Effectiveness of ICD therapy in real clinical practice. The Olomouc ICD Registry

BACKGROUND

Clinical parameters linked to a low benefit of ICD implantation and increased mortality risks are needed for an individualized assessment of potential benefits and risks of ICD implantation.

METHODS

Analysis of a prospective registry of all patients hospitalized from 2009 to 2019 in a single centre for a first implantation of any type of ICD.

RESULTS

A total of 2,681 patients were included in the registry. Until the end of follow-up (38.4 ± 29.1 months), 682 (25.4%) patients died. The one-year mortality in all patients, the one-year CV mortality, the three-year mortality in all patients, and the three-year CV mortality were 7.8%, 5.7%, 20.6%, and 14.8%, respectively. There was a statistically significant difference when the subgroups were compared according to the type of cardiomyopathy. No significant difference was found between primary and secondary prevention and between the types of devices. Male gender, age ≥ 75 years, diabetes mellitus, and atrial fibrillation were associated with a significantly increased mortality risk.

CONCLUSION

In an analysis of a long-term follow-up of 2,681 ICD patients, we found no mortality difference between patients with ischemic or non-ischemic cardiomyopathy and in the device type. A higher mortality risk was found in men, patients older than 75 years, diabetics, and those with atrial fibrillation.

Changing Views: Safety and Efficacy of Implantable Cardioverter- Defibrillator Therapy in Athletes

The implantable cardioverter-defibrillator (ICD) is highly effective in reducing sudden death from ventricular tachyarrhythmia among high-risk cardiac patients. Conventional advice given to patients with ICD is to avoid physical activity more strenuous than playing golf or bowling. This recommendation is given due to a theoretical risk of arrhythmia precipitation, and thus increased risk of death due to failure to defibrillate, injury resulting from loss of control caused by arrhythmia-related syncope or shock, and also due to sport related direct damage to the ICD system. Recent prospective data from an international registry involving 372 athletes with ICDs in situ and actively participating in sports has been published. This indicates that, although physical activity resulted in an increased number of shocks compared to rest, there was no significant difference between intensive physical activity and any other activity (10% vs. 8%, p=0.34) in frequency of shocks. Furthermore, over a median follow-up period of 31 months (21-46 months), in the period of sports activity and 2 hour rest directly after there were no occurrences of death, resuscitated arrest or arrhythmia, or shock-related injury. This data is likely to start a shift in every-day clinical decision-making leading to revision of the high level of precautions imposed on the rapidly enlarging ICD recipient population.

Fragmented QRS predicts the arrhythmic events in patients with heart failure undergoing ICD implantation for primary prophylaxis: more fragments more appropriate ICD shocks

BACKGROUND

Fragmented QRS complex (fQRS) is associated with cardiovascular outcomes in various patient populations. Although there were clinical studies investigating the association of fQRS with arrhythmic events in patients with systolic heart failure, the results were conflicting regarding the association of implantable cardioverter defibrillator (ICD) shocks and fQRS. In this study, we aimed to evaluate the association between the presence and extent of fQRS with appropriate ICD shocks and/or all-cause mortality.

METHODS

A total of 215 patients (age: 58.2 ± 11.6 years, 72.5 % male) with the diagnosis of left ventricular systolic heart failure in whom ICD had been implanted for primary prophylaxis were enrolled. Standard ECG evaluation revealed fQRS complex in 123 patients (57.2 %). The phenomenon of fQRS was defined as deflections at the beginning of the QRS complex, on top of the R wave, or in the nadir of the S wave similar to the definition in CAD.

RESULTS

At mean 23.5 ± 12.1 months follow-up, all-cause mortality was observed in 45 (20.9 %) patients and 111 (51.6 %) patients experienced appropriate ICD shocks. Median number of ECG leads with fQRS were higher in patients with appropriate ICD shocks (3 [2-6] vs 1 [0-2], P < 0.001, respectively). The presence of fQRS (HR: 6.64, 95 % CI: 3.54-12.4, P < 0.001) and the number of leads with fQRS (HR: 1.35, 95% CI: 1.22-1.67) were found as independent predictors of appropriate ICD shocks. Additionally, there was a negative correlation between left ventricular ejection fraction and the number of leads with fQRS (r = -0.434, P < 0.001). Rates of all-cause mortality did not differ between the fQRS(+) (29 [24 % ]) and fQRS(-) (16 [17 % ]) groups (P = 0.27).

CONCLUSION

Our findings suggest that the presence and extent of fQRS complex on standard 12-lead ECG predicts appropriate ICD shocks in patients with left ventricular systolic heart failure who underwent ICD implantation for primary prophylaxis.