Interatrial Conduction Delay Research Articles

Permanent left atrial pacing therapy may improve symptoms in heart failure patients with preserved ejection fraction and atrial dyssynchrony: a pilot study prior to a national clinical research programme

Our group has recently shown that in some patients, heart failure with preserved ejection fraction (HFPEF) may be explained by 'atrial dyssynchrony syndrome' (ADS) due to interatrial conduction delay (IACD), a short left atrioventricular interval (LAVI), and increased left atrial (LA) stiffness. Our primary objective was to evaluate LA pacing therapy as a new treatment to restore left ventricular active filling in patients with no other known causes for HF than ADS. Six patients with severe HFPEF with IACD (P wave duration >120 ms in lead II), short LAVI during electrophysiological studies (<70 ms), a restrictive filling pattern (E/e' >15), and no standard indication for a pacemaker were implanted with a lead screwed inside the coronary sinus for active LA pacing. After 3 months of active pacing, a 2 week randomized double-blind crossover phase compared active vs. inactive LA pacing. After 3 months of pacing, the mean distance walked in 6 min (6MWD) was 21% greater (240 ± 25 m vs. 190 ± 15m, P < 0.05), mitral A wave duration was longer (104 ± 8 vs. 158 ± 25 ms, P = 0.002), and E/A and E/e' ratios were smaller (3.4 ± 1.3 vs. 1.8 ± 0.9, P = 0.009, and 22.6 ± 4.6 vs. 15.3 ± 4.3, P = 0.006, respectively). Inactivation of pacing for 1 week led to a significant reduction in the 6MWD, with an on/off response. The beneficial effects of LA pacing observed in this pilot study will have to be confirmed by the randomized, controlled crossover 'LEAD' study.

Extent of Left Ventricular Hypertrophy Is Related to Interatrial Conduction Delay in Hypertensive Patients

The aim of this study was to investigate the relationship between left ventricular mass (LVM) and interatrial conduction delay (CD) measured by tissue Doppler echocardiography. In enrolled 66 hypertensive patients, positive correlation between interatrial CD and LVM index (r = 0.32) was detected. Meanwhile, intra-atrial CD was correlated to early diastolic tissue Doppler mitral annular velocity measured from septum (r = 0.34), tricuspid annular velocity (r = 0.29), and left atrial volume index (r = 0.26). By using stepwise linear regression analysis, LVM index was determined as an independent predictor of interatrial CD.

Abstract 8927: Double-hump Syndrome: The Presence Of Extreme Interatrial Conduction Delay is Associated With Regularization and Progressive Slowing of Atrial Arrhythmias in a Subgroup of Patients With Hypertrophic Cardiomyopathy

Background: In patients with hypertrophic cardiomyopathy (HCM) extreme interatrial activation delay (IAD), indicated by complete separation of the right and left atrial activation on the surface ECG (double hump P wave), was associated with regularization and increase of the cycle length (CL) of recurrent atrial tachycardias (ATs).We aimed to determine the prevalence and the predisposing clinical factors for this clinical entity. Methods: We used data from our HCM registry (n=174 pts, mean age: 53±14 yrs). Data of patients with separated P wave, regularization and slowing of ATs (group I, 5 pts, 2.9%) were compared with 122 control patients with HCM without ATs (group II.). The following parameters were analyzed: P wave morphology and change in P wave duration (ΔP and Pmax), changes in AT CL (ΔATCL), echocardiography parameters including interatrial septal thickness (IAS-T), E/A ratio, E/E prime ratio and fractional shortening (FS) and results of genetic testing. Results: Overall, 9 pts (5.1%) had double hump P waves. This was associated with AT CL prolongation in 5 pts, who were older (66±11 yr vs. 50±14 yr, p=0.016) and had longer follow-up (13,8±1,8 years vs. 7,8± 4,7 years, p=0.005). The ΔATCL was 121±134 ms (range [40-360]) in group I. Echocardiography confirmed double mitral and tricuspid inflow A waves in all group I. pts. Pmax and ΔP were significantly larger in group I (166±33 ms vs. 105±22 ms, p&lt;0.001; 52±26 ms vs. 9±13 ms, p&lt;0.001, respectively). Group I. had an increased LA size as compared to group II. (58±12 mm vs. 45±8 mm, p=0.001) and higher E/A and E/E prime ratios (1,99±1,2 vs. 1,23±0,5, p=0.005 and 20,9±13 vs. 13,1±6,0, p=0.011, respectively). There were no differences in IAS-T and in FS (superior IAS: 4,4±0,1 mm vs. 5,2±1,7 mm, p=NS; inferior IAS: 5,8±0.1 mm vs. 5,7±2,2 mm, p=NS; 38,4±5 % vs. 40,4±9 %, p=NS, respectively). All identified mutations were typical Dutch founder mutations of the MYBPC3 gene. Conclusions: A subgroup of HCM patients have an unique combination of symptoms of separated P wave, regularization and slowing of ATs. Interatrial conduction delay is not related to IAS-T, however, it is associated with larger atria and higher LA pressures. The presence of double hump syndrome is associated with MYBPC3 myosin binding protein mutations.

Atrial arrhythmia, triggering events and conduction abnormalities in isolated murine RyR2‐P2328S hearts

RyR2 mutations are associated with catecholaminergic polymorphic tachycardia, a condition characterized by ventricular and atrial arrhythmias. The present experiments investigate the atrial electrophysiology of homozygotic murine RyR2-P2328S (RyR2(S/S)) hearts for ectopic triggering events and for conduction abnormalities that might provide a re-entrant substrate. Electrocardiograph recordings were made from regularly stimulated RyR2(S/S) and wild type (WT) hearts, perfused using a novel modified Langendorff preparation. This permitted the simultaneous use of either floating intracellular microelectrodes to measure action potential (AP) parameters, or a multielectrode array to measure epicardial conduction velocity (CV). RyR2(S/S) showed frequent sustained tachyarrhythmias, delayed afterdepolarizations and ectopic APs, increased interatrial conduction delays, reduced epicardial CVs and reduced maximum rates of AP depolarization ((dV/dt)(max)), despite similar effective refractory periods, AP durations and AP amplitudes. Effective interatrial CVs and (dV/dt)(max) values of APs following ectopic (S2) stimulation were lower than those of APs following regular stimulation and decreased with shortening S1S2 intervals. However, although RyR2(S/S) atria showed arrhythmias over a wider range of S1S2 intervals, the interatrial CV and (dV/dt)(max) of S2 APs provoking such arrhythmias were similar in RyR2(S/S) and WT. These results suggest that abnormal intracellular Ca(2+) homoeostasis produces both arrhythmic triggers and a slow-conducting arrhythmic substrate in RyR2(S/S) atria. A similar mechanism might also contribute to arrhythmogenesis in other conditions, associated with diastolic Ca(2+) release, such as atrial fibrillation.

Sinus node dysfunction with interatrial conduction delay observed after left atrial myxoma resection through the superior septal approach

We report on a 64-year-old female patient who underwent cardiac surgery for left atrial myxoma, using the superior septal approach with large atrial septal wall resection and patch closure. The superior septal approach is reported to be a relatively safe method for preventing the development of sinus node dysfunction after cardiac surgery. However, this patient developed sinus node dysfunction after surgery and required the implantation of a permanent pacemaker. Moreover, in this case, determining the appropriate positions of the pacemaker leads was difficult because of the presence of a large conduction delay in the interatrium. Selecting the appropriate atrioventricular delay settings was important in order to achieve proper sequential contractions between the left atrium and the left ventricle.

P‐Wave Morphology: Underlying Mechanisms and Clinical Implications

Increasing awareness of atrial fibrillation (AF) and its impact on public health revives interest in identification of noninvasive markers of predisposition to AF and ECG-based risk stratification. P-wave duration is generally accepted as the most reliable noninvasive marker of atrial conduction, and its prolongation has been associated with history of AF. However, patients with paroxysmal AF without structural heart disease may not have any impressive P-wave prolongation, thus suggesting that global conduction slowing is not an obligatory requirement for development of AF. P-wave morphology is therefore drawing increasing attention as it reflects the three-dimensional course of atrial depolarization propagation and detects local conduction disturbances. The factors that determine P-wave appearance include (1) the origin of the sinus rhythm that defines right atrial depolarization vector, (2) localization of left atrial breakthrough that defines left atrial depolarization vector, and (3) the shape and size of atrial chambers. However, it is often difficult to distinguish whether P-wave abnormalities are caused by atrial enlargement or interatrial conduction delay. Recent advances in endocardial mapping technologies have linked certain P-wave morphologies with interatrial conduction patterns and the function of major interatrial conduction routes. The value of P-wave morphology extends beyond cardiac arrhythmias associated with atrial conduction delay and can be used for prediction of clinical outcome of a wide range of cardiovascular disorders, including ischemic heart disease and congestive heart failure.

The Effect of Antithyroid Treatment on Atrial Conduction Times in Patients with Subclinical Hyperthyroidism

Prolonged atrial conduction time measured by tissue Doppler imaging (TDI) has been associated with increased risk of atrial fibrillation. We aimed to evaluate the effect of subclinical hyperthyroidism (SH) and antithyroid treatment on atrial conduction time. A total of 30 patients with SH (26 females; mean age 34.8 ± 8.5 years) and 30 age- and gender-matched controls were included. Using TDI, atrial conduction time was measured from the lateral mitral annulus, septal mitral annulus, and lateral tricuspid annulus. Intra- and interatrial conduction delay were calculated. TDI and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. Patients were followed for 14 ± 3 weeks. Atrial conduction time at the lateral and septal mitral annulus were significantly higher in patients with SH compared to controls. Both inter-, right, and left intraatrial electromechanical delay were prolonged in patients with SH compared to control subjects (21.3 ± 6.1 vs. 13.9 ± 4.3, P < 0.001 and 4.2 ± 3.5 vs. 2.3 ± 1.9, P = 0.014 and 17.1 ± 6.0 vs. 11.6 ± 3.8, P < 0.001, respectively). After achievement of euthyroid state, inter- and left intraatrial electromechanical delay were significantly decreased compared to baseline values and approximated to the values of the control group (P < 0.001). SH is associated with prolonged atrial conduction time. After achievement of euthyroid state, decrement in atrial conduction time may reveal how the antithyroid treatment may prevent the development of atrial fibrillation in these patients.

Atrial dyssynchrony syndrome: an overlooked phenomenon and a potential cause of ‘diastolic’ heart failure

The purpose of the present study was too explore the role of interatrial dyssynchrony in heart failure with preserved ejection fraction (HFPEF). For the case study we selected seven patients with severe HFPEF, with interatrial block on electrocardiogram (ECG), and a delayed and interrupted A wave on mitral Doppler. Echocardiographic left atrial (LA) volumes/functions, mitral E/A and E/e' ratios, mitral A wave duration/deceleration time, and interatrial mechanical delays (IAMDs) at tissue Doppler, were studied. We performed right heart catheterization, and an electrophysiological study (EPS) for the measurement of interatrial conduction delay (IACD) and left atrioventricular interval (LAVI). Mean IAMD was 106 ms. All the patients exhibited a restrictive mitral Doppler pattern, high E/A and E/e' ratios, and short A wave duration/deceleration time. Left atrial volume was increased, with severely depressed functions. Right heart catheterization showed severe post-capillary pulmonary hypertension. The EPS showed an IACD of 170 ± 20 ms, with a short LAVI. Left atrial pacing through the coronary sinus reduced the IACD to 25 ± 15 ms. In the pilot study, 29 patients with HFPEF were compared with 27 age-matched control patients. HFPEF patients had longer P waves, shorter A waves, and a longer IAMD than the controls. Prevalence of severe IAMD >60 ms was 59% in HFPEF and 0% in controls. In the HFPEF group, patients with an IAMD >60 ms had significantly shorter A waves and higher E/e' ratio. Some HFPEF patients present with IACD, delayed LA systole, shortened LA emptying, decreased LA compliance, and increased filling pressures. Whether the condition of these patients could be improved by atrial resynchronization deserves further investigation.

Prediction of early postoperative atrial fibrillation after cardiac surgery : is it possible?

Postoperative atrial fibrillation is common after cardiac surgery. In this study, we aimed to investigate the value of interatrial conduction time for the prediction of early postoperative atrial fibrillation, using intra-operative transoesophageal echocardiography. A total of 65 patients undergoing cardiac surgery in our hospital between January and March 2007 were prospectively evaluated, and 59 patients with sinus rhythm were included in the study. We performed transoesophageal echocardiography on all patients, and intra-operatively measured the interatrial conduction time, as recently described. The patients with episodes of atrial fibrillation during the postsurgery hospitalisation period were defined as group 1 and those without episodes were defined as group 2. Mean interatrial conduction time was 74 ± 15.9 ms in group 1 and 54 ± 7.9 ms in group 2. The difference in interatrial conduction time between the two groups was statistically significant (p < 0.05). In this study we found a statistically significant interatrial conduction delay between the groups. Postoperative atrial fibrillation was more frequent in patients with a longer interatrial conduction time. Increased interatrial conduction time may cause postoperative atrial fibrillation and it can be measured intraoperatively by transoesophageal echocardiography.

A contribution for validation of ECG criteria for interatrial conduction delay

The electrophysiological phenomena related to AF are still incompletely understood, and despite the advances in pharmacological and non-pharmacological management of AF, we are far from being satisfied with the available treatment modalities and predictors of their success. Impaired interatrial conduction has been demonstrated in patients with AF [1], and it has been indicated that this condition can be associated with a reduced left atrial function [2]. In the intact human heart, conduction from the right atrium to the left atrium (LA) is known to occur through Bachmann bundle (BB), the posterior rim of fossa ovalis (FO), and the coronary sinus ostial region (CS) [3]. Impairment of interatrial conduction has been evaluated by ECG as prolongation of P wave duration or its morphology changes. Changes of P wave duration (>120 ms) andmorphology (+/−) in leads D3 and aVF have been utilized to indicate the existence of a conduction delay through Backmann bundle [4]. A +/−P-wave morphology in V1 has been advocated as expression of an interatrial conduction defect through the posterior rim of FO [3]. The latter interatrial delay can be further evidenced measuring P-wave terminal force (PTF), defined as product of the duration (D) by the amplitude (A) of the terminal phase of the P-wave in V1 [5]. The aim of our study was to furnish a contribution for verifying the diagnostic accuracy of these electrocardiographic criteria by comparison of ECG and electroanatomic mapping. Patients were studied just before catheter ablation of atrial fibrillation. At the time of electroanatomic mapping all patients were in sinus rhythm. A quadripolar diagnostic catheter was placed in the coronary sinus for time reference. Electroanatomic mapping was performed using the Carto system (Biosense Webster, Diamond Bar CA USA) with either a 7F Navistar or Thermocool catheter (Biosense Webster). ⁎ Corresponding author at: University of Florence, Department of Medical and Surgical Critical Care, Viale Morgagni 85, 50134 Florence, Italy. Tel.: +39 055 7947514. E-mail address: gemma@gmx.it (G. Filice). Fig. 3. Coronary angiography of the right internal thoracic artery “free” graft to the left anterior descending artery (A, B) after angioplasty of its proximal third (white arrow). Angiogram of the saphenous vein graft to a diagonal branch (C) shows the disappearance of the collateral circulation between the grafts (black arrow).

Abstract 8575: Effects of Permanent Left Atrial Pacing in Patients with Heart Failure and Preserved Ejection Fraction.

Background Although numerous patients are suffering from heart failure with preserved ejection fraction (HFPEF), no specific treatments have been shown to be efficient as the underlying mechanisms involved in this entity are still poorly understood. We hypothesized that inter-atrial conduction delay (IACD) associated with a short left atrio-ventricular interval (LAVI) may impair left ventricular active filling as it reduces the left atrium “kick” which occurs against the closing mitral valve. We assessed the clinical efficacy and safety of left atrial pacing therapy as a new treatment to restore the left ventricular active filling in severe HFPEF patients with IACD and a short LAVI. Methods Six NYHA class III patients with severe HFPEF and no other cause for heart failure symptoms than a short LAVI with IACD were implanted with pacemakers for left atrial permanent stimulation via the coronary sinus (lead screwed inside the Cs at 1 to 2 cm from the ostium). All patients were in sinus rhythm with an IACD defined as a p wave prolongation greater than 120ms in lead II, normal QRS interval. During electrophysiological (EP) studies, they all had a left atrio-ventricular interval (LAVI) shorter than 70ms. None of them had a standard indication for pacemaker implantation. This double-blind, randomized, crossover study compared the responses of the patients during two periods: a two-week period of inactive pacing (ventricular inhibited pacing at a basic rate of 30 bpm) and a two-week period of active (left atrial permanent pacing with dedicated algorithm for AF prevention). The primary end point was the distance walked in six minutes (6MWD). The secondary endpoint was the patient's treatment preference. Results During the inactive phase, two patients developed an acute heart failure 24 and 72 hours after the pacemaker was turned off. The mean (±SD) distance walked in six minutes was 21 percent greater with active pacing (237 ± 30m vs. 187 ± 18m, P&lt;0.001). Active pacing was preferred by 100 percent of the patients. Conclusions Although the beneficial effects of left atrial permanent pacing need to to be confirmed by larger studies, this new pacing strategy may improve exercise tolerance in patients with HFPEF and short left atrio-ventricular interval.

Assessment of atrial electromechanical function by tissue Doppler echocardiography and atrial fibrillation promotion in alloxan-induced diabetic rabbits: an experimental study

PurposeDiabetes mellitus is an independent risk factor for atrial fibrillation (AF). However, the underlying mechanisms are still not clearly elucidated. The aim of this study was to evaluate atrial electromechanical...

Assessment of Atrial Conduction Time in Patients with Coronary Artery Ectasia

Coronary artery ectasia (CAE) is associated with increased sympathetic activity, plasma levels of inflammatory markers, and oxidative stress. These factors can also cause arrhythmias such as atrial fibrillation. Atrial conduction abnormalities in patients with CAE have not been investigated in terms of atrial electromechanical delay obtained by tissue Doppler echocardiography. Ninety patients with pure CAE (n = 30), nonobstructive coronary artery disease (NO-CAD) (n = 30), and angiographically normal coronary arteries "controls" (n = 30) were compared in terms of electrocardiographic P-wave measurements, echocardiographic atrial electromechanical coupling (AEC) parameters, and interatrial conduction delay. The mean left atrium diameter in the CAE group was similar to the NO-CAD group but significantly greater than the control group (3.62 ± 0.28 vs 3.46 ± 0.32 vs 3.41 ± 0.31 cm, P = 0.021). P maximum and P-wave dispersion were significantly increased in the CAE group compared to the NOCAD group and the control group (108.6 ± 6.6 vs 97.9 ± 6.6 vs 93.5 ± 6.2, P = 0.0001; 34.4 ± 7.6 vs 23.2 ± 7.8 vs 19.4 ± 7.7 ms, P < 0.0001). Mitral AEC, septal AEC, and tricuspid AEC were significantly higher in the CAE group than the NO-CAD group and the control group (68 ± 4.5 vs 57 ± 4.5 vs 53 ± 4.6 ms, P < 0.0001; 50.7 ± 7 vs 42.7 ± 7 vs 41.7 ± 7.2 ms, P = 0.0001; 47 ± 6.7 vs 39.1 ± 6.7 vs 38.1 ± 6.6 ms, P < 0.0001). Interatrial conduction delay was significantly increased in the CAE group compared to the NO-CAD group and the control group (21 ± 5.5 vs 17.8 ± 5.6 vs 15 ± 5.6 ms, P < 0.0001).The correlation analysis demonstrated that the interatrial conduction delay and P-wave dispersion (Pd) were positively correlated with number of ectatic segments (ESN) (r = 0.41, P = 0.024 vs r = 0.49, P = 0.006). Stepwise multiple linear regression analysis revealed that the ESN was the only independent determinants of interatrial conduction delay (P = 0.024). Pd and interatrial conduction delay are prolonged in patients with CAE compared to NO-CAD patients and the healthy controls.

Biatrial pacing improves atrial haemodynamics and atrioventricular timing compared with pacing from the right atrial appendage

Patients with interatrial conduction delay may have suboptimal left atrioventricular (AV) timing due to delayed contraction of the left atrium with foreshortening of ventricular filling. This may be an issue in pacemaker patients, especially those requiring resychronization therapy. Pacing from the high interatrial septum (IAS) or the distal or proximal coronary sinus (CSD and CSP) may improve left AV synchrony compared with pacing from the right atrial appendage (RAA). Our aim was to compare haemodynamics of these pacing sites. A total of 24 patients undergoing radiofrequency ablation for paroxysmal atrial fibrillation were studied. Left atrial pressures were recorded in sinus rhythm, and during pacing from the RAA, IAS, CSD, CSP, and with biatrial (BiA) pacing from the IAS + CSD. Amplitudes, +dP/dT(max), and timing of the a-wave were compared between recordings. Left atrial contractility, measured by +dP/dT(max), was greatest during BiA pacing (P ≤ 0.03 for all comparisons). There was a marked reduction in delay to peak a-wave when pacing from all sites compared with the RAA, with BiA pacing yielding the shortest delay (P ≤ 0.001). However, AV conduction was shortened by all alternative pacing sites, which mitigated the anticipation of left atrial contraction with respect to ventricular activation, except for BiA pacing (P < 0.001). Pacing of the IAS did not result in any improvement in haemodynamics or AV synchrony. Multisite atrial pacing results in favourable acute atrial haemodynamics and left AV synchrony. This may be a solution in pacemaker patients with interatrial conduction delay.

Catheter Ablation of Atrial Tachyarrhythmia in Patients with Prior Valvular Surgery: The Limitation of the Surface Electrocardiography

Background: Postoperative atrial tachyarrhythmia may be caused by the focal or reentrant mechanism. The diagnostic potential of the surface electrocardiography (ECG) might be limited because of the presence of surgical scar and interatrial conduction delay. Methods: Eight patients with prior valvular surgery underwent catheter ablation for drug-refractory and symptomatic atrial tachyarrhythmia. The 12-lead ECGs during tachycardia were evaluated. Group 1 consisted of 5 patients with negative flutter waves in inferior leads and leads V5–6, positive waves in leads V1–V2. Group 2 consisted of 3 patients with ECG presentations different from those in group 1. Results: Electrophysiologic study and three-dimensional electroanatomic mapping showed 2 typical right atrial (RA) flutter, 1 left atrial (LA) double loop scar-related flutter, 1 scar-related RA atypical flutter and 1 scar-related aortic root atrial tachycardia in group 1; 1 RA typical flutter, 1 RA appendage atrial tachycardia and 1 atrioventricular nodal reentrant tachycardia in group 2. The ECG presentation of RA typical flutter can not diagnose the true isthmus dependent RA flutter (Area under curve 0.533). Conclusions: Among the patients with prior valvular surgery and atrial tachyarrhythmia, 37.5% patients presented a typical RA flutter. However, the diagnostic ability of the 12-lead ECG for those patients is limited.

107 Atrial dyssynchrony syndrome: an overlooked cause of heart failure with normal ejection fraction

Pathophysiology of heart failure with normal ejection fraction (HFNEF) is still poorly understood. We identified 7 patients with HFNEF associated with interatrial block (IAB) and a particular Doppler mitral inflow pattern. The patients were selected during the past 2 years, because they had severe HFNEF, and a short, abruptly terminated mitral A wave. We analyzed their echo-Doppler, hemodynamic and electrophysiologic features. There were 1 male and 6 female patients, mean age was 75 ± 7. Pulsed wave mitral Doppler was restrictive and triphasic, including high velocity E wave, a mid-diastolic “L” wave, and a delayed and shortened A wave (figure). Mean E/A and E/E’ ratios were 3.7 ± 1.3 and 23 ± 4, respectively. Mean mitral A wave duration was 98 ± 15 ms compared to 170 ± 24 ms at the tricuspid valve (p = 0,001). TDI study of A’ at the lateral tricuspid and mitral annulus showed an interatrial mechanical delay of 110 ± 43 ms. Catheterization showed severe postcapillary pulmonary hypertension: mean pulmonary artery pressure 44 ± 7, wedge pressure 26 ± 5 with a V wave of 49 ± 11 mmHg. Electrophysiologic study showed an interatrial conduction delay of 140 ± 20 ms, a normal right atrio-ventricular interval (170 ± 30 ms), and a short left atrio-ventricular interval (30 ± 20 ms). All 7 patients exhibited 1) severely raised filling pressures, 2) features consistent with decreased left atrial (LA) compliance, and 3) IAB with a delayed LA systole. We believe that severe IAB may be responsible for a delayed LA activation that occurs against a closing mitral valve, thereby interrupting the active LV filling. Furthermore, the hindered LA emptying may induce pressure overload and increase LA stiffness. We identified a category of HFNEF patients with a stereotyped presentation, in which IAB could be one major explanation. Whether these patients could be improved by atrial resynchronization deserves further investigation.Download : Download full-size image

Right atrial appendage pacing in cardiac resynchronization therapy – haemodynamic consequences of interatrial conduction delay

The present case report describes a patient with an artificial mitral valve and dual chamber pacemaker implanted due to perioperative complete atrio-ventricular block. One year later an upgrade to cardiac resynchronization therapy (CRT) combined with ICD function was performed due to significant progression of heart failure symptoms. Beneficial effects of CRT are demonstrated, but unfavourable haemodynamic consequences of right atrial appendage pacing are also underlined. Important interatrial conduction delay during atrial paced rhythm resulted in a significant time difference between optimal sensed and paced atrio-ventricular delay (AVD). This report provides a practical outline how to determine the interatrial delay and the sensed-paced AVD offset under echocardiography in patients treated with CRT.

Marked Interatrial and Atrioventricular Conduction Delay With Enhanced Atrial-Based Managed Ventricular Pacing

Enhanced AAIR↔DDDR pacing (atrial-based Managed Ventricular Pacing [MVP]) is a novel pacing mode that facilitates intrinsic conduction whenever possible to mitigate the deleterious effects of prolonged duration right ventricular (RV) electric stimulation on left ventricular contractility. The following case illustrates uncommon ECG and hemodynamic consequences of this algorithm in a patient with marked atrioventricular (AV) conduction delay. A 58-year-old man with a history of acute myeloid leukemia, subsequent bone marrow transplantation, nonablated paroxysmal atrial flutter, and tachy-brady syndrome underwent implantation of a Medtronic Adapta ADDR01 permanent dual-chamber pacemaker (Medtronic Inc., Minneapolis, Minn.) for symptomatic junctional bradycardia with leads positioned in the right atrial (RA) appendage and RV apex. After implantation, flecainide 100 mg twice daily was added to extended-release diltiazem 240 mg daily with a resultant absence of arrhythmia on serial pacemaker telemetry interrogations. His pacemaker was programmed with enhanced …

Paradoxical Effects of Interatrial Conduction Delay in a Hypertrophic Cardiomyopathy Patient in the Long-Term: Time is a Great Healer

We present a unique case where early proarrhythmic and late antiarrhythmic characteristics of interatrial conduction delay were observed during the long-term progression of HCM. Occurrence of AT constantly increased as the interatrial conduction delay became more prominent, while the P-wave width in sinus rhythm and the AT cycle length both showed an instantaneous increase in parallel. As the interatrial delay reached a critical point, the right and left atrial P-wave became virtually separated, as demonstrated by the findings of ECGs and echocardiography. This phenomenon resulted in the complete cessation of tachycardias.

Device therapy in patients with heart failure and preserved ejection fraction (HFPEF): a new frontier?

Device therapy in patients with heart failure and preserved ejection fraction (HFPEF): a new frontier?