Anaesthetic challenges in a patient with Wolff-Parkinson-White (WPW) syndrome for orchidectomy

Abstract

Wolff-Parkinson-White (WPW) syndrome is an extremely rare congenital cardiac conduction disorder. It is due to an aberrant pathway between the atrium and ventricle. This manuscript entails a man with an underlying WPW who was posted for an elective orchidectomy. We discussed the important perioperative precautions to prevent the precipitation of acute cardiac events.

Background

It is very rare for patients with Wolff-Parkinson-White (WPW) syndrome to present for surgery.¹ Anaesthetists should be aware of the perioperative considerations for patients with WPW syndrome. We present and discuss a successful management of our patient with WPW syndrome who underwent an elective orchidectomy under subarachnoid block (SAB).

Case presentation

A 23-year-old man (75 kg, 162 cm), with a known case of WPW syndrome for 1 year, was electively posted for an orchidectomy. He was recently diagnosed of non-seminomatous right testicular carcinoma and had completed chemotherapy. He gave a 1-year history of frequent palpitation and shortness of breath, which worsened during sports activities but relieved by rest. He developed a presyncopal attack while lying flat 6 months ago. On examination, he was asymptomatic with a blood pressure (BP) of 132/75 mm Hg and pulse rate (PR) of 75 beats/min. His airway and spine assessment were normal. The scrotal examination showed a hard mass on the right testis measuring 9 cm×7 cm.

Investigations

• His 12 leads ECG was consistent with WPW syndrome as evidenced by shortened PR interval, delta waves and prolonged QRS complexes (figure 1).

• An echocardiogram showed an ejection fraction of 62% with normal cardiac contractility and valves.

• A 24-hour Holter monitoring did not show any atrial fibrillation (AF) or paroxysmal supraventricular tachycardia (SVT), thus not requiring further cardiac interventions.

• The haemoglobin and electrolytes were within normal limits.

Figure 1.

Perioperative ECG showing delta waves with shortened pulse rate interval, consistent with Wolff-Parkinson-White syndrome.

Differential diagnosis

The provisional diagnosis based on his ECG and clinical symptoms was suspected WPW syndrome.

Treatment

A high-risk written consent was obtained, focusing on the potential intraoperative cardiac complications which included life-threatening arrhythmias, myocardial ischaemia and death. He was given premedication with tablet midazolam 7.5 mg on the night before and in the morning of the day of surgery. He fasted and avoided solid foods for 8 hours prior to surgery.

In the operating theatre, two 16G intravenous cannula were secured after lignocaine 2% (20 mg) subcutaneous infiltration. Subsequently, intravenous dexmedetomidine dose of 1 μg/kg was loaded over 10 min and then continued at a rate of 0.3 μg/kg/hour. Additionally, a preload of 250 mL of normal saline 0.9% was given over 20 min before he was gently transferred to the operating table. A 5-lead ECG and other routine monitoring were initiated in accordance with American Society of Anaesthesiology guidelines. An arterial catheter was also cannulated into the right radial artery for intra-arterial BP monitoring after subcutaneous infiltration with lignocaine 2% (10 mg). We prepared lifesaving drugs such as ephedrine, phenylephrine, atropine and lignocaine, together with a defibrillator which was positioned nearby for emergency use.

Patient was carefully sat up and his lumbar 4–5 (L4–L5) interspace level was identified for SAB. Lignocaine 2% (20 mg) was infiltrated on the skin gently. After 2 min, a mixture of 12 mg of hyperbaric bupivacaine 0.5% and fentanyl 10 μg (total mixture volume=2.6 mL) was injected into the intrathecal space via single attempt using 25G pencil point spinal needle. The patient was then supinated with nasal prong 3 L/min oxygen supplement and capnography monitoring. A maximum sensory blockade up to T8 level and modified Bromage score of 3 were elicited. Right orchidectomy was allowed to proceed in supine position after confirmation of SAB via right inguinal incision. The surgeons gently manipulated the tumour with the aim to avoid stimulating a vagal reflex and bradycardia when handling the spermatic cord. Adequate blanket and fluid warmers were put in place to prevent shivering. The intraoperative BP and PR ranged 103/75–124/82 mm Hg and 53–70 beats/min, respectively. Dexmedetomidine infusion was maintained at a range of 0.2–0.3 μg/kg/hour. The ECG was stable throughout with occasional prominence of delta waves and shortened PR interval which occurred when the patient was repositioned supine from sitting after completion of spinal anaesthesia and during transfer to the recovery room (figure 2). The patient was successfully managed with negligible bleeding.

Figure 2.

Intraoperative ECG showing Wolff-Parkinson-White syndrome with a heart rate of 75 beats/min.

Outcome and follow-up

He was discharged to ward with dexmedetomidine infusion continued at 0.2 μg/kg/hour for 1 day with vital signs monitoring. Analgesia was supplemented with a one-off subcutaneous bupivacaine 0.5% (50 mg) over the incision postoperatively and tablet paracetamol 1 gram and intravenous parecoxib 40 mg three times per day. He was discharged home 2 days later with cardiology and surgical follow-up.

Discussion

WPW syndrome is an uncommon electrophysiological cardiac disorder with a prevalence of 0.7–1.7 per 1000 population and higher among men.¹ It is a pre-excitation syndrome which occurs due to the presence of abnormal congenital fibromuscular connections, also known as Bundle of Kent, between the atria and ventricles. It may connect the left atrium with ventricle or right atrium to the right ventricle and can conduct the electrical impulses bidirectionally. In normal healthy conduction, the impulse from the sino-atrial node (SAN) will be conducted to the atrioventricular node (AVN) before being dispersed to both ventricles via Purkinje fibres. For WPW syndrome, in addition to the physiological conduction to the AVN, there is a direct transmission of impulse from SAN to the accessory pathways (APs), bypassing the AVN, to depolarise the ventricles. This AP may merge with the normal cardiac conduction pathway to form an atrioventricular re-entrant tachycardia.^{2 3} This lack of physiological delay of impulse causes early pre-excitation of the ventricles which result in shortened PR interval in the ECG. The typical pathognomonic of WPW pattern is the presence of delta waves. It is due to early rapid depolarisation of the ventricles through the APs which is later followed by depolarisation down the His-Purkinje system. This fusion causes a widening of broad QRS complex which appeared to be fused immediately after the P waves.

Expert opinions estimated that 40% of patients over 30 years old with WPW pattern of resting ECG are asymptomatic.² Patients may present with symptoms such as palpitation, shortness of breath, dizziness or chest pain due to tachycardia and increased myocardial oxygen demand. Common precipitating factors are stress, anxiety, pain and various operative procedures.

Managing a patient with WPW syndrome perioperatively is very challenging as it may complicate into uncontrolled AF, ventricular tachycardia, SVT, ventricular fibrillation and sudden cardiac death.⁴ Meticulous preoperative cardiac assessment, focusing on the presence of symptoms, is crucial. Symptomatic patients may benefit from pharmacological heart rate control using amiodarone, procainamide or sotalol with the idea of prolonging the AP. Digoxine and verapamil are contraindicated as it can accelerate conduction via the AP.⁵ An unstable patient will need a direct current cardioversion. The definitive treatment of WPW syndrome is destruction of AP via radiofrequency ablation (RFA). However, it can lead to complications such as haemopericardium, atrial perforation and air embolism in coronary arteries in 3.5% of the population.⁶ In our patient, RFA was not performed prior to the orchidectomy as he was responding well to oral pharmacotherapies and the service was not available in our centre.

The intraoperative aims for patients with WPW syndrome are to maintain stable haemodynamics and avoid conditions that may cause a sympathetic surge. This includes anxiety, fear, pain, laryngoscopy, intubation, shivering, light plane of anaesthesia, extubation, hypoxaemia, hypercapnia, nausea, vomiting and hypovolemic shock. Preloading with fluids prior to anaesthesia ensures adequate myocardial filling and contractility to prevent intraoperative hypotension and tachycardia. Anaesthetic agents such as propofol, thiopentone, isoflurane and sevoflurane are safe as they have no direct effect on the refractory period of the AP nor AVNs.^{7 8} Cardiostable muscle relaxants such as rocuronium and vecuronium are preferred. Drugs that may augment the AP and precipitate tachycardia are best avoided (table 1).

Table 1.

Drugs to be avoided in Wolff-Parkinson-White syndrome

Anaesthetic drugs	Halothane, desflurane, ketamine
Muscle relaxants	Pancuronium, atracurium, mivacurium, suxamethonium
Antiarrhythmic drugs	Adenosine, beta blockers, calcium channel blockers, digoxin
Anticholinesterases	Neostigmine
Anticholinergics	Atropine, glycopyrrolate

Patients with WPW syndrome requiring anaesthesia should be carefully considered based on the extensiveness of the surgery. There are many advantages of regional anaesthesia (RA) as compared with general anaesthesia. RA avoids laryngoscopy, intubation, polypharmacy and postoperative nausea vomiting. Subsequently, patients undergoing RA is awake and early signs of sympathetic surge such as palpitation, syncopal attacks and dizziness can be easily elicited. In this patient, we opted for RA for the aforementioned reasons; specifically, spinal anaesthesia because it was more easily performed than an epidural block.

Intrathecal administration with hyperbaric bupivacaine and fentanyl improves the quality of blockade, reduced postoperative analgesia requirements and decreased the incidences of hypotension.^9–12 However, a high or total spinal block may cause blockade of cardioaccelerator nerves that may suppress the normal AVN pathway and potentiate the AP.¹³ Thus, a reasonable dosage of hyperbaric bupivacaine should be carefully considered. In our patient, SAB was sufficient as orchidectomy was done via a small right inguinal incision which correspond to T12-L1 dermatomal levels by experienced urosurgeons.

We supplemented dexmedetomidine infusion in addition to SAB for our patient for anxiolysis and prevention of sympathetic surge intraoperatively. He was very calm with stable heart rates and BPs. Dexmedetomidine is a potent alpha-2-agonist with good anxiolytic, sedative, analgesic properties with preservation of spontaneous respiration.¹⁴ In addition, dexmedetomidine had been shown to possess good antiarrhythmic properties for acute termination of re-entrant SVT due to its sympatholytic and parasympathomimetic properties.^{15 16}

Patient’s perspective.

I developed on and off palpitation for the past one year without knowing the cause, until this year of which I was told to have this rare congenital heart rhythm called WPW Syndrome. I am sad that I have a testicular malignancy which required me to undergo surgery. However, I am happy with the good management team of the cardiology, and anaesthesiology here who took care of my health and optimized me throughout the surgery. I wish to share my experiences with BMJ and the world regarding this success.

Learning points.

• The anaesthetic aims in managing patients with Wolff-Parkinson-White (WPW) syndrome are to maintain stable haemodynamics in addition to avoidance of certain drugs and factors that may precipitate tachyarrhythmias.

• A good preoperative cardiac assessment, conscientious intraoperative monitoring and prompt management for any eventual cardiorespiratory embarrassment is crucial.

• Perioperative usage of dexmedetomidine is recommended in patients with WPW syndrome.