Premature ventricular contraction patterns associated with nonsustained ventricular tachycardia

BACKGROUND

Occurrence of nonsustained ventricular tachycardia (NSVT) is associated with negative outcomes. It is not clear whether specific electrocardiographic characteristics of premature ventricular contractions (PVCs) are associated with the occurrence of NSVT. The aim of this study was to identify electrocardiographic patterns associated with the presence of NSVT during 24-h electrocardiographic monitoring in patients with >10 PVCs per hour.

METHODS

This was a retrospective, observational, cross-sectional study. We reviewed consecutive patients who received 24-h ECG monitoring performed at a single outpatient cardiology center. Patients who received 24-h electrocardiographic monitoring, with a PVC burden ≥10 PVCs/h were included. Occurrence of NSVT during 24-h electrocardiographic monitoring was the main outcome.

RESULTS

A total of 343 patients were analyzed (mean [SD] age, 69.7 [12.5] years; 177 men [51.6 %]). NSVT occurred in 72 patients who were compared with 271 patients without NSVT. The novel term "premature beat ratio", which aims to correlate the coupling interval and compensatory pause, was introduced; a value >0.5 was independently associated with NSVT according to the multivariate model (OR = 3.73, 95 % CI = 1.57-8.82; P = 0.002). PVC burden (OR = 1.09, 95 % CI = 1.02-1.17; P = 0.006), and triplets (OR = 18.19, 95 % CI = 7.32-45.18 P = 0.0) were also associated with NSVT in the multivariate model.

CONCLUSION

These findings suggest that patients with a high PVC burden, triplets, and a premature beat ratio greater than 0.5 have an increased probability of presenting with NSVT and may benefit from more rigorous follow-up.

Prognostic significance of the Holter-derived T-wave variability in patients with ventricular tachyarrhythmias complicating acute coronary syndrome-TWIST study

BACKGROUND

We aimed to investigate the association between ventricular repolarization instability and sustained ventricular tachycardia and ventricular fibrillation (VT/VF) occurring within 48 h (acute-phase VT/VF) after the onset of acute coronary syndrome (ACS) and the prognostic role of repolarization instability and heart rate variability (HRV) after discharge from the hospital.

METHODS

We studied 572 ACS patients with a left ventricular ejection fraction >35%. The ventricular repolarization instability was assessed by the beat-to-beat T-wave amplitude variability (TAV) using high-resolution 24-h Holter ECGs recorded at a median of 11 days from the date of admission. We calculated the HRV parameters including the deceleration capacity (DC) and non-Gaussian index calculated on a 25 s timescale (λ25s). The DC and λ25s were dichotomized based on previous studies' thresholds.

RESULTS

Acute-phase VT/VF developed in 43 (7.5%) patients. In-hospital mortality was significantly higher among VT/VF patients (4.7% vs. 0.9%, p = .03). An adjusted logistic model showed that the maximum TAV (odds ratio 1.02, 95% confidence interval [CI] 1.00-1.29, p = .04) was associated with acute-phase VT/VF. During a median follow-up period of 2.1 years, 19 (3.3%) patients had cardiac deaths or resuscitated cardiac arrest. Acute-phase VT/VF (p = .12) and TAV (p = .72) were not significant predictors of survival. An age and sex-adjusted Cox model showed that the DC (p < .01), λ25s (p < .01), and emergency coronary intervention (p < .01) were independent predictors.

CONCLUSION

T-wave amplitude variability was associated with acute-phase VT/VF, but the TAV was not predictive of survival post-discharge. The DC, λ25s, and emergency coronary intervention were independent predictors of survival.

[Current strategies in the treatment of ventricular tachycardia by catheter ablation : A review]

The treatment of ventricular tachycardia has recently undergone relevant changes as certain interventional treatment options, such as radiofrequency catheter ablation, have gained in importance. Numerous current publications have demonstrated the advantages of catheter ablation compared to conventional therapy with antiarrhythmic drugs in terms of effectiveness and morbidity. Improving the ablation technique and identifying those patient collectives who are most likely to benefit from ablation are still the objectives of current research. The treatment of ventricular tachycardia in the setting of different cardiac and non-cardiac conditions can be challenging and requires understanding of the current procedures and the recommendations for catheter ablation of ventricular tachycardia. This review succinctly summarizes the current research in this evolving field of interventional cardiology.

Premature Ventricular Contraction Coupling Interval Variability Destabilizes Cardiac Neuronal and Electrophysiological Control: Insights From Simultaneous Cardioneural Mapping

BACKGROUND

Variability in premature ventricular contraction (PVC) coupling interval (CI) increases the risk of cardiomyopathy and sudden death. The autonomic nervous system regulates cardiac electrical and mechanical indices, and its dysregulation plays an important role in cardiac disease pathogenesis. The impact of PVCs on the intrinsic cardiac nervous system, a neural network on the heart, remains unknown. The objective was to determine the effect of PVCs and CI on intrinsic cardiac nervous system function in generating cardiac neuronal and electric instability using a novel cardioneural mapping approach.

METHODS AND RESULTS

In a porcine model (n=8), neuronal activity was recorded from a ventricular ganglion using a microelectrode array, and cardiac electrophysiological mapping was performed. Neurons were functionally classified based on their response to afferent and efferent cardiovascular stimuli, with neurons that responded to both defined as convergent (local reflex processors). Dynamic changes in neuronal activity were then evaluated in response to right ventricular outflow tract PVCs with fixed short, fixed long, and variable CI. PVC delivery elicited a greater neuronal response than all other stimuli (P<0.001). Compared with fixed short and long CI, PVCs with variable CI had a greater impact on neuronal response (P<0.05 versus short CI), particularly on convergent neurons (P<0.05), as well as neurons receiving sympathetic (P<0.05) and parasympathetic input (P<0.05). The greatest cardiac electric instability was also observed after variable (short) CI PVCs.

CONCLUSIONS

Variable CI PVCs affect critical populations of intrinsic cardiac nervous system neurons and alter cardiac repolarization. These changes may be critical for arrhythmogenesis and remodeling, leading to cardiomyopathy.