The Prevalence of Apical Wall Motion Abnormalities in Patients with Long-Term Right Ventricular Apical Pacing

The differences between conventional lead, thin lead, and leadless pacemakers regarding effects on tricuspid regurgitation in the early phase

PURPOSE

Trans-venous pacemaker leads are associated with worsening of tricuspid regurgitation (TR) after pacemaker implantation (PMI) in some cases. Recently, leadless pacemakers and thin ventricular pacemaker leads without a stylet lumen have become popular. However, the differences in the effects of these leads on TR are unclear. We investigated differences in the changes in TR in the early phase after PMI in patients with conventional leads, thin leads, and leadless pacemakers.

METHODS

We enrolled 65 patients who underwent PMI (32 males, 79 ± 8 years), including 48 with trans-venous PMI (29 with conventional 6.0-Fr leads and 19 with 4.1-Fr thin leads) and 17 with leadless pacemakers. Transthoracic echocardiography was performed before and 1 month after PMI for assessment of conventional echocardiographic parameters and severity of TR by quantitative assessment.

RESULTS

Atrial fibrillation was the most frequent indication for PMI in patients with leadless pacemakers (p = 0.015). In the before and 1 month after PMI comparison, left ventricular ejection fraction decreased after PMI only in the conventional lead group (p = 0.022). The TR effective regurgitant orifice area (EROA) decreased post PMI in the leadless (p = 0.002) and thin lead groups (p = 0.001), but not in the conventional lead group (p = 0.596). The change in TR EROA was greater in the leadless and thin lead groups as compared with the conventional lead group (p < 0.05).

CONCLUSION

The decrease in TR EROA in the early phase after PMI differed according to the type of pacemaker lead. The thin lead might be beneficial for reduction of TR after PMI.

Effect of pacing mode and pacing site on torsional and strain parameters and on coronary flow

BACKGROUND

Right ventricular apical pacing may induce detrimental effects on left ventricular function and coronary flow. In this study, the effects of pacing site and mode on cardiac mechanics and coronary blood flow were evaluated.

METHODS

This prospective study included 25 patients who received dual-chamber pacemakers with the ventricular lead placed in the right ventricular apex and presented in sinus rhythm (SR) at their regularly scheduled visits at the pacemaker clinic. Patients underwent complete transthoracic echocardiographic examinations while in SR, followed by noninvasive Doppler assessment of coronary flow in the left anterior descending coronary artery (LAD) and speckle-tracking echocardiography of short-axis planes in SR, atrial pacing (AAI-P), atrioventricular (dual-chamber) pacing (DDD-P), and ventricular pacing (VVI-P).

RESULTS

Rotation of the base was significantly decreased with VVI-P compared with AAI-P. Left ventricular twist decreased significantly with DDD-P compared with AAI-P. Circumferential strain of the base significantly decreased with DDD-P and VVI-P compared with SR. The velocity-time integral of diastolic flow in the LAD decreased significantly with DDD-P compared with SR (10.7 ± 2.2 vs 10.2 ± 2.2 vs 8.9 ± 1.6 vs 8.7 ± 2.6 cm in SR and with AAI-P, DDD-P, and VVI-P, respectively, P = .003). Basal rotation and time from onset of the QRS complex to peak basal rotation as a percentage of systole were independently associated with the velocity-time integral of diastolic flow in the LAD during SR and the three pacing modes.

CONCLUSIONS

Acute right ventricular apical pacing showed a detrimental effect on left ventricular twist and basal mechanics, with the latter being independently associated with decreased LAD diastolic flow velocity parameters.

Worsening left ventricular apical peak strain early after right ventricular pacing

We aimed to determine the effect of short-term right ventricle pacing (RV) on left ventricle (LV) mechanics using speckle tracking analysis. Conventional echocardiography and two-dimensional strain imaging was studied in 38 patients, mean age 81.6 ± 7.0, that had undergone pacemaker placement and were greater than 90% ventricularly paced. Mean duration of 24 months of RV pacing resulted in a significant decline in: LV apical diastolic rotational velocities (-59.0 ± -38.9 °/s to -28.0 ± -11.5 °/s, p 0.02), peak strain in the LV apical septal wall (-15.6 ± 8.5 to -13.5 ± 7.6, p 0.02), peak strain in LV apical lateral wall (-13.4 ± 8.9 to -11.4 ± 7.3, p 0.02). Thus, with only 24 months of RV pacing, there was a significant decline in peak strain of the LV apex and in apical diastolic rotational velocity that could account for eventual decline in left ventricular function.

Reverse left ventricular remodeling is more likely in non ischemic cardiomyopathy patients upgraded to biventricular stimulation after chronic right ventricular pacing

BACKGROUND

Chronic right ventricular (RV) apical pacing may lead to left ventricular (LV) dyssynchrony and LV dysfunction. In heart failure due to RV pacing, upgrading to biventricular stimulation (CRT) can improve NYHA Class and LV function. A proportion of patients do not respond to upgrading. Aim was to assess whether etiology of LV dysfunction accounts for responses to CRT in RV-paced patients.

METHODS

Sixty-two patients treated by CRT, under RV pacing from 50.2 ± 5.4 months, were studied. Cause of LV dysfunction was non-ischemic (NIC) in 28 and ischemic cardiomyopathy (IC) in 34 patients. Clinical and conventional echocardiographic parameters were available within 1 month before RV pacing, within 1 month before CRT and at 12 ± 2 months of follow-up (FU).

RESULTS

Decreased LVEF (from 37.0 ± 8.8 to 25.6 ± 6.1%, p <0.001), increased LV end-systolic dimensions (LVESD) (from 48.1 ± 8.6 to 55.2 ± 7.9 mm, p <0.001) and worsened NYHA Class (from 1.9 ± 1.1 to 3.2 ± .6, p < 0.005) were found before CRT, compared to pre RV-pacing. After CRT, 44/62 patients showed a ≥ 1 NYHA Class improvement; >10% decrease in LVESD was observed in 24 patients: 5 with IC, 19 with NIC (p < .0.001). The association between cause of LV dysfunction with >10% decrease in LVESD remained highly significant (p < 0.001) adjusting for pre-CRT QRS duration, NYHA Class, LVEF, LVESD, treatment or RV pacing duration.

CONCLUSIONS

CRT improves functional class even after long-lasting pacing. Reverse remodeling is evident in a small population, more likely with NIC.