The effects of acute blood loss on blood pressure recovery from the Valsalva maneuver.

Human baroreflex regulation plays an important role in stabilising blood pressure. Though we have several indices to quantify cardiovagal responses, sympathetic baroreflex gain remains difficult to assess. We investigated how the recently validated pressure recovery time (PRT) and sympathetic baroreflex gain (SBRS) derived from the Valsalva maneuver was influenced by acute blood loss.

Bi-atrial and right atrial activation times help to differentiate focal from macroreentrant right atrial tachycardias.

Objective: The objective was to study atrial activation intervals and their relation to the tachycardia cycle length (TCL) as electrophysiologic parameters differentiating focal (FAT) from macroreentrant atrial tachycardias (MRAT) originating in the right atrium.

Methods: In 21 patients (8 men) with 30 successfully ablated right atrial tachycardias (15 focal) the endocardial activity during tachycardia was registered using multipolar catheters in the right atrium and the coronary sinus. Using this catheter configuration we measured the tachycardia cycle length (TCL), biatrial activation (BAA), right atrial activation (RAA), left atrial activation (LAA), as well as the proportion of those intervals to TCL.

Ice mapping during tachycardia in close proximity to the AV node is safe and offers advantages for transcatheter ablation procedures.

Background: Ablation during ongoing orthodromic reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT) is not recommended using radiofrequency energy when the arrhythmia substrate is located in close proximity to the atrioventricular (AV) node due to a significant risk for inadvertent AV block. The aim of the study is to test the feasibility of ice mapping during tachycardias involving arrhythmia substrate located in close proximity to the AV node.

Methods: This was a single-centre, prospective, randomized study.

[Treatment of arrhythmias associated with congenital heart disease using transcatheter ablation].

Unlabelled: Rhythm disturbances are common long after surgical repair of congenital heart disease. These arrhythmias caused by the progression of the disease itself, however, a significant proportion is a result of the presence of surgical scar. Although interventional electrophysiology procedures are complex and encounter difficulties, pharmacological therapy is often very disappointing.

Mid-term echocardiographic follow up of left ventricular function with permanent right ventricular pacing in pediatric patients with and without structural heart disease.

Background: Chronic right ventricular apical pacing may have detrimental effect on left ventricular function and may promote to heart failure in adult patients with left ventricular dysfunction.

Methods: A group of 99 pediatric patients with previously implanted pacemaker was studied retrospectively. Forty-three patients (21 males) had isolated congenital complete or advanced atrioventricular block.

Evolution of left ventricular function in paediatric patients with permanent right ventricular pacing for isolated congenital heart block: a medium term follow-up.

Aims: We aimed to assess the evolution of left ventricular (LV) systolic function in children with right ventricular apical (RVA) pacing for isolated congenital heart block (ICHB) and to identify possible predictors of LV function deterioration. Right ventricular apical pacing can be detrimental to LV function in a significant number of adults. Effects in children are still controversial.

[Valsalva maneuver, Müller maneuver: hemodynamic and reflex mechanisms, relevance].

The time honored ancient reflex tests, the Valsalva and Müller maneuvers are still popular in the everyday clinical practice. These maneuvers are capable of imitating both trivial situations and significant pathological conditions. The Valsalva maneuver is still frequently used for the assessment of autonomic neuropathy.

Unusual Wenckebach phenomenon due to an atrial tachycardia arising from the apex of Koch's triangle in the presence of dual AV nodal physiology.

A case of a patient with narrow QRS tachycardia and without structural heart disease is presented. The electrophysiologic study revealed an atrial tachycardia in the presence of dual atrioventricular (AV) nodal physiology and AV block at suprahisian level, the latter two leading to an unusual Wenckebach periodicity. The entire septal area was mapped as was the coronary sinus (CS) os and the earliest atrial activation was found at the apex of Koch's triangle in close vicinity to the His bundle (HB).

A simple algorithm for defining the mechanism and the chamber of origin in atrial tachycardias.

Introduction: Although macroreentrant atrial tachycardia (MRAT) and focal atrial tachycardia (FAT) can be successfully cured by catheter ablation, the proper diagnosis and treatment of these arrhythmias can still be challenging.

Aim: The objective of this study is to develop an algorithm allowing rapid diagnosis of the mechanism and the chamber of origin of atrial tachycardia based on intracardiac catheter recordings from the right atrium and the coronary sinus (CS).

Methods: A 2-stepped algorithm was designed: (1) The time of biatrial activation expressed as a percentage of the tachycardia cycle length served to discriminate FAT from MRAT.

Right diaphragmatic paralysis following endocardial cryothermal ablation of inappropriate sinus tachycardia.

Inappropriate sinus tachycardia (IST) is a rare disorder amenable to catheter ablation when refractory to medical therapy. Radiofrequency (RF) catheter modification/ablation of the sinus node (SN) is the usual approach, although it can be complicated by right phrenic nerve paralysis. We describe a patient with IST, who had symptomatic recurrences despite previous acutely successful RF SN modifications, including the use of electroanatomical mapping/navigation system.

[Intracardiac echocardiography in clinical cardiac electrophysiology: review and first Hungarian experience].

During the last two decades revolutionary diagnostic and therapeutic changes were implemented in the management of patients with arrhythmias. Since the arrhythmia substrate is frequently associated with certain anatomical structures or morphological variants, improved imaging has increasing role in the improvement of these treatments. Furthermore, novel catheter ablation approaches require catheter placement to sites, which may be associated with increased complication risk.

Preventing complicated transseptal puncture with intracardiac echocardiography: case report.

Background: Recently, intracardiac echocardiography emerged as a useful tool in the electrophysiology laboratories for guiding transseptal left heart catheterizations, for avoiding thromboembolic and mechanical complications and assessing the ablation lesions characteristics. Although the value of ICE is well known, it is not a universal tool for achieving uncomplicated access to the left atrium. We present a case in which ICE led to interruption of a transseptal procedure because several risk factors for mechanical complications were revealed.

Human autonomic responses to blood donation.

In order to characterize autonomic responses to acute volume loss, supine ECG, blood pressure (BP) and uncalibrated breathing signal (UBS) recordings were taken before and after blood donation in 48 healthy volunteers. Time and frequency domain parameters of RR interval (RRI), BP and UBS variability were determined. Baroreflex gain was calculated by the technique of the spontaneous sequences and cross-spectral analysis.

Cardiovascular autonomic dysfunction in primary Sjögren's syndrome.

Objective: To assess the occurrence and clinical significance of a cardiovascular autonomic nervous system dysfunction in primary Sjögren's syndrome (pSS).

Methods: Fifty-one pSS patients participated in this case-control study. Heart rate and blood pressure variability measurements, spontaneous baroreflex sensitivity examinations and cardiovascular reflex tests were performed.

Oesophageal acid stimulation in humans: does it alter baroreflex function?

The aim of this study was to investigate if oesophagel acid stimulation (Bernstein test) had an influence on heart rate and blood prsure variability and baroreflex gain. We compared the cardiovascular responses in 10 patients with established gastro-esophageal reflux disease (Group 1) and 10 control subjects (Group 2) during esophageal saline and 0.1 mol/l hydrochloric acid instillation.

Measures of cardiovascular autonomic regulation derived from spontaneous methods and the Valsalva maneuver.

The response of heart rate to a given change of systolic blood pressure is a fundamental characteristic of the cardiovascular system. The assessment of baroreflex gain (BRS) as an index of baroreflex function is based on the quantification of RR interval changes related to blood pressure changes. The spontaneous sequence and cross spectral methods describe baroreflex gain derived from spontaneous fluctuations of these parameters, yielding the up sequence and down sequence BRS and the alfa index.