Syncope associated with supraventricular tachycardia. An expression of tachycardia rate or vasomotor response?

2024 HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play

Youth and adult participation in sports continues to increase, and athletes may be diagnosed with potentially arrhythmogenic cardiac conditions. This international multidisciplinary document is intended to guide electrophysiologists, sports cardiologists, and associated health care team members in the diagnosis, treatment, and management of arrhythmic conditions in the athlete with the goal of facilitating return to sport and avoiding the harm caused by restriction. Expert, disease-specific risk assessment in the context of athlete symptoms and diagnoses is emphasized throughout the document. After appropriate risk assessment, management of arrhythmias geared toward return to play when possible is addressed. Other topics include shared decision-making and emergency action planning. The goal of this document is to provide evidence-based recommendations impacting all areas in the care of athletes with arrhythmic conditions. Areas in need of further study are also discussed.

Differential relationship between decreased muscle oxygenation and blood pressure recovery during supraventricular and ventricular tachycardia

Vasoconstriction during tachyarrhythmia contributes to maintenance of arterial pressure (AP) by decreasing peripheral blood flow. This cross-sectional observational study aimed to ascertain whether the relationship between peripheral blood flow and AP recovery occurs during both paroxysmal supraventricular (PSVT, n = 19) and ventricular tachycardias (VT, n = 17). Peripheral blood flow was evaluated using forearm tissue oxygen index (TOI), and mean AP (MAP) was measured using a catheter inserted in the brachial or femoral artery during an electrophysiological study. PSVT and VT rapidly decreased MAP with a comparable heart rate (P = 0.194). MAP recovered to the baseline level at 40 s from PSVT onset, but not VT. The forearm TOI decreased during both tachyarrhythmias (P ≤ 0.029). The TOI response was correlated with MAPrecovery (i.e., MAP recovery from the initial rapid decrease) at 20-60 s from PSVT onset (r = -- 0.652 to - 0.814, P ≤ 0.0298); however, this association was not observed during VT. These findings persisted even after excluding patients who had taken vasoactive drugs. Thus, restricting peripheral blood flow was associated with MAP recovery during PSVT, but not VT. This indicates that AP recovery depends on the type of tachyarrhythmia: different cardiac output and/or vasoconstriction ability during tachyarrhythmia.

Speech-induced Atrial Tachycardia with Presyncope

Speech-induced atrial tachycardia (AT) with presyncope is extremely rare. A 52-year-old woman employed at a supermarket reported recurrent presyncope while speaking out loud at her job. Holter electrocardiography revealed AT while swallowing without presyncope. The patient's blood pressure decreased during AT, and she experienced presyncope while saying "IRASSHAIMASE" loudly during a tilt table test. Accordingly, bisoprolol 1.25 mg was prescribed, and the patient did not experience episodes of presyncope with recurrence of AT for 2 years. This case suggests that provocation of arrhythmia in the tilting position may be useful for demonstrating a relationship between arrhythmia and presyncope and/or syncope.

Clinical applications of heart rhythm monitoring tools in symptomatic patients and for screening in high-risk groups

Recent technological advances have facilitated and diversified the options available for the diagnosis of cardiac arrhythmias. Ranging from simple resting or exercise electrocardiograms to more sophisticated and expensive smartphones and implantable cardiac monitors. These tests and devices may be used for varying periods of time depending on symptom frequency. The choice of the most appropriate heart rhythm test should be guided by clinical evaluation and optimized following accurate characterization of underlying symptoms, 'red flags', risk factors, and consideration of cost-effectiveness of the different tests. This review provides evidence-based guidance for assessing suspected arrhythmia in patients who present with symptoms or in the context of screening, such as atrial fibrillation or advanced conduction disturbances following transcatheter aortic valve implantation in high-risk groups. This is intended to help clinicians choose the most appropriate diagnostic tool to facilitate the management of patients with suspected arrhythmias.

International Validation of the Canadian Syncope Risk Score : A Cohort Study

BACKGROUND

The Canadian Syncope Risk Score (CSRS) was developed to predict 30-day serious outcomes not evident during emergency department (ED) evaluation.

OBJECTIVE

To externally validate the CSRS and compare it with another validated score, the Osservatorio Epidemiologico della Sincope nel Lazio (OESIL) score.

DESIGN

Prospective cohort study.

SETTING

Large, international, multicenter study recruiting patients in EDs in 8 countries on 3 continents.

PARTICIPANTS

Patients with syncope aged 40 years or older presenting to the ED within 12 hours of syncope.

MEASUREMENTS

Composite outcome of serious clinical plus procedural events (primary outcome) and the primary composite outcome excluding procedural interventions (secondary outcome).

RESULTS

Among 2283 patients with a mean age of 68 years, the primary composite outcome occurred in 7.2%, and the composite outcome excluding procedural interventions occurred in 3.1% at 30 days. Prognostic performance of the CSRS was good for both 30-day composite outcomes and better compared with the OESIL score (area under the receiver-operating characteristic curve [AUC], 0.85 [95% CI, 0.83 to 0.88] vs. 0.74 [CI, 0.71 to 0.78] and 0.80 [CI, 0.75 to 0.84] vs. 0.69 [CI, 0.64 to 0.75], respectively). Safety of triage, as measured by the frequency of the primary composite outcome in the low-risk group, was higher using the CSRS (19 of 1388 [0.6%]) versus the OESIL score (17 of 1104 [1.5%]). A simplified model including only the clinician classification of syncope (cardiac syncope, vasovagal syncope, or other) variable at ED discharge-a component of the CSRS-achieved similar discrimination as the CSRS (AUC, 0.83 [CI, 0.80 to 0.87] for the primary composite outcome).

LIMITATION

Unable to disentangle the influence of other CSRS components on clinician classification of syncope at ED discharge.

CONCLUSION

This international external validation of the CSRS showed good performance in identifying patients at low risk for serious outcomes outside of Canada and superior performance compared with the OESIL score. However, clinician classification of syncope at ED discharge seems to explain much of the performance of the CSRS in this study. The clinical utility of the CSRS remains uncertain.

PRIMARY FUNDING SOURCE

Swiss National Science Foundation & Swiss Heart Foundation.

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope

The baseline electrocardiogram (ECG) is less informative in neurally mediated syncope (NMS) than in arrhythmic syncope. However, some of the ECG patterns present in NMS can have diagnostic and prognostic value in such patients. Electrocardiographic documentation of a syncopal spell and thus identification of the ECG changes can be performed during tilt table test (TTT) or during prolonged ECG monitoring. This work reviews the specific ECG patterns in NMS, which are primarily related to the cardioinhibitory reflex. In addition, there are other ECG findings present in patients with NMS that are being analyzed, such as increased heart rate variability as well as specific QRS voltage patterns. In addition to the diagnostic and prognostic value, these ECG patterns in NMS may help improving the selection of patients for pacemaker implant.

Syncope associated with supraventricular tachycardia: Diagnostic role of implantable loop recorders

Syncope represents a relatively uncommon symptom of supraventricular tachycardia (SVT). It is likely that an impaired autonomic vasomotor response to the hemodynamic stress of tachycardia is the determinant of hemodynamic changes leading to cerebral hypoperfusion and syncope. In this regard, tilt‐table test may detect abnormalities in the autonomic nervous function and predict the occurrence of syncope during SVT. Electrophysiology studies may reproduce the SVT, distinguish it from other life‐threatening ventricular tachyarrhythmias, and exclude other causes of syncope. Not infrequently mixed syncope mechanisms are revealed during the above diagnostic workup raising doubts about the operating mechanism in the clinical setting. In such cases of uncertainty, an implantable loop recorder, providing long‐term cardiac monitoring, may play a pivotal role in the establishment of the diagnosis, confirming the association of an arrhythmic event with the symptom. Herein, we present four such cases with recurrent unexplained syncope finally attributed to paroxysmal SVT guiding them to a potentially radical treatment through radiofrequency catheter ablation.

Heart rhythm characterisation during unexplained transient loss of consciousness in dogs

The identification of the heart rhythm during an episode of transient loss of consciousness (TLOC) is considered the reference standard method to elucidate the underlying aetiology. This study aimed to characterise heart rhythm in dogs during TLOC using Holter and external loop recorder monitoring. We retrospectively reviewed 24-h Holter monitoring and external loop recorder tracings from 8084 dogs. Heart rhythms from dogs that experienced TLOC during the recording was analysed to identify rhythm disturbances that occurred during episodes of TLOC. Electrocardiograms (ECGs) were subsequently categorised into Type 1 (ventricular arrest), Type 2 (sinus bradycardia), Type 3 (no/slight rhythm variations), and Type 4 (tachycardia). Transient LOC was documented in 92 dogs over 230 episodes of TLOC. Percentage of cases with ECGs compatible with each classification were as follows: 72.1%, Type 1; 6.1%, Type 2; 20.9%, Type 3; and 0.9%, Type 4. Cardiac rhythm during the TLOC could have been a consequence of a neurocardiogenic mechanism in 46.7% cases, while intrinsic rhythm disturbances of the sinus node or of the atrioventricular node were diagnosed in 31.5% cases. In two cases, tachycardia was the possible cause of the TLOC. ECG patterns in dogs presenting with multiple TLOC episodes were completely reproducible during each episode. TLOC in dogs was primarily caused by ventricular arrest. Most dogs with TLOC had electrocardiographic finding suggestive of a reflex or neurally-mediated syncope, but one third had an ECG more suggestive of a conduction disorder. Distinguishing these two entities could help inform diagnostic, therapeutic, and prognostic plans.

Uncommon presentation of a common disorder: Syncope with AVNRT in setting of a structural anomaly

Syncope in setting of AV nodal re-entrant tachycardia should prompt the clinician to perform further workup for comorbid conditions, including structural cardiac abnormalities. In complex cases, ICE may be helpful in delineating the anatomy to facilitate safe ablations.

Syncope: Electrocardiographic and Clinical Correlation

Syncope is a frequent condition, owing to a transient global cerebral hypoperfusion, that may depend on a reduction of vascular total peripheral resistance and/or cardiac output. Cardiac syncope doubled the risk of death from any cause and increased the risk of nonfatal and fatal cardiovascular events. Arrhythmias are the most common cardiac causes of syncope. Both bradyarrhythmias and tachyarrhythmias may predispose to syncope. The first line evaluation relies on clinical history, physical examination, active standing test, 12-lead echocardiogram. The diagnostic yield of electrophysiological study in detecting the cause of syncope depends highly on the pretest probability.

Syncope due to Autonomic Dysfunction: Diagnosis and Management

Syncope is one of several disorders that cause transient loss of consciousness. Cerebral hypoperfusion is the proximate cause of syncope. Transient or fixed autonomic nervous system dysfunction is a major contributor in many causes. A structured approach to the evaluation of syncope allows for more effective therapy.

Clinical Predictors of Pacemaker Implantation in Patients with Syncope Receiving Implantable Loop Recorder with or without ECG Conduction Abnormalities

BACKGROUND

Implantable loop recorders (ILR) allow prolonged cardiac rhythm monitoring and improved diagnostic yield in syncope patients. Predictive factors for pacemaker (PM) implantation in the ILR population with unexplained syncope have not been adequately investigated. In this single center, retrospective, observational study we investigated factors that predict PM implantation in this population.

METHODS

We retrospectively analyzed our ILR database of patients aged over 18 years who underwent ILR implantation for unexplained syncope between January 2009 and June 2013. Patient case notes were examined for demographics, history, electrocardiogram (ECG) abnormalities, investigations, and events during follow-up. The primary end-point was the detection of a symptomatic or asymptomatic bradycardia requiring PM implantation.

RESULTS

During a period of 4.5 years, 200 patients were implanted with ILR for unexplained syncope, of who n = 33 (16.5%) had clinically significant bradycardia requiring PM implantation. After multivariable analysis, history of injury secondary to syncope was found to be the strongest independent predictor for PM implantation (odds ratio [OR]:9.1; P < 0.001; 95% confidence interval [CI]: (3.26-26.81). Other significant predictors included female sex, PR interval > 200msec, and age >75 years. In patients without conduction abnormalities on the ECG, history of injury secondary to syncope was found to be the strongest independent predictor for PM implantation (OR: 8.16; P = 0.00027; 95% [CI]: (2.67-26.27).

CONCLUSIONS

A history of injury secondary to syncope and female sex were independent predictive factors for bradycardia necessitating PM implantation in patients receiving an ILR for syncope with or without ECG conduction abnormalities.

Evaluation of the effect of radiofrequency catheter ablation on autonomic function in patients with atrioventricular nodal reentrant tachycardia by head-up tilt table test

Background:

One of the recommended treatments for atrioventricular nodal reentrant tachycardia (AVNRT), is radiofrequency catheter ablation (RFCA). However, RFCA may affect the autonomic system. This study aims to evaluate the effect of RFCA on autonomic system in patients with PSVT by head-up tilt table (HUTT) test.

Materials and Methods:

In a before–after study, 22 patients with PSVT were enrolled. Data were collected with a data collection form that included two parts. Electrocardiogram (ECG), echocardiogram, 24-h Holter monitoring, HUTT test, heart rate variability (HRV) indexes, and symptoms of all patients were recorded 24 h before and 1 month after the ablation. Wilcoxon, McNemar, Mann–Whitney U, and Chi-square tests were used to analyze the data.

Results:

Of the total 22 patients, 31.8% were male and 68.2% were female. There were significant differences in heart palpitation (P < 0.0001) and non-specific symptoms (P = 0.031) and no significant difference in head-up tilt test results and HRV indices before and after RFCA. The results showed that there were no significant differences in specific and non-specific symptoms in patients with AVNRT with positive and negative HUTT before and after RFCA.

Conclusions:

The observed difference in heart palpitation and non-specific symptoms emphasized the role of AVNRT in causing these symptoms. Autonomic dysfunction is more probably an accompanying condition of AVNRT than causing symptoms. We could not find any significance in the results of HUTT after RFCA. HUTT cannot determine or predict the symptoms after RFCA.

"Vasovagal" response during ventricular fibrillation: incidence and implications

BACKGROUND

The purpose of this study was to assess the relationship between changes in sinus node cycle length (SNCL) during ventricular fibrillation (VF) and the peripheral changes in blood pressure (BP) and sympathetic nerve activity (SNA) in human subjects. We hypothesized that patients with no SNCL shortening during VF have a vasovagal-like response with a greater decrease in BP and SNA when compared to patients with SNCL shortening.

METHODS

SNCL, BP, and SNA recordings were attempted in 24 patients undergoing the implantation of a dual-chamber implantable defibrillator. Changes were measured during the first 5 seconds of VF and compared with the 5 seconds prior to VF induction.

RESULTS

SNCL shortened during VF in nine patients (mean%∆SNCL = -12 ± 8%) and remained unchanged or lengthened in seven patients (mean%∆SNCL = 7 ± 7%). Eight patients had ventriculoatrial (VA) conduction prohibiting assessment of SNCL changes. In patients with SNCL shortening, the %∆MBP (mean BP) was -47 ± 6% compared to -58 ± 8% in patients with no SNCL shortening (P < 0.01). In patients with VA conduction, the %∆MBP was -54 ± 3%. SNA recordings were successfully obtained in four patients. When compared to baseline, SNA increased by 34 ± 30% in two patients with SNCL shortening, decreased by 25% in one patient with SNCL lengthening, and by 90% in the fourth patient with VA conduction.

CONCLUSIONS

We have shown that patients with no SNCL shortening have a significantly greater decrease in MBP during VF when compared to patients with SNCL shortening. The underlying mechanism appears to be reflex mediated with a vasovagal-like response in patients with no SNCL shortening.

Syncope: diagnosis and management

Syncope is defined as transient loss of consciousness due to global cerebral hypoperfusion. It is characterized by having a relatively rapid onset, brief duration with spontaneous and full recovery. The major challenge in the evaluation of patients with syncope is that most patients are asymptomatic at the time of their presentation. A thorough history and physical examination including orthostatic assessment are crucial for making the diagnosis. After initial evaluation, short-term risk assessment should be performed to determine the need for admission. If the short-term risk is high, inpatient evaluation is needed. If the short-term risk is low, outpatient evaluation is recommended. In patients with suspected cardiac syncope, monitoring is indicated until a diagnosis is made. In patients with suspected reflex syncope or orthostatic hypotension, outpatient evaluation with tilt-table testing is appropriate. Syncope units have been shown to improve the rate of diagnosis while reducing cost and thus are highly recommended.

[Cardiac syncope : diagnosis and therapy]

The second most frequent category of syncope is cardiac syncope. In contrast to syncope of noncardiac causes, the 1-year mortality of patients presenting with cardiac syncope without treatment is as high as 33%. Therefore, immediate diagnosis and treatment are necessary. Bradyarrhythmias or tachyarrhythmias are the most common causes of cardiac syncope. In many cases, an initial evaluation including history, physical examination, and electrocardiogram identifies the cause of syncope, so that specific treatment can be initiated immediately. In the remainder of cases, implantable loop recorders are useful to identify arrhythmias, while the presence or absence of structural cardiac disease is diagnosed by echocardiography. Syncope due to arrhythmias is typically treated with implantation of a pacemaker or an implantable cardioverter-defibrillator; treatment of syncope of other cardiac causes requires therapy of the underlying heart disease.

Effect of blood pressure on vascular hemodynamics in acute tachycardia

Paroxysmal supraventricular tachycardia is accompanied by hypotension, which can affect vascular hemodynamics. Here, we hypothesized that a fall in blood flow as a result of hypotension has a larger effect on hemodynamics in medium-sized peripheral arteries compared with increased pulsatility in rapid pacing. To test this hypothesis, we experimentally and theoretically investigated hemodynamic changes in femoral, carotid, and subclavian arteries at heart rates of 95-170 beats/min after acute pacing. The arterial pressure, blood flow, and other hemodynamic parameters remained statistically unchanged for heart rates ≤ 135 beats/min. Systemic pressure and flow velocities, however, showed an abrupt decrease, resulting in larger alteration of hemodynamic parameters for heart rates ≥ 155 beats/min after pacing (initial period) and then recovered close to baseline after several minutes of pacing (recovery period). During the initial period, the pressure dropped from 88 mmHg (baseline) to 44 mmHg, and the flow velocity decreased to about one-third of baseline at heart rate of 170 beats/min. A hemodynamic analysis showed a velocity profile with a near-wall retrograde flow or a fully reversed flow during the initial period, which vanished at the recovery period. It was concluded that the initial fall of blood flow due to pressure drop led to transient flow reversal and negative wall shear stress because this phenomena was not observed at the recovery period. This study underscores the significant effects of hypotension on vascular hemodynamics, which may have relevance to physiology and chronic pathophysiology in paroxysmal supraventricular tachycardia.

[Comparison of patients with paroxysmal junctional tachycardia and syncope with those without syncope]

INTRODUCTION

The purpose of the study was to determine the possible mechanisms of presyncope in patients who have paroxysmal junctional tachycardias (PJT) and a normal surface ECG between tachycardias.

METHODS

Among 419 patients consecutively recruited for PJT, aged from 10 to 88 years (47+/-19), 78 of them had presented at least one syncope; they had a normal ECG in sinus rhythm. Transesophageal programmed atrial stimulation was performed using one and two atrial extrastimuli delivered in control state and if necessary after infusion of 20-30 microg of isoproterenol; arterial blood pressure was monitored; vagal maneuvers and tilt test (n=25) were performed; echocardiogram was systematic.

RESULTS

Age, sex, method of induction, tachycardia mechanism and the mean heart rate in tachycardia were similar in patients with and without syncope. Syncope was related to a vagal reaction induced by the PJT in 31 patients, to a fast rate during PJT in 15 patients, to a sinus node dysfunction in six patients, to a coronary ischemia in five patients, to a tetany induced by PJT in three patients, to an advanced age in three patients, to multiple causes in three patients and remained unexplained in eight patients. Radiofrequency ablation of reentrant circuit, performed in 28 patients, suppressed syncope in 26 of them.

CONCLUSION

Presyncope or syncope occurred in 18% of patients who had a history of paroxysmal junctional tachycardia. Several mechanisms were implicated; the most frequent causes were coronary ischemia or sick sinus syndrome in old patients, vasovagal reaction or fast rate in tachycardia or tetany in patients of all ages.

Supraventricular tachycardia and the struggle to be believed

BACKGROUND

Little research exists examining patient experiences of life with supraventricular tachycardia (SVT). Realistic expectations of symptoms, patient management strategies, and treatment options are important components of patient education and treatment decisions.

AIM

This descriptive qualitative study explored patients' experiences living with SVT.

METHODS

Grounded theory methodology was used with semi-structured interviews of 25 SVT patients undergoing radiofrequency ablation treatment.

RESULTS

The main core category that emerged from the data was the "struggle to be believed". The struggle or work of living with SVT entails: (1) living with the uncertainty of the occurrence and duration of an episode, (2) "covering up" to manage symptoms and appear normal, (3) searching for causative factors to prevent further episodes, and (4) experimenting with management techniques to shorten or end episodes.

CONCLUSION

Clinical diagnosis and referral for ablation treatment were more difficult for women suggesting existence of a gender bias. As with many other chronic conditions, the illness trajectory work is formidable. Patients in this study with SVT, however, reported facing the additional difficulty of being believed. Disruptions in self-esteem and personal relationships are the effects of not being believed. Providers could avoid minimizing women's symptoms by listening seriously and offering realistic expectations; including insight into patient experiences and the trajectory of the dysrhythmia; and efficacy of drug and ablation treatments.

Unusual case of orthostatic tachycardia

Bevezetés: Az orthostasis intolerancia, az orthostaticus tachycardia gyakran jelez hypovolemiát, gyógyszermellékhatást vagy autonóm elégtelenséget. Az orthostasisszal provokálható tachyarrhythmia ritka jelenség, emelt fejvégű billenőasztal vizsgálatsorozatokban csak elvétve fordul elő. Célkitűzés: A szerzők egy olyan beteget mutatnak be, akinek AV-csomó reentry tachycardiás paroxysmusait függőleges testhelyzet provokálta. Módszer: Vagusmanőverekkel az anterográd lassú pálya vezetésének blokkolása révén sikeresen szüntették a tachycardiát. Eredmények: Figyelemre méltó, hogy a vagusmanőverek csak vízszintes testhelyzetben bizonyultak hatásosnak. Következtetés: Ez a megfigyelés felhívja a figyelmet a manőverek pontos kivitelezésének fontosságára.

The Wolff–Parkinson–White electrocardiogram pattern in athletes: how and when to evaluate the risk for dangerous arrhythmias. The opinion of the paediatric cardiologist

Although diagnostic assessment and treatment have been described in detail in patients with symptomatic Wolff-Parkinson-White (WPW) syndrome, the management of asymptomatic subjects remains controversial. Usually they are assumed to have a benign prognosis, although they do very occasionally present with ventricular fibrillation (VF) as the first manifestation of the syndrome. Discovering a WPW pattern in a previously asymptomatic athlete on a routine electrocardiogram (ECG) identifies the necessity for more accurate screening tests. However, non-invasive methods (Holter monitoring, exercise treadmill testing) seem to be relatively incomplete for risk stratification, especially for athletes. Current guidelines do not always recommend a routine electrophysiological study (EPS) in patients with an asymptomatic WPW ECG pattern, especially in children younger than 12 years. Individuals who engage in high-risk occupations or those patients who have a pre-excitation pattern which precludes them from following their chosen career or activities may be exceptions. The presence of inducible reciprocating tachycardia during EPS, especially when it triggers atrial fibrillation with short RR interval, can represent a specific risk marker of dangerous arrhythmias.

Acute Blood Pressure Changes After the Onset of Atrioventricular Nodal Reentrant Tachycardia: A Time-Course Analysis

INTRODUCTION

We aimed to characterize blood pressure (BP) response at the beginning of atrioventricular nodal reentrant tachycardia (AVNRT) and its relationship to orthostatic challenge and variable atrioventricular interval.

METHODS AND RESULTS

In this prospective study of 17 consecutive patients with documented AVNRT, mean BP was analyzed in the supine and upright positions during sinus rhythm, AVNRT, and pacing with atrioventricular delay of 150 msec (AV150) and 0 msec (AV0). Mean BPs were compared at 3-5 seconds, 8-10 seconds, and 28-30 seconds after the onset of AVNRT or pacing. BP decreased immediately after AVNRT initiation, with gradual recovery during the first 30 seconds from 71.9 +/- 16.5 mmHg to 86 +/- 13.8 mmHg, P < 0.01. A similar pattern was observed during AV0, but not during AV150, pacing. While supine, mean BP decrease was more pronounced during AVNRT and AV0 pacing (-26.1% and -32.1%, respectively) than during AV150 pacing (-8%, P = 0.02 and P = 0.07, respectively). This difference subsided 30 seconds after the onset of AVNRT or pacing. When upright, the mean BP time course was similar, but mean BP recovery during AVNRT was slower, and the difference between mean BP during AVNRT and AV150 persisted at 30 seconds.

CONCLUSIONS

The initial mean BP decrease during AVNRT recovered gradually within 30 seconds. A short atrioventricular interval is associated with a greater mean BP decrease at the onset of tachycardia. These observations may explain clinical symptoms immediately after the onset of AVNRT.

Palpitations: A proper evaluation and approach to effective medical therapy

Palpitations are a common complaint seen in the outpatient setting and the vast majority are benign, although they are occasionally a manifestation of potentially life-threatening conditions. We offer a step-wise guide to the evaluation and management of these patients with the primary goal to identify patients at highest risk for serious arrhythmias. We offer a brief overview of effective management of the varied causes of palpitations.