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

Patient with sick sinus syndrome and implanted dual-chamber pacemaker with reduced P-wave duration following low interatrial septal pacing: Case report

INTRODUCTION

A dual-chamber pacemaker (DDD/R) for a sinus node disease is sometimes referred to as a physiological pacemaker as it maintains atrioventricular synchrony, however several clinical trials have proved its inferiority to a nonphysiological single-chamber ventricular back-up pacing.

PATIENT CONCERNS

A subject of the study is a 74-year-old woman with a sick sinus syndrome (SSS) and a previously implanted physiological DDD/R pacemaker. The SSS was diagnosed because of patient's very slow sinus rhythm of about 36 bpm, and due to several episodes of dizziness. After the DDD/R implantation the percentage of atrial pacing approached 100%, with almost none ventricular pacing.

DIAGNOSES

Sick sinus syndrome, complete Bachmann's bundle block, atrial fibrillation, atrial flutter.

INTERVENTIONS

The patient was previously implanted with a physiological DDD/R pacemaker. Several years after the implantation, the atrial fibrillation was diagnosed and the pulmonary vein isolation was then performed by cryoablation. During the follow-up after pulmonary vein isolation, the improvement of mitral filling parameters was assessed using echocardiography. Shortly thereafter the patient developed the persistent paroxysm of a typical atrial flutter which was successfully terminated using a radiofrequency ablation. No recurrence thereof has been observed ever since (24 months).

OUTCOMES

The atrial electrode of the pacing system was implanted within the low interatrial septal region that resulted in a reduced P-wave duration compared to native sinus rhythm P-waves. The said morphology was deformed because of the complete Bachmann bundle block. That approach, despite a nonphysiological direction of an atrial activation, yielded relatively short P-waves (paced P-wave: 179 ms vs intrinsic sinus P-wave: 237 ms). It also contributed to a significantly shorter PR interval (paced PR: 204 ms vs sinus rhythm PR: 254 ms).

CONCLUSIONS

The authors took into consideration different aspects of alternative right atrial pacing sites. This report has shown that in some patients with a sinus node disease, low interatrial septal pacing can reduce the P-wave duration but does not prevent from the development of atrial arrhythmias.

Cardiac hemodynamics and proinflammatory cytokines during biatrial and right atrial appendage pacing in patients with interatrial block

Purpose

Interatrial block (IAB) frequently coexists with sinus node disease and is considered a risk factor of left atrial dysfunction, atrial arrhythmias, and heart failure development. Conventional right atrial appendage (RAA) pacing impairs intra- and interatrial conductions and consequently prolongs P wave duration. Biatrial (BiA) pacing helps correct IAB, but its advantageous influence remains controversial. The aim of the study was to compare the effects of BiA and RAA pacing on cardiac hemodynamics and serum concentrations of inflammatory markers and neuropeptides.

Methods

Twenty-eight patients with IAB and preserved atrio-ventricular conduction treated with BiA pacing were studied. Standard invasive hemodynamic measurements were performed during BiA and RAA pacings. Furthermore, the influence of 1 week of BiA and RAA pacing on neuropeptides: atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) and markers of inflammation: high sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and neopterin was examined.

Results

BiA pacing resulted in significant increase of cardiac output (CO) and reduction of pulmonary capillary wedge pressure. We demonstrated significantly lower concentrations of ANP, hs-CRP, IL-6, and neopterin after 1 week of BiA in comparison to RAA pacing. BNP levels remained unchanged.

Conclusions

BiA pacing in comparison to RAA pacing improves hemodynamic performance in patients with IAB and preserved atrio-ventricular conduction. BiA pacing is associated with reduction of ANP and markers of inflammation (hs-CRP, IL-6, and neopterin).

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

AIMS

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.

METHODS AND RESULTS

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.

CONCLUSION

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.

Atrial function during different multisite atrial pacing modalities in patients with bradycardia--tachycardia syndrome

BACKGROUND

Multisite atrial pacing (MAP) was introduced to improve atrial electrical synchrony and prevent recurrence of atrial fibrillation (AF).

METHODS AND RESULTS

In the present study there were 57 patients with sinus node disease, AF recurrence and prolonged P-wave on ECG with 2 MAP modalities. In all patients 1 lead was implanted in the coronary sinus (CS) ostium area. In the right atrial appendage (RAA)+CS group (28 patients) the other atrial lead was in the RAA, and in the BB+CS group (29 patients) in the Bachmann's bundle (BB) region. Tissue Doppler was used to register the electromechanical delay (EMD) in the atrial walls and estimate the atrial contraction synchrony. Cardiac output and myocardial performance index did not differ during the 2 MAP modalities. During BB+CS, in comparison with RAA+CS pacing, the peak of the mitral atrial wave occurred earlier (P<0.01), the usual right-left atrial contraction sequence was reversed more frequently (P<0.004), all atrial EMDs except for the lateral left atrium (LA) were shorter (P<0.05), and LA synchrony was greater (P<0.001).

CONCLUSIONS

In patients treated with MAP, implanting 1 of the atrial leads in the BB area instead of the RAA has no influence on global cardiac hemodynamics, but does result in earlier LA contraction, and reversal of the typical right-left atrial contraction sequence, as well as providing greater LA contraction synchrony.

Understanding changes in cardiovascular pathophysiology

Cardiovascular pathophysiological changes, such as hypertension and enlarged ventricles, reflect the altered functions of the heart and its circulation during ill-health. This article examines the normal and altered anatomy of the cardiac valves, the contractile elements and enzymes of the myocardium, the significance of the different factors associated with cardiac output, and the role of the autonomic nervous system in the heart beat. It also explores how certain diseases alter these functions and result in cardiac symptoms. Nurses can benefit from knowledge of these specific changes, for example, by being able to ask relevant questions in order to ascertain the nature of a patients condition, by being able to take an effective patient history and by being able to read diagnostic results, such as electrocardiograms and cardiac enzyme results. All this will help nurses to promote sound cardiac care based on a physiological rationale.

Assessment of Atrial Regional Wall Motion Using Strain Doppler Imaging During Biatrial Pacing in the Bradycardia-Tachycardia Syndrome

INTRODUCTION

Biatrial pacing is expected to have preventive effects on atrial fibrillation.

METHODS

We evaluated atrial regional wall motion by strain Doppler imaging (SDI) in 6 patients (62.5 +/- 11.3 [SD] years), who suffered from atrial fibrillation, with an implanted biatrial pacemaker. SDI was performed and atrial regional wall motion was estimated during biatrial (BiA) and right atrial appendage (RAA) pacing.

RESULTS

There was no significant difference in the interval from the pacing spike to the peak strain of the atrium in the lateral right atrium (LRA) between BiA and RAA pacing. However, there was a significant difference in the septal atrium (SA) between BiA and RAA pacing (225.0 +/- 19.9 vs 267.2 +/- 15.7 ms, P < 0.0001) and in the lateral left atrium (LLA) between BiA and RAA pacing (216.7 +/- 21.6 vs 275.0 +/- 16.2 ms, P < 0.0001). There were significant differences in the time difference of peak strain between BiA and RAA pacing in each atrial segment (LRA-AS: 2.2 +/- 5.9 vs 45.0 +/- 11.9 ms, P = 0.0016, SA-LLA: -8.3 +/- 5.5 vs 7.8 +/- 2.7 ms, P < 0.0011, LRA-LLA: -6.1 +/- 3.9 vs 52.8 +/- 13.2 ms, P = 0.0002). There was no significant difference in the interval from the pacing spike to the inflection point of atrial strain (S-I) of LRA. However, there were significant differences in S-I of SA (83.9 +/- 24.1 vs 129.9 +/- 30.6 ms, P = 0.0086) and LLA (102.2 +/- 37.9 vs 166.1 +/- 13.4 ms, P = 0.0028).

CONCLUSION

BiA pacing improved the synchronicity of regional wall motion of both atrium.

Beneficial effects of biatrial pacing on cardiac function in patients with bradycardia -- tachycardia syndrome

BACKGROUND

Biatrial (BiA) pacing prevents atrial fibrillation. By an unknown mechanism. The purpose of this study was to use Doppler echocardiography to evaluate the hemodynamic effects during BiA pacing.

METHODS AND RESULTS

The subjects were 7 patients with bradycardia - tachycardia syndrome with an implanted pacemaker. Atrial pacing sites were the right atrial appendage (RAA) and coronary sinus. P wave duration during BiA pacing (123 +/-16 ms) was significantly shorter than during either RAA pacing (167+/-19 ms, p<0.05) or sinus rhythm (148+/-12 ms, p<0.05). Doppler echocardiography revealed a greater cardiac output during BiA pacing than during RAA pacing (4.1+/-1.1 vs 3.5+/-0.7 L/min, p=0.042). The Doppler waveform of transmitral flow indicated that the left ventricular contraction interrupted the atrial filling wave during RAA pacing. The interval between the end of the atrial filling wave of transmitral flow and the mitral valvular closing sound was significantly increased by BiA pacing compared with RAA pacing (56+/-65 vs 40+/-57 ms, p=0.047).

CONCLUSION

Cardiac hemodynamics were improved by BiA pacing and reduction of left atrial load may be one of the mechanisms.

Acute Hemodynamic Benefits of Bi-Atrial Atrioventricular Sequential Pacing With the Optimal Atrioventricular Delay

OBJECTIVES

We evaluate the acute effects on hemodynamics of bi-atrial (BiA) pacing with the optimal atrioventricular (AV) delays, in comparison with high right atrial (HRA) pacing and coronary sinus (CS) pacing.

BACKGROUND

Bi-atrial pacing has been suggested as one of the alternative therapy for preventing the recurrence of atrial fibrillation (AF). There are, however, few reports on the hemodynamic effects of BiA pacing, and the results that exist are controversial.

METHODS

Twenty patients were paced from HRA, left lateral site of CS, and both sites with the optimal AV delays at 80 and 100 beats/min, in random order. After 5-min pacing, maximal P-wave duration in a 12-lead electrocardiogram, cardiac output (CO), pulmonary capillary wedge pressure (PCWP), and the transmitral flow pattern by transthoracic echocardiography were measured.

RESULTS

Compared with HRA and CS pacing, BiA pacing delivered the shortest P-wave duration (HRA: 130 +/- 14 ms, CS: 132 +/- 19 ms, and BiA: 94 +/- 8 ms, respectively, p < 0.001) and the most improvement in CO and PCWP (HRA: 3.63 +/- 0.67 l/min and 9.2 +/- 4.3 mm Hg, CS: 3.71 +/- 0.70 l/min and 8.8 +/- 3.4 mmHg, and BiA: 3.88 +/- 0.63 l/min and 8.0 +/- 3.1 mmHg, respectively, p < 0.01). Bi-atrial pacing also significantly increased the mitral flow time velocity integral and peak A-wave velocity by transthoracic echocardiography, compared with HRA and CS pacing (HRA: 7.6 +/- 1.4 cm and 68.8 +/- 12.2 cm/s, CS: 7.8 +/- 1.4 cm and 70.5 +/- 14.5 cm/s, and BiA: 8.2 +/- 1.2 cm and 76.3 +/- 14.2 cm/s, respectively, p < 0.01). Bi-atrial pacing most significantly decreased the intervals between the atrial pacing spike and the peak of A-wave (HRA: 180 +/- 28 ms, CS: 165 +/- 21 ms, and BiA: 157 +/- 19 ms, respectively, p < 0.01). These improvements in hemodynamics significantly correlated with interatrial conduction delay.

CONCLUSIONS

Bi-atrial pacing made the most significant improvements of hemodynamics. These benefits may be due to the improvements in interatrial conduction delay and atrial dyssynchrony.