Electrophysiological features in patients with sinus node dysfunction and vasovagal syncope.

Introduction: Syncope is a common presentation of sinus node dysfunction (SND). Some patients who receive a permanent pacemaker due to SND do not benefit from it and further diagnostic workup leads to the diagnosis of vasovagal syncope (VVS). The aim of the study was to identify electrophysiological criteria that can be used for identification of patients with SND and concurrent VVS.

Survival analysis in patients with preserved left ventricular function and standard indications for permanent cardiac pacing randomized to right ventricular apical or septal outflow tract pacing.

Background: Optimal right ventricular (RV) pacing site in patients referred for permanent cardiac pacing remains controversial. A prospective randomized trial was done to compare long-term effect of permanent RV apex (RVA) vs RV outflow tract (RVOT) pacing on the all-cause and cardiovascular mortality.

Methods And Results: A total of 122 consecutive patients (70 men, 69 +/-11 years), with standard pacing indications were randomized to RVA (66 patients) or RVOT (56 patients) ventricular lead placement.

Right ventricular apex versus right ventricular outflow tract pacing: prospective, randomised, long-term clinical and echocardiographic evaluation.

Introduction: In patients treated with permanent pacing, the electrode is typically placed in the right ventricular apex (RVA). Published data indicate that such electrode placement leads to an unfavourable ventricular depolarization pattern, while right ventricular outflow tract (RVOT) pacing seems to be more physiological.

Aim: To compare long-term effects of RVOT versus RVA pacing on clinical status, left ventricular (LV) function, and the degree of atrioventricular valve regurgitation.

Biventricular pacing demonstrates similar effects in elderly and younger patients with advanced heart failure in the mid-term follow-up.

Background: Biventricular (BIV) pacing has been shown to improve haemodynamics and functional status of patients (pts) with advanced chronic heart failure (CHF). No study has determined the effects of BIV in relation to the age of pts.

Aim: To compare the clinical outcome in two groups of pts: > or =65 years (yrs) and <65 yrs referred for BIV pacing in our centre with at least 6 months of follow-up.

Comparison of defibrillation efficacy using implantable cardioverter-defibrillator with single- or dual-coil defibrillation leads and active can.

Introduction: The reduction of defibrillation threshold (DFT) in patients treated with an implantable cardioverter-defibrillator increases patients' safety and prolongs ICD battery life.

Aim: To evaluate the possibility of reducing the defibrillation threshold in ICDs with an active can and an additional atrial defibrillation coil instead of the typical intracardiac single-coil lead.

Method: This study involved 138 patients (36 F and 102 M, mean age 54+/-15 years) including 62 subjects with dual-coil defibrillation lead (group A) and 76 ones with single-coil defibrillation lead (group B).

Clinical predictors of defibrillation threshold in patients with implantable cardioverter-defibrillators.

Background: Safety of patients with malignant ventricular arrhythmias, treated with implantable cardioverter defibrillators (ICD), depends on the possibility of immediate and effective intracardiac defibrillation. It is especially important in those patients in whom there is a risk of increased defibrillation threshold (DFT) of ventricular fibrillation (VF). Thus, it is important to know whether some clinical parameters may predict a high DFT.

[Electrical remodeling in a patient with biventricular pacemaker].

Electrical remodelling in a patient with biventricular pacemaker - a case report. A case of a 70-year-old patient with dilated cardiomyopathy is presented. The patient underwent biventricular pacemaker implantation and improved markedly.

[Attempt to assess the risk of recurrence of life-threatening ventricular arrhythmia using simple non-invasive tests].

Unlabelled: Baroreflex sensitivity (BRS), as assessed using phenylephrine method, and depressed 24-hour heart rate variability (HRV) have been shown to be powerful predictors of life-threatening ventricular arrhythmias. However, before these tests are widely used, their methodology has to be simplified. The aim of this study was to assess the prognostic value of simple non-invasive BRS parameter (Robbe index, BRS-RI) and short-term HRV, together with left ventricular ejection fraction (LVEF) and late potentials (LP) assessment in patients after myocardial infarction (MI) with documented history of ventricular tachycardia (VT) and ventricular fibrillation (VF).

Different predictive values of electrophysiological testing and autonomic assessment in patients surviving a sustained arrhythmic episode.

Background: Recent data suggest that the electrophysiological study (EPS) has limited value in the identification of high risk patients, so the aim of the present study was to evaluate if non-invasive measurement of baroreflex sensitivity (BRS), a marker of autonomic balance, provides additional prognostic information in patients surviving a sustained arrhythmic episode.

Methods And Results: The study group comprised 112 post myocardial infarction patients consecutively referred for EPS following documented ventricular fibrillation (VF) (20), sustained ventricular tachycardia (VT) (74) or a syncopal episode with subsequently documented non-sustained VT at Holter monitoring (18). BRS was assessed according to the transfer function method.

[Remodeling of coronary arteries examined by arteries intravascular ultrasonography].

Unlabelled: In most papers atherosclerotic remodelling was assessed in one segment of each studied artery. Such mode of study makes impossible to investigate the homogeneity of the remodelling. The aim of the study was intravital assessment by means of intravascular ultrasonography (IVUS) of the incidence of positive and negative remodelling in coronary artery segments and verification of the hypothesis that remodelling is inhomogeneous within the same artery.

Left ventricle systolic volume in vasovagal syncope patients.

One of the hypotheses put forward concerning the mechanism of vasovagal syncope is that the vagal afferent fibres are activated during vigorous contractions against a partly empty left ventricle. The aim of the study was to confirm this hypothesis by using 2D echocardiography during a head-up tilt test. The study was carried out on 39 patients (17 male, 22 female, age range 21-64 years), all with a history of recurrent syncope.

Hemodynamic effects of alternative atrial pacing sites in patients with paroxysmal atrial fibrillation.

Recently, multisite atrial pacing has been suggested as an alternative therapy to prevent recurrences of paroxysmal atrial fibrillation (PAF). A study was conducted to compare the acute effects of biatrial (BiA), left atrial (LA), and right atrial appendage (RAA) pacing on cardiac hemodynamics. In 14 patients with PAF and a BiA pacemaker (with leads in the RAA and coronary sinus), cardiac output (CO), right (RV) and left ventricular (LV) filling, RA-LA contraction delay [PA(m-t)] and the difference in A wave duration [Adif(m-p)] at the level of the mitral valve (Adurm) and pulmonary veins (Adurp) during RAA, BiA, and LA pacing were examined by echo-Doppler measurements.

Permanent cardiac pacing and its influence on tricuspid valve function.

Implantation of transvenous devices is a widespread procedure in clinical cardiology. It is well known that the presence of the electrodes in the cardiovascular system can induce fibrosis or fibrous adhesions between them and cause tricuspid regurgitation. Moreover there are suggestions that the placement of the electrode in the tricuspid orifice may also play a role in the development of tricuspid insufficiency because of the thickening of reactive leaflets and the impairment of their mobility in morphological studies.

Shortening the second phase duration of biphasic shocks: effects of class III antiarrhythmic drugs on defibrillation efficacy in humans.

Introduction: The specific waveform providing optimal defibrillation threshold (DFT) is unknown. We compared the defibrillation efficacy of biphasic pulses with second phases (P2) of 2 and 5 msec in a randomized prospective clinical study.

Methods And Results: Intraoperative DFTs of 62 patients (age 54 +/- 13 years; ejection fraction 43% +/- 17%; amiodarone 47%, d,l-sotalol 13%) were determined in random order using a binary search protocol.

Efficacy and safety of dofetilide in the prevention of symptomatic episodes of paroxysmal supraventricular tachycardia: a 6-month double-blind comparison with propafenone and placebo.

Background: Existing drug therapies for paroxysmal supraventricular tachycardia (PSVT) have potentially serious adverse effects. Dofetilide, a pure class III antiarrhythmic agent, may offer an effective and safe alternative for treating PSVT. This study compared the efficacy and safety of dofetilide with that of propafenone and placebo in the prevention of PSVT.

Implantation and follow-up of ICD leads implanted in the right ventricular outflow tract.

Unipolar ICD electrodes are routinely implanted at the right ventricular apex (RVA). However, inappropriate pacing/sensing parameters and/or high DFT may limit the appropriateness of the lead's implantation at the RVA. This study examined the effects on DFT of ICD leads implanted in the RVOT, attached to the high interventricular septum as an alternate location.

The terminal portion of the T wave: a new electrocardiographic marker of risk of ventricular arrhythmias.

Experimental studies have shown that transmural dispersion of repolarization (DoR), defined as the difference in action potential duration between mid-myocardial M-cells, epicardial, and endocardial cells is reflected in the duration of the terminal portion of the T wave (TpTe) on the surface ECG. Since DoR is an important factor associated with the propensity for reentrant arrhythmias, this study examined if TpTe may serve as a marker of risk of ventricular arrhythmias. Data from 18 patients with coronary artery disease and inducible sustained ventricular tachycardia (VT group) were compared with those of 16 survivors of myocardial infarction without inducible VT (control group).

Assessment of baroreflex sensitivity in patients with preserved and impaired left ventricular function by means of the Valsalva manoeuvre and the phenylephrine test.

The purpose of the present study was to assess the agreement between measurements of baroreflex sensitivity (BRS) obtained by the Valsalva manoeuvre and by the phenylephrine test in patients with previous myocardial infarction and different degrees of left ventricular dysfunction. Patients with a previous myocardial infarction were enrolled consecutively into two groups according to their left ventricular ejection fraction (LVEF): 40% (n=52). All patients underwent BRS assessment by the phenylephrine technique (Phe-BRS) and by the Valsalva manoeuvre, with the latter using both the overshoot part of phase IV (Ov-VM-BRS) and the whole of phase IV (IV-VM-BRS).

The localisation of the electrode in permanently paced heart--an echocardiographical study.

Unlabelled: Permanent cardiac pacing is a widely applied procedure in invasive cardiology. The aim of our study was the analysis of the localisation of the tip of the pacemaker lead and its course in the right ventricle. Research was carried out on a group of 12 patients (5F, 7M), from 40 to 93 years of age (average 70 +/- 15 yrs) with permanent cardiac pacing or implantable cardioverter-defibrillator (ICD).

[Recurrent ventricular fibrillation in a patient with Prinzmetal angina pectoris--case report].

The description of the case of 35 years old patient with paroxysmal ventricular fibrillation in a course of Prinzmetal angina pectoris treated unsuccessfully with antiarrhythmic drugs who required implantation of cardioverter/defibrillator. The via-venous cardioverter/defibrillator was implanted (ICD). During 6 months observation ventricular tachycardia and ventricular fibrillation occurred four times and was effectively interrupted by the cardioverter/defibrillator.

Multicenter randomized trial and a systematic overview of lidocaine in acute myocardial infarction.

Background: More than 20 randomized trials and 4 meta-analyses have been conducted on the use of prophylactic lidocaine in acute myocardial infarction (MI). The results suggest that lidocaine reduces ventricular fibrillation (VF) but increases mortality rates in acute MI.

Methods And Results: Patients with ST-elevation MI who were examined <6 hours after symptom onset (n = 903) were randomly assigned to either lidocaine or no lidocaine and to either streptokinase and heparin or heparin alone.

Electrical atrial remodeling assessed by monophasic action potential and atrial refractoriness in patients with structural heart disease.

Unlabelled: The present study was performed to assess the effect of induced atrial fibrillation (AF) on atrial monophasic action potentials (MAPs) and atrial refractory period (ERP) in patients with structural heart disease. An electrode MAP catheter was placed in the right atrium to continuously measure atrial potential duration (APD90) in 13 patients (coronary artery disease, 10 patients; dilated cardiomyopathy, 2 patients; hypertrophic cardiomyopathy, 1 patient) without spontaneous AF episodes. AF was induced by rapid atrial stimulation (300-1500/min).