Vasovagal syncope (VVS) is due to a common autonomic reflex involving the cardiovascular system. It is associated with bradycardia (cardioinhibitory response) and/or hypotension (vasodepressor response), likely mediated by parasympathetic activation and sympathetic inhibition. While generally a situational, isolated and/or self-limited event, for some, VVS is recurrent, unpredictable and debilitating. Conservative, non-pharmacological management may help, but no specific medical therapy has been proven widely effective. Permanent pacing may have specific benefit, but its value has been debated. The temporal causative association of bradycardia with syncope in those with VVS may help identify which patient could benefit from pacing but the timing and type of pacing in lieu of blood pressure changes may be critical. The mode, rate, pacing algorithm and time to initiate dual-chamber pacing preferentially with respect to the vasovagal reflex may be important to prevent or ameliorate the faint but completely convincing data are not yet available. Based on available data, DDD pacing with the closed loop stimulation algorithm appears a viable, if not the best, alternative presently to prevent recurrent VVS episodes. While several knowledge gaps remain, permanent pacing appears to have a role in managing select patients with VVS.
Background
While Beta blockers(BB) and Angiotensin system blockers(ACEinh/ARB) are important components in advanced heart failure therapy, their use after left ventricular assist device (LVAD) implantation remains controversial. Concern has been raised about possible adverse effects of BB on right ventricular(RV) function while tolerance and efficacy/outcome data for ACEinh are lacking. This study aimed to characterize the use of medical therapy post-LVAD implantation and to evaluate its safety and efficacy.
Methods
Demographic, clinical and echocardiographic variables of patients implanted with a continuous-flow LVAD between 2012 and 2015 at a single center were retrospectively reviewed. Mortality and heart failure(CHF) hospitalizations were followed from 6-18 months’ post-implant.
Results
Of a total of 98 patients, the mean age was 57 years, 81% were men and 61% had ischemic disease. While the use of diuretics decreased considerably post LVAD, over 50% continued to require diuretics. At 6th month post-implantation, 73% of patients were on BB, and these patients had significantly lower proBNP at 6 and 12 months follow up. Despite significant prevalence of RV dysfunction in the cohort (>75% at 6 months), there was no significant difference in CHF hospitalizations based on BB use (14% vs 15%) and instead a trend towards less deaths in those on BB (6% vs 15%). ACEinh/ARB use was likewise common at 6 month (61%) and these patients had lower proBNP at 6 and 12 months, lower right atrial(RA) pressures (9 vs 12 mmHg, p=0.03), and a significantly lower mortality—a finding which remained on multivariate analysis.
Conclusion
The use of ACEinh/ARB appeared to be associated with subsequent improved survival, lower proBNP and RA pressures. The use of BB post-LVAD appears safe and was associated with a lower proBNP, even in a patient population with a significant prevalence of RV dysfunction.
Background
Three‐dimensional (3D) echocardiography is the most accurate echocardiographic method for ventricular chamber quantification. It is unclear how two‐dimensional (2D) techniques perform against 3D technology and whether 2D methods can be extrapolated to obtain 3D data.
Methods
Retrospective review of transthoracic echocardiography was performed, with comparison of ejection fraction (EF), end‐diastolic volume (EDV), end‐systolic volume (ESV), and 2D strain‐derived global longitudinal strain (GLS) and synchrony index.
Results
One‐hundred patients were identified. Using 3D echocardiography as reference standard, good correlation was noted with 2D strain‐derived EF (r = 0.89, P < 0.01) and with 2D standard biplane EF (r = 0.90, P < 0.01) and similarly for EDV (r = 0.84 and r = 0.81, respectively, both P < 0.01). Two‐dimensional strain‐derived EDV by 8% and 2D biplane‐derived EDV underestimated by 8% (P < 0.01). In relation to 3D EF, 2D strain underestimated by 2% and 2D standard biplane overestimated by 2% (P < 0.01). There was a negative correlation between GLS and 3D EF (r = 0.84, P = 0.001). On multivariate analysis, 3D EF could be derived from 2D strain [3D EF = 34.345 + (0.125 * EDV) + (−0.289 * ESV) + (−1.141 * GLS)]. Three‐dimensional echocardiography‐derived synchrony parameter (ie, standard deviation from mean time to minimum systolic volume from 16 subvolumes) did not correlate with 2D strain‐derived synchrony index (r = 0.171).
Conclusions
Two‐dimensional standard biplane and 2D strain EF and EDV strongly correlate with 3D EF and EDV. Although 2D methods are predictive of 3D findings, over‐ and underestimations may occur. Three‐dimensional echocardiography should be used when available.
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