Abstract Body (Do not enter title and authors here): Introduction/Background
Electrocardiographic left ventricular hypertrophy is a strong predictor of cardiovascular morbidity and mortality. Further, smoking cessation provides a range of health benefits; however, its association with left ventricular hypertrophy is unclear.

Research Questions/Hypothesis
What impact does smoking cessation have on left ventricular hypertrophy regression?

Goals/Aims
We investigated the association between smoking cessation and regression of left ventricular hypertrophy.

Methods/Approach
We compared electrocardiographic left ventricular hypertrophy between baseline and 6 years after smoking cessation follow-up visits in 752 non-hypertensive subjects (695 males, 47.8±9.2 years), from available datasets of 234 596 health check-ups. Left ventricular hypertrophy on ECG was assessed using the Sokolow-Lyon voltage criteria: SV1+RV5 (mV), with left ventricular hypertrophy defined as >3.5 mV.

Results/Data
After 6 years of smoking cessation, body weight was found to increase (from 65.7±10.5 to 68.1±10.8 kg, p<0.0001) and systolic blood pressure also increased (from 112.9±12.7 to 122.0±14.2 mmHg, p<0.0001). Nevertheless, left ventricular hypertrophy on ECG regressed significantly (from 2.47 to 2.41 mV, p<0.0001), and the proportion fulfilling the criteria for left ventricular hypertrophy also decreased from 8.4 to 6.5%. In addition, the antihypertensive drug prescription rate due to elevated blood pressure after 6 years was 13.7% (103/752). Therefore, the regression of left ventricular hypertrophy with or without antihypertensive drug use was assessed. The results showed that left ventricular hypertrophy regressed significantly both [2.68→2.45 mV (p<0.0001)] and [2.44→2.40 mV (p=0.01)] in the groups administered (n=103) and not administered (n=649) antihypertensive drugs, respectively.

Conclusions
Smoking cessation was found to be associated with regression of electrocardiographic left ventricular hypertrophy, despite being potentially associated with future weight gain, increased blood pressure, and with or without antihypertensive drugs. The results indicated that the health benefits of left ventricular hypertrophy regression from smoking cessation may outweigh the negative effects of weight gain and increased blood pressure from smoking cessation.