Year : 2010 | Volume
: 13 | Issue : 3 | Page : 246--248
Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate
Amit Jain, Kajal Jain, Hemant Bhagat, Kishore Mangal, Yatinder Batra
Department of Anaesthesia & Intensive Care, Post Graduate Institute of Medical Education & Research, Chandigarh, India
Department of Anaesthesia & Intensive Care, Post Graduate Institute of Medical Education & Research, Chandigarh
We describe the anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate. Anesthetic challenges included prevention and management of perioperative arrhythmias, maintenance of adequate preload, afterload and heart rate to relieve left ventricular outflow tract obstruction and considerations related to the presence of dual-chamber pacemaker and TURP. We recommend preoperative reprogramming of the DDD pacemaker, avoidance of magnet application during the procedure, application of electrosurgical unit current returning pad to the anterior aspect of the thigh, especially if monopolar cautery is used, use of central venous pressure line for estimation of preload and careful titration of anesthetic drugs to maintain stable hemodynamics.
|How to cite this article:|
Jain A, Jain K, Bhagat H, Mangal K, Batra Y. Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate.Ann Card Anaesth 2010;13:246-248
|How to cite this URL:|
Jain A, Jain K, Bhagat H, Mangal K, Batra Y. Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate. Ann Card Anaesth [serial online] 2010 [cited 2020 Feb 25 ];13:246-248
Available from: http://www.annals.in/text.asp?2010/13/3/246/69043
Permanent dual-chamber pacing (DDD) at optimum atrioventricular (AV) interval is occasionally being used in hypertrophic obstructive cardiomyopathy (HOCM) patients refractory to medical therapy to reduce the left ventricular outflow tract (LVOT) gradient and improve the functional tolerance.  Anesthesiologists may have to deal with such patients during cardiac or noncardiac surgery. We report a rare case of HOCM with a high subaortic gradient with permanent dual-chamber pacemaker undergoing transurethral resection of the prostate (TURP).
A 60-year-old male with the diagnosis of HOCM presented with dyspnea on exertion and angina (NYHA II), and was scheduled for TURP. A permanent dual-chamber pacemaker (Medtronic SIGMA SD 203, manufactured by Medtronic Rel Inc, Humacao, PR, USA) with short AV interval was applied 10 years ago following refractoriness to the medical therapy. Pacing caused significant reduction in the severity of symptoms. Due to worsening symptoms with increased LVOT gradient, percutaneous alcohol septal ablation was performed 4 months back, but failed to provide any benefit.
Physical examination was unremarkable, except the presence of a pacemaker generator in the right pectoral region. Electrocardiogram (ECG) showed normal sinus rhythm. Two-dimensional echocardiography revealed a peak gradient of 96 mmHg across the LVOT with a grade III systolic anterior motion (SAM) of the mitral valve leaflet, mild mitral regurgitation and interventricular septal thickness of 23 mm. The left ventricular ejection fraction was 70%. Angiographic studies revealed normal coronaries. Ultrasonography showed grade II prostatomegaly (52 cc) with mild bilateral hydronephrosis. Cardiology consultation and interrogation with the manufacturer were sought. Reprogramming of the dual-chamber synchronized AV pacing was performed and the paced AV interval was decreased to 120 ms and sensed AV interval was decreased to 100 ms. The lower rate was maintained at 50 bpm but the upper tracking rate was increased from 110 bpm to 120 bpm. Ventricular safety pacing was switched on.
The patient was premedicated with oral diazepam on the morning of surgery along with propanolol 40 mg. In the operating room, ECG (5-lead, with pacemaker filter disabled) and standard monitoring were applied. He was sedated with intravenous 50 μg fentanyl. Invasive radial and central venous pressure (CVP) lines were inserted. The patients baseline blood pressure was 140/90 mmHg, with heart rate of 50 bpm, and all beats were paced one. Induction of general anaesthesia was performed with fentanyl 50 μg and thiopentone 150 mg. Phenylephrine 50 μg was given to maintain baseline arterial blood pressure within 10% of the baseline. Atracurium was used to facilitate tracheal intubation. During laryngoscopy, esmolol 25 mg was administered to maintain baseline heart rate of 50 bpm and arterial blood pressure within 10% of the baseline. Anesthesia was maintained with oxygen-nitrous oxide (50:50) and halothane (0.5-1.0%). CVP was maintained between 12 and 14 mmHg using 1 L Ringer's lactate. Heart rate above 50 bpm was treated with repeat boluses of esmolol 25 mg. After lithotomy, an electrosurgical unit (ESU) current returning pad was applied on the anterior aspect of the right thigh. Monopolar cautery was used for TURP in short intermittent bursts at the lowest possible energy. No significant electromagnetic interference (EMI) was noted intraoperatively. Glycine 1.5% was used as an irrigation fluid. The total duration of the procedure was 45 min. The trachea was extubated after reversal of neuromuscular blockade. The patient was conscious and pain-free on recovery. Postoperatively, cardiac rhythm and peripheral pulses were monitored with ECG, pulse oximeter and arterial waveform in high-dependency unit and the device was interrogated by a competent authority.
HOCM is characterized by asymmetrical ventricular septal hypertrophy and a dynamic LVOT pressure gradient, related to a narrowing of the subaortic area as a consequence of the mid-systolic apposition of the anterior mitral valve leaflet against the hypertrophied septum.  Hemodynamic evidence of a reduction of the subaortic gradient by DDD led to occasional attempts to treat HOCM with a pacemaker,  with significant improvement in the functional capacity in some patients. 
The present patient had HOCM with DDD pacemaker and was undergoing TURP. Anesthetic challenges included prevention and management of perioperative arrhythmias, maintenance of adequate preload, afterload and heart rate to relieve LVOT obstruction and considerations related to the presence of dual-chamber pacemaker and TURP. In the preoperative period, continuation of b-blocker with premedication avoids anxiety-induced tachycardia. TURP is generally performed under regional anesthesia.  However, in patients with HOCM, general anesthesia is preferred. , Also, the restricted fluid therapy in TURP  patient opposes the liberal fluid therapy in HOCM. , Hence, CVP monitoring is worthwhile. Insertion of a pulmonary artery catheter carries arrythmogenic risk in HOCM patients and may be associated with pacemaker malfunction.  .The patient was induced with intravenous thiopentone 150 mg administered slowly. A bolus of phenylephrine 50 μg was administered to maintain the mean arterial pressure within 10% of the baseline. A combination of low-dose fentanyl with oxygen and nitrous oxide (50:50) and halothane (0.5-1%) was used for maintenance of anesthesia. Dose-dependent myocardial depression of halothane is ideal as negative inotropy reduces the degree of SAM. 
The key factor in pacing for HOCM is the AV interval. The effective AV interval during pacing must be shorter than the AV interval in sinus rhythm so that the ventricular activation sequence is altered and good apical preexcitation is obtained.  Although our patient developed relative refractoriness to DDD (characterized by increased symptomatology and worsening LVOT gradient), switching off the pacemaker may result in further increase of the LVOT gradient, which may aggravate the patient's symptoms. Hence, pacemaker activity was retained throughout the perioperative period. AV nodal blocking drugs are frequently necessary to maximize pacing conditions. Optimum left ventricular filling is necessary and can be obtained only by maintaining appropriate atrio-ventricular synchronization.  Therefore, intraoperatively, we maintained the patient's heart rate at 50 bpm, even though the upper tracking rate was 100 bpm.
TURP generally uses monopolar ESU.  Monopolar ESU is more likely to cause problems with pacemaker functions than bipolar ESU. Reprogramming the pacemaker to an asynchronous mode (as may occur following the application of magnet) at a rate greater than the patient's underlying rate ensures that no over or under sensing from EMI will take place.  However, pacemaker inhibition, loss of pacing (i.e., from native conduction, junctional rhythm, EMI) or AV dyssynchrony can lead to deteriorating hemodynamics in HOCM patients. Hence, the application of magnet should be avoided in HOCM patients with DDD pacemaker.  Additionally, setting a device to the asynchronous mode has the potential of creating a malignant rhythm in the patient with structurally compromised myocardium. To prevent EMI, the cathode was kept far away from the device and the lowest possible amplitude was used and the operator applied electrocautery in short bursts. As a dual-chamber pacemaker can produce R-on-T pacing, by decreasing the AV delay (to 100 ms), we decreased the likelihood of pacing during the vulnerable period of the ventricle. Also, ventricular safety pacing was switched on.
In summary, perioperative management of HOCM with DDD for TURP is discussed. We recommend preoperative reprogramming of the dual-chamber pacemaker, avoidance of magnet application during the procedure, application of ESU current returning pad to the anterior aspect of the thigh, especially if monopolar cautery is used, use of CVP line for estimation of preload and careful titration of anesthetic drugs to maintain stable hemodynamics.
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