ECG Challenge

A 58-year-old man is snowmobiling with friends when he develops crushing substernal chest pain. He immediately stops his snowmobile and waves his arms for help—but by the time his friends reach him, he is lying on the ground, clutching his chest.

When asked what happened, he tells his friends that he’s been experiencing chest pain for the past hour but didn’t want to stop or interrupt their fun. He further reveals that he’s had chest “twinges” for the past 2 months, but they were always brief, and he didn’t think they were anything to be concerned about. He acknowledges that the current episode is “far worse” than what he previously experienced.

Because they are in the wilderness, no one in the group is able to establish cellphone service to call 911. The patient is loaded onto the back of another snowmobile for the 30-minute ride to the parking lot, where cellular service is accessible. They call 911, and an ACLS ambulance arrives about 50 minutes later.

An ECG is obtained in the field and transmitted to the receiving hospital, and the catherization lab is notified of an incoming patient. Transport to the hospital takes an hour; during the trip, the patient is administered oxygen, morphine, nitroglycerin, and an aspirin, and he is noted to have several nonsustained episodes of polymorphic ventricular tachycardia. The patient arrives at the hospital about 4 hours after onset of chest pain.

Medical history includes longstanding uncontrolled hypertension, recent onset of type 2 diabetes, and gastric reflux. He has never had shortness of breath, dyspnea on exertion, syncope, or near-syncope.

Current medications include lisinopril and metformin. However, the patient informs you that he hasn’t taken lisinopril in more than 3 months, and although he’s been given a prescription for metformin, he hasn’t filled it. He has no known drug allergies.

The patient is a mechanic at a local auto dealership. He smokes between 1 and 1.5 packs of cigarettes per day and has attempted to quit several times. He also consumes about 1 case of beer per week.

He is divorced, has no children, and lives alone. Both parents died in an automobile accident. The patient knows his father had several heart attacks beginning in his mid-50s and his mother “had thyroid problems.” His grandparents were known to have coronary artery disease and diabetes.

Review of systems is positive for a longstanding smoker’s cough and a healing burn on his right forearm, attributed to a welding injury.

His pretransport vital signs include a blood pressure of 178/88 mm Hg; pulse, 88 beats/min; respiratory rate, 18 breaths/min^-1; and temperature, 97.6ºF. His stated weight is 265 lb and his height, 69 in.

Your findings on the physical exam corroborate those called in by the paramedics: an obese white male in obvious distress but alert and cooperative. His lungs reveal diffuse rales and crackles that clear with vigorous coughing. His cardiac exam reveals a regular rhythm at a rate of 80 beats/min with no murmurs or rubs. The abdomen is obese but otherwise normal. There is no peripheral edema. Pulses are strong and equal bilaterally. The neurologic exam is grossly intact. A bandaged second-degree burn is noted on the lower right forearm.

A repeat ECG shows a ventricular rate of 80 beats/min; PR interval, 162 ms; QRS duration, 106 ms; QT/QTc interval, 370/426 ms; P axis, 51°; R axis, –20°; and T axis, 70°. What is your interpretation?

Three days ago, a 64-year-old man underwent a tricuspid valve replacement for severe tricuspid regurgitation of unknown etiology. The surgical procedure included implantation of a 29-mm porcine valve and 2 epicardial right ventricular epicardial pacing leads.

The patient’s preoperative echocardiogram had shown severe tricuspid regurgitation with anterior leaflet prolapse and severe right atrial and ventricular enlargement. Preoperatively, the peak velocity of the tricuspid valve was 3.4 m/s, and the right ventricular systolic pressure was measured at 55 mm Hg. There was no mitral valvular disease or evidence of ischemia, and the overall left ventricular function was preserved, with a normal ejection fraction.

Preoperative history included 3-year progression of shortness of breath, dyspnea on exertion, and bilateral lower extremity edema. Over the past 2 months, he has had signs of hepatic congestion, including elevated serum transaminase, alkaline phosphatase, and direct bilirubin levels. A physical exam had revealed an enlarged liver that was tender to deep palpation. Social and family histories are noncontributory to the case as presented.

This morning, the patient is in no distress, sitting comfortably in a chair, and is alert and cooperative. Vital signs include a blood pressure of 118/64 mm Hg; pulse, 60 beats/min; respiratory rate, 16 breaths/min; and temperature, 96.4°F.

The surgical incision is clean, dry, and well approximated, and the patient is back to his preoperative weight. Pulmonary exam reveals clear breath sounds, with the exception of the left base, which demonstrates crackles that change with coughing. There are no wheezes. The cardiac exam reveals a regular rhythm at a rate of 60 beats/min, with a soft grade II/VI systolic murmur at the left lower sternal border. A late systolic friction rub is also evident. The abdomen is soft and nontender, with good bowel sounds and no organomegaly. Peripheral pulses are strong bilaterally, and there is trace pitting edema in both lower extremities. Neurologic exam is normal.

This morning’s ECG reveals a ventricular rate of 56 beats/min; PR interval, unmeasurable; QRS duration, 106 ms; QT/QTc interval, 400/386 ms; P axis, 36°; R axis, 120°; and T axis, 7°. What is your interpretation of this ECG?

During morning rounds at a skilled nursing facility (SNF), a 74-year-old woman is found to have a rapid heart rate. She is placed on telemetry, which reveals a wide complex tachycardia. Concerned about possible ventricular tachycardia, the charge nurse contacts the on-call physician, who recommends calling 911. The patient is transferred via ACLS ambulance to your facility.

When you see her, she seems embarrassed by all the attention she’s receiving and expresses her desire to return to the SNF before she misses lunch. She is in no pain or discomfort, is not particularly short of breath, and does not feel dizzy or lightheaded. According to reports, she was friendly and conversive with both the nursing staff at the SNF and the paramedics during transport.

History is remarkable for several transient ischemic attacks with no residual sequelae, hypertension (under good control), and hypothyroidism (treatedwith medication). Surgical history includes a hyster-ec­tomy, a cholecystectomy, and an open reduction and metal plate fixation of a high (right) ankle break—all of which were performed more than 10 years ago.

Her medications include warfarin, hydrochlorothiazide, ator­vastatin, and levothyroxine. She has no known drug allergies.

The patient is a retired junior high school principal. Her husband died of lung cancer 4 years ago. She has 3 adult children who are all in good health. She has never smoked but does enjoy a daily nightcap. She denies alcohol abuse or illicit drug use.

Family history reveals her parents died in a train accident and her paternal grandparents died of tuberculosis. She does not know her maternal grandparents’ medical history.

Review of systems is positive for chronic constipation and chronic hip and knee discomfort. Vital signs include a blood pressure of 124/88 mm Hg; pulse, 140 beats/min; respiratory rate, 14 breaths/min; and temperature, 97.6°F. Her weight is 158 lb, and her height is not measured.

Physical exam reveals a pleasant elderly woman in no distress. She is dressed appropriately, her hair is styled, and she is wearing makeup as she usually does. The HEENT exam reveals hearing aids and corrective lenses. Her neck has no jugular venous distention, carotid bruits, or thyromegaly.

Her lungs are clear in all fields. Her heart has a rapid and questionably irregular rhythm. There are no appreciable murmurs or rubs. Her abdominal exam is normal, with the exception of well-healed surgical scars. There is no peripheral edema, and all pulses are equal bilaterally in both upper and lower extremities. The neurologic exam is grossly normal with normal affect and mood.

An ECG reveals a ventricular rate of 152 beats/min; PR interval, 128 ms; QRS duration, 88 ms; QT/QTc interval, 280/445 ms; P axis, 27°; R axis, 23°; and T axis, 232°. What is your interpretation?

Approximately 5 am yesterday, a 59-year-old man was awakened by a racing heart rate. When he got out of bed, he felt lightheaded enough to need to lay back down. After about 5 minutes, his heart rate and rhythm abruptly returned to normal.

Feeling fine, he went about his normal workday—but in the afternoon, while sitting at his desk, his rapid heart rate returned. He called over a coworker, who observed that he was “pale” and “sweaty.” His pulse was 130 beats/min. After “a few minutes,” the rapid heart rate spontaneously terminated, and he decided to take off the rest of the day.

This morning, he again awoke with a rapid heart rate and lightheadedness—but he also felt like the room was spinning. At that point, he called 911. By the time the paramedics arrived, his rapid heart rate had spontaneously terminated. Understandably concerned, however, he requested transport to your facility.

The patient says he is in normal health, with no prior cardiac history. He denies any chest pain, dyspnea, shortness of breath, nausea, vomiting, syncope, or near-syncope associated with his recent episodes.

Medical history is remarkable for hypertension, hyperlipidemia, and type 2 diabetes. He has had no surgical procedures. His medications include aspirin, lisinopril, and lovastatin; he says he takes his medications as prescribed and there have been no recent changes to the drugs or dosages. He has no known drug allergies.

Family history includes myocardial infarction in both parents; they are alive and well. The patient’s younger brother has Wolff-Parkinson-White syndrome and underwent an ablation at age 24.

The patient is a practicing attorney for a local firm. He is married with 2 children. He has no history of alcohol, tobacco, or illicit drug use.

Review of systems is positive for a 10-lb weight gain over the past 6 months and new-onset nocturia.

During the physical exam, the patient informs you that his heart is racing again. The exam is suspended, and a 12-lead ECG is quickly performed. It shows a ventricular rate of 155 beats/min; no measurable PR interval; QRS duration, 78 ms; QT/QTc interval, 272/437 ms; P axis, unmeasurable; R axis, 34°; and T axis, –50°.

The physical exam is completed after the tachycardia spontaneously terminates. The patient’s blood pressure is 148/88 mm Hg; pulse, 94 beats/min and regular; respiratory rate, 18 breaths/min^-1; and temperature, 97.9°F. He appears frightened but otherwise healthy. Pertinent findings of the physical exam include a normal fundoscopic examination with sharp disc margins, clear breath sounds bilaterally, normal heart sounds with no murmur or rub, a soft abdomen with no palpable masses, strong and equal pulses bilaterally in both upper and lower extremities, and a normal neurologic exam with no cognitive deficits.

Now that the physical exam is complete, what is your interpretation of this ECG?

A 64-year-old man presents with a 6-month history of skipped heart beats. He says this occurs most often in the evenings, when he’s resting, and he has been awakened by it. He denies chest pain, dyspnea with exertion, syncope, or near-syncope. He has been otherwise asymptomatic from a cardiac and pulmonary standpoint.

However, he is increasingly concerned that his heart may “just stop beating” when he is asleep. When pressed further, he reveals he is afraid to go to sleep at night, knowing “my heart will start skipping beats and I’ll die!” He has discussed his fear of dying in his sleep with a psychologist, who told him that although he experiences fatigue and loss of energy and has recurrent thoughts of death, he does not meet DSM-5 criteria for major depressive disorder. The psychologist obtained an ECG and noticed pauses, which prompted referral of the patient to you.

Past medical history is remarkable for hypertension, cirrhosis, and osteoarthritis. Surgical history includes bilateral knee and left hip replacements. A screening colonoscopy 1 month ago yielded a diagnosis of stage 1 colorectal cancer.

The patient’s medication list includes hydrochlorothiazide and celecoxib. He is allergic to oxycodone (anaphylaxis).

The patient is divorced, which he attributes to his ongoing alcoholism. He drinks half a bottle of whiskey daily to “help with my nerves” and “get drunk enough to sleep.” He reports a lifetime of heavy drinking; he has tried Alcoholics Anonymous but kept dropping out to drink. He also smokes up to 1.5 packs/d of cigarettes. He has no children. He worked as a machinist in a factory but was laid off a year ago when the company downsized.

Family history is positive for alcoholism (father, 2 brothers) and hypothyroidism (mother).

Review of systems is positive for a chronic smoker’s cough, lower abdominal cramping following his colonoscopy, and arthritic pain in his wrists and ankles.

Vital signs include a blood pressure of 174/92 mm Hg; pulse, 74 beats/min; respiratory rate, 14 breaths/min; and O₂ saturation, 97% on room air. His weight is 247 lb and his height, 69 in. His BMI is 36.5.

Physical exam reveals a somewhat disheveled male in no apparent distress. He wears corrective lenses and has tobacco stains on his mustache. His HEENT exam is surprisingly normal, and there is no evidence of rhinophyma. There is no jugular venous distention, thyromegaly, or lymphadenopathy. There are crackles and late expiratory wheezes in both lower lung fields.

The cardiac exam reveals a regular rate and rhythm of 74 beats/min, with no murmurs, rubs, or extra heart sounds. Peripheral pulses are strong and equal bilaterally. The abdomen is obese but nontender, and there are no palpable masses. There are surgical scars over both knees and the left hip. Arthritic changes are noticeable in the fingers on both hands. There are no neurologic deficits.

Through the electronic medical record, you access the ECG taken in the psychologist’s office. It shows a ventricular rate of 56 beats/min; no measurable PR interval; QRS duration, 144 ms; QT/QTc interval, 438/422 ms; P axis, 47°; R axis, –24°; and T axis, 55°. What is your interpretation of this ECG?

For several years, a 75-year-old woman has been followed for aortic stenosis. Historically, she has done well—but about a year ago, she began experiencing shortness of breath. Within the past 2 months, she has had significantly increasing dyspnea with minimal activity and has experienced 2 episodes of near-syncope. This morning, she complains of chest tightness.

Her medical history is remarkable for hypertension, rheumatoid arthritis, and coronary artery disease. Two years ago, catheterization for chest pain revealed stenoses of her left anterior descending artery (LAD), a diagonal branch of the LAD, and an occluded right coronary artery. A drug-eluding stent was placed, and she has had no symptoms since. She also has a history of paroxysmal atrial fibrillation but has had no episodes in the past year.

An echocardiogram performed 1 week ago revealed severe aortic valve stenosis with a trileaflet valve with heavily calcified leaflets; an aortic valve gradient of 0.4 cm², with a peak velocity of 5 m/s and a mean gradient of 61 mm Hg; and mild aortic regurgitation. It also showed an enlarged left atrium and mild-to-moderate mitral regurgitation.

Her current medications include senna glycoside, prednisone, metoprolol, atorvastatin, and apixaban. She has a true anaphylactic allergy to penicillin.

The patient, a retired administrative assistant, was widowed 4 years ago, when her husband died as a result of an automobile accident. They had no children. She has never smoked but reports having 1 to 2 glasses of wine each night.

Review of symptoms is positive for joint pain, particularly in her hands, hips, and knees. It is worse in the morning and improves as the day progresses. She tried NSAIDs but experienced bleeding, so she was recently started on prednisone. She also has chronic constipation, for which she takes senna with reasonable results. She denies any significant constitutional, respiratory, urologic, or neurologic symptoms.

Vital signs include a blood pressure of 146/86 mm Hg; pulse, 70 beats/min; respiratory rate, 14 breaths/min^-1; temperature, 97.6°F; and O₂ saturation, 96% on room air. Her weight is 139 lb and her height, 5 ft 5 in; her BMI is 23.1.

Physical exam reveals corrective lenses and bilateral hearing aids. The patient has multiple bruises of varying stages on both upper extremities. Her teeth are in good repair. There is no significant jugular venous distention or thyromegaly. The lungs are clear in all fields.

The cardiac exam is remarkable for a regular rate and rhythm, with a grade III/VI crescendo-decrescendo systolic murmur best heard at the right upper sternal border. She also has a grade II/VI late systolic murmur at the apex in the left lateral decubitus position. The A₂ component of the second heart sound is absent, and there are no gallops or rubs.

The abdominal exam is normal, without palpable masses. Her peripheral pulses are strong and equal bilaterally. She has arthritic changes in her hands bilaterally and has no focal neurologic symptoms.

Her ECG reveals a ventricular rate of 71 beats/min; PR interval, 152 ms; QRS duration, 142 ms; QT/QTc interval, 476/517 ms; P axis, 76°; R axis, –48°; and T axis, 161°. What is your interpretation?

A 49-year-old woman establishes care at your clinic after moving to the area. When asked about previous health care provision, she reports being followed for a “valve problem” and high blood pressure—although she admits she hasn’t kept many of her scheduled appointments. Two past echocardiograms documented valvular heart disease, although she can’t remember which valve. She was told it was nothing to worry about but that she should have follow-up. She also says she’s been prescribed medication to help with her hypertension but in the past 6 months hasn’t taken any because she’s been “too busy” to get the script filled.

She denies a history of chest pain or dyspnea on exertion, but she has had at least 2 episodes of palpitations and difficulty catching her breath that woke her from sleep. She also denies syncope or near-syncope.

Medical history is remarkable for resection of 2 lipomas on her left arm and leg. She has had 2 uncomplicated pregnancies and 1 in which she had preeclampsia. All 3 deliveries were Cesarean. She is currently taking no medications and has no known drug allergies.

Family history is remarkable for hypothyroidism and type 2 diabetes (in her mother). When the patient was 4, her mother remarried, so she does not know her biological father’s health history. She has 2 sons and 1 daughter who are in good health.

Divorced for 7 years, the patient is not currently in a relationship. She is a project manager for a start-up software company where she works long, stressful hours and drinks “a lot” of coffee. She does not drink alcohol or smoke.

The review of systems is consistent with premenopausal symptoms including hot flashes, night sweats, and irregular menses. She has no gastrointestinal or urinary symptoms. She has had no recent weight loss or gain.

Vital signs include a blood pressure of 168/98 mm Hg; pulse, 80 beats/min; respiratory rate, 12 breaths/min^-1; O₂ saturation, 96% on room air; and temperature, 98.2°F. Her height is 64 in and her weight, 164 lb.

Physical exam reveals a pleasant, well-kept woman in no distress. She wears contact lenses and has no oropharyngeal lesions. Her teeth are capped with porcelain. There is no thyromegaly, jugular venous distention, or carotid bruits. The lungs are clear in all lung fields. The cardiac exam is remarkable for a regular rate and rhythm of 80 beats/min, with a mid-to-late systolic murmur best heard when the patient is in the left lateral decubitus position. She has no extra heart sounds or rubs.

The abdomen is soft and nontender, with a well-healed Pfannenstiel surgical scar. The extremities have full range of motion with no peripheral edema. She has a recent full-sleeve tattoo on her right arm, which is well healed with no erythema. The neurologic exam is grossly intact.

As part of her workup, you order an ECG. It reveals a ventricular rate of 79 beats/min; PR interval, 184 ms; QRS duration, 76 ms; QT/QTc interval, 382/438 ms; P axis, 48°; R axis, –29°; and T axis, 33°. What is your interpretation of this ECG?

A 54-year-old man presents for preoperative workup for surgical repair of a partial tear of his right rotator cuff. He sustained the injury about 8 months ago, while rock climbing. His clinical work-up included MRI, magnetic resonance arthrogram, and dynamic musculoskeletal ultrasound. Initial treatment included physical therapy and 2 corticosteroid injections, without relief. A repeat arthrogram showed no resolution of the tear and revealed tendon retraction and muscular atrophy. The patient declined further physical therapy and opted for surgical intervention instead, because the injury is in his dominant shoulder and the pain continues to interfere with his job as a general contractor.

His medical history is positive for hypertension and hypercholesterolemia, which have been managed with medications. There is also a history of myocardial infarction (MI), which occurred 3 years ago when he was lifting a heavy truss at a job site; it manifested as acute chest pain, shortness of breath, and diaphoresis. He waited 3 days before seeking medical care because he “needed to get that project done.” He has had no further chest pain, but he‘s felt “a twinge” now and again in the past 2 months. He denies shortness of breath, dyspnea on exertion, or exertional chest pain. He has had no palpitations, syncope, or near-syncope.

His current medications include diltiazem, atorvastatin, and isosorbide. He tried metoprolol but did not like how he felt when taking it. He has no known drug allergies.

Family history is positive for familial hyperlipidemia on his father’s side. His father died of a heart attack at age 51. His mother has type 2 diabetes mellitus. His 2 older brothers have had MIs; his younger sister has no known health issues.

The patient is a self-employed general contractor. He has been married for 20 years and has a 21-year-old son who works for him. He smokes 1 to 1.5 packs a day and takes a shot of bourbon every night before dinner.

A review of systems reveals an 8-lb weight gain over the past 6 months. He denies fever, chills, and gastrointestinal and urologic symptoms. He believes he is depressed because his rotator cuff injury prevents him from doing what he would like.

Vital signs include a blood pressure of 138/88 mm Hg; pulse, 72 beats/min; respiratory rate, 14 breaths/min; O₂ saturation, 98% on room air; and temperature, 97.4°F. His height is 70 in and his weight, 208 lb.

Physical exam reveals an anxious male in no distress wearing a sling on his right upper extremity. The HEENT exam is remarkable for corrective lenses. There are no lesions in the oropharynx, and his tobacco-stained teeth are in otherwise good repair. The neck is supple, and there are no carotid bruits, jugular venous distention, or thyromegaly. The pulmonary exam reveals coarse, scattered crackles with end-expiratory wheezing that clears with coughing.

Cardiac exam reveals a regular rate and rhythm of 72 beats/min. There are no murmurs, extra heart sounds, or rubs.

The abdomen is soft and nontender without palpable organomegaly or pulsatile masses. The lower extremities reveal no edema. The right upper extremity exam is deferred because the patient is very apprehensive about any movement of his shoulder. Peripheral pulses are strong and equal bilaterally. The neurologic exam is grossly intact.

As part of the preoperative workup, an ECG is ordered. It shows a ventricular rate of 72 beats/min; PR interval, 158 ms; QRS duration, 106 ms; QT/QTc interval, 400/438 ms; P axis, 33°; R axis, 38°; and T axis, –15°. What is your interpretation of this ECG?

For the past 5 days, a 57-year-old man with “the flu” hasn’t been able to work. This morning, he awoke with chest tightness but denies chest pain. Because work has been busy lately, he just wants an antibiotic to help get him back on the job.

His primary symptom is a persistent, nonproductive cough that prevents him from getting a good night’s sleep. Associated symptoms include rhinorrhea, myalgias and arthralgias, and (for the first 3 days of illness) a low-grade fever. He’s been coughing so hard and for so long that his chest has begun to hurt. His cough is aggravated when lying down and somewhat relieved when sitting upright. He denies wheezing. He presents with specific requests: a chest x-ray to rule out pneumonia and prescriptions for azithromycin and codeine/acetaminophen (the latter for cough suppression).

Past medical history is remarkable for chronic obstructive pulmonary disease (COPD) and chronic bronchitis. Six months ago, a pulmonary function test revealed an FEV₁ of 76% and an FEV₁/FVC of 60%. He has chronic, mild to moderate shortness of breath with exertion. He has never had pneumonia or any anginal symptoms. Past surgical history is remarkable for an open reduction and internal fixation repair of his right tibia and an appendectomy. Current medications include acetaminophen for fever. He has used an albuterol inhaler in the past but has not had one for more than a year. He has no known drug allergies.

The patient is a crane operator for a large construction business. He is divorced and has an adult son with whom he has no contact. He’s been smoking 1.5 to 2 packs a day since he was 16. He used recreational marijuana until his employer began conducting random drug screenings 3 years ago. He drinks about 2 six-packs of beer a week—most of it on the weekends.

Family history is positive for COPD (mother), acute abdominal aortic dissection (father), and myocardial infarction (paternal grandfather).

The review of systems is positive for myalgias and arthralgias, which have been exacerbated by his recent illness. He denies a productive cough and any changes in heart rhythm and bowel or bladder function. He has no neurologic symptoms.

His vital signs include a blood pressure of 164/96 mm Hg; pulse, 80 beats/min; respiratory rate, 18 breaths/min^-1; O₂ saturation, 92% on room air; and temperature, 99.8°F.

Physical exam reveals an anxious, tired man in mild distress. His weight is 164 lb and his height, 70 in. The HEENT exam reveals ill-fitting corrective contact lenses, disheveled hair, and a nicotine-stained beard and mustache. His teeth are in poor repair; however, none are loose or missing. The neck is supple, and there is no thyromegaly. There is jugular venous distention, but not to the angle of the jaw. His respirations are shallow, requiring the use of accessory muscles. Deep inhalation causes uncontrollable coughing. Although there is anterior-posterior chest wall enlargement, it is insufficient to consider the patient barrel chested. Auscultation reveals diffuse, coarse rhonchi and end-expiratory wheezing.

The cardiac exam reveals a regular rate and rhythm of 80 beats/min, with a soft diastolic murmur (grade II/VI) that is best heard along the left sternal border. There are no extra heart sounds or rubs. The abdomen is tender to deep palpation in the right upper quadrant, with no evidence of rebound to suggest peritonitis. There are no abdominal or femoral arterial bruits. The extremities demonstrate 2+ pulses bilaterally with 1+ pitting edema in the lower legs. The neurologic exam is grossly intact.

The previously undocumented murmur prompts you to order an ECG. It shows a ventricular rate of 83 beats/min; PR interval, 178 ms; QRS duration, 110 ms; QT/QTc interval, 406/477 ms; P axis, 67°; R axis, 126°; and T axis, –57°. What is your interpretation of this ECG?

Two days ago, a 76-year-old man underwent surgical repair of a left femoral fracture sustained in an automobile accident. Last night, his vital signs were concerning for asymptomatic bradycardia, prompting an order for ECG prior to morning rounds. His postoperative surgical course has been otherwise uneventful, and he is using minimal narcotic analgesia.

The patient has a long history of mild hypertension, which is well controlled with hydrochlorothiazide (50 mg/d). Otherwise, his medical history shows no angina, dyspnea, shortness of breath, or palpitations. There is no history of thyroid dysfunction or renal disease.

A pack-a-day smoker since age 15, the patient has been using a nicotine patch during his hospital stay. In the past 36 hours, he has taken 4 acetaminophen/oxycodone tablets (325/5 mg).

The patient works on a 400-acre ranch with about 100 head of cattle. His alcohol consumption was heavy until about 12 years ago, when he “blacked out” and gave up drinking altogether. He attends Alcoholics Anonymous meetings and leads sessions at his church. He denies recreational or illicit drug use.

Family history is positive for prostate cancer in his father and lung cancer in two brothers. His mother died of a hemorrhagic stroke at age 84.

The review of systems is remarkable only for discomfort due to an indwelling Foley catheter placed at the time of the surgery. He has no other specific complaints.

This morning, his vital signs include a blood pressure of 108/60 mm Hg; pulse, 42 beats/min; and O₂ saturation, 100% on 2L of oxygen via nasal prongs.

When you arrive at the patient’s room, the ECG is in progress. The technician expresses concern about the tracing and shows you that the electrodes are placed properly. Looking at the ECG, you see a ventricular rate of 42 beats/min; PR interval, unmeasured; QRS duration, 130 ms; QT/QTc interval, 514/429 ms; P axis, +83°; R axis, +84°; and T axis, –43°. What is your interpretation?