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breastfeeding.153 As a substrate of cytochrome p450 (CYP) 3A4, ivabradine should be avoided or used with caution with concomitant administration of CYP44A inhibitors (ketoconazole, verapamil, diltiazem, clarithromycin, and grapefruit juice) or inducers (rifampin and carbamazepine).154 The limited and disappointing evidence, reported from small observational studies, suggests that catheter ablation should not be considered as part of the routine management of most patients with IST.155161

11.1.1.3 Sinus node re-entrant tachycardia Sinus node re-entrant tachycardia arises from a re-entry circuit involving the sinus node and, in contrast to IST, is characterized by paroxysmal episodes of tachycardia.176 This uncommon arrhythmia may be associated with paroxysmal symptoms of palpitation, dizziness, and light-headedness. On the ECG, the polarity and configuration of the P waves are similar to the configuration of sinus P waves.163

11.1.1.3.1 Diagnosis. The diagnosis of sinus node re-entrant tachycardia is suspected on ECG and Holter ECG. It can be confirmed with an EPS. 11.1.1.3.2 Therapy. Medical treatment is empirical, and no drugs have been studied in controlled trials. Verapamil and amiodarone have demonstrated variable success, whereas beta-blockers are often ineffective.163 Sinus node re-entrant tachycardia may be effectively and safely treated with catheter ablation targeting the site of earliest atrial activation with respect to the P wave. This approach has been shown to be feasible with a good long-term outcome.164166

11.1.1.4 Postural orthostatic tachycardia syndrome POTS is defined as a clinical syndrome usually characterized by an increase in heart rate of >_30 b.p.m. when standing for >30 s (or >_40 b.p.m. in individuals aged 12 - 19 years) and an absence of orthostatic hypotension (>20 mmHg drop in systolic blood pressure).177,178 The prevalence of POTS is 0.2% and it represents the most common cause of orthostatic intolerance in the young,178 with most patients aged between 15 and 25 years, and >75% being female. Although the long-term prognosis of POTS has been poorly explored, 50% of patients spontaneously recover within 1 - 3 years. A number of mechanisms have been described in patients with POTS, including autonomic nervous system dysfunction, peripheral autonomic denervation, hypovolaemia, hyperadrenergic stimulation, diabetic neuropathy, deconditioning, anxiety, and hypervigilance.178181

11.1.1.4.1 Diagnosis. POTS is diagnosed during a 10 min active stand test or head-up tilt test with non-invasive haemodynamic

Recommendations for the therapy of sinus tachycardias

Recommendation Classa Levelb

Inappropriate sinus tachycardia Evaluation and treatment of reversible causes is recommended.139,144,162 I C Ivabradine alone or in combination with a beta-blocker should be considered in symptomatic patients.146149,151,152 IIa B Beta-blockers should be considered in symptomatic patients.139,147 IIa C Sinus nodal re-entrant tachycardia Non-dihydropyridine calcium channel blockers (verapamil or diltiazem) in the absence of HFrEF, may be considered in symptomatic patients.163 IIb C Catheter ablation should be considered in symptomatic patients who do not respond to drug therapy.164166 IIa C Postural orthostatic tachycardia syndrome A regular and progressive exercise programme should be considered.167169 IIa B The consumption of >_23 L of water and 1012 g of sodium chloride daily may be considered.170,171 IIb C Midodrine, low-dose non-selective betablocker, or pyridostigmine may be considered.167,170,172174 IIb B Ivabradine may be considered.175 IIb C

HFrEF = heart failure with reduced ejection fraction. aClass of recommendation. bLevel of evidence. ©ESC 2019

Sinus tachycardia

Ivabradine

(IIa B)

Treatment of reversible causes

(I C)

Verapamil or

diltiazem (IIb C) Catheter

ablation (IIa C)

Ivabradine with a

beta-blocker

(IIa B)

Beta-blocker

(IIa C)

Yes No

Yes No

If ineffective

If ineffective If ineffective

If ineffective

Symptomatic and recurrent sinus

node re-entry

Drug therapy

desirable

Figure 6 Therapy of sinus tachycardias. Downloaded from academic.oup.com/eurheartj/article/41/5/655/5556821 by guest on 07 October 2026