A 75 Year Old Hospitalized Patient Complains Of A Sudden Feeling That Her Heart Is Racing

A 75 year old woman is an inpatient at 2 days after a successful femoral-popliteal bypass. The surgery was performed because of a significant atheroscerotic peripheral vascular disease causing severely impeded blood flow to her right leg. The patient has been doing well since the completion of her surgery but on the 2nd post operative day she describes a sudden feeling that her heart is beating very fast , which seems like racing. She denies any chest pain, dizziness, or difficulty breathing. She says that she has never experienced a similar feeling before.
Past History: Peripheral vascular disease, Hypertension and mild Coronary artery disease.
Medication: Her medications include ASA, clopidogrel ( started post operatively), metoprolol, and enalapril. Prior to surgery she was taking pentoxifylline.
Patient was a heavy smoker for several years but quit 2 years ago.

On auscultation of her chest there was a rapid heart beat with significant irregularity.
Her H/R was 120 beats/min and BP was 145/83 mmHg.
As ECG was done and following was seen:

Irregular QRS rate with no discernible P waves

Diagnosis : Atrial Fibrillation


Case Discussion:
Atrial Fibrillation is a condition of uncoordinated atrial contractions with independent sporadic ventricular contractions. It occurs due to rapid, disorderly firing from a second atrial focus.

Risk factors: include:

• Left atrial enlargement
• Coronary artery disease
• Hypertension
• Anemia
• Valvular disease
• Pericarditis
• COPD
• Pulmonary embolism
• Hyperthyroidism
• Rheumatic heart disease
• Sepsis
• Alcohol use
• Electrolyte abnormalities

Clinical Features: Patients may be asymptomatic or may complain of palpitations, dyspnea or chest pain. On examination there is an irregularly irregular pulse and a rapid heart beat. 

ECG : shows no discernible P waves and an irregular QRS rate.

Treatment:

1. Rapid control via calcium channel blockers, B blockers or digoxin.

2. The initial attempt at rate control and cardioversion is 5 mg IV metoprolol. 

3. IV metoprolol may be repeated twice before attempting to control the rate with IV diltiazem

4. Anti coagulation (i.e heparin and later warfarin) is frequently required unless the arrhythmia is controlled within 24 hours of onset.

5. Any associated electrolyte abnormalities should be corrected. 

6. In some cases electric cardioversion may be required.