Abstract
- 1.
Severe RV or left ventricular dysfunction and sustained VT should be an indication for ICD placement in patients with severe forms of CHD.
- 2.
Avoid placing pacing or defibrillation leads through prosthetic AV valves.
- 3.
In patients with severe recurrent atrial arrhythmias despite multiple therapies (drugs, catheter ablation, and surgery), it is important to keep considering repeat catheter ablation procedures with alternative technology as and when they become available.
- 4.
Similarly, consideration should be given to referral to more specialized centers in such cases
- 5.
VT in patients with Ebstein anomaly commonly arises from the diaphragmatic aspect of the atrialized RV and should be considered for catheter ablation.
Keywords
Atrial flutter, Atrial tachycardia, Ebstein’s anomaly, Implantable defibrillator, Tricuspid valve surgery, Ventricular tachycardia
Case Synopsis
Diagnoses
Ebstein anomaly of the tricuspid valve (TV).
TV repair with right atrial (RA) cryoablation and epicardial pacemaker, February 2015.
TV replacement, March 2016.
Very troublesome atrial tachyarrhythmia with multiple direct current (DC) cardioversions and ablations.
Type 2 diabetes.
Gout.
Varicose veins.
Initial Assessment, 2011
The patient is a 49-year-old male seen in our center for the first time in October 2011 following referral from his local cardiologist. He had been under follow-up at another center for a number of years. He is working as an electrician and is a keen body builder.
He described increasing breathlessness over the previous 12 months. He reported occasional dizziness, mainly related to eating and very occasional palpitations. He was on simvastatin for hypercholesterolemia and metformin for type 2 diabetes. His other medical problems are gout and varicose veins.
At initial assessment, he was normally saturated at rest; heart rate, 60 bpm; and BP, 140/88 mmHg, with a soft flow murmur at the left sternal edge.
Electrocardiography (ECG): SR and PR 234 ms and QRS 142 ms (right bundle branch block). ECG was not submitted, as its quality has degraded.
Transthoracic echocardiography showed severe tricuspid regurgitation (TR) with flow reversal in hepatic veins and dilated right ventricle (RV).
Assessment 2013–14
The patient did not attend a number of office visits in 2011/12 and was seen again in March 2013 when he felt more breathless and dizzy. Dizziness was more prominent after exercise. Palpitations were lasting up to 15 s. He was advised to cut down alcohol consumption (he was drinking 20 pints of beer over a 3-day weekend). Jugular venous pulse was just visible at the root of the neck. His weight was 110 Kg. The systolic murmur was soft and liver was not palpable.
Findings of a 24-h Holter monitor were unremarkable. Sinus throughout in first-degree heart block and there were occasional supraventricular and ventricular ectopics.
Bicycle cardiopulmonary exercise (CPEX) test: completed 9.5 min of a 20-W ramp. The test was stopped because it was felt that he had gone into supraventricular tachycardia (on review, this was not convincing—it looked on review to be a gradual onset sinus tachycardia). At this point, his V o 2 was 14.2 mL/Kg/min. No desaturation was observed.
MRI examination during November 2013 showed RV end-diastolic volume, 454 mL (195 mL/m 2 ); RV end-systolic volume, 222 mL; and RV ejection fraction, 51%. Septal leaflet of TV displaced 56 mm. Severe TR with an estimated regurgitation fraction of 63%. RA dilated (97 cm 2 ). Left side of the heart was normal, and there was no other abnormality. No evidence of a shunt was seen.
He underwent an electrophysiologic (EP) study under local anesthesia on March 6, 2014. The report included the following.
Atrial tachycardia (AT) induced using catheter manipulation. Cycle length (CL), 308 ms (but with some variability). Variable atrioventricular (AV) conduction (ventricular rate never above 90 bpm). Patient was asymptomatic. Accelerated following atrial burst pacing to 220 ms. Eventually terminated with atrial burst at 180 ms.
Diagnostic catheterization showed a mean RA pressure of 10 mmHg (with peak of 23 mmHg due to TR); a RV pressure of 32 mmHg, with end-diastolic pressure of 3; and a right pulmonary artery pressure of 32/5 mmHg, with a mean of 16 mmHg.
Summary
No evidence of accessory pathway conduction.
No AV nodal reentry tachycardia.
Inducible AT with variable AV block.
Normal pulmonary artery pressures.
An ablation was not attempted because there was a provisional plan for him to undergo surgery.
The CPEX test was repeated in April 2014. He managed 7 min of the Bruce protocol and made a good effort (maximal test). His V o 2 max was 15.9 mL/Kg/min; heart rate, 72 bpm baseline, 147 bpm at peak; blood pressure (BP), 110/80 mmHg baseline, 160/80 mmHg at peak.
Subsequent coronary angiography showed very mild left anterior descending artery atheroma, and he was accepted for TV surgery with concomitant RA cryoablation.
First Episode of Clinically Evident Atrial Arrhythmia, September 2014
The patient was seen in clinic in September 2014, before he had undergone surgery, when he gave a history of being significantly more easily breathless with chest discomfort and an increased heart rate. His jugular venous pressure was elevated to 4 cm, and there was a small amount of ankle edema. ECG showed atrial flutter with a ventricular rate of 70 bpm. He had been started on furosemide and was anticoagulated with warfarin. There was a mild abnormality of the liver function tests suggestive of hepatic congestion. He underwent successful DC cardioversion. Given the forthcoming surgery, baseline first-degree heart block, and slow ventricular response in atrial flutter, a regular antiarrhythmic was not prescribed.
First Operation—February 2015, Subsequent Episodes of Atrial Flutter
In February 2015, surgery was performed and consisted of TV repair, RA cryoablation, and permanent epicardial dual chamber pacemaker implantation. Mild to moderate residual TR was noted at intraoperative transesophageal echocardiography and was accepted.
Early after operation, he was back in atrial flutter with an intrinsic ventricular rate of 65 bpm. It was not possible to pace-terminate via the pacemaker. He was discharged on bisoprolol and amiodarone. Six weeks after discharge, he remained in atrial flutter and was <0.1% atrial and ventricular paced. A further attempt to pace-terminate the flutter was not successful and he underwent a successful DC cardioversion.
In May 2015, he presented again with atrial flutter and a further DC cardioversion was performed.
He was keen to stop amiodarone (there were also mildly deranged thyroid function tests) and this was discontinued after uptitrating bisoprolol in July 2015.
A further DC cardioversion was performed in August 2015 and he was changed from bisoprolol to sotalol 80 mg BD.
Recurrence of Severe Tricuspid Regurgitation Noted October 2015
In October 2015, he was 97% atrially and 100% ventricularly paced. Transthoracic echocardiography suggested recurrence of severe TR, and he described becoming breathless and tired very easily. He had not noticed any symptomatic improvement following his surgery.
A further DC cardioversion was performed in November 2015.
A further EP study and ablation was performed in December 2015. Transesophageal echocardiography at the time confirmed severe TR. The EP study found the following.
The patient had an inducible atrial flutter, CL 460 ms, and attempted pace termination was unsuccessful, although he managed to accelerate tachycardia. There was significant scar laterally and posteriorly and it identified an area of scar anterolaterally running inferiorly from the region of superior vena cava (SVC)/RA junction.
A line of block was created from scar anterior and inferior to lateral TV annulus with progressive lengthening of CL from 460 to 580 ms (rate 103) with 1:1 conduction. In all, a 10cm burn was performed.
There was spontaneous cessation of tachycardia into sinus bradycardia with a long PR interval. The study concluded that the flutter was significantly modified with ablation, with remaining tachycardia of CL 580 ms (rate 103), and a decision was made to not pursue it further.
Tricuspid Valve Replacement, March 2016, Further Troublesome Atrial Flutter
He was keen to undergo any procedure that might improve his symptoms and underwent redo sternotomy with a 33-mm Hancock II porcine biological TV replacement in March 2016. Consideration was given to perform a bidirectional cavopulmonary shunt at the time, given the poor RV function, but he came off bypass easily and this was not felt necessary at the time.
He again presented in May 2016 with atrial flutter and a further EP study was performed acutely. An ablation was performed with an extension of the linear lesion between the TV annulus and the inferior vena cava, as well as areas of fractionated atrial electrograms in the inferior portion of the RA. The tachycardia ceased during the procedure and could not be reinduced. A few weeks later, there had been no recurrence of atrial arrhythmia and he was 88% atrially paced and 98% ventricularly paced.
In July 2016, at a routine clinic review, he was again found to be in atrial flutter and a further EP study and ablation was performed. This time a PentaRay catheter was used to create geometry and timing map. The patient was in AT with a CL of 390 ms at the beginning of the case. The earliest signals were in the atrial appendage with early signals meeting late signals around the base of the appendage and SVC. A voltage map in this region suggested a scar laterally (atriotomy) and a scar around the base of the atrial appendage. A discontinuous area of scar was seen in posterior RA, with isthmus of active tissue with perfect return cycle on entrainment.
A line of lesions was created from SVC posterior to TV annulus with a change in tachycardia CL to 440 ms. A limited remap showed the RA appendage outside the circuit but now with interesting electrograms in inferolateral RA with concealed entrainment and a perfect return cycle.
Further ablation in a low lateral RA position linking scars and then a further burn across a line of double potentials was done with cessation of tachycardia.
However, there was further induction of tachycardia with burst atrial pacing with a different CL from previous tachycardia (280–300 ms) suggesting an RA focus. So further lesions were placed to extend the lateral line inferior and anterior to further scar.
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