Vasovagal syncope in patients with reduced left ventricular function

Vasovagal syncope is associated with poor prognosis in patients with left ventricular dysfunction

Vasovagal syncope (VVS) is known to have a benign prognosis and be associated with enhanced contraction and activation of the left ventricular (LV) mechanoreceptors. However, a little is known about VVS in patients with LV dysfunction. The present study aimed to investigate the prevalence and prognosis of VVS in patients with LV dysfunction. We enrolled 368 patients with unexplained syncope. In 7 of these patients, LV ejection fraction was lower than 40%. The results of a head-up tilt test (HUT) and the recurrence of syncope were compared between these 7 patients with LV dysfunction and the remaining patients. Positive HUT was obtained in the 6 patients (86%) with LV dysfunction; this rate tended to be higher as compared with normal cardiac function (192/361, 53%, P = 0.069). In patients with LV dysfunction, response in HUT was mostly vasodepressor type (62%); however, most of HUT responses were mixed type in patients with normal LV function (67%). Among patients with positive HUT, the recurrent rate of syncope after HUT was higher in those with LV dysfunction than in those with normal LV function (67 vs. 21%, P = 0.008). VVS in patients with LV dysfunction may be refractory to treatment and could be associated with poor prognosis.

A risk prediction score model for predicting occurrence of post-PCI vasovagal reflex syndrome: a single center study in Chinese population

Background

The vasovagal reflex syndrome (VVRS) is common in the patients undergoing percutaneous coronary intervention (PCI). However, prediction and prevention of the risk for the VVRS have not been completely fulfilled. This study was conducted to develop a Risk Prediction Score Model to identify the determinants of VVRS in a large Chinese population cohort receiving PCI.

Methods

From the hospital electronic medical database, we identified 3550 patients who received PCI (78.0% males, mean age 60 years) in Chinese PLA General Hospital from January 1, 2000 to August 30, 2016. The multivariate analysis and receiver operating characteristic (ROC) analysis were performed.

Results

The adverse events of VVRS in the patients were significantly increased after PCI procedure than before the operation (all P< 0.001). The rate of VVRS [95% confidence interval (CI)] in patients receiving PCI was 4.5% (4.1%–5.6%). Compared to the patients suffering no VVRS, incidence of VVRS involved the following factors, namely female gender, primary PCI, hypertension, over two stents implantation in the left anterior descending (LAD), and the femoral puncture site. The multivariate analysis suggested that they were independent risk factors for predicting the incidence of VVRS (all P < 0.001). We developed a risk prediction score model for VVRS. ROC analysis showed that the risk prediction score model was effectively predictive of the incidence of VVRS in patients receiving PCI (c-statistic 0.76, 95% CI: 0.72–0.79, P < 0.001). There were decreased events of VVRS in the patients receiving PCI whose diastolic blood pressure dropped by more than 30 mmHg and heart rate reduced by 10 times per minute (AUC: 0.84, 95% CI: 0.81–0.87, P < 0.001).

Conclusion

The risk prediction score is quite efficient in predicting the incidence of VVRS in patients receiving PCI. In which, the following factors may be involved, the femoral puncture site, female gender, hypertension, primary PCI, and over 2 stents implanted in LAD.

Tinnitus as a warning for preventing vasovagal syncope

It has been widely outlined by our group the possibility that a sufferance of the inner ear can take place as a consequence of hemodynamic imbalance which could affect young and healthy people and recognize a merely functional origin. As reported in previous papers, an altered reaction of the autonomic nervous system could actually jeopardize the labyrinthine perfusion even in absence of other damages. From this standpoint, the hypothesis that a hyperactivity of the vagal response to an acute sympathetic drive may result in an inner ear sufferance deserves to be explored. A mechanism which appears to fit to this model is represented by the Bezold-Jarisch reflex (BJR), which is considered to be responsible for vasovagal syncope and is characterized by a dynamic reasonably compatible with our findings. According to these premises, especially considering that the inner ear has a less active protective mechanism against ischemia as compared to brain, in predisposed subjects tinnitus, when considered as an initial symptom of inner ear hypoperfusion, can represent a warning able to prevent the lack of consciousness related to the syncope.

Sympathetic nerve activity restrains reflex vasodilatation in heart failure

BACKGROUND

Blunted reflex muscle vasodilatory response during exercise in heart failure (HF) patients may be secondary to augmented vasoconstriction. We tested the hypothesis that the exaggerated sympathetic nerve activity restrains the reflex muscle vasodilatation during exercise in HF patients.

METHODS

We studied the reflex vasodilatory response (plethysmography) during 3 min static handgrip exercise at 30% maximal voluntary contraction in 10 advanced HF patients (45 +/- 3 year, NYHA Functional Class III/IV) and 10 age-matched normal controls (NC, 40 +/- 3 year, P = 0.23) during intra-arterial infusion of: (1) saline control; and (2) alpha-adrenergic blocker (phentolamine).

RESULTS

Baseline forearm vascular conductance (FVC) was lower in HF patients than in NC (2.07 +/- 0.2 vs. 4.26 +/- 0.6 units, respectively; P = 0.002). FVC responses during exercise increased significantly in NC, but not in HF patients (delta changes: 1.05 +/- 0.4 vs. 0.05 +/- 0.2 units, respectively). Phentolamine significantly increased resting FVC in HF patients (from 2.07 +/- 0.2 to 5.74 +/- 0.7 units, P = 0.00004) and restored reflex vasodilatory responses during exercise (delta changes: from 0.05 +/- 0.2 to 1.82 +/- 0.9 units) eliminating the difference in FVC between both groups.

CONCLUSIONS

The blunted reflex muscle vasodilatory response during exercise in advanced HF patients is, at least in part, due to the increase in sympathetic nerve activity.