Impact of single chamber and dual chamber permanent pacemaker implantation on left ventricular function:An observational study

BACKGROUND Permanent pacemaker implantation has the potential to impact left ventricular(LV)function and hence quality of life(QoL)in the long term.AIM To assess the effect of single-and dual-chamber pacing on LV function and QoL.METHODS This study included 56 patients who underwent permanent pacing:Dual pacing,dual sensing,dual responsive and rate responsive(DDDR)for the initial 3 months,ventricular sensing,inhibited response and rate responsive(VVIR)for the next 3 months,and DDDR mode for the last 3 months.Throughout the study period,various echocardiographic parameters,functional status,and QoL were measured to assess the impact of pacing on LV function compared with baseline and at every 3 months interval.RESULTS A significant change appeared in cardiac function after VVIR pacing which was in diastolic properties of LV as shown by increase in isovolumic relaxation time from(85.28±9.54 ms)to(89.53±9.65 ms).At the 3-,6-,and 9-month follow-up,reduction in LV ejection fraction was observed to be 62.71±4.66%,61.07±4.41%,and 58.48±3.89%,respectively.An increase in the QoL scores was noted at every follow-up visit.CONCLUSION An apparent depressant effect on LV function due to right ventricular pacing,with a higher incidence of adverse outcomes in the VVIR mode.In addition,an upsurge in QoL scores for the study population was noted,which indicates improvement in the QoL of patients post-pacing,irrespective of the mode.Generally,the DDDR mode is a highly preferable pacing mode.

Temporary coronary sinus pacing to improve ventricular dyssynchrony with cardiogenic shock: A case report

BACKGROUND Temporary transvenous pacing through the coronary sinus is a novel approach rarely used in treating unstable bradycardia.This modality could provide cardiac pacing while achieving better ventricular synchrony.We present a case who received cardiac pacing through the coronary sinus and provide a summary of evidence in the current literature.CASE SUMMARY A 55-year-old woman with a history of advanced heart failure was admitted to the rehabilitation ward after a recent stroke.During hospitalization,she had paroxysmal atrial fibrillation with rapid ventricular response resulting from fluid overload.While atrial fibrillation was spontaneously reversed to sinus rhythm after diuresis,she developed multiple episodes of polymorphic ventricular tachycardia along with sinus bradycardia and prolonged QTc interval.She became hypotensive despite appropriate medical management.Pacing through her implantable cardioverter-defibrillator was attempted but worsened her hypotension.Ventricular dyssynchrony was suspected.Temporary transvenous atrial pacing through the coronary sinus was performed,which stabilized her blood pressure and improved end-organ perfusion.A permanent biventricular pacemaker was later implanted,and she was safely discharged to a nursing home.CONCLUSION Temporary transvenous pacing through the coronary sinus,a novel approach to treat unstable bradycardia,may reduce ventricular dyssynchrony.

Improved Cardiac Contractility of Human Recombinant Growth Hormone on the Congestive Heart Failure of Pig

The enhanced cardiac contractility effect of human recombinant growth hormone (hr-GH) on the congestive heart failure (CHF) was studied on the pig. To build a pig model of congestive heart failure, a temporary artificial cardiac pacemaker was implanted in the pig’s body and paced at 220 beats to 240 beats per minute for 1 week. After the model of congestive heart failure was successfully set up, the frequency of the pacemaker was changed to 150 beats to 180 beats per minute to maintain the CHF model stable. Pigs were divided into three groups: The hr-GH group in which 0.5 mg/kg per day of hr-GH was administrated intramuscularly for 15 days, the injection control group in which an equal amount of physiological saline was injected intramuscularly, and a normal control group. The left ventricular diastolic end pressure was (10.60±2.41) mmHg in the hr-GH group, but (19.00±3.81) mmHg in the saline control group (P<0.01); Cardiac output was (1.86±0.13) L/min in the hr-GH group, but (1.56±0.18) L/min in the saline control group (P<0.05); Peripheral vascular resistance was (56.88±7.51) mmHg·(L/min) -1 in the hr-GH group, whereas (70.30±11.59) mmHg·(L/min) -1 in the saline control group (P<0.05); +dp/dt max was (2900±316.23) and (2280±286.36) in the hr-HG group and the saline control group respectively (P<0.05). The results show that hr-GH enhances myocardial contractility of CHF, and the CHF model built by a temporary artificial cardiac pacemaker at a high rate of stimulation is reasonable and applicable.