Evaluating palpitations in Primary Care

Today we will discuss the topic of palpitations including the evaluation, workup, and the myriad of causes and types.  Patients may describe or define what they are feeling during palpitations as a racing heart sensation, slowing of the heart, flopping in the chest, or maybe even feeling like their heart is beating out of their chest.  On the other end of the spectrum, a patient may be entirely asymptomatic as well.

Cardiac transmission typically involves the discharge of electric impulse at the sinoatrial node (SA node).  This impulse then travels down the wall of the right atrium to the atrioventricular node (AV node), then it is spread throughout the bundle of His and Purkinje system to cause depolarization of the ventricles.

If there is any malfunction in this pathway, it may lead to an arrhythmia.  Other than cardiac malformations, numerous noncardiac conditions can lead to an arrhythmia and perceived palpitations.  These may include a pheochromocytoma, thyroid disease, anxiety, panic attacks, anemia, and somatization disorder to name a few.

caridac and non cardiac causes palpitations
Am Fam Physician. Palpitations: Evaluation in the Primary Care Setting. 2017 Dec 15;96(12):784-789.

 

palpitations etiology
Am Fam Physician. Palpitations: Evaluation in the Primary Care Setting. 2017 Dec 15;96(12):784-789.

 

Uncovering the underlying cause of a patient’s palpitations is essential to evaluate to assess a patient’s long-term risks accurately.  Palpitations makeup around 16 percent of office visits to a primary care provider and are the second most common cause for a visit to the cardiologist.1

First and foremost, any patient who presents with palpitations should be assessed for an underlying cardiac ischemic etiology. 

Many cardiac causes whether it be due to an underlying arrhythmia or a structural issue, have a genetic component making family medical history taking crucial.  Additionally, history questions should include if activity makes the symptoms worse, if they occur at rest, if there are any pounding or pulsatile sensation in the neck region, history of anxiety or panic attacks, or thyroid disease.

Additional characteristics to assess are if the patient’s symptoms worsen with positional change.  Those who have palpitations due to atrioventricular nodal reentry tachycardia may note that their symptoms are aggravated by standing up, or with bending over. 

Determining whether a patient loses consciousness (syncope) is an important factor in assessing in a patient with palpitations.  If a patient does have syncopal episodes, one should question if there is ventricular tachycardia or structural heart disease (hypertrophic cardiomyopathy) with outflow obstruction.

 

Medications and Substance Abuse

Medications and substance abuse risk should be assessed in all patients with palpitations.  Prescription medications such as stimulants for the treatment of ADHD or short-acting bronchodilators for asthma or COPD may lead to palpitations.  Over-the-counter medications such as nasal decongestants, herbal medicines, and supplements (omega-3 polyunsaturated fatty acids, coenzyme Q10, and carnitine) may also be an underlying cause of palpitations.

Patients should also be evaluated for substance abuse.  Cocaine, marijuana, anabolic steroids, and methamphetamine abuse can lead to palpitations.  Other substances such as caffeine, nicotine, and alcohol can even cause palpitations as well.

assessing palpitations

Am Fam Physician. Palpitations: Evaluation in the Primary Care Setting. 2017 Dec 15;96(12):784-789.

 

Evaluating the Patient in Primary Care

Next, we will discuss the work up with a patient who has suspected palpitations.  Baseline laboratory testing such as a CBC, CMP, and TSH should be completed.  Other testing may include a serum or urine Hcg and urine or serum drug screen.

One of the most significant initial tests that should be completed is an EKG. Specific findings can be indicative of underlying arrhythmias.  A prolonged QT interval may point towards polymorphic ventricular tachycardia.  A shortened PR interval or delta wave may signify a reentrant tachycardia through an accessory pathway.

Non-specific ST segment changes and T-wave abnormalities may be findings consistent with potential myocardial disease.  Even though these nonspecific changes may be considered a normal variant, in symptomatic patients, there is an increase in death rates due to pathologic arrhythmias.1

Just because a single EKG in your office is normal, this does not rule out arrhythmias.  In these instances, one can consider getting a 24 to 48-hour Holter monitor.  If symptoms are less frequent an event monitor can be completed for around 30 days.  Additionally, there is a newer implantable loop monitor that are active continuously and provide live, real-time data.

If your patient has symptoms with exertion, they should be evaluated with exercise stress testing due to the fact that they would be at a higher risk for morbidity and mortality.1  In patients who have syncope or near syncope, tilt table testing and echocardiography may be helpful in the evaluation of their symptoms.

 

Arrhythmias

Lastly, we will discuss some treatment options for specific types of arrhythmias; however, a more specific evaluation, work-up, and treatment for atrial fibrillation have been addressed in a prior article and podcast. 

Ventricular premature contractions are common findings in patients who have underlying heart disease.  If findings on testing show isolated, monomorphic ventricular premature contractions, these are more likely to be benign, compared to frequent, consecutive, or multiform ventricular ectopy.

When evaluating patients with VPCs, the first step is to figure out if there is underlying cardiac or structural heart disease with echocardiography, due to the mortality being increased in this patient population.1 

Patients who have at least 25 percent of their heartbeats being VPCs have an increase in their risk for VPC-induced cardiomyopathy.  The prognosis in these cases is good in patients who have no other heart problems.

Supraventricular tachycardia (SVT) will present with narrow complex (QRS <120 ms) or wide complex (QRS equal to or greater than 120 ms) tachycardia.  It most often will present with recurrent, random episodes that may increase in frequency and severity with time.

SVT is not typically correlated with structural heart disease, but may be seen in association with hypertrophic cardiomyopathy and the Ebstein abnormality. 

Wide complex tachycardia should be assumed to be ventricular tachycardia when the diagnosis is unclear, particularly if it occurs in the presence of patient’s with structural heart disease.  The presence of delta waves indicates an accessory pathway.

wide complex tachycardia

Am Fam Physician. Palpitations: Evaluation in the Primary Care Setting. 2017 Dec 15;96(12):784-789.

 

In patients with narrow complex SVT, infrequent episodes that resolve on their own may not require therapy.  However, if symptoms are persistent treatment may include adenosine, calcium channel blockers, beta blockers, or other antiarrhythmics.  In refractory cases, synchronized cardioversion can be considered or radiofrequency catheter ablation.

Ventricular tachycardia is defined as three or more consecutive heartbeats starting in the ventricles at a rate greater than 100 bpm.  It can be sustained (>30 seconds) or nonsustained (<30 seconds), as well as monomorphic (one QRS morphology) or polymorphic (more than one QRS morphology).

The risk of sudden cardiac death in patients with ventricular tachycardia is correlated with the number of beats during an arrhythmic episode.  Those with three or fewer beats do not have an increased risk of sudden death, however, the risk increases in persons who have four to seven beats or more consecutively.

Long QT syndrome is characterized by a prolonged QT interval on EKG (>460 ms in females and >440 ms in males).  It may be life-threatening, and the patient should see cardiology immediately.  In these patients, medications such as beta blocker are contraindicated as they may increase the risk of syncope and sudden death.1

 

Resources

  1. Am Fam Physician. Palpitations: Evaluation in the Primary Care Setting. 2017 Dec 15;96(12):784-789.
  2. UpToDate. Overview of Palpitations in Adults.  Accessed: December 25, 2018.