Treatment Guideline Chart

Tachycardia is defined as a cardiac rate that is increased to >100 beats/minute (bpm).

Tachyarrhythmia is used to describe tachycardia in the presence of cardiac rhythm abnormality.

Divided into supraventricular and ventricular tachycardia.

Signs and symptoms related to rapid heart rate are altered sensorium, angina, shortness of breath, myocardial infarction, hypotension and other signs of shock (eg cold clammy skin, low urine output), heart failure or pulmonary congestion.

Tachycardia Diagnosis


  • Establish that the signs of cardiovascular compromise are rate-related
  • Provide immediate synchronized cardioversion for unstable and deteriorating patients
  • If the patient is stable, evaluate cardiac rhythm and its possible etiology to determine treatment options
    • Patient history and physical examination should focus on the presence of underlying cardiac diseases, duration of symptoms, past and current medications, and use of implants (cardioverter defibrillator, pacemaker)
    • Identify triggers, alleviating or predisposing factors, onset, nature and frequency of symptoms, and family history of arrhythmias
  • Consider referral to a specialist


  • Divided into supraventricular and ventricular tachycardia
    • Supraventricular tachycardias (SVTs) include tachycardias with triggering circuits originating from tissues above the level of the ventricles (sinus node, atria, atrioventricular node, His bundle)
      • Paroxysmal SVTs are SVTs with regular rhythm and abrupt onset and termination, and include atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), sinoatrial nodal reentrant tachycardia (SANRT), intraatrial reentrant tachycardia (IART), junctional ectopic tachycardia, and focal atrial tachycardia
      • SVTs with irregular rhythm include atrial fibrillation, atrial flutter, and multifocal atrial tachycardia (MAT)
    • Ventricular tachycardias (VTs) are tachycardias with driving circuits originating from the ventricles or Purkinje fibers

Evaluation of Cardiac Rhythm

Interpretation of ECG

  • Determine if narrow-complex or wide-complex tachycardia
  • Determine regularity 
  • Identify sinus from non-sinus tachycardia

Narrow-Complex Tachycardia

  • HR of >100 beats per minute (bpm) with QRS complex of <0.12 seconds duration
  • Ventricles are being activated in a rapid manner suggesting that the driving circuit is that of sinus or supraventricular origin

Wide-Complex Tachycardia

  • HR of >100 bpm with QRS complex of ≥0.12 seconds duration
  • Aberrant driving circuit originating from ventricular tissues or any site outside the normal conduction system
  • Other SVTs can also produce wide-complex tachycardias

Regular Narrow-Complex Tachycardias

Sinus Tachycardia

  • Occurs when the sinus node discharge rate is >100 per minute as a physiological response to a variety of stimulus
  • A normal physiologic response to increased adrenergic stimulation or decrease in parasympathetic tone producing accelerated sinus node depolarization
    • May result from physiological causes (eg emotion, pain, physical exercise, pregnancy, sexual intercourse), pathological causes (eg anemia, anxiety, dehydration, fever, infection, malignancies, panic attack, pheochromocytoma, etc), caffeine or alcohol intake, drugs (Atropine, beta agonists, Daunorubicin, Dobutamine, Dopamine, Doxorubicin, Epinephrine, methylxanthines, Norepinephrine, amphetamines, cocaine, beta-blocker withdrawal)
  • Upper limit of sinus tachycardia is age-related
  • Uniform and upright P waves on leads I, II, III and aVL, negative in aVR
  • P wave appears before every QRS complex with normal PR intervals

Inappropriate Sinus Tachycardia (IST) (Chronic Nonparoxysmal Sinus Tachycardia)

  • Characterized by sinus heart rate of >100 bpm at rest and mean 24-hour heart rate of >90 bpm not caused by underlying diseases such as anemia, fever or hyperthyroidism; it is caused by increased automaticity of the sinus node or an automatic atrial focus near the sinus node resulting from a defect in the sympathetic nerve control of the SA automaticity
  • Occurs in persons without apparent heart disease and they may present asymptomatically or with accompanying symptoms such as palpitations, lightheadedness, and fatigue
  • P wave axis and morphology similar to sinus rhythm

Postural Orthostatic Tachycardia Syndrome (POTS)

  • Characterized by an increase in heart rate of ≥30 bpm when standing for >30 seconds or ≥40 bpm in individuals aged 12-19 years, without orthostatic hypotension defined as >20 mmHg drop in systolic blood pressure
  • Predominantly seen in young women without structural heart disease and symptoms such as exercise intolerance, fatigue, lightheadedness and palpitations manifest upon assuming a standing position

Supraventricular Tachycardia (SVT)

  • Surpasses the upper limits of sinus tachycardia at rest (>150 bpm) with or without discernible P waves
  • Regarded as ventricular in origin if the QRS complex is narrow or if the QRS complex is wide and bundle branch aberrancy is present
  • QRS complex identical to sinus rhythm

Atrioventricular Nodal Reentrant Tachycardia (AVNRT)

  • The most common SVT originating from the AV node with a QRS complex of supraventricular origin
  • Characterized by rate of 150-250 bpm and regular rhythm, with the P wave hidden within the QRS complex
  • The presence of an atrial premature beat or a premature ventricular stimulation, which causes prolongation of AV nodal conduction time, precipitates AV nodal reentry
    • In typical AVNRT (also known as slow-fast AVNRT), anterograde conduction passes through the slow AV nodal pathway with retrograde conduction occurring in the fast pathway when an atrial complex blocks anterograde conduction in the fast pathway
    • Atypical AVNRT utilizes anterograde conduction through the fast AV nodal pathway with retrograde conduction in the slow pathway, or anterograde conduction via the slow pathway and another slow pathway for retrograde conduction

Atrioventricular Reentrant (or Reciprocating) Tachycardia (AVRT) Associated with an Accessory Pathway

  • A reentrant tachycardia utilizing the AV accessory pathway for conduction of impulses
  • Reentry of impulses may be concealed during retrograde excitation, producing an AV reciprocating tachycardia
  • Types of AVRT include orthodromic and antidromic AVRT
    • Orthodromic AVRT, the more common type of AVRT (90-95%) especially in patients with Wolff-Parkinson-White (WPW) syndrome, is characterized by anterograde conduction of atrial premature beats via the atrioventricular nodal pathway and retrograde conduction using the accessory pathway, and vice versa for ventricular premature beats
    • Antidromic AVRT uses the accessory pathway to direct reentrant impulse anterogradely from the atrium to the ventricles, and vice versa via the atrioventricular node to direct impulse in the retrograde direction
  • Depression in the ST segment signifies reentry involving the accessory pathway
  • Permanent form of junctional reciprocating tachycardia (PJRT), an uncommon form of AVRT, features a long RP interval
    • Due to the delayed atrial activation coming from an accessory pathway with slow retrograde conduction
    • Characterized by deeply inverted retrograde P waves in leads II, III and aVF

Focal Atrial Tachycardia

  • Characterized by rate of 100-250 bpm and regular atrial rhythm with activity originating from one localized site in the atrium
  • P wave may appear similar to sinus tachycardia when foci is near the sinus node
    • Left atrium foci: Positive P wave in lead V1, negative P waves in leads I and aVL
    • Cranial portion of the left or right atrium: Positive P waves in leads II, III and aVF
    • Paraseptal tissue or left or right atrial free wall: Shorter P-wave duration
    • An isoelectric interval may be seen between P waves
  • Commonly seen in patients with significant structural heart disease (coronary heart disease, MI, heart failure, cor pulmonale), and Digitalis intoxication

Intraatrial Reentrant Tachycardia (IART)

  • A type of paroxysmal reentrant SVT, is a macroreentrant atrial tachycardia that does not use the cavotricuspid pathway for reentry
  • Initiated by atrial premature beats and atrial pacing; ventricular premature beat triggers are rare
  • Incisional IART is a subtype of IART used to diagnose patients with a history of surgical procedure (congenital cardiac disease repair, incisional tachycardia, surgical or catheter-based management of atrial fibrillation) usually present in patients with IART
    • Occurrence depends on the patient’s underlying cardiac condition and type of surgery

Junctional Ectopic Tachycardia

  • Also called focal junctional tachycardia 
  • Pathologic impulse arises from the AV junction which may feature irregular rhythm and atrioventricular dissociation
  • Rate of 120-220 bpm
  • An ectopic focus in the AV junction producing erroneous automaticity may be the cause
  • Most often seen in post-op infants for management of a congenital heart disease

Nonparoxysmal AV Junctional Tachycardia (Accelerated AV Junctional Rhythm)

  • Rate of 70-150 bpm
  • Often associated with automaticity, Digoxin toxicity, or myocardial infarction
  • Features retrograde atrial capture, AV dissociation with sinus node atrial control, and AV dissociation with atrial fibrillation

Sinoatrial Nodal Reentrant Tachycardia (SANRT)

  • Also called sinus node reentry or sinus node reentrant tachycardia
  • A microreentrant tachycardia that does not use the atrioventricular node or accessory pathways for reentry, with an activation sequence similar to normal sinus rhythm
  • Rate 100-150 bpm with P waves identical to sinus rhythm but with abrupt onset and termination of arrhythmias

Irregular Narrow-Complex Tachycardias

Atrial Fibrillation

  • Most common
  • A documented standard 12-lead ECG or a single-lead ECG tracing taken for ≥30 seconds is recommended for the diagnosis of atrial fibrillation
    • Irregular atrial activations, absent distinct repeating P waves and irregular R-R intervals confirm atrial fibrillation
  • SVT with low amplitude baseline oscillations, ventricular response is irregularly irregular with rate ranging from 100-200 bpm, narrow QRS complex, and without aberrant conduction or preexisting bundle branch block
  • First diagnosed atrial fibrillation is atrial fibrillation that is not diagnosed before, regardless of duration, presence/severity of symptoms
  • Classified according to duration of episodes into paroxysmal, persistent, long-standing persistent and permanent atrial fibrillation
    • Paroxysmal atrial fibrillation also known as self-terminating or intermittent atrial fibrillation terminates spontaneously or with intervention within 7 days of onset
    • Persistent atrial fibrillation is atrial fibrillation that is continuously sustained >7 days including episodes terminated by cardioversion after ≥7 days
    • Long-standing persistent atrial fibrillation is continuous atrial fibrillation of >12 months' duration
    • Permanent atrial fibrillation is used to identify patients with persistent atrial fibrillation where both patient and physician has decided to stop further attempts to restore and/or maintain sinus rhythm

Atrial Flutter

  • Also known as macroreentrant atrial tachycardia 
  • A type of IART, characterized by the reentrant loop just above the atrioventricular node in the right atrium
    • Cardiac rate tends to be faster that IART
  • Rate usually >250-350 bpm 
  • Less common; may also have regular rhythm
  • Classified into cavotricuspid isthmus (CTI)-dependent atrial flutter and non-isthmus-dependent atrial flutter
    • CTI-dependent atrial flutter
      • Characterized by regular “sawtooth” P-waves on inferior ECG leads and a positive P wave in lead V1
      • Conducts signals around the tricuspid valve in a counterclockwise direction (typical CTI-dependent atrial flutter)
      • When impulse travels in a clockwise direction, this is referred to as reverse typical CTI-dependent atrial flutter
    • Non-isthmus-dependent atrial flutter (atypical flutter or isthmus independent)
      • Uses other pathways other than the CTI (eg perimitral flutter, left atrial roof reentry, left or right atrial scar region reentry)
      • Biphasic V1 deflection with clockwise rotation around the tricuspid valve; positive P waves in leads II, III, and aVF
      • May co-exist with CTI-dependent atrial flutter

Multifocal Atrial Tachycardia (MAT)

  • Also called chaotic atrial tachycardia
  • Often associated with an underlying disease in older patients such as chronic obstructive pulmonary disease (COPD), pulmonary hypertension, coronary heart disease, congestive heart disease, or Theophylline therapy
  • Characterized by atrial rates of 100-130 bpm, irregular rhythm, with atrial activation originating from numerous sites, and ≥3 P wave morphologies
  • A 12-lead ECG is needed to distinguish MAT from atrial fibrillation; distinct isoelectric period between P waves differentiate MAT from atrial fibrillation

Regular Wide-Complex Tachycardia

Urgent care should be given to unstable patients with ventricular tachycardia

Ventricular Tachycardia (VT)

  • Includes outflow tract VTs, VTs of miscellaneous origin, and idiopathic ventricular fibrillation
  • Series of >3 consecutive, abnormally-shaped, wide-complex beats
    • May be monomorphic (uniform or similar QRS morphology) or polymorphic (multiform or changing QRS morphology) 
  • Rate 70-250 bpm
  • Sustained VT is VT that lasts for >30 seconds and patients experience hemodynamic collapse, and nonsustained VT stops spontaneously within 30 seconds after onset
  • Likely VT when initial R wave is present with peak time of ≥50 milliseconds, initial R or Q wave >40 milliseconds, QRS complex is not observed on all precordial leads
  • There is AV dissociation with increased ventricular rate more than atrial rate
  • Fatal VTs include ventricular flutter and ventricular fibrillation
  • Presence of these severe tachyarrhythmias is a diagnostic sign that death may occur within minutes if not resolved
  • Heart rate of 150-300 bpm; ventricular fibrillation can go as high as 400-600 bpm
  • QRS complexes, ST segments, and T waves are absent; irregular contour and amplitude can be seen

Irregular Wide-Complex Tachycardias

  • Most commonly atrial fibrillation with bundle branch block
  • Other possible causes: Atrial fibrillation with ventricular pre-excitation in WPW syndrome, polymorphic VT, SVT with intraventricular conduction defect, electrolyte or metabolic disorder, use of accessory pathway
    • The long QT syndrome (LQTS) is associated with increased risk of life-threatening cardiac arrhythmia which is polymorphic VT, also known as torsades de pointes
  • Pre-excitation syndrome: Visible delta wave characteristic of WPW syndrome during normal sinus rhythm prior to the onset of atrial fibrillation

Laboratory Tests

12-Lead Electrocardiogram (ECG)

  • Main test used to detect and diagnose cardiac arrhythmias
  • Initial assessment of ECG findings should include rate, rhythm, morphology, axis, and QRS complex duration
    • Normal sinus rhythm is defined as a heart rate of 60-100 bpm, an upright P wave in leads I, II and aVF, and a negative P wave in lead aVR; PR interval of 0.12-0.20 seconds, QRS complex duration of <0.11-0.12 seconds and corrected QT interval (QTc) of ≤0.44-0.45 seconds
    • Normal values may vary between individuals reflecting the differences in age, body habitus, race, sex, heart orientation and physiology
  • Differences between tachyarrhythmias usually depend on the presence of P waves and QRS complexes
  • A 24-hour ambulatory ECG monitor may be considered when signs and symptoms of arrhythmia occur at least once a day and the abnormal rhythm has not been captured on a resting 12-lead ECG

Other Tests

  • The following blood work may be performed to identify other underlying causes of tachycardia
    • Complete blood count (CBC): To check for anemia or infection
    • Basic metabolic panel: To check for electrolyte imbalance
    • B-type natriuretic peptide (BNP): Present in congestive heart failure (CHF)
    • Cardiac enzymes: To determine the presence of myocardial infarction or ischemia
    • Thyroid-stimulating hormone (TSH): Decreased in hyperthyroidism



  • Used to assess ventricular function and detect structural abnormalities
  • Indicated in patients highly suspected of having structural cardiac disease and are at increased risk for ventricular arrhythmia (eg history of acute myocardial infarction, dilated right ventricular cardiomyopathies) especially if with positive family history of sudden cardiac death
  • Stress echocardiography is recommended for patients at risk of ventricular arrhythmias triggered by ischemia and unable to tolerate exercise, or those with resting ECG abnormalities

Cardiac Magnetic Resonance Imaging (CMR)

  • Used to evaluate cardiac structure (chamber volume, left ventricular mass) and ventricular function
  • Also used as a guide prior to catheter ablation

Cardiac Computed Tomography (Cardiac CT)

  • Alternative imaging test used to evaluate cardiac structures when echocardiography and CMR are not available
  • Used to quantify chamber volumes, ejection fraction and mass, and coronary artery calcification
  • Myocardial perfusion single-photon emission CT (SPECT) may be considered in patients suspected of having ventricular arrhythmias triggered by ischemia who are unable to tolerate exercise, or if with resting ECG abnormalities

Electrophysiological Study (EPS) and Cardiac Mapping

  • EPS is used to identify the presence of ventricular tachycardia, as a guide prior to catheter ablation or implantable cardioverter defibrillator (ICD) placement, and to evaluate the cause of syncope
  • EPS should be considered to risk-stratify patients with asymptomatic pre-excitation, especially patients with high-risk occupation or athletes involved in competitive sports
  • Cardiac mapping is performed during EPS to pinpoint specific site/s of origin of an aberrant signal in the myocardium for possible ablation

Coronary Angiography

  • Used in patients with VT in ST-elevation MI (STEMI) and monomorphic or polymorphic VT in suspected coronary artery disease (CAD)
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