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Objectives: To investigate the relationship between the plasma B-type natriuretic peptide (BNP) level and the occurrence of atrial fibrillation (AF) in nonobstructive hypertrophic cardiomyopathy (HCM) patients., Methods: Patients (n=97) were classified into chronic AF (CAF; n=14), paroxysmal AF (PAF; n=18) and normal sinus rhythm (NSR; n=65) groups. The plasma BNP values were analyzed with logarithmic transformation., Results: The PAF group showed significantly higher plasma BNP levels than the NSR group [mean (range; -l SD and +1 SD); 248.3 (143.5, 429.5) vs. 78.2 (27.9, 218.8 ng/L), p<0.0001]. The CAF group also showed significantly higher plasma BNP levels than the NSR group [291.1 (161.4, 524.8 ng/L), p<0.0001]. Multivariate analysis with other clinical factors selected association of PAF as one of the factors that increased the plasma BNP level., Conclusions: The present study indicated that plasma BNP level is clinically useful for identification of nonobstructive HCM patients who have a risk of PAF.

Background: Differentiating atrioventricular nodal reentrant tachycardia (AVNRT) from orthodromic atrioventricular reentrant tachycardia (AVRT) can be difficult. The His bundle and atria are activated sequentially over the AV node during entrainment of AVNRT from the ventricle but simultaneously during supraventricular tachycardia (SVT). They are activated in parallel during entrainment of AVRT but sequentially during SVT., Objective: The purpose of this study was to test the hypothesis that a DeltaHA (HA((entrainment)) - HA((SVT))) cutoff value of 0 reliably differentiates AVNRT from AVRT., Methods and Results: Of 61 patients undergoing electrophysiologic evaluation for paroxysmal SVT, retrograde His-bundle potentials were recorded in 57 (93%) and entrainment performed in 49 (34 AVNRT, 15 AVRT). DeltaHA values during entrainment from the ventricle were significantly longer during AVNRT than AVRT (31 +/- 24 ms vs -38 +/- 31 ms, P <.001). All DeltaHA values were positive (minimum: 3 ms) for AVNRT and negative (maximum: -2 ms) for AVRT. DeltaHA of 0 had sensitivity, specificity. and positive predictive value of 100% for correct diagnosis., Conclusion: The DeltaHA criterion during entrainment of tachycardia from the ventricle reliably differentiates AVNRT (positive values) from AVRT (negative values).

Introduction: The experimental concept that "atrial fibrillation (AF) begets AF" implies that atrial tachyarrhythmia (AT)/AF burden uniformly increases over time. However, the temporal patterns of paroxysmal AT/AF burden progression, its conversion to persistent AF, and the relationship to underlying disease in humans are unknown. We analyzed the average daily AT/AF burden in patients with concomitant bradycardia and paroxysmal AF to examine these issues., Methods: Three hundred thirty patients with a history of paroxysmal AF (mean age 70 +/- 10 years; 61% male) were implanted with a pacemaker that automatically recorded the cumulative daily AT/AF burden. Persistent AT/AF was defined as 7 consecutive days with >23 hours of AT on the device data logs. Antiarrhythmic drug therapy was required to be stable for at least 7 months., Results: Average follow-up was 401 +/- 123 days. Seventy-eight patients (24%) progressed to persistent AT/AF during the follow-up period with a mean interval of 147 +/- 149 days. Mean AT/AF burden increased progressively (slope 14 s/d, P < .001) over 500 days after implant, and median AT/AF burden also increased (P < .01) in this subgroup of patients. This increase was highly correlated with the presence of structural heart disease (P < .001). There was a concomitant decrease in atrial premature beat (APB) frequency. Most patients transitioning to persistent AF were in sinus rhythm with minimal AT/AF burden in the days immediately before persistent AF. Neither mean nor median AT/AF burden increased over time in patients remaining in paroxysmal AF (slope 0 s/d, P = .7) despite a higher APB frequency than in patients with heart disease (P =.003) and a higher likelihood of daily AT/AF events (P < .001)., Conclusions: Temporal patterns of AT/AF burden in patients developing persistent AF show a progressive increase with a sudden transition to persistent AF. This is more consistent with substrate changes, rather than increased density of triggering APBs or paroxysmal AT/AF events. Thus, progression to persistent AF is probably related to an AF substrate, which is undergoing progressive structural remodeling owing to heart disease and other factors and is now suddenly capable of sustaining prolonged or multiple ATs. Therapies directed at the atrial substrate may be needed to prevent persistent AF.

Aims: Animal studies revealed that the hyperpolarization-activated pacemaker current, I(f), contributes to action potential (AP) generation in sinoatrial node (SAN) and significantly determines heart rate. I(f) is becoming a novel therapy target to modulate heart rate. Yet, no studies have demonstrated that I(f) is functionally present and contributes to pacemaking in human SAN. We aimed to study I(f) properties in human SAN., Methods and Results: In a patient undergoing SAN excision, we identified SAN using epicardial activation mapping. From here, we isolated myocytes and recorded APs and I(f) using patch-clamp techniques. Pacemaker cells generated spontaneous APs (cycle length 828 +/- 15 ms) following slow diastolic depolarization, maximal diastolic potential - 61.7 +/- 4.3 mV, and maximal AP upstroke velocity 4.6 +/- 1.2 V/s. They exhibited an hyperpolarization-activated inward current, blocked by external Cs(+) (2 mmol/L), characterizing it as I(f). Fully-activated conductance was 75.2 +/- 3.8 pS/pF, reversal potential - 22.1 +/- 2.4 mV, and half-maximal activation voltage and slope factor of steady-state activation - 96.9 +/- 2.7 and - 8.8 +/- 0.5 mV. Activation time constant ranged from approximately 350 ms (-130 mV) to approximately 1 s (-100 mV), deactivation time constant 156 +/- 45 ms (-40 mV). The role of I(f) in pacemaker activity was demonstrated by slowing of pacemaker cell diastolic depolarization and beating rate by Cs(+)., Conclusion: I(f) is functionally expressed in human SAN and probably contributes to pacemaking in human SAN.

Aims: Paroxysmal atrial fibrillation (PAF) is frequently encountered in pacemaker patients, most commonly in sick sinus syndrome. The combination of site-specific pacing in conjunction with an overdrive algorithm combined with antiarrhythmic drugs on the incidence of PAF in patients with a conventional indication for pacing is unknown., Methods and Results: Patients with pacemaker indication and PAF received a DDDR-pacemaker, which included an automatic atrial overdrive (AO) algorithm. The atrial lead was implanted in either the right atrial appendage (RAA) (n = 83) or the right low-atrial septum (LAS) (n = 94). The algorithm was switched on or off in a 3 month, single blind crossover design and antiarrhythmic drugs were kept stable. A control group of 96 patients (LAS, n = 14; RAA, n = 84) without PAF served as controls to assess any proarrhythmic effect of overdrive pacing. Atrial fibrillation (AF) burden defined as cumulative time in mode switch was not reduced during automatic AO from either the RAA or from the LAS. The reduction was not effective both for AF of short (<24 h) and long (> or =24 h) duration. There was no atrial proarrhythmia induced by the overdrive algorithm in the control group., Conclusions: We could not demonstrate a reduction of AF burden defined as cumulative time in AF by the AO algorithm, in patients who are paced for standard indications and PAF, neither from the RAA nor from the LAS.

Aims: The PAFS study is a randomized, multicentre investigation of the effects of third generation anti-atrial fibrillation pacemaker algorithms in patients with paroxysmal atrial fibrillation (PAF)., Methods and Results: 182 patients (72 +/- 9 years, 55% male) with at least three symptomatic episodes of PAF within prior 3 months resistant to two anti-arrhythmics were enrolled. A pacemaker-derived atrial fibrillation (AF) burden of 1-50% was required in the initial induction phase. Seventy-nine patients fulfilled these criteria and were randomized to four, month-long phases in a crossover design. Algorithm phases were 'rate soothing' on, 'ventricular rate stabilization' on, and 'All on', which included these two algorithms plus post-AF response. The algorithm phases were compared to 'All off' dual chamber universal mode (DDD 60) for the analysis. Forty-two percent of patients enrolled in the monitoring phase had no AF. The percentage of AF induced by premature atrial contractions (PACs) was significantly reduced by rate soothing from 25 to 17% (P < 0.05). There was no significant change in AF burden, AF episode number, quality of life, or symptoms with any algorithm (P = ns)., Conclusion: The rate-soothing algorithm by atrial overdrive pacing reduced PAC-initiated PAF. However, there was no overall change in AF burden, PAF episodes, patient symptoms, or quality of life. Forty-two percent of PAF patients did not show any AF after enrollment, suggesting that bradycardia pacing alone eliminates AF.

Background: The dimensions and electrophysiological characteristics of the antral region of human pulmonary veins (PVs) were investigated., Methods and Results: Fifty-five consecutive patients with symptomatic paroxysmal atrial fibrillation underwent PV isolation targeting the PV antrum potentials with a 31 mm multielectrode basket catheter (MBC). The most distal and proximal electrode pairs along the MBC spline where radiofrequency ablation was carried out were identified and the longitudinal distance between those ablation sites (Ld) was measured. When the Ld was > or =6 mm, the PV antrum was defined as noncoaxial. In 56% of the left superior PVs, 42% of the right superior PVs, 63% of the left inferior PVs and 56% of the right inferior PVs, a noncoaxial PV antrum was identified. In each PV, the radiofrequency ablation delivery duration and energy to complete the PV antrum isolation were significantly larger in the PVs with a noncoaxial PV antrum than in those with a coaxial PV antrum., Conclusion: The PV antrum is noncoaxial to the PV in >50% of the PVs, a feature that may increase the complexity of the circumferential isolation technique.

The coronary sinus (CS) has been described as a substrate being involved in the atrial fibrillation (AF) process. However, there are no data describing the CS as a single source of AF. We report a patient with paroxysmal AF who demonstrated an arrhythmogenic focus within the proximal CS as single source initiating and driving AF. This discrete spot was characterized by a sharp "pulmonary vein-like" spike potential preceding every beat during AF and following the atrial potential during sinus rhythm. Radiofrequency ablation at that site led to elimination of the spike potential, disappearance and noninducibility of AF.

During episodes of paroxysmal supraventricular tachycardia (PSVT), electrocardiograms frequently show ST-segment depressions, and patients may experience typical chest pain prompting invasive coronary angiography. We evaluated 114 patients presenting with PSVT for concomitant coronary artery disease (CAD). Patients were classified as to the type of PSVT, symptoms during PSVT, and cardiovascular risk factors. Maximum heart rate, extent of ST-segment depression, and cardiac troponin levels during PSVT were recorded. Patients were subjected to exercise testing and/or coronary angiography. During PSVT, symptoms suggestive of myocardial ischemia, including chest pain (31%), ST-segment depression (61%), and elevated troponin levels (12%), were common. Sixty-seven patients (59%) underwent coronary angiography. The overall prevalence of significant CAD was found to be low (4%) and did not correlate to symptoms during tachycardia. Routine coronary angiography cannot be recommended in patients with PSVT unless routine evaluation outside episodes of tachycardia suggests the presence of significant CAD.

Objective: The objective of this study was to evaluate production or release of CNP in individuals without CHF., Methods: Nineteen patients with symptomatic paroxysmal supraventricular tachycardia (PSVT) and normal left ventricular systolic function were enrolled into the study. Blood samples were collected from the coronary sinus (CS), the femoral artery (FA), and the peripheral vein (PV) before pacing, after rapid RA pacing, and post electrophysiological study (EPS) and/or radiofrequency (RF) ablation., Results: The CNP level in the CS, compared to FA and PV, was significantly higher before pacing (CS, 3.2+/-0.8; FA, 2.6+/-0.7; PV, 2.5+/-0.5 pg/ml; CS vs. either FA or PV, both p<0.001), after the pacing (CS, 3.2+/-1.3; FA, 2.4+/-0.6 pg/ml; p=0.004), and post the EPS and/or RF ablation (CS, 3.1+/-0.7; FA, 2.6+/-0.9; PV, 2.5+/-0.8 pg/ml; CS vs. either FA or PV, both p<0.01)., Conclusion: The myocardium regularly produces or releases CNP in patients with normal LV systolic function. Brief periods of rapid RA pacing, PSVT, or EPS does not change the production and/or release.

We describe a case of a 44-year old man with recurrent atrial arrhythmias (atrial ectopy, atrial tachycardia and fibrillation) originating from the vein of Marshall (VoM). Stress, exertion and isoproterenol increased frequency and duration of highly symptomatic arrhythmia paroxysms. In 2002 he underwent two sessions of RF ablation. In the area of the left inferior pulmonary vein ostium (LIPV) and along the course the VoM, spiky, firing potentials were recorded. Ablation of the VoM region induced high frequency focal firing (CL approximately 200 ms) with 1: 1 VoM-->LA conduction. Before sinus rhythm return, a gradual increase of conduction of VoM-->LA block was observed. During the second session residual breakthroughs were recorded. During 5 years of follow-up the patient remained free from arrhythmia without antiarrhythmic drugs.

This study aimed to validate left atrial (LA) wall contraction velocity during atrial contraction (LAWV) in assessing LA function in 22 patients with paroxysmal atrial fibrillation. LAWV at the posterobasal LA wall was measured by transthoracic tissue Doppler echocardiography. LAWV was lower in patients with paroxysmal atrial fibrillation than in control subjects. It was more correlated with LA appendage velocity (r = 0.81) and fractional shortening (r = 0.85) than with parameters related to mitral inflow velocity or ring motion. With a LAWV cut-off value of 1.0 cm/s, receiver operator characteristic analysis curve showed a diagnostic sensitivity of 92% and a specificity of 80% in the identification of patients with spontaneous echocontrast. Among 8 patients with LAWV < or = 1.0 cm/s, cerebral embolism was evident in 3 and LA thrombus in 2, whereas the patients with LAWV greater than 1.0 cm/s had neither. LAWV may be useful to evaluate LA function and risk of embolism.

The mechanisms of human atrial fibrillation (AF) are poorly understood. Experimental studies have demonstrated that cholinergic AF in the sheep heart is maintained by high-frequency reentrant sources (drivers) that result in a consistent left-to-right frequency gradient. More recently, clinical studies have confirmed the existence of a hierarchical organization in the rate of activation of different regions in the atria of patients with paroxysmal and chronic AF. Although maximal dominant-frequency sites were found to play a crucial role in the maintenance of AF in some patients, whether AF drivers in humans are focal or reentrant and whether changes in driver activity alter spatial frequency gradients are unclear. To test the hypothesis that localized functional reentry maintains AF in humans, we determined the effects of adenosine infusion on local dominant frequency at different sites of both atria. In patients with paroxysmal AF, adenosine infusion increases local dominant frequencies, particularly at the pulmonary vein-left atrial junction region, amplifying a left-to-right frequency gradient. In patients with chronic AF, dominant frequency is significantly higher than in patients with paroxysmal AF in all atrial regions surveyed, with the highest adenosine increase of frequencies outside the pulmonary vein region. Adenosine-induced driver acceleration is strongly suggestive of a reentrant mechanism in both groups of AF patients.

Pulmonary vein antrum isolation offers safe and effective treatment of atrial fibrillation by eliminating the potential triggers of this arrhythmia. The pulmonary vein antra encompass, in addition to the pulmonary veins, the left atrial roof and posterior wall and, in the case of the right pulmonary vein antra, a portion of the interatrial septum. Compared with pulmonary vein ostial isolation, this technique offers a higher success rate and a lower complication rate. In patients with nonparoxysmal atrial fibrillation, extension of septal ablation to the region of the mitral annulus is associated with better outcomes. Further adjunctive strategies include ablation in the coronary sinus, atrial side of inferior mitral annulus, superior vena cava, and along the cristae terminalis, targeting complex fragmented electrograms. We usually reserve these adjunctive ablative therapies for patients with persistent or chronic atrial fibrillation and those with unsuccessful prior catheter ablation.

This review focuses on the importance of autonomic nervous system (ANS) activity in the induction of paroxysmal atrial fibrillation (PAF). Clinical studies suggest that both sympathetic and parasympathetic nervous systems are important in mediating PAF. Consistent with that hypothesis, heart rate variability analyses showed that sympathovagal imbalance is present before the onset of PAF episodes. The importance of the ANS in PAF is further supported by animal experiments and recent clinical studies showing that vagal denervation enhances the efficacy of circumferential pulmonary vein ablation in preventing AF recurrence. In vitro studies show that ANS activation facilitates early afterdepolarization and triggered activity by simultaneously prolonging the intracellular calcium (Ca(i)) transient (sympathetic effect) and shortening the action potential duration (parasympathetic effect). By simultaneously mapping the membrane potential and Ca(i) transient in canine pulmonary vein during sympathetic stimulation, we demonstrated that spontaneous (voltage-independent) sarcoplasmic reticulum calcium release underlies the mechanisms of focal discharges. We developed and studied canine models of PAF induced by electrical, structural, and neural remodeling. We also have developed methods for long-term continuous recording of sympathetic and vagal nerve activity in ambulatory dogs. Preliminary results show that simultaneous sympathovagal discharges precede the onset of PAF in these dogs. ANS activity and Ca(i) transient dynamics are important in the development of PAF. These studies suggest that new methods or drugs aimed at modification of cardiac ANS activity may lead to new opportunities for AF control.

The electrophysiological properties within the pulmonary vein (PV) and PV-left atrial (LA) junction were evaluated using a basket catheter in patients with paroxysmal atrial fibrillation. The effective refractory period of the distal PV was significantly shorter than that of the PV-LA junction. The conduction delay from the distal to proximal PV was significantly longer than that from the proximal to distal PV. During initiation of AF, a reentry involving exit and entrance breakthrough points at the PV-LA junction was observed. The presence of anisotropic conduction properties at the PV-LA junction may be critical to promote reentry formation.

The paper contains recommendations on treatment of supraventricular paroxysmal tachycardias (SVPT) during pregnancy. The recommendations are based on contemporary literature data and authors" own data. SVPT in postural syndrome are shown to be benign and to demand no continuous antiarrhythmic therapy, while tachycardiac attacks are terminated by vagal tests and adenosine application. Relapsing and steady forms of SVPT with a high heart rate are accompanied by subjective symptoms and require preventive antiarrhythmic therapy, which should be conducted considering risk/benefit ratio. According to the authors, sotalol is the most effective and safe pharmaceutical.

Aim of the study was to investigate interrelationship between serum markers of myocardial fibrosis: matrix metalloproteinase -1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and parameters of echocardiography in patients with arterial hypertension (AH) and paroxysmal form of atrial fibrillation (n=39). We revealed positive correlation of levels of TIMP-1 with thickness of interventricular septum in diastole (r=0,47, p=0,02), peak velocity of late filling of the right ventricle (r=0,46, p=0,01), and negative relation between MMP-1 levels and degree of mitral and tricuspid regurgitation (r=0,43, p=0,005 and r=0,38, p=0,04, respectively). In the group of patients with increased left ventricular myocardial mass index (LVMMI) TIMP-1 level was significantly higher than in patients with normal LVMMI (p < 0,05). In the group combining patients with concentric and eccentric LV hypertrophy TIMP-1 level was significantly higher than in the group combining patients with LV concentric remodeling and normal geometry (p < 0,05). No correlations were revealed between MMP-1 and TIMP-1 levels and parameters of diastolic dysfunction. In patients with AH increase of serum concentrations of TIMP-1 was associated with increased thickness of interventricular septum, increase of LVMMI, and with prognostically unfavorable types of LV remodeling.

Background: It is unclear whether atrial fibrillation (AF) drivers in humans are focal or reentrant. To test the hypothesis that functional reentry is involved in human AF maintenance, we determined the effects of adenosine infusion on local dominant frequency (DF) at different atrial sites. By increasing inward rectifier potassium channel conductance, adenosine would increase DF of reentrant drivers but decrease it in the case of a focal mechanism., Methods and Results: Thirty-three patients were studied during AF (21 paroxysmal, 12 persistent) using recordings from each pulmonary vein-left atrial junction (PV-LAJ), high right atrium, and coronary sinus. DFs were determined during baseline and peak adenosine effect. In paroxysmal AF, adenosine increased maximal DF at each region compared with baseline (PV-LAJ, 8.03+/-2.2 versus 5.7+/-0.8; high right atrium, 7+/-2.2 versus 5.4+/-0.7; coronary sinus, 6.6+/-1.1 versus 5.3+/-0.7 Hz; P=0.001) and increased the left-to-right DF gradient (P=0.007). In contrast, in persistent AF, adenosine increased DF only in the high right atrium (8.33+/-1.1 versus 6.8+/-1.2 Hz; P=0.004). In 4 paroxysmal AF patients, real-time DF mapping of the left atrium identified the highest DF sites near the PV-LAJ, where adenosine induced an increase in DF (6.7+/-0.29 versus 4.96+/-0.26 Hz; P=0.008). Finally, simulations demonstrate that the frequency of reentrant drivers accelerates proportionally to the adenosine-modulated inward rectifier potassium current., Conclusions: Adenosine accelerates drivers and increases frequency differently in paroxysmal compared with persistent human AF. The results strongly suggest that AF is maintained by reentrant sources, most likely located at the PV-LAJ in paroxysmal AF, whereas non-PV locations are more likely in persistent AF.

Introduction: Paroxysmal Supraventricular Tachycardia (PSVT) resulting from any cause can at times lead to diagnostic difficulty mainly when due to AVNRT and AVRT. In this study we used a non-invasive approach using esophageal ECG (ECGe) and ECG derived from the various right parasternal chest leads (RPCL) to correctly diagnose the type of PSVT as well the accessory pathways involved in AVRT., Methods and Results: We studied a total of 161 patients (89 male) all having a history of palpitation. All the patients underwent routine 12 lead ECG, ECGe, RPCL and electrophysiologic study. With use of ECGe and RPCL, 71 (44.1%) were diagnosed as having AVNRT and 90 (55.9%) having AVRT with various accessory pathways compared to only 49 (30.4%) and 22 (13.7%) respectively with routine 12 lead ECG. With combined ECGe and RPCL, 80 (49.7%) showed accessory pathway in the left free wall, 4 (2.5%) showed in the right free wall, 6 (3.7%) septal accessory pathway, 60 (37.3%) in the anterior wall and 30 (18.6%) in the posterior wall. In comparison, EPS could show accessory pathways in the left free wall in 81 (50.3%), in the right free wall in 5 (3.1%), in the septum in 4 (2.5%), in the anterior wall in 53 (32.9%) and in the posterior wall in 37 (23.0%) out of the 161 patients., Conclusions: ECGe+RPCL can be used as a reliable noninvasive diagnostic tool to identify the nature of tachycardia and the pathways involved in the reentrant ring of PSVT especially in those with multiple atrioventricular accessory pathways or a combination of atrioventricular accessory pathways and dual atrioventricular nodal pathway.

Objective: Cryoenergy is a new valuable treatment option to perform ablation close to the atrioventricular (AV) node in the cure of supraventricular tachycardias because of its favourable properties, such as the possibility of creating reversible lesions. The aim of this study was to report our experience on the effectiveness and safety of catheter cryoablation performed in "critical areas" to treat a large cohort of patients with supraventricular arrhythmias., Methods: One hundred and thirty-one patients suffering from supraventricular tachycardias underwent catheter cryoablation using a 7F catheter. Eighty-seven patients presented with AV nodal re-entrant tachycardia (AVNRT), 39 had accessory pathways (APs) either manifest or concealed (15 midseptal, 24 parahissian), three had ectopic right atrial tachycardia (AT), and two patients had a permanent junctional reciprocating tachycardia (PJRT). When the optimal parameters were recorded, ice mapping at -30 degrees C was performed for 80 s to validate the ablation site. If the expected result occurred, cryoablation was carried out by lowering the temperature to -75 degrees C for 4 min., Results: In two patients cryoablation was not performed because of technical reasons. Cryoablation was acutely successful in 84 out of 85 patients with AVNRT, in 37 of 39 with APs and in all patients with AT and PJRT. No complications occurred in any patient. Transient AV conduction impairment occurred in seven patients with midseptal APs and in two patients with AVNRT. In particular, in these patients no late permanent AV block was observed at follow-up. At a mean follow-up of 27 +/- 12.9 months, clinical success rate was 87%., Conclusions: Cryoablation is a safe and effective technique with a high success rate in the long term. It may be particularly useful when performing ablation close to the AV node or His bundle owing to the possibility of validating the ablation site with ice mapping, which creates only a reversible lesion, mainly in the midseptal APs.

A new measure of heart rate variability is proposed to investigate the interaction of the sino-atrial (SA) and atrio-ventricular (AV) pacemakers. Using electrocardiogram (ECG) fiduciary markers corresponding to the depolarization time of the SA and AV pacemakers, the variability of SA and AV depolarization rate is jointly analyzed by spectral analysis. The result of this joint analysis provides evidence of a distinct pattern of interaction between the SA and AV nodes prior to the onset of paroxysmal atrial fibrillation (PAF): frequency entrainment between the primary and secondary pacemakers of the heart, occurring at the respiratory frequency. We propose a measure of this entrainment as a diagnostic indicator for PAF, and compare it to standard diagnostic measures. The entrainment measure is found to have greater diagnostic power than five other common ECG-derived measures.

Background: Stepwise segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) have been developed to treat patients with atrial fibrillation (AF), but the preferable approach for paroxysmal AF (PAF) has not been established., Methods and Results: One hundred and ten patients with symptomatic PAF were randomized into a stepwise SPVI group (n=55) or CPVI group (n=55). Systemic SPVI combined with left atrial linear ablation tailored by inducibility of AF was performed in the stepwise SPVI group. Circumferential linear ablation around the left and right-sided pulmonary veins (PVs) guided by 3-dimensional electroanatomic mapping was performed in the CPVI group. The endpoints of ablation are non-induciblity of AF in the stepwise SPVI group and continuity of circular lesions combined with PV isolation in the CPVI group. After the initial procedures, atrial tachyarrhythmis (ATa) recurred within the first 3 months in 23 of the 55 patients (41.8%) who underwent stepwise SPVI and in 20 of the 55 patients (36.4%) who had CPVI (p=0.69). Repeat procedures were performed in 7 patients from the stepwise SPVI group and 5 from the CPVI group (p=0.76). During the 3-9 months after the last procedure, 46 patients (83.6%) from the CPVI group and 43 (78.2%) from the stepwise SPVI group did not have symptomatic ATa while not taking anti-arrhythmic drugs (p=0.63). Severe subcutaneous hematoma or PV stenosis occurred in 3 patients., Conclusions: The efficacy of stepwise SPVI is comparable to that of CPVI for patients with PAF.

Azimilide hydrochloride (azimilide), an investigational antiarrhythmic drug, has shown variable efficacy in preventing atrial fibrillation (AF). This study was designed to assess its efficacy in maintaining sinus rhythm in patients with paroxysmal AF and heart disease. Patients with symptomatic paroxysmal AF were screened for 1 month by transtelephonic monitoring. After recording 1 episode of AF in the screening period, they were randomized to receive azimilide 125 mg or placebo once daily. Patients were stratified by the presence or absence of congestive heart failure or coronary heart disease (CHF/CHD). A maximum of 220 patients without CHF/CHD were randomized, with the remainder having CHF/CHD. Patients with CHF/CHD were monitored for 3 days during loading. The primary efficacy analysis was the time to the first symptomatic recurrence of AF in the CHF/CHD group. Secondary analyses were the time to the first recurrence in the entire population and the time to the first recurrence in those with significant structural heart disease. The median time to recurrence of AF in the CHF/CHD group was 10 days in the 2 treatment arms. Nonsignificant trends were seen toward efficacy of azimilide in the CHF/CHD group (hazard ratio 1.28, 95% confidence interval 0.97 to 1.70, p=0.087), structural heart disease group (hazard ratio 1.22, 95% confidence interval 0.96 to 1.56, p=0.11), and overall group (hazard ratio 1.22, 95% confidence interval 1.00 to 1.49, p=0.053). No patient died. In conclusion, azimilide showed a nonsignificant trend toward efficacy in maintaining sinus rhythm in patients with AF.

Aim: Paroxysmal supraventricular tachycardia (PSVT) is a very frequent type of arrhythmia. Atrioventricular nodal reciprocating tachycardia (AVNRT) and atrioventricular reciprocating tachycardia through extranodal accessory pathways (AVRT) are the most common types of paroxysmal supraventricular tachycardia. We describe our experience in diagnosing these tachycardia by electrophysiological transesophageal study (ETS)., Methods: Three hundred patients, 155 men and 145 women, (mean age, 37.2 +/- 16 years), with a history of palpitations underwent clinical evaluation and ETS. The clinical features of those with AVNRT and those with AVRT were compared., Results: Of a total of 300 patients, tachycardia was diagnosed only in 234, of which 136 (58%) had AVNRT and 98 (42%) had AVRT. AVNRT patients were older than those with AVRT (P = or < 0.004); patients with AVRT had palpitations earlier (P = or < 0.0001). Dyspnea and asthenia were the most frequent symptoms in the AVNRT patients (P = or < 0,02; P = or < 0.04). There were statistically significant differences between the two patient groups in Wencke-bach time (P = or < 0.05), ventricular-atrial (V-A) interval (P = or < 0.03) and period of induced tachycardia (P = or < 0.04)., Conclusions: ETS revealed important clinical and electrophysiological differences between patients with AVRT and those with AVNRT.

Background: The difference between the first postpacing interval (PPI) after tachycardia entrainment from the right ventricular apex and the tachycardia cycle length (TCL) can be used as an index of proximity to the circuit., Objectives: The purpose of this study was to determine whether the response to entrainment of tachycardia during ventricular stimulation with correction for AV node delay is a useful, simple maneuver for differentiating AV nodal reentrant tachycardia (AVNRT) from orthodromic reciprocating tachycardia (ORT) using a concealed accessory pathway., Methods: The study consisted of 193 consecutive patients who underwent electrophysiologic study and ablation of regular paroxysmal supraventricular tachycardia without preexcitation during sinus rhythm. Tachycardia entrainment was attempted through trains of 5 to 15 right ventricular apex pacing pulses. The increment in AV nodal conduction time in the first PPI was subtracted from the PPI-TCL difference (corrected PPI-TCL)., Results: Electrophysiologic study demonstrated ORT in 84 patients and AVNRT in 109 patients. Transient entrainment was achieved in all but 12 patients. The mean corrected PPI-TCL difference was significantly shorter in 77 patients with ORT (66 +/- 27 ms) than in 104 AVNRT patients (151 +/- 28 ms; P <.0001). Patients with septal accessory pathways had shorter corrected PPI-TCL differences than patients with free-wall accessory pathways. The presence of a corrected PPI-TCL difference <110 ms identified all but one patient with ORT, and no patients with AVNRT had such a difference., Conclusion: The return cycle after tachycardia entrainment by right ventricular apex stimulation with correction for AV node delay is a rapid, useful maneuver for differential diagnosis of AVNRT vs ORT in patients without preexcitation. The presence of a corrected PPI-TCL <110 ms accurately identified with high reliability those patients with ORT.

A 23-year old man with paroxysmal, poorly tolerated and spontaneously terminating palpitations, was referred to our department for electrophysiological study. Burst pacing from high right atrium using a cycle length of 350 ms induced a slowfast atrioventricular nodal reentry tachycardia. We excluded the presence of accessory atrioventricular tracts. During tachycardia a constant alternans of QRS morphology and cycle length was observed. The cycle length alternans could be due to the presence of three nodal pathways and activation circulating in a figure-of-eight pattern using alternatively two slow pathways as the antegrade arm of the reentry loop. The alternans could also originate from altering decremental properties of a single slow pathway that changed its conduction properties with relation to the length of the preceding cycle. The QRS alternans occurred both during burst pacing and tachycardia. As it was related to the rate and the changing cycle length, we concluded that it could reflect aberration in intraventricular conduction.

Tachydysrhythmias arise from different mechanisms that can be characterized as being caused by re-entrant circuits, enhanced or abnormal automaticity, or triggered after-depolarizations. The approach to the tachydysrhythmia should begin with distinguishing sinus from non-sinus rhythms, then assessing QRS complex width and regularity. This article review tachydysrhythmias.

Efficacy and tolerability of propafenone were studied in the process of long-term treatment of patients with various forms of paroxysmal atrioventricular arrhythmias. It was established that propafenone appears to be highly effective remedy for prophylaxis of paroxysms of atrioventricular reciprocal nodal tachycardia and atrioventricular tachycardia in Wolf-Parkinson-White syndrome. The preparation did not exert negative influence on functional state of the heart. Side reactions requiring withdrawal of propafenone were observed in 12.7% of cases.

It is known that the atrial fibrillation is a sorrow "privilege" of the senile groups of people. The aim of the given paper was to study the reasons of atrial fibrillation arising in old (60-74 years) and senile (75-89 years) patients and possibility of prevention paroxysms of atrial fibrillation and its complications with help of prolonged selective beta-blocker egilok retard pro daily doses 50-100 mg. The results which were received after the examination and treatment of 147 patients who were under stationary and dispensary treatment at the Research Institute of Experimental and Clinical therapy for 12 months. We have achieved full absence of paroxysmal atrial fibrillation in 89.8% patients (132 patients). The use of egilok retard gives stable hypotensive effect in old and senile patients, provides the regression of the left ventricular hypertrophy with improvement of its parameters and diastolic function, which is especially important for the studied contingent of the patients.

The term paroxysmal sympathetic storms is used to define episodic alterations in body temperature, blood pressure, heart and respiratory rate, size of pupil, and level of consciousness coinciding with hyperhidrosis, excessive salivation and extensor posturing. All the cases were presented after severe diffuse axonal head injury. We present two young patients with diffuse axonal head injury that develop in their evolution hypertension, tachycardia and fever without evidence during the episodes of epileptiform activity and without any infectious cause with excellent answer to the treatment with beta-blockers and morphine. We consider that the correct diagnosis of this entity minimizes the application of unnecessary studies allowing an appropriate treatment.