Effects of loading conditions and inotropic state on rapid filling phase of left ventricle

1985 ◽  
Vol 248 (4) ◽  
pp. H523-H533 ◽  
Author(s):  
R. C. Bahler ◽  
P. Martin
Keyword(s):  
Right Ventricular ◽  
Time Course ◽  
Left Ventricular ◽  
Atrial Pacing ◽  
Ventricular Pacing ◽  
Descending Aorta ◽  
Right Ventricular Pacing ◽  
Inotropic State ◽  
Venae Cavae ◽  
Activation Sequence

Afterload, activation sequence, inotropism, and extent of shortening affect the time constant (T) of left ventricular (LV) isovolumic pressure decay, yet it is unknown if they modify peak lengthening velocity of the LV minor axis [(dD/dt)/D]. Accordingly, we studied their effects on (dD/dt)/D, measured by sonomicrometry, in nine anesthetized open-chest dogs during atrial pacing at 2 Hz. Afterload was increased 20-40 mmHg by 1) constricting the ascending aorta and 2) occluding the descending aorta for four beats. Activation was altered by right ventricular pacing. These interventions, plus constriction of venae cavae, were studied during four inotropic states. Aortic stenosis increased (dD/dt)/D (P less than 0.05), whereas occlusion of the descending aorta, vena caval constriction, and right ventricular pacing decreased (dD/dt)/D (P less than 0.05). Left atrial pressure was constant except during vena caval constriction. Alterations in inotropic state modified (dD/dt)/D (P less than 0.001). Extent of shortening and (dD/dt)/D were directly related (r = 0.80, P less than 0.001). Changes in (dD/dt)/D and T were inversely related (r = 0.70, P less than 0.001), and alterations in the interval from -dP/dtpeak to the end of rapid filling were directly related to changes in T (r = 0.75, P less than 0.001). We conclude that (dD/dt)/D can be modified by systolic and diastolic load perturbations, activation sequence, and inotropic interventions. These effects relate to changes in extent of shortening, time course of inactivation, or both.

Influence of pacing site on canine left ventricular contraction

1986 ◽  
Vol 251 (2) ◽  
pp. H428-H435 ◽  
Author(s):  
D. Burkhoff ◽  
R. Y. Oikawa ◽  
K. Sagawa
Keyword(s):  
Right Ventricular ◽  
Time Course ◽  
Peak Pressure ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Atrial Pacing ◽  
Free Wall ◽  
Ventricular Pacing ◽  
Right Ventricular Free Wall ◽  
Isolated Hearts

We investigated the influence of pacing site on several aspects of left ventricular (LV) performance to test the hypothesis that "effective ventricular muscle mass" is reduced with direct ventricular pacing. All studies were performed on isolated supported canine hearts that were constrained to contract isovolumically. To determine the influence of pacing site on magnitude and time course of isovolumic LV pressure (P) generation, LVP waves were recorded in eight isolated hearts paced at 130 beats/min. Pacing was epicardially from atrium, LV apex, LV free wall, right ventricular free wall (RVF), and endocardially from right ventricular endocardium. In a given heart, peak LVP was greatest with atrial pacing and smallest with RVF pacing, the difference being on average 26 +/- 10% (mean +/- SD) of the former pressure. The other pacing sites produced intermediate peak LVPs. When instantaneous LVP waves, obtained while pacing from each of the five sites, were normalized by their respective amplitudes, they were virtually superimposable up to the time of peak pressure and only slightly different during the remainder of the cardiac cycle. With changes in pacing site there was a linear negative correlation (r = 0.971) between changes in peak pressure and changes in duration of the QRS complex of a bipolar epicardial electrogram with an average slope of -0.51 mmHg/ms. Compared with atrial pacing, the slope of the end-systolic pressure-volume relation, Ees, was decreased with ventricular pacing, but Vo, the volume axis intercept, was relatively constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of asynchrony on myocardial relaxation at rest and during exercise in conscious dogs

1988 ◽  
Vol 254 (5) ◽  
pp. H817-H822 ◽  
Author(s):  
G. R. Heyndrickx ◽  
P. J. Vantrimpont ◽  
M. F. Rousseau ◽  
H. Pouleur
Keyword(s):  
Heart Rate ◽  
Right Ventricular ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Right Atrial ◽  
Atrial Pacing ◽  
Ventricular Pacing ◽  
Right Ventricular Pacing ◽  
Relaxation Phase

The effect of left ventricular asynchrony induced by right ventricular pacing on relaxation indexes was studied at rest and during exercise in seven conscious dogs instrumented for chronic measurements of left ventricular pressure, coronary blood flow, and arterial pressure and with right atrial and ventricular pacing electrodes. Increasing heart rate with atrial pacing resulted in an increase in both left ventricular maximum and minimum rates of pressure development, LV dP/dtmax and LV dP/dtmin, respectively, as well as in a decrease in the relaxation constant T. In contrast, increasing heart rate with ventricular pacing resulted in a decrease in LV dP/dtmax, a small increase in LV dP/dtmin, and a significant decrease in T. During exercise with heart rate kept constant with atrial pacing, both LV dP/dtmax and LV dP/dtmin increased and T decreased to the same extent as during exercise in sinus rhythm. In contrast, exercising during right ventricular pacing resulted in a significant increase in T, expressing a slowing of relaxation. It is concluded that increasing heart rate alone in the presence of asynchrony of LV contraction induced by abnormal electrical activation results in a depressed contractile response, while the relaxation phase is not significantly affected. However, during sympathetic stimulation, a condition where synchronization should be improved, the relaxation phase is considerably lengthened.

Backup Right Ventricular Pacing with a 0.035″ Guidewire during Implantation of Left Ventricular Leads

2009 ◽  
Vol 32 ◽  
pp. S12-S15
Author(s):  
HARAN BURRI ◽  
HENRI SUNTHORN ◽  
MARC ZIMMERMANN ◽  
CARINE STETTLER ◽  
DIPEN SHAH
Keyword(s):  
Right Ventricular ◽  
Left Ventricular ◽  
Ventricular Pacing ◽  
Right Ventricular Pacing

scholarly journals Changes in Left Ventricular Global and Regional Longitudinal Strain During Right Ventricular Pacing

2016 ◽  
Vol 7 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Alaa Solaiman Algazzar ◽  
Azza Ali Katta ◽  
Khaled Sayed Ahmed ◽  
Nasima Mohamed Elkenany ◽  
Maher Abdelaleem Ibrahim
Keyword(s):  
Right Ventricular ◽  
Longitudinal Strain ◽  
Left Ventricular ◽  
Ventricular Pacing ◽  
Right Ventricular Pacing

scholarly journals Conduction System Pacing for Post Transcatheter Aortic Valve Replacement Patients: Comparison With Right Ventricular Pacing

2021 ◽  
Vol 8 ◽  
Author(s):  
Hong-Xia Niu ◽  
Xi Liu ◽  
Min Gu ◽  
Xuhua Chen ◽  
Chi Cai ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Valve Replacement ◽  
Right Ventricular ◽  
Transcatheter Aortic Valve Replacement ◽  
Left Ventricular ◽  
Conduction System ◽  
Ventricular Pacing ◽  
Right Ventricular Pacing ◽  
Transcatheter Aortic Valve ◽  
Qrs Duration

Introduction: For patients who develop atrioventricular block (AVB) following transcatheter aortic valve replacement (TAVR), right ventricular pacing (RVP) may be associated with adverse outcomes. We assessed the feasibility of conduction system pacing (CSP) in patients who developed AVB following TAVR and compared the procedural and clinical outcomes with RVP.Methods: Consecutive patients who developed AVB following TAVR were prospectively enrolled, and were implanted with RVP or CSP. Procedural and clinical outcomes were compared among different pacing modalities.Results: A total of 60 patients were enrolled, including 10 who were implanted with His bundle pacing (HBP), 20 with left bundle branch pacing (LBBP), and 30 with RVP. The HBP group had significantly lower implant success rate, higher capture threshold, and lower R-wave amplitude than the LBBP and RVP groups (p < 0.01, respectively). The RVP group had a significantly longer paced QRS duration (153.5 ± 6.8 ms, p < 0.01) than the other two groups (HBP: 121.8 ± 8.6 ms; LBBP: 120.2 ± 10.6 ms). During a mean follow-up of 15.0 ± 9.1 months, the LBBP group had significantly higher left ventricular ejection fraction (LVEF) (54.9 ± 6.7% vs. 48.9 ± 9.1%, p < 0.05) and shorter left ventricular end-diastolic diameter (LVEDD) (49.7 ± 5.6 mm vs. 55.0 ± 7.7 mm, p < 0.05) than the RVP group. While the HBP group showed trends of higher LVEF (p = 0.016) and shorter LVEDD (p = 0.017) than the RVP group. Four patients in the RVP group died—three deaths were due to progressive heart failure and one was due to non-cardiac reasons. One death in the LBBP group was due to the non-cardiac reasons.Conclusions: CSP achieved shorter paced QRS duration and better cardiac structure and function in post-TAVR patients than RVP. LBBP had a higher implant success rate and better pacing parameters than HBP.

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