, the atrioventricular node and the bundle of His [2]. Here hemorrhage frequently involves the transitional cell zone of the atrioventricular junction producing heart block, which may be transient [3]. A hematoma may also dissect through interstitial tissue of the atrial myocardium to the subintimal layer of the right atrium (leading to rupture and hemopericardium [2]) or down the interventricular septum (leading to tricuspid insufficiency [5] or rupture into the right ventricle [6]). Rarely, progression of an aortic dissection down the right coronary artery may also produce complete heart block [7]. As well, at least 1 case has been reported from an autopsy series where complete heart block accompanied aortic dissection without the presence of hematoma of the atrial septum or any other discernible cause [8].
In the present case, we presume the mechanism involved a dissecting hematoma in the atrial septum, but we have no histologic confirmation and other causes are possible. However, the absence of (1) an antecedent history of bradyarrhythmias and (2) coronary occlusions at preoperative arteriography causes us to favor this mechanism. If the presumed hematoma of the atrial septum was present, the decision to replace the aortic valve may have been advantageous. Aortic valve replacement, unlike resuspension, is likely to close the site of origin of a dissecting hematoma into the atrial septum, and may lessen the risk of subsequent rupture. In prior cases where surgical repair has been attempted without aortic valve replacement, no surgical survivors were reported. Because of the grave prognosis associated with aortic dissection presenting with heart block, urgent surgical intervention is advised.
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Footnotes
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Address reprint requests to Dr Jessen, Division of Thoracic and Cardiovascular Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75235-8879.
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References
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- Slater EE, DeSanctis RW. The clinical recognition of dissecting aortic aneurysm. Am J Med 1976;60:625–33.[Medline]
- Yacoub MH, Schottenfeld M, Kittle CF. Hematoma of the interatrial septum with heart block secondary to dissecting aneurysm of the aorta. A clinicopathologic entity. Circulation 1972;46:537–45.[Abstract/Free Full Text]
- Thiene G, Rossi L, Becker AE. The atrioventricular conduction system in dissecting aneurysm of the aorta. Am Heart J 1979;98:447–52.[Medline]
- Moar N, Lorber A, Weiss D. Atrioventricular block complicating dissecting aneurysm of the aorta. Int J Cardiol 1987;15:352–4.[Medline]
- Vyas PR, Wright CB, Drieger H, Flege JB Jr. Tricuspid incompetence resulting from retrograde aortic dissection. J Cardiovasc Surg 1987;28:585–7.[Medline]
- Perryman RA, Gay WA. Rupture of dissecting thoracic aortic aneurysm into the right ventricle. Am J Cardiol 1972;30:277–81.[Medline]
- Kamp TJ, Goldschmidt-Clermont PJ, Brinker JA, Resar JR. Myocardial infarction, aortic dissection, and thrombolytic therapy. Am Heart J 1994;128:1234–7.[Medline]
- Levinson DC, Edmeades DT, Griffith GC. Dissecting aneurysm of the aorta: its clinical, electrocardiographic and laboratory features. A report of fifty-eight autopsied cases. Circulation 1950;1:360–87.[Medline]
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Abstract
Introduction
