Impact of dexmedetomidine on electrophysiological properties and arrhythmia inducibility in adult patients referred for reentrant supraventricular tachycardia ablation

BACKGROUND

Drugs used for sedation/analgesia may affect the basic cardiac electrophysiologic properties or even supraventricular tachycardia (SVT) inducibility. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist with sedative and analgesic properties. A comprehensive evaluation on use of DEX for reentrant SVT ablation in adults is lacking. The present study aims to systematically assess the impact of DEX on cardiac electrophysiology and SVT inducibility.

METHODS

Hemodynamic, electrocardiographic, and electrophysiological parameters and SVT inducibility were assessed before and after DEX infusion in patients scheduled for ablation of reentrant SVT.

RESULTS

The population of this prospective observational study included 55 patients (mean age of 58.7 ± 14 years, 29 males [52.7%]). A decrease in systolic and diastolic blood pressure and in heart rate was observed after DEX infusion (p = 0.001 for all). DEX increased corrected sinus node refractory time, atrial effective refractory period, AH interval, AV Wenckebach cycle length, and AV node effective refractory period without affecting the His-Purkinje conduction or ventricular myocardium refractoriness. No AV blocks or sinus arrests occurred during DEX infusion. Globally, there was no difference in SVT inducibility in basal condition or after DEX infusion (46/55 [83.6%] vs. 43/55 [78.1%] patients; p = 0.55), without a difference in isoprenaline use (p = 1.0). In 4 (7.3%) cases, the SVT was inducible only after DEX infusion. In 34.5% of cases, DEX infusion unmasked the presence of an obstructive sleeping respiratory pattern, represented mainly by snoring.

CONCLUSIONS

DEX depresses sinus node function and prolongs atrioventricular refractoriness without significantly affecting the rate of SVT inducibility in patients scheduled for reentrant SVT ablation.

889 ATRIOVENTRICULAR BLOCK, AN UNUSUAL CLINICAL PRESENTATION OF CALCIFIED BICUSPID AORTIC VALVE

Background

Bicuspid aortic valve (BAV) is the most frequent congenital valve disease in adults. It is often associated with other congenital cardiac defects. Sometimes it is associated with aortic dilatation. BAV is an heterogeneous disease with varying valve morphology (asymmetrical cusp size and rafe), annulus geometry and size, asymmetrical calcification of the aortic valve and left ventricular outflow tract.

Case Report

A 32 year-old male patient was diagnosed with bicuspid aortic valve after several cardiologic visits for eligibility to competitive sport. Since April 2021 he developed a progressive exertional dyspnea for strenuous efforts. In February 2022, he was referred to our department after a Holter ECG showed a bradyarrhythmia with complete atrioventricular block. The echocardiography evaluation demonstrated a preserved ejection fraction and a bicuspid aortic valve with a mild-moderate regurgitation. The coronary computed tomography showed a thick and calcified bicuspid aortic valve with a coarse calcification of the anterior cuspid that involve the pars membranacea of the interventricular septum. The ergometric exercise demonstrated chronotropy incompetence. The tomography confirmed the mildy aortic root dilatation. Therefore, an MRI was performed and reported a small laminar LGE on the infero-lateral wall of the left ventricle, of unclear significance. He underwent Dual-Chamber permanent pacemaker implantation. A conservative approach was preferred over valvular replacement, considering the mild aortic root dilatation on a background of mild-to- moderate aortic insufficiency.

Conclusion

Our case is unusual given the bicuspid aortic valve concomitant with atrioventricular block, which was connected with the location of the calcification. Thus, the aim of our case report is, to describe a complication to this condition which, although rare, represents a different clinical presentation of the pathology itself in a young adult.

Comparison of bivalirudin and unfractionated heparin plus protamine in patients with coronary heart disease undergoing percutaneous coronary intervention (from the Antithrombotic Regimens aNd Outcome [ARNO] trial)

Previous studies have compared bivalirudin and unfractionated heparin (UFH) plus the routine use of glycoprotein IIb/IIIa inhibitors. They have demonstrated that bivalirudin can decrease bleeding complications without a significant increase in ischemic complications, resulting in a better net clinical outcome, as defined by the efficacy (ischemic complications) or safety (bleeding complications) end point. The aim of the present study was to compare bivalirudin and UFH plus protamine in patients undergoing elective percutaneous coronary intervention and pretreated with clopidogrel and aspirin. We randomly assigned 850 patients with stable or unstable coronary artery disease to bivalirudin or UFH followed by protamine at the end of the percutaneous coronary intervention. The primary end point was in-hospital major bleeding. The main secondary end points were the 1-month composite of death, myocardial infarction, unplanned target vessel revascularization; and the 1-month net clinical outcome. The rate of major bleeding (primary end point) was 0.5% in patients randomized to bivalirudin and 2.1% in patients randomized to UFH (p = 0.033). At 30 days, the rate of major bleeding was 0.9% in the bivalirudin arm and 2.8% in the UFH arm (p = 0.043). The composite of death, myocardial infarction, and target vessel revascularization rate and the net clinical outcome rate was 2.8% and 6.4% (p = 0.014) and 3.3% and 7.8% (p = 0.004), respectively, in the bivalirudin and UFH arms. In conclusion, in percutaneous coronary intervention patients pretreated with clopidogrel and aspirin, bivalirudin was associated with less major bleeding and fewer ischemic complications and a better net clinical outcome than UFH.

Impact of complete revascularization with percutaneous coronary intervention on survival in patients with at least one chronic total occlusion

AIMS

This study sought to determine the impact on survival of successful drug-eluting stent-supported percutaneous coronary intervention (PCI) for chronic total occlusion (CTO).

METHODS AND RESULTS

Comparison of long-term cardiac survival of consecutive patients who underwent PCI for at least one CTO and who were stratified into successful and failure procedures. From 2003 to 2006, 486 patients underwent PCI for 527 CTO. CTO-PCI was successful in 344 patients (71%) and 361 lesions (68%). Multivessel PCI was performed in 62% in the CTO-PCI failure group and in 71% in the CTO-PCI success group (P = 0.062). Cardiac survival rate was higher in the CTO-PCI success group compared with CTO-PCI failure group (91.6 +/- 2.0 vs. 87.4 +/- 2.9%; P = 0.025), in patients with multivessel disease and CTO-PCI success compared with CTO-PCI failure (91.4 +/- 2.2 vs. 86.6 +/- 3.1%; P = 0.021), and in patients with complete revascularization when compared to patients with incomplete revascularization (94.0 +/- 1.7 vs. 83.8 +/- 3.6%; P < 0.001).

CONCLUSION

Successful CTO-PCI confers a long-term survival benefit. Improvement in survival is driven by the differences in the outcome of patients with multivessel disease and who were completely revascularized.

Prevalence, predictors, time course, and long-term clinical implications of left ventricular functional recovery after mechanical reperfusion for acute myocardial infarction

This study prospectively evaluated the prevalence, predictors, time course, and prognostic impact of left ventricular (LV) functional recovery after successful primary percutaneous coronary intervention in 228 consecutive patients with acute myocardial infarctions (AMIs) and LV dysfunction. Serial echocardiographic exams were performed within 24 hours (time 1) and at 1 month (time 2) and 6 months (time 3) after AMI. Overall, 133 patients (58%) showed significant LV functional recovery (> or =10% ejection fraction increase compared with time 1 or ejection fraction > or =50%) at time 3. Early (from time 1 to time 2) and late (from time 2 to time 3) functional recovery patterns were detected in 102 patients (45%) and 31 patients (14%), respectively. Independent predictors of LV functional recovery were enzymatic infarct size (p = 0.0001), time from symptom onset to reperfusion (p = 0.022), extent and severity of baseline LV wall motion abnormalities (p = 0.007), and female gender (p = 0.031). Six-month LV remodeling rates were 36% and 64% in patients with and without LV functional recovery (p = 0.0001). The five-year cardiac death rate was significantly lower in patients with LV functional recovery than in those without (8% vs 18%, respectively, p = 0.024). The time course of LV functional recovery during 6 months did not significantly affect long-term survival. In conclusion, after successful mechanical reperfusion of AMIs, nearly half of patients showed poor LV functional recovery. The presence of significant LV functional recovery 6 months after reperfused AMI, but not the specific time course of recovery, is clearly associated with a better long-term clinical outcome. Simple baseline variables can predict the improvement of cardiac function after reperfused AMI.