'Inappropriate' sinus tachycardia: does the 100 beats per min cut-off matter?

The Effect of Antipsychotics and Their Combinations with Other Psychotropic Drugs on Electrocardiogram Intervals Other Than QTc among Jordanian Adult Outpatients

The ECG changes produced by antipsychotics and other psychotropic medications are studied mostly regarding QTc interval prolongation. This study aimed to investigate ECG changes beyond long QTc interval produced by psychotropic medications. A cross-sectional study was conducted to assess the effect of these agents on RR, PR, TpTe intervals and TpTe/QT ratio among Jordanian outpatients. The RR interval was significantly shorter among patients on TCAs versus those not receiving TCAs and among patients on polytherapy versus those on monotherapy (p < 0.05 for both comparisons), when adjusted for age, gender, BMI, caffeine intake, smoking, presence of diabetes mellitus, cardiovascular disease and medications known to produce heart rate changes. Positive correlations were found between the PR interval and age in patients treated with SGAs, SSRIs, citalopram, polytherapy and in the total sample (p < 0.01 for all). Inverse correlations were found between the RR interval and the number of psychotropic medications among patients treated with SSRIs and in the whole study sample (p < 0.01 for both). In conclusion, various ECG changes beyond QTc interval prolongation are observed in patients on antipsychotics and other psychotropic medications, in those on polytherapy. It is recommended to obtain an ECG before starting patients on psychotropic drugs known to produce electrocardiographic changes and their combinations.

Inappropriate Sinus Tachycardia: Etiology, Pathophysiology, and Management: JACC Review Topic of the Week

Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Although the most common symptom is palpitations, it can be accompanied by a myriad of symptoms, including anxiety, dizziness, presyncope, and syncope. The pathogenesis of IST is not well understood and considered multifactorial, with autonomic dysfunction being the central abnormality. IST is a diagnosis of exclusion. Management presents a clinical challenge. The overall efficacy of lifestyle modifications and medical therapy may be limited. Recent advances in catheter and surgical sinus node sparing ablation techniques have led to improvement in outcomes. In addition, increased focus has led to development of multimodality team-based interventions to improve outcomes in this group of patients. In this review, we discuss the mechanistic basis of IST, review current approaches to diagnosis, and outline contemporary therapeutic approaches.

Electrocardiogram Alterations Associated With Psychotropic Drug Use and CACNA1C Gene Variants in Three Independent Samples

Several antipsychotics and antidepressants have been associated with QTc prolongation or other electrocardiogram (ECG) alterations, but their impact is still debated and other risk factors are known to affect QTc. We investigated the effect of antidepressants and antipsychotics on QTc and other ECG intervals/waves in three samples. Two discovery samples (cross-sectional sample n = 145 and prospective sample n = 68, naturalistic treatment) and a replication prospective sample (Clinical Antipsychotic Trials of Intervention Effectiveness, n = 515, randomized treatment) were analysed. In both prospective samples, baseline/follow-up changes in ECG parameters were analysed in relation to the number of psychotropic drugs stratified according to their known cardiovascular risk. In the cross-sectional sample, ECG parameters were compared among drugs with different risk profile. The possible effect of single nucleotide polymorphisms (SNPs) in the CACNA1C gene on QTc was also investigated. There was no evidence of mean QTc prolongation or increased risk of clinically relevant QTc prolongation (≥20 msec.) in association with psychotropic drugs stratified according to their known cardiovascular risk. The prescription of drugs with cardiovascular risk was less common in older individuals or individuals with cardiovascular comorbidities. Other factors (gender, baseline QTc, renal function) affected QTc. rs1006737 and SNPs in linkage disequilibrium with it modulated QTc duration/changes in all samples. An association between risk drugs and shorter RR interval or higher heart rate was found in all samples. A relevant effect of psychotropic drugs with cardiovascular risk on QTc duration was not observed. A number of factors other than psychotropic drugs may influence QTc. CACNA1C rs1006737 may modulate QTc in patients treated with psychotropic drugs.

Treatment for Inappropriate Sinus Tachycardia

Inappropriate Sinus Tachycardia (IST) is a chronic medical condition with a wide variety of clinical presentations making it, sometimes, very insidious at the time of the diagnosis. Several therapeutic options, including, pharmacotherapy, cardiac rehabilitation, and modification or ablation of the sinus node, have been proposed for the management of IST, but because of the complexity and lack of understanding of pathophysiology, it can be difficult to manage, despite the numerous treatment options currently available. The purpose of this review is to analyze the treatment for IST, focusing on the role of newer therapy and the potential benefits in the management of this cardiac rhythm disturbance.

Management of tachycardia

Tachycardia, conventionally, but arbitrarily, defined as an atrial and/or ventricular rate of >100 beats per minute, is encountered commonly and can be physiological or pathological in origin. Various adverse consequences from tachycardia have been recognized, and an important one is the association between persistent tachycardia and cardiomyopathy. In this article, we provide an up-to-date review on the etiology of tachycardia, management strategies, and the prognosis of patients presenting with tachycardia and cardiomyopathy.