29. Cardiac Resynchronization Therapy Defibrillator Implantation in Atrial Fibrillation

Published on 26/02/2015 by admin

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Last modified 26/02/2015

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History

Since 1980 this patient was treated periodically with venosections as a result of hemochromatosis. He had received medical therapy for hypertension since 1985 and was diagnosed with hypertensive nephropathy in 1994. He had a non-Q anterior myocardial infarction in 1996, with following postinfarction angina pectoris.
The patient was hospitalized in 2004 for unstable angina pectoris. A coronary angiogram demonstrated triple vessel disease, and he successfully underwent coronary artery bypass surgery.
In 2011 he was admitted to hospital because of a paroxysm of atrial fibrillation, which converted spontaneously to sinus rhythm during the stay.
During late winter 2012 the patient experienced increasing exercise intolerance and fatigue. He had no chest pain. He developed pitting edema of the lower extremities, which soon extended above his knees, and he had noticed intermittent palpitation. He had episodes of orthopnea, causing him to sleep sitting in a chair at night.
He was admitted to hospital on April 13, 2012 with signs of congestive heart failure. An electrocardiogram (ECG) showed atrial fibrillation with rapid ventricular response, left bundle branch block (LBBB), and QRS width of approximately 160 ms. An echocardiogram the next day demonstrated a dilated left ventricle with an end-diastolic diameter of 66 mm and obvious dyssynchronous contractility. The left ventricular ejection fraction (LVEF) was reduced, at 20%, because of apical akinesia and inferior and lateral hypokinesia. No significant valvular disease was present. Chest radiography on admission showed cardiac enlargement and signs of pulmonary congestion.
The patient was initially treated with an intravenous diuretic, a beta blocker, an angiotensin receptor blocker, and a mineralocorticoid receptor antagonist, but the uptitration of these drugs was limited by hypotension, renal failure, and a tendency to hyperkalemia. The patient had to be periodically treated with dobutamine and dopamine, and he also received an infusion of levosimendan. Atrial fibrillation and periodic atrial flutter with insufficient rate control was initially treated with amiodarone, and direct current cardioversion was planned. Preparing for cardioversion, transesophageal echocardiography was performed, revealing a thrombus in the left atrial appendage. This finding caused cardioversion to be postponed and amiodarone to be discontinued because rhythm conversion was considered unfavorable in this situation. Instead, digoxin was added. On this treatment the patient showed some improvement clinically and the LVEF increased to approximately 30%, but he was still symptomatic even at minimal physical exertion.
The patient was monitored on telemetry, which revealed short runs of nonsustained ventricular tachycardia. On April 25, 2012, with the patient still hospitalized and on telemetry, a run of ventricular tachycardia degenerated into ventricular fibrillation. He was immediately resuscitated and defibrillated into atrial fibrillation and suffered no neurologic sequelae. Amiodarone was commenced. He had no signs of acute coronary syndrome.

Current Medications

The patient was taking bumetanide 4 mg daily, candesartan 16 mg daily, carvedilol 12.5 mg twice daily, hydrochlorothiazide 25 mg daily, spironolactone 12.5 mg daily, atorvastatin 40 mg daily, warfarin 5 mg daily, amiodarone 200 mg twice daily, and digoxin 0.125 mg daily.

Comments

The patient was intolerant to angiotensin-converting enzyme inhibitors because of cough.

Current Symptoms

The patient was experiencing dyspnea and was in New York Heart Association (NYHA) class III. He also had peripheral edema and ventricular tachyarrhythmia.

Comments

The patient had symptomatic heart failure despite optimal pharmacologic therapy.

Physical Examination

Laboratory Data

Electrocardiogram

Findings

The ECG obtained on admission on April 13, 2012 showed atrial fibrillation with a ventricular rate of 80 to 130 bpm, LBBB, and a QRS width of approximately 160 ms (Figures 29-1 and 29-2). The ECG obtained after cardiac resynchronization therapy defibrillator (CRT-D) implantation on May 10, 2012 demonstrated a high degree of biventricular pacing, despite atrial dysrhythmia. The QRS width was approximately 120 ms (Figures 29-3 and 29-4).

Chest Radiograph

Findings

A chest radiograph was obtained on admission. Sternal circlages were noted on the frontal and lateral views. The cardiothoracic ratio was 0.57, which indicated cardiac enlargement. Mild enlargement of the perihilar vessels and Kerley B lines were seen, suggestive of pulmonary congestion (Figures 29-5 and 29-6

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