Several studies have shown that the clinical and haemodynamic meaning of frequent premature ventricular contractions (PVC) remains uncertain as this condition may lead to cardiomyopathy and left ventricular systolic dysfunction (by unclear mechanism) that is reversible by elimination of the frequent PVCs using catheter ablation.
In this backdrop DC Cozma and coworkers performed the present study to assess the influence of PVC burden and coupling interval in the occurrence of diastolic heart failure (DHF) in patients with frequent PVC and no structural heart disease.
The researchers enrolled 145 patients with mean age 53.5±17.2 years old with >2000 monomorphic PVC/24 hour, no structural heart disease and normal ejection fraction. These patients were divided in 2 groups:
Group 1: 47 pts with DHF and
Group 2: 98 pts without DHF
As a part of study procedure in these patients the PVC ventricular coupling interval was measured on 12 lead ECG. Moreover LA volume (LAV) was assessed apical four chamber view at end-systole (maximal). Also aortic flow pattern was analyzed both in sinus rhythm and after PVC occurrence and diastolic heart failure was detected using echocardiographic conventional validated parameters.
The following were the findings of the study:
In pts with ventricular coupling interval <370ms absence of aortic flow after PVC was demonstrated.
Ventricular coupling interval <370 ms was found in 15 pts of DHF group and 12 pts without DHF group (p = 0.008) while PVC burden >15.000/24 hours: 24 pts of DHF group vs. 9 pts without DHF group (p < 0.0001).
Similar age between both groups 57.4±16.7 (DHF) vs 52±15.9 (without DHF, p = 0.062) was found.
LAV was markedly increased 78.5±14.5ml vs 54.3±9.8ml and PVC burden was <15.000/24 hour in patients with PVC burden >15.000/24 hour, (p < 0.0001).
In conclusion the study showed that frequent PVCs might contribute to worsening the ventricular function in a time dependant process. Factors of progression of heart failure in pts with frequent PVC may be high PVC burden and shorter ventricular coupling interval due to overlapping atrial and ventricular systoles and absence of effective cardiac output and increased diastolic pressure.