Impact of air pollution on cardiac arrhythmias



by LORENZO CIOTTI

Impact of air pollution on cardiac arrhythmias

Arrhythmia refers to a clinical condition in which the normal frequency or regularity of the heart rhythm is missing, or the physiological atrio-ventricular activation sequence is altered. A rhythm is regular when the distance between consecutive beats does not exceed 160 msec.

Cci refers to a normal rate, in the adult at rest, with a variation from 60 to 100 beats / min. Normal conduction occurs when the P wave is <120 msec on the ECG, the PR interval does not exceed 200 msec, and the QRS complex is <100 msec in duration.

Allorhythmia is a uniform and continuous irregularity of the heartbeat and pulse. What differentiates it from arrhythmia is the periodicity, which in the latter is irregular. Allorhythmias are usually found in heart patients, but they can also appear in people with apparently healthy hearts.

A particular case of allorhythm is bigeminy, a condition in which every beat is regularly followed by an extrasystole. Both the allorhythmia and the arrhythmia can be ascertained through some instruments such as the electrocardiogram, the phonocardiogram (a method now totally disused), the echocardiogram, the continuous electrocardiographic monitoring according to Holter.

Acute Impact of Fine Particulate Air Pollution on Cardiac Arrhythmias in a Population-Based Sample of Adolescents: The Penn State Child Cohort, published on the Journal of the American Heart Association, is a retrospective study on the subject.

The researchers explain: "Background Fine particulate (fine particles with aerodynamic diameters ≤2.5 μm [PM2.5]) exposure has been associated with a risk of cardiac arrhythmias in adults. remains unclear. Methods and Results To investigate the association and time course between PM2.5 exposure with cardiac arrhythmias in adolescents, we analyzed the data collected from 322 adolescents who participated in the PSCC (Penn State Child Cohort) follow-up examination.

We obtained individual-level 24-hour PM2.5 concentrations with a nephelometer. Concurrent with the PM2.5 measure, we obtained 24-hour ECG data using a Holter monitor, from which cardiac arrhythmias, including premature atrial contractions and premature ventricular contractions (PVCs) , were identified.

PM2.5 concentration and numbers of premature atrial contractions / PVCs were summarized into 30-minute-based segments. Polynomial distributed lag models within a framework of a negative binomial model were used to assess the effect of PM2.5 concentration on numbers of premature atrial contractions and PVCs.

PM2.5 exposure was associated with an acute increase in number of PVCs. Specifically, a 10 μg / m3 increase in PM2.5 concentration was associated with a 2% (95% CI, 0.4% -3.3%) increase in PVC counts 0.5 to 1.0, 1.0 to 1.5, and 1.5 to 2.0 hours after the exposure.

Cumulatively, a 10 μg / m3 increment in PM2.5 was associated with a 5% (95% CI, 1% -10%) increase in PVC counts within 2 hours after exposure. PM2.5 concentration was not associated with premature atrial contraction. Conclusions PM2.5 exposure was associated with an acute increased number of ventricular arrhythmias in a population-based sample of adolescents. The time course of the effect of PM2.5 on ventricular arrhythmia is within 2 hours after exposure."