History
This patient had a history of lymph node tuberculosis during childhood, thyroid carcinoma (treated surgically and with radiotherapy), and depressive disorders.
A normal electrocardiogram (ECG) was recorded 20 years earlier at the time of the thyroidectomy. However, a progressive left bundle branch block (LBBB) pattern appeared with a QRS duration of 120 and 135 ms, 8 and 2 years earlier, respectively. Transthoracic echocardiography was performed 2 years earlier and showed normal left ventricular ejection fraction (LVEF) of 60%.
Comments
The patient’s history demonstrated a progressive widening of QRS complex and appearance of LBBB with a normal left ventricular function.
Current Medications
The patient is currently taking levothyroxine 75 mcg daily.
Current Symptoms
Over a 1-year period, the patient progressively experienced exercise intolerance, weight gain related to lower extremity edema, and shortness of breath (New York Heart Association [NYHA] class III). Treatment by ramipril, bisoprolol, and furosemide was initiated without significant efficacy. She was then hospitalized for a first episode of congestive heart failure.
Comments
The patient’s clinical history is suggestive of progressive congestive heart failure.
Physical Examination
Laboratory Data
Comments
The blood analysis showed only mild anemia, probably related to the congestive heart failure.
Electrocardiogram
Findings
The ECG showed sinus rhythm to be 80 bpm, normal atrioventricular conduction (PR interval, 160 ms), typical LBBB with a QRS duration of 135 ms, and a QRS axis of −35 degrees (Figure 4-1).
Comments
The LBBB is typical, with a QRS of 120 ms or greater; broad, notched, or slurred R wave in the lateral leads; absence of Q waves in leads I, V5, and V6; an upstroke of the R wave greater than 60 ms in leads V5 and V6; and ST and T waves opposite to the QRS polarity.
Echocardiogram
Findings
M-mode analysis of the left ventricle in parasternal long-axis view revealed a left ventricular end-diastolic diameter of 55 mm and a septal flash (Figure 4-2, A). LVEF was measured at 33% using the biplane Simpson method (see Figure 4-2, B). A mild mitral regurgitation also was observed (not shown). The atria were not dilated (diameter 3.2 cm and area 15 cm²).
Comments
Although left ventricular function is impaired, the left ventricle is not dilated (<33 mm/m²).
Findings
On the echocardiogram, the pulmonary preejection time was measured from the beginning of QRS complex to the beginning of the pulmonary flow velocity curve recorded by pulse-wave Doppler in the left parasternal view at 85 ms (Figure 4-3, A). The aortic preejection time measured from the beginning of QRS complex to the beginning of the aortic flow velocity curve recorded by pulse wave Doppler in the apical five-chamber view was 183 ms (Figure 4-3, B). The intraventricular mechanical delay was 98 ms, demonstrating interventricular dyssynchrony. Major atrioventricular dyssynchrony was demonstrated by left ventricular filling time over the RR cycle length ratio less than 40% (128/709 ms = 18%) (Figure 4-3, C). The apical four-chamber view showed (in red) the delayed motion of the anterolateral left ventricular wall (Figure 4-3, D). Delay between septal (red arrow) and anterolateral (yellow arrow) left ventricular walls of 301 ms demonstrated intraventricular dyssynchrony (Figure 4-3, E).
![image](/wp-content/uploads/2015/02/f04-01-9781455742370.jpg)
FIGURE 4-1
Catheterization
Coronary Angiography
Findings
Catheterization revealed normal coronary arteries with no stenosis.
Comments
Given the fact that the most common cause of left ventricular dilation is represented by coronary artery disease, a coronary angiography should always be performed to rule out coronary stenosis (an exercise test often is not helpful in patients with an LBBB pattern on the ECG). Usually, significant stenosis of the left anterior descending artery or of more than two other arteries is necessary to induce cardiomyopathy.
Focused Clinical Questions and Discussion Points
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