Participants

Sixty-one healthy nonsmoking volunteers (30 men; mean age, 26 ± 5 years) were prospectively enrolled in the study. All had no histories of hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, or LV hypertrophy. All participants had normal blood pressures at the time of examination. All findings were normal on physical examination, resting electrocardiography, and echocardiography. All subjects were in sinus rhythm. This study was approved by the ethics committee and the institutional review board of Erciyes University Medical School, and informed consent was obtained from each subject.

Study Protocol

All subjects were asked to abstain from caffeine and alcohol in the 12 hours preceding the test. Body mass index and body surface area were measured. Baseline systolic and diastolic blood pressure and heart rate were obtained. Blood samples were taken in a heparinized syringe by venipuncture for carboxyhemoglobin (COHb) measurements, and an echocardiographic examination was performed. All subjects were then asked to spend 30 min in a smoking room. Immediately after passive smoking, subjects were moved to an adjacent room. After resting in a supine position for 5 min, their systolic blood pressure and diastolic blood pressure and heart rate were measured, blood samples were again taken for COHb measurement, and the echocardiographic examinations were repeated. The difference between the post–smoke exposure and baseline measurements of heart rate, systolic blood pressure, diastolic blood pressure, and COHb levels were assessed.

Smoking Room

The smoking room (2.5 × 6.5 m with a 3-m ceiling) was next to the room in which the echocardiographic examinations were performed. Carbon monoxide (CO) concentration was measured using a Pulsar Single-Gas Detector (Mine Safety Appliances Company, Pittsburg, PA). The detector was equipped with an autocalibration feature and was zeroed in clean air, and CO levels in the smoking room were measured every 5 min for all subjects.

Standard Echocardiography

All measurements were performed using a commercially available machine (Vivid 7; GE Vingmed Ultrasound AS, Horten, Norway) with a 3.5-MHz transducer, for at least three consecutive cardiac cycles. Echocardiograms were evaluated by two experienced, independent physicians. All patients were studied in the left lateral recumbent position after a 10-min resting period for baseline measurements according to the recommendations of the American Society of Echocardiography, and the second measurements were assessed within 5 min after exposure.

M-mode echocardiography was used to measure ventricular wall thickness and diameters. The following measurements were recorded: interventricular septal diastolic thickness, LV posterior wall diastolic thickness, LV end-systolic diameter, and LV end-diastolic diameter. Simpson’s method in the two-dimensional echocardiographic apical four-chamber view was used to assess LV end-systolic volume, LV end-diastolic volume, and ejection fraction (EF), as recommended by American Society of Echocardiography guidelines.

Conventional Doppler Echocardiography

LV diastolic function was assessed using transmitral and pulmonary venous flow parameters. The transmitral peak rapid filling velocity (E), peak atrial filling velocity (A), E-wave deceleration time, and E/A ratio were measured. The isovolumetric relaxation time was also recorded from the apical four-chamber view by a simultaneous recording of the aortic and mitral flow. The pulmonary venous flow velocities were recorded in the apical four-chamber view by placing the pulsed-wave Doppler sample volume approximately 1 cm into the right upper pulmonary vein. The difference between the post–smoke exposure and baseline measurements of transmitral E velocity (ΔE) was assessed.

Measurement of Myocardial Color Doppler Tissue Velocities (Color Doppler Tissue Imaging [DTI])

Two-dimensional color DTI data were obtained in the apical four-chamber view during end-expiration with a 5-mm sample size at the lateral wall, at the junction with the mitral annulus, and included peak systolic annular velocity (Sm), peak early diastolic annular velocity (Em), and peak late diastolic annular velocity (Am) waves. The difference between the post–smoke exposure and baseline measurements of mitral annular Em velocity (ΔEm) was assessed. Color DTI loops were obtained at the highest possible frame rate, ≥90 Mhz. Postprocessing analysis was performed using a special software program (EchoPAC version 6.3; GE Vingmed Ultrasound AS). Two independent physicians were blinded to the time of the experiment during offline analysis of color tissue Doppler data ( Figure 1 ).

Color Doppler echocardiographic (A) and color DTI (B) measurements of a 24-year-old female participant before exposure (1) and after exposure (2) .

Statistical Analysis

Continuous variables were tested for normal distribution using the Kolmogorov-Smirnov test, and they were normally distributed. All data are expressed as mean ± SD. Paired Student’s t tests were used for comparisons of parameters before and after passive smoking in all subjects and separately for men and women. Unbalanced two-way analysis of variance was performed to compare the acute deleterious effects of passive smoking on transmitral, pulmonary venous flow and mitral annular velocities between men and women before and after exposure. Pearson’s correlation coefficients were used to examine the degree of relationships between examined variables. Stepwise linear regression models were used to investigate multivariate relationships between ΔE and ΔEm with the selected variables, including age, gender, body mass index, and body surface area and changes in heart rate, systolic blood pressure, diastolic blood pressure, and COHb level. We assessed the intraobserver and interobserver reproducibility of transmitral and mitral annular velocity measurements in 25 volunteers who were selected randomly from study population. P values <.05 were considered significant. All statistical analyses were performed using SPSS for Windows version 13 (SPSS, Inc., Chicago, IL).

COHb Levels and Hemodynamic Measurements

As shown in Table 1 , the mean COHb level increased significantly, while heart rate, systolic blood pressure, and diastolic blood pressure did not change after passive smoking in the overall population. However, when the hemodynamic measurements were analyzed separately for men and women, it was determined that heart rate and systolic and diastolic blood pressure increased significantly in women (71.0 ± 6.9 vs 75.8 ± 6.1 beats/min, 118 ± 9.7 vs 122.7 ± 7.8 mm Hg, and 71.6 ± 7.5 vs 74.5 ± 7.8 mm Hg, respectively, P < .01) but remained unchanged in men (68.8 ± 7.5 vs 67.4 ± 9 beats/min, 122 ±11 vs 119 ±10 mm Hg, and 73.5 ± 6.4 vs 72.5 ± 6.2 mm Hg, respectively, P > .05).

LV Dimensions, Volumes, and Systolic Function

The M-mode echocardiographic findings before and after passive smoking are summarized in Table 2 . No significant changes in LV volumes, dimensions, and EF were observed as a result of passive smoking. Sm was found to be unchanged after exposure to passive smoke. When LV dimensions, volumes, and systolic function were analyzed separately for gender, it was determined that LV end-systolic diameter, LV end-diastolic diameter, LV end-systolic volume, LV end-diastolic volume, LV EF, and Sm velocity did not change after passive smoking in both women and men (3.2 ± 0.33 vs 3.4 ± 0.12 cm and 3.1 ± 0.27 vs 3.0 ± 0.25 cm, 4.8 ± 0.2 vs 4.6 ± 2.3 cm and 4.6 ± 0.31 vs 4.5 ± 0.28 cm, 36.1 ± 2.6 vs 38.2 ± 2.2 mL and 30.1 ± 2.6 vs 32 ± 0.8 mL, 87.7 ± 5.2 vs 86.8 ± 4.3 mL and 84.7 ± 3.0 vs 86.5 ± 2.1 mL, 62 ± 2.0% vs 63 ± 1.8% and 65 ± 2.5% vs 67 ± 0.8%, and 5.7 ± 2.2 vs 5.6 ± 1.9 m/sec and 8.1 ± 1.9 vs 8.0 ± 2 m/sec, respectively, P > .05).

LV Diastolic Function Assessed by Conventional Doppler Echocardiography

Table 3 summarizes the transmitral and pulmonary venous flow parameters in the study population. The transmitral E-wave velocity, pulmonary venous D-wave velocity, and transmitral E/A ratio decreased, while transmitral A-wave velocity did not change. Pulmonary venous flow S and peak atrial reverse flow velocity were not affected by passive smoking. When the transmitral flow velocities were analyzed separately according to gender, it was determined that mitral E velocity decreased and isovolumetric relaxation time increased significantly in women (0.92 ± 0.1 vs 0.68 ± 0.12 m/sec and 87.1 ± 8 vs 98.1 ± 15 ms, respectively, P < .01), while no significant change was observed in men (0.84 ± 0.1 vs 0.82 ± 0.2 m/sec and 72.9 ± 13 vs 73.9 ± 14 ms, respectively, P > .05). Moreover, it was determined that there was a significant decrement in transmitral E velocity and pulmonary D velocity and increment in isovolumetric relaxation time in women compared with men after exposure ( P = .001, P = .002, and P = .02, respectively).

As shown in Table 4 , E velocity after exposure had significant negative correlations with heart rate, systolic blood pressure, and COHb level ( r = −0.70, r = −0.62, r = −0.58, and r = −0.64, respectively, P < .001), but no relationship was observed with diastolic blood pressure ( r = −0.28, P = .42). It was also found that ΔE was significantly correlated with heart rate, systolic blood pressure, and COHb level after exposure ( r = 0.62, r = 0.66, and r = 0.66, respectively, P < .001), while there was no significant correlation with diastolic blood pressure ( r = 0.32, P = .25). As shown in Table 5 , stepwise multivariate linear regression analysis indicated that ΔE was significantly associated with changes in heart rate, systolic blood pressure, and COHb level (β = 0.458, β = 0.486, and β = 0.691, respectively, P = .001). In addition, it was found that gender was not related to ΔE when heart rate and systolic blood pressure were present in the stepwise regression model.

Table 5

Multivariate regression analysis for ΔE and ΔEm, including age, gender, BMI, BSA, and absolute changes in values of HR, SBP, DBP, and COHb level during the study

	ΔE		ΔEm
Variable	β	P	B	P
Age	0.051	>.05	0.079	>.05
BMI	0.082	>.05	0.111	>.05
BSA	0.056	>.05	0.06	>.05
Gender	0.201	>.05	0.183	>.05
ΔHR	0.458	<.001	0.147	>.05
ΔSBP	0.486	<.001	0.181	>.05
ΔDBP	0.101	>.05	0.082	>.05
ΔCOHb	0.691	<.001	0.568	<.001

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