Introduction

Sinus Tachycardia is also called sinus tach and defined as a rate greater than 100 beats/min (bpm) in an average adult. The electrical signals originate in the sinoatrial node (SA) (Abed et al., 2016). There are three types of tachycardia:

1. Sinus Tachycardia
2. Atrial or Supraventricular Tachycardia (SVT)
3. Ventricular Tachycardia

Causes of Sinus Tachycardia

Causes of Sinus Tachycardia include:

• Fever
• Anaemia
• Pain
• Excitement
• Hyperthyroidism
• Heart failure
• Mercury poisoning
• Kawasaki disease
• Sepsis
• Dehydration
• Hypovolemia with hypotension and shock
• Pheochromocytoma
• Pulmonary embolism
• Acute coronary ischemia and myocardial infarction
• Hypoxia
• Intake of stimulants such as nicotine, cocaine etc.
• Electric shock
• Drug withdrawal
• Porphyria

Pathophysiology of Sinus Tachycardia

Pathophysiology:

The pathophysiology of ST is very complex and not well understood. Clinical studies have shown many pathophysiological mechanisms in ST. It is generally accepted that the pathogenesis of ST is multifactorial. Others may include β-adrenergic hypersensitivity, abnormal baroreflex activity, regional autonomic dysregulation and M2 anticholinergic hyposensitivity (Abed, Fulcher, Kilborn & Keech, 2016) The range of contribution of every mechanism in isolation will remain unknown.

Interpretation of rhythm strip of Sinus Tachycardia

There are five common variations of sinus rhythm:

• Normal sinus rhythm (60-100 BMP)
• Sinus bradycardia (<60 bpm)
• Sinus tachycardia (>100 bp)
• Sinus pause/arrest

Sinus rhythm is the normal regular rhythm of the heart set by the natural pacemaker of the heart called as sinoatrial node. It is in the wall of the right atrium.

The following table summarizes the key features of Sinus Tachycardia rhythm strip:

There are five steps to identify Normal Sinus Rhythm:

Sinus tachycardia

• Positive P wave in lead 2-> impulse initiated in sinus node
• Regular P-R interval
• Usually, it is caused by increased adrenergic tone (stress, exercise)
• R-R interval varies
• Heart rate:

      – Increases during inspiration

      – Decreases during expiration

P-wave value:

• First deviation from the isoelectric line
• It should be upright and rounded
• P-wave is the Sa node pacing or firing at regular intervals

The questions include:

1. Is P-wave present?
2. Are they occurring regularly?
3. Is there 1 P-wave present for every QRS complex present?
4. Do all P-waves look similar? 

PR Interval Normal:

• It measures the time interval from onset of atrial contraction to onset of ventricular contraction (Sinha, D., 2016).
• Measured from the P-wave to the QRS complex.
• Normal interval is 0.12-0.20 seconds (3-5 small squares)

      PR Interval:

1. Are the PR intervals greater than 0.20 seconds?
2. Are the PR intervals less than 0.12 seconds?

  QRS Complex:

   The questions include:

1. Are the QRS complexes greater than 0.12 seconds (in width)?
2. Are the QRS complexes less than 0.06 seconds (in width)?
3. Are the QRS complexes similar in appearance across the strip?

A sequential beating of the heart as a result of the generation of electrical impulses

It can be defined as:

Regular pattern: Interval between the R waves is regular.

Irregular pattern: Interval between the R waves is not regular.

Regular Rhythm:

If the interval is less than 0.06 seconds 0r 1.5 small boxes, then the rhythm is considered to be regular.

Asking the patient some questions regarding symptoms, carrying out a physical exam and ordering some tests diagnose Sinus Tachycardia

Electrocardiogram (ECG)

An electrocardiogram (ECG or EKG) shows the heart’s electrical activity as line tracing on paper (Do?an, 2011). The spikes and dips in the tracing are known as waves. There are two ways for ECG interpretation:

1. ECG recorded patterns
2. ECG recorded electrical vectors

Electrodes are attached to the patient’s skin to measure the electrical impulses given off by the heart. This test also helps to show any previous heart disease that may contribute to the tachycardia.

Echocardiogram

It is a type of ultrasound investigation (Gascho, 2015).

Blood Tests:

Blood tests help to determine whether thyroid problems or other substances may be factors contributing to the patient’s tachycardia (Marlais, Francis, Fell & Rawat, 2011).

Holter Monitor Machine:

In this patient wears a portable device that records all the heartbeats and it is worn under the clothes and records the information about the electrical activity of the heart (BegumS. & Singh, 2012).

Cardiac Event Recorder:

Cardiac event recorder is a device similar to a Holter monitor, but it does not record all the heartbeats. These are of two types:

A phone is used to transmit signals from the recorder while the patient is experiencing symptoms.

Cardiac event recorder is useful for diagnosing rhythm disturbances that happen at random moments (Saygi et al., 2016)

Electrophysiological testing (EP studies):

EP testing is painless, non-surgical that can help to determine the type of arrhythmia. The test is carried out in an EP lab (Maris, 2011).

Tilt-table test:

If the patient experiences dizziness, or lightheadedness, and neither the ECG nor the Holter revealed any arrhythmias, a tilt-table test is performed. This monitors the patient’s heart rhythm, blood pressure, and heart rate while they are moved from a lying to an upright position (Gursul et al., 2014).

Chest X-ray:

The X-ray images help the doctor to check the state of individual’s heart and lungs (“Building a better x-ray analysis “, 2008).

 Complications of Tachycardia:

It depends on several factors:

• The severity
• Rate of tachycardia
• Duration of tachycardia

Common complications:

• Blood clots- This will increase the risk of heart attack and stroke
• Heart failure
• Fainting spells
• Sudden death- generally only linked to ventricular fibrillation

Treatment   

Not required for physiological sinus tachycardia (Zoeller, 2017).

Interpretation of pathology tests:

Cardiac stresses such as hypotension, fever, anaemia, hypovolemia, thyrotoxicosis, pulmonary embolic, shock leads to Sinus Tachycardia or increased cardiac demands related to myocardial infarction or congestive heart failure. A drug such as atropine, nicotine, isoproterenol, thyroid hormones, and aminophylline can cause sinus tachycardia. It is a no paroxysmal condition and usually presents as an inappropriate high resting sinus rate and a marked increase in rate with minimal activity. Although the mechanism remains undefined, the imbalance between sympathetic and parasypathetic controls are thought to be one of the contributing factors (O’Connor, 2006).

The therapy for appropriate sinus tachycardia involves treatment of a primary condition such as infections by antibiotics, hypotension with fluid replacement, and thyrotoxicosis by β-blockers and anti-thyroid drug (Nishiuchi, Nogami & Naito, 2013). Β-blockers therapy is the first line of therapy and results in control of sinus and associated symptoms. In patients who are nonresponsive to blockers and calcium-channel blockers, modification of the sinoatrial node with radiofrequency catheter ablation results in slowing of the sinus node. Catheter ablation for sinus node modification deals with the small risk of patients requiring permanent pacemakers. Although sinus node modification has a high initial success rate, there is a high incidence of recurrence (Yedlapati, N., & Fisher, J.2014).

Sinus node accounts for less than 5% of patients with supraventricular tachycardia. The diagnosis is suggested when the P wave during tachycardia are identical to the P wave in sinus rhythm and have a similar relationship to QRS complex, and further by an abrupt termination of the tachycardia (Bogossian et al., 2014). Sinus node tachycardia can be terminated by intravenous adenosine, verapamil, or blockers. Oral therapy with calcium-channel blockers (Mookerjee & Mehta, 2013).

The three nursing interventions and specific assessment criteria are:

A patient is in sinus tachycardia. Which nursing interventions are appropriate?

1. Observe the patient’s effects on cardiac function.
2. Administer two readings of acetaminophen (Tylenol) per physician prescription if an elevated temperature is present.
3. If hypovolemia is suspected as the cause, then administer normal saline 0.9% at the prescribed rate of 200 ml per hour.

Assessment

It uses a systematic, dynamic way to collect and analyse the data about a client, the first step in delivering nursing care. Assessment includes not only physiological, spiritual, economic and lifestyle factors as well.

Example: A nurse’s assessment of a hospitalized patient includes not the physical causes and manifestations of pain, but the patient’s response- an inability to get out of bed, refusal to

Eat, withdraw from family members, anger directed at hospital staff, or request for more pain medication (Fonseca, 2012)

Abnormal Pathology Result

Electrolyte Imbalance:

• Electrolyte imbalance causes cardiac dysrhythmia.
• Potassium:

Plays  key role in both depolarization and repolarization.

Causes dramatic ECG changes.

High or low levels of  potassium in the blood causes heart problems.

• Sodium:
• No effect on the cardiac rhythm nor the ECG.
• Magnesium:
• Hypomagnesaemia causes atrioventricular and intraventricular conduction disturbances.

Why it causes Sinus Tachycardia:

As potassium, plays key role in many factors like depolarization which causes ECG changes and causes many problems related to heart. Magnesium helps muscles to contract or relax. It balances the heartbeat. Lack of magnesium results in the speedup of heartbeat. External influences on the heart such as hypotension, fever, blood loss, anaemia and exercise. Many forms of sinus tachycardia is found to be more common among females when compared to males.

Impact on the patient (Mrs.Jackson):

The patient’s resting heart rate becomes abnormally high- greater than 100 beats/minute.

Sinus tachycardia commonly affects elderly people resulting in a condition called “Heart Block”,as the faster heart rate happens more frequently and lasts longer as the older one gets.

Diagnosis of Sinus Tachycardia:

Conclusion:

The reasons like exercise, anaemia, fever, hypoxemia, dehydration or shocks etc lead to Sinus Tachycardia (Hutton, 2011). Treatments for tachycardia are designed to address the cause of the condition as well as slow a fast heart rate it occurs, prevent future episodes and minimize complications (Cuneo, B. (2008).

Ways to slow a heartbeat includes:

• Vagal maneuvers
• Medications
• Cardioversion

Treatments:

The following treatments are used to prevent or manage episodes of tachycardia:

• Catheter ablation
• Pacemaker
• Implantable cardioverter
• Surgery
• Blood clots preventio

References

Abed, H., Fulcher, J., Kilborn, M., & Keech, A. (2016). Inappropriate sinus tachycardia: focus on ivabradine. Internal Medicine Journal, 46(8), 875-883.

BegumS., G., & Singh, V. (2012). ECG Data from Holter Monitor. International Journal Of Computer Applications, 47(20), 16-21.

Bogossian, H., Ninios, I., Frommeyer, G., Bandorski, D., Eckardt, L., Lemke, B., & Zarse, M. (2014). U Wave during Supraventricular Tachycardia: Simulation of a Long RP Tachycardia and Hiding the Common Type AVNRT. Annals Of Noninvasive Electrocardiology, 20(3), 292-295.

X-ray analysis machine. (2008). Physics Today.

Dogan, N. (2011). ECG analysis in people without any cardiac symptoms and findings. Turkiye Aile Hekimligi Dergisi, 15(4), 173-177.

Fonseca, C. (2012). Nursing Care Indicators to Nursing Homes. Journal Of Nursing & Care, 01(03).

Gascho, J. (2015). ECG for Pericardial Effusion. The Permanente Journal.

Gursul, E., Bayata, S., Tuluce, S., Berilgen, R., Safak, O., Ozdemir, E., & Tuluce, K. (2014). Parameters of Heart Rate Variability Can Predict Prolonged Asystole before Head-Up Tilt Table Test. Annals Of Noninvasive Electrocardiology, 19(5), 477-482.

Lee, M., & Hanger, H. (2017). Audit of anticholinergic medication changes in older hospitalized patients using the Anticholinergic Drug Scale. Internal Medicine Journal, 47(6), 689-694.

Maris, E. (2011). Testing in electrophysiological studies. Psychophysiology, 49(4), 549-565.

Marlais, M., Francis, N., Fell, J., & Rawat, D. (2011). Blood tests and histological correlates in children with eosinophilic oesophagitis. Acta Paediatrica, 100(8), e75-e79.

Mookerjee, R., & Mehta, G. (2013). All beta-blockers are created equal, but some beta-blockers are equal than others. Liver International, 33(4), 501-503.

Nishiuchi, S., Nogami, A., & Naito, S. (2013). Ventricular Tachycardia. Journal Of Cardiovascular Electrophysiology, 24(7), 825-827.

O’Connor, N. (2006). Screening of pathology tests controls costs: thrombophilia testing. Journal Of Clinical Pathology, 59(5), 556-556.

Saygi, M., Ergul, Y., Ozyilmaz, I., Sengul, F., Guvenc, O., & Aslan, E. et al. (2016).. Annals Of Noninvasive Electrocardiology, 21(5), 500-507.

Zoeller, B. (2017). Fetal Supraventricular Tachycardia. Current Treatment Options In Cardiovascular Medicine, 19(1).

Hutton, D. (2011). Sinus Bradycardia and Sinus Tachycardia. Plastic Surgical Nursing, 31(2), 75-79.

Cuneo, B. (2008). Treatment of fetal tachycardia. Heart Rhythm, 5(8), 1216-1218.

Yedlapati, N., & Fisher, J. (2014). Pacemaker Diagnosis. Pacing And Clinical Electrophysiology, 37(9), 1189-1197.

Sinha, D. (2016). Comparison of Intraoperative ECG Variations (QRS and PR Interval Prolongation) .Journal Of Medical Science And Clinical Researc