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ANSWER
The correct interpretation includes sinus bradycardia with first-degree block, a single premature atrial beat with aberrancy, right bundle branch block, left anterior fascicular block (bifascicular block), left ventricular hypertrophy, and T-wave inversions in the inferior leads.
In sinus bradycardia, there is a P wave for every QRS complex with a rate less than 60 beats/min. First-degree block is evidenced by a PR interval ≥ 200 ms.
A single premature atrial contraction is seen as the ninth beat on the ECG. Aberrancy refers to the appearance of the QRS complex; the impulse arises above the AV node but propagates down the AV node and His-Purkinje system to the ventricles before the conduction system is fully repolarized. This results in a QRS complex with intrinsic conduction similar to a normally conducted beat, which then becomes wide and uncharacteristic. Additionally, it resets the sinus node, resulting in a pause before the next normally conducted P wave.
A right bundle branch block is evidenced by the presence of normal conduction with a QRS duration > 120 ms, a terminal R wave in lead V1 (R, rR’, rsR’, or qR), and slurred S waves in leads I and V6.
The presence of left anterior fascicular block is confirmed by the left-axis deviation (–59° in this ECG), a qR complex in leads I and aVL, and an rS pattern in leads II, III, and aVF. The presence of both a right bundle and left anterior fascicular block constitutes bifascicular block. (This is a conduction problem and does not refer to blockage in the arteries, as the patient believed!)
Criteria for left ventricular hypertrophy are met when the sum of the S wave in V1 and the R wave in either V5 or V6 is ≥ 35 mm and the R wave in aVL is ≥ 11 mm.
Two other things to note in this ECG are the presence of T-wave inversions in the inferior leads (II, III, aVF) which are of unclear reason; and the presence of biphasic P waves that do not meet criteria for either right or left atrial hypertrophy.
ANSWER
The correct interpretation includes sinus bradycardia with first-degree block, a single premature atrial beat with aberrancy, right bundle branch block, left anterior fascicular block (bifascicular block), left ventricular hypertrophy, and T-wave inversions in the inferior leads.
In sinus bradycardia, there is a P wave for every QRS complex with a rate less than 60 beats/min. First-degree block is evidenced by a PR interval ≥ 200 ms.
A single premature atrial contraction is seen as the ninth beat on the ECG. Aberrancy refers to the appearance of the QRS complex; the impulse arises above the AV node but propagates down the AV node and His-Purkinje system to the ventricles before the conduction system is fully repolarized. This results in a QRS complex with intrinsic conduction similar to a normally conducted beat, which then becomes wide and uncharacteristic. Additionally, it resets the sinus node, resulting in a pause before the next normally conducted P wave.
A right bundle branch block is evidenced by the presence of normal conduction with a QRS duration > 120 ms, a terminal R wave in lead V1 (R, rR’, rsR’, or qR), and slurred S waves in leads I and V6.
The presence of left anterior fascicular block is confirmed by the left-axis deviation (–59° in this ECG), a qR complex in leads I and aVL, and an rS pattern in leads II, III, and aVF. The presence of both a right bundle and left anterior fascicular block constitutes bifascicular block. (This is a conduction problem and does not refer to blockage in the arteries, as the patient believed!)
Criteria for left ventricular hypertrophy are met when the sum of the S wave in V1 and the R wave in either V5 or V6 is ≥ 35 mm and the R wave in aVL is ≥ 11 mm.
Two other things to note in this ECG are the presence of T-wave inversions in the inferior leads (II, III, aVF) which are of unclear reason; and the presence of biphasic P waves that do not meet criteria for either right or left atrial hypertrophy.
ANSWER
The correct interpretation includes sinus bradycardia with first-degree block, a single premature atrial beat with aberrancy, right bundle branch block, left anterior fascicular block (bifascicular block), left ventricular hypertrophy, and T-wave inversions in the inferior leads.
In sinus bradycardia, there is a P wave for every QRS complex with a rate less than 60 beats/min. First-degree block is evidenced by a PR interval ≥ 200 ms.
A single premature atrial contraction is seen as the ninth beat on the ECG. Aberrancy refers to the appearance of the QRS complex; the impulse arises above the AV node but propagates down the AV node and His-Purkinje system to the ventricles before the conduction system is fully repolarized. This results in a QRS complex with intrinsic conduction similar to a normally conducted beat, which then becomes wide and uncharacteristic. Additionally, it resets the sinus node, resulting in a pause before the next normally conducted P wave.
A right bundle branch block is evidenced by the presence of normal conduction with a QRS duration > 120 ms, a terminal R wave in lead V1 (R, rR’, rsR’, or qR), and slurred S waves in leads I and V6.
The presence of left anterior fascicular block is confirmed by the left-axis deviation (–59° in this ECG), a qR complex in leads I and aVL, and an rS pattern in leads II, III, and aVF. The presence of both a right bundle and left anterior fascicular block constitutes bifascicular block. (This is a conduction problem and does not refer to blockage in the arteries, as the patient believed!)
Criteria for left ventricular hypertrophy are met when the sum of the S wave in V1 and the R wave in either V5 or V6 is ≥ 35 mm and the R wave in aVL is ≥ 11 mm.
Two other things to note in this ECG are the presence of T-wave inversions in the inferior leads (II, III, aVF) which are of unclear reason; and the presence of biphasic P waves that do not meet criteria for either right or left atrial hypertrophy.
A 69-year-old man presents for a routine appointment. His cardiac history is remarkable for systemic hypertension, nonischemic cardiomyopathy, pulmonary hypertension, and dyspnea on exertion. He says a previous provider told him his ECG had “a couple of blocks,” which he believes are “somewhere in the arteries.” He regularly feels lightheaded if he rises from a lying or sitting position too quickly, but he has never lost consciousness. He denies any history of chest pain or symptoms suggestive of angina. Reviewing his prior cardiac workup, you find an echocardiogram that shows moderate left ventricular enlargement with a left ventricular ejection fraction estimated at 35% to 40%; a severely enlarged left atrium; and mild thickening of the mitral leaflets as well as mild mitral regurgitation. A report from an old ECG (conducted at an outside institution) reveals sinus bradycardia, bifascicular block, and left ventricular hypertrophy. Cardiac catheterization performed two years ago showed diffuse disease with no lesions > 30%. Pulmonary function testing showed mild airflow obstruction, no restrictive component, and mildly decreased diffusing capacity. Medical history is positive for two benign colonic polyps that were removed during his last colonoscopy and a remote history of malaria while traveling in Africa 10 years ago. He also has a history of depression, which has been well controlled by medication. His list of medications includes carvedilol, fluoxetine, melatonin, and lisinopril. He is allergic to atenolol and metoprolol. His family history is remarkable for type 1 diabetes (mother). He is a retired baggage handler for a major airline at a nearby international airport. Since high school, he has smoked between one-half and one pack of cigarettes per day. He typically consumes a 12-pack of beer on the weekends. The review of systems is remarkable for corrective lenses, occasional headaches, and dyspnea. The patient denies any other symptoms. Physical examination reveals a blood pressure of 138/80 mm Hg; pulse, 64 beats/min; respiratory rate, 14 breaths/min-1; and O2 saturation, 97%. His height is 188 cm; weight, 107 kg; and BMI, 30. The lungs are clear to auscultation and percussion. The cardiac exam reveals no jugular venous distention, a normal rate and rhythm with occasional skipped beats, and a soft, grade II/VI blowing systolic murmur best heard at the left lower sternal border. The point of maximum impulse is palpable in the left anterior axillary line. The abdomen is soft and nontender, with no organomegaly. The genitourinary exam is normal. Peripheral pulses are 2+ bilaterally in both upper and lower extremities. There is no peripheral edema, and the neurologic exam is grossly intact. The patient is sent for a chest x-ray and an ECG. The latter reveals the following: a ventricular rate of 59 beats/min; PR interval, 284 ms; QRS duration, 130 ms; QT/QTc interval, 472/467 ms; P axis, 70°; R axis, –59°; and T axis, –29°. What is your interpretation of this ECG?
