ARRHYTHMOGENIC right ventricular dysplasia (ARVD) is a recently described form of cardiomyopathy characterized by the occurrence of ventricular tachycardia of right ventricular origin. 1,2ARVD is characterized by fibrofatty replacement of the right myocardium, linked in part to both apoptotic cell death and patchy myocarditis. 3,4ARVD is an important cause of sudden arrhythmic death in young patients, especially during physical exercise, and severe forms of the disease may also lead to congestive heart failure. Diagnosis is based on clinical criteria and results from specialized testing—in particular, contrast ventriculography. 5Antiarrhythmic drug therapy is the first step of treatment, but the severity of ventricular tachycardia (VT) may necessitate surgical or catheter ablative techniques or an implantable defibrillator. 6,7Specific problems that may be encountered during the perioperative period have not been described. We report the specific management of severe head trauma in a patient with known ARVD.
A 19-yr-old man was admitted to the intensive care unit after multiple traumas in a motorcycle accident. Two years earlier, a family screening had been performed after the sudden cardiac death of his father at the age of 39 yr, which was related to one of the most severe form of ARVD, Uhl disease. At this time, the patient was asymptomatic, but diagnosis of ARVD was performed according to the guidelines of the ARVD Task Force 5on the presence of two major criteria: (1) familial disease, confirmed by histological findings, and (2) fibrofatty replacement of right ventricular myocardium on endomyocardial biopsy. The patient also had three minor criteria of the disease: (1) mild segmental right ventricular dilatation with normal left ventricle, (2) inverted T waves in leads V2and V3on the electrocardiogram, and (3) frequent premature ventricular complexes (PVCs) detected by Holter monitoring. Antiarrhythmic treatment with sotalol was started, and its efficacy was confirmed by a decrease in the number of PVCs.
The first examination of lesions, performed by the physician of the prehospital critical care team a few minutes later, revealed a severe closed head injury with a Glasgow Coma Scale score of 3, requiring immediate tracheal intubation and mechanical ventilation. Hemodynamic parameters at this time were stable, with a regular sinus rhythm at a rate of 55 beats/min with no PVCs detected by electrocardiographic recording and an arterial blood pressure of 150/80 mmHg. Therapeutic measures to control intracranial pressure, including mechanical ventilation and sedation with 10 mg/h midazolam and 200 μg/h fentanyl and maintenance of systolic arterial blood pressure above 90 mmHg with fluid loading when necessary were started by the physician before the patient was taken to the hospital. After hospital admission, blood glucose and hemoglobin concentrations and arterial oxygen tension (Pao2) were maintained within normal range, and a mild hypocapnia was induced to prevent secondary cerebral ischemia. Computed tomography of the body and radiography performed at the time of arrival at the hospital revealed right temporal extradural hematoma and severe brain injury with multiple areas of focal hemorrhage disseminated in the brain, facial trauma with maxillary sinus fracture, right wrist fracture, and sprained right ankle.
Surgical evacuation of the extradural hematoma was planned. Heart rate and arterial blood pressure (by radial artery catheter) were continuously monitored. Anesthesia was deepened with isoflurane and fentanyl. Intraoperative electrocardiographic monitoring showed a sinus rhythm with rare PVC. Arterial blood pressure remained stable throughout the procedure. At the end of surgery, an intraparenchymatous pressure catheter was inserted, and intracranial pressure monitoring was started.
During the 6 h after surgery, intracranial pressure increased progressively to 25 mmHg, despite conventional therapy to control intracranial hypertension. Thus, the problem of increasing arterial blood pressure to reach a cerebral perfusion pressure of at least 60 mmHg arose. At this step, according to the protocol at our institution, invasive hemodynamic monitoring would have been indicated. In our patient, it was decided not to insert a Swan Ganz catheter to reduce the risk of severe ventricular arrhythmia during insertion of the catheter in the right ventricle. Fluid loading with 300 ml gelatin, repeated three times over 4 h, was not sufficient to reach the desired value of arterial blood pressure. Echocardiographic assessment of ventricular load was planned. Transthoracic rather than transesophageal echocardiography was performed because it was more rapidly available. Underlying hypovolemia could be eliminated, and vasopressor therapy was therefore indicated. To reduce the risk of ventricular arrhythmia, 0.25 μg · kg−1· min−1norepinephrine, instead of dopamine, which is usually tried first in this condition, was administered via a central line placed through the right jugular vein. Norepinephrine was effective in restoring cerebral perfusion pressure, but despite maintenance of enteral sotalol therapy, which kept the heart rate at approximately 60 beats/min, frequent ventricular PVC (5–25 per minute) with a prolonged period of bigeminy were observed. A short period of VT, lasting less than 10 s, occurred only once and did not require specific treatment. During the 8 following days, several prolonged periods of ventricular bigeminy and a short period of VT, lasting less than 10 s, occurred. This was not related to reflex bradycardia induced by the increase in intracranial pressure but may have been promoted by the brain injury–induced sympathetic stimulation. Potassium serum concentration remained within normal range, and a mild hypomagnesemia observed 3 days after admission was treated with intravenous magnesium sulfate. The arrhythmias were hemodynamically well-tolerated, and the treatment was not modified. Neurologic status deteriorated progressively, with the aggravation of intracerebral edema and intracranial hypertension. Despite a ventriculostomy drainage, intracranial hypertension led to brain death on the ninth postoperative day.
Arrhythmogenic right ventricular dysplasia is a rare but severe familial disease, with autosomal dominant inheritance and polymorphic phenotype expression. Diagnosis usually occurs in adolescents or young adults after exercise-induced ventricular arrhythmias, which range from frequent PVC to sustained poorly tolerated VT, characterized by an unusual pattern of left bundle branch block. 5,8Ventricular fibrillation and sudden death have been observed during strenuous exercise. 9A definitive diagnosis of ARVD is based on histologic demonstration of transmural fibrofatty changes of the right ventricle. Recently, the ARVD Task Force has proposed diagnosis criteria, including the presence of encompassing structural, histologic, electrocardiographic, arrhythmic, and genetic factors. 5
Perioperative reduction of the risk for ventricular arrhythmia must rely on the understanding of arrhythmogenesis mechanisms in ARVD. Frequent provocation of arrhythmias during exercise, efficacy of antiarrhythmic agents with antiadrenergic properties, and sensitivity toward catecholamines have suggested the involvement of the adrenergic system. In this regard, localized sympathetic denervation of the right ventricle has been demonstrated in 83% of patients with ARVD. 10This inhomogeneity may increase dispersion of refractory periods and conduction times among cardiomyocytes during adrenergic stimulation. Furthermore, the increase in heart rate and the shortening of the coupling intervals observed during adrenergic stimulation were suggested to be the main determinants of VT in ARVD. 8Therefore, the anesthetic protocol should aim at reducing adrenergic stimulation. On the other hand, class I antiarrhythmic agents or sotalol, a β-blocker agent with class III properties, are widely used to prevent ventricular arrhythmias when left ventricular function is preserved. Amiodarone was reported to be better tolerated in left ventricular dysfunction. However, concern about the efficacy of drug treatment to prevent sudden death has emerged recently. 6
At the time cerebral perfusion pressure decreased, despite a fluid challenge, we had to administer a vasopressor. Among the catecholamines available, norepinephrine was chosen because it exerts a potent α-adrenoceptor and moderate β-adrenoceptors agonist action. However, its effect on β adrenoceptors was sufficient to favor ventricular arrhythmias. Reinforcement of β-adrenergic blockade, possibly by intravenous infusion of a β blocker, could have been discussed at this step. Alternately, an agent with prominent α-adrenergic and weak β-adrenergic agonist properties, such as phenylephrine, may have a lower potential for ventricular arrhythmia. However, the lack of significant inotropic effect of this agent at clinically relevant doses may induce a decreased cardiac index, which is difficult to evaluate in the absence of hemodynamic monitoring.
Adrenergic stimulation is the main precipitating factor of severe ventricular arrhythmia in ARVD. Perioperative management should include close monitoring of heart rhythm, maintenance of antiarrhythmic drugs, and limitation of sympathetic stimulation.