A 75-year-old man is on vacation, visiting his daughter and her family. He wakes with abdominal discomfort and distention, and at his daughter’s insistence, presents to the urgent care center at the local emergency department. He states that he has not had a bowel movement for six days, and that he has had intermittent cramping for the past three days and passed a small amount of liquid stool on one occasion. He denies dysphagia, nausea, vomiting, hematemesis, diarrhea, melena, or hematochezia. 

Medical history is remarkable for a myocardial infarction approximately 10 years ago and hypertension. Surgical history is remarkable for an appendectomy and open reduction of a compound fracture to his left femur. The patient is a retired fisherman and does not seek or maintain routine medical care. Indeed, his history of myocardial infarction was discovered on a preoperative ECG prior to his appendectomy.

His medications include “a handful of ibuprofen when I need them.” He is supposed to be taking metoprolol but hasn’t had the prescription filled for the past three years. He smokes a pack and a half of cigarettes a day and routinely drinks a six-pack of beer over the course of a week.

The review of systems is remarkable for an unexplained 20-lb weight loss over the past four months. The patient has a chronic smoker’s cough with production in the early morning hours, which clears with coughing over the course of the day. He denies shortness of breath, chest pain, paroxysmal nocturnal dyspnea, or peripheral edema. He admits having dysuria, as well as urgent frequency and difficulty starting a stream of urine. There are no complaints of weakness, seizures, memory changes, or depression.

On physical exam, the patient’s weight is 178 lb and his height is 72 in. Other vital statistics include a blood pressure of 174/92 mm Hg; pulse, 70 beats/min and regular; respiratory rate, 14 breaths/min; and O₂ saturation, 92% on room air. He is afebrile. The patient is a thin, somewhat malnourished elderly man who is agitated and uncomfortable.

There is no evidence of jugular venous distention, and a carotid bruit is present on the right side. The chest has coarse breath sounds in all fields, which clear on coughing. There are a few scattered wheezes but no rales. The cardiac exam reveals a regular rate and rhythm with no murmurs or rubs. The abdominal exam is remarkable for distention, hyperactive bowel sounds, and tenderness to deep palpation but no guarding. There is no hepatosplenomegaly, and no pulsatile masses. A well-healed surgical scar is present in the right lower quadrant. 

A rectal examination reveals firm, impacted stool and a large, nodular prostate. A firm, palpable mass distinct from the stool or prostate is also present. Inguinal lymph nodes are not palpable. The extremities are remarkable for a well-healed surgical scar over the left thigh, and there is no peripheral edema. The neurologic exam shows no focal signs, and the patient is alert and cooperative. 

As part of his admission workup, samples for a chemistry panel and complete blood count are drawn, and an ECG is obtained. While you are waiting for the laboratory results, you review the ECG, which shows a ventricular rate of 62 beats/min; PR interval, 512 ms; QRS duration, 96 ms; QT/QTc interval, 398/403 ms; R axis, 76°; and T axis, 27°. What is your interpretation of this ECG?

ANSWER

The ECG shows sinus rhythm with marked PR prolongation. A normal PR interval range is 120 to 200 ms. If the PR interval is greater than 200 ms, atrioventricular conduction block (first-degree block) is present. In this case, a PR interval of 512 ms is markedly prolonged. The P waves are not conducted retrograde from the ventricles because their appearance is normal (not inverted, as one would expect with retrograde conduction). The patient also has an old septal myocardial infarction, evidenced by absence of R waves in leads V₁ to V₃ and isoelectric RS waves in V₄.

Further workup of this man revealed fecal impaction as a result of mass effect from colon cancer.