This result was confirmed by the multivariate analysis of determinants of ventricular arrhythmias using the “step-up” multiple regression method. Using the hourly frequency of VPC as an index of ventricular arrhythmias we could not detect any clinical/functional parameter able to explain a significant amount of the overall variance of the dependent variable (Table 5). This result and the result of the Mann-Whitney test previously reported were the rationale for developing a comprehensive, quantitative and qualitative score of ventricular arrhythmias to be used as a dependent variable in the “step-up” regression model. Only PFR was significantly associated with this score (Table 6). The arrhythmogenic role of aging was not confirmed in our group of patients. Finally, the “step-up” regression was applied to detect a model for the variance of atrial arrhythmias. The Pa02 and PaCOz were the only variables significantly associated with the hourly frequency of APC (Table 7). buy levaquin online

Table 5—Stepwise Selection and Model Fitting Results for Ventricular Arrhythmias Expressed as VFC per Hour* 

Dependent Variable: VPC/h

Variables not in Model

Variables in Model

F-Enter

Coefficient

Standard

Error

t Value

Constant

-13.80

48.81

-0.28

Age

1.41

0.45

0.38

1.16

PER

0.14

2.91

5.39

0.54

Pa02

0.13

0.07

0.71

0.10

Clinical score

0.09

LVEF

0.09

PFR

0.04

PaC02

0.01

*r squared = 0.11.

Table 6—Stepwise Selection and Model Fitting Results for Ventricular Arrhythmias Expressed as Derived Score of Myerburg et al 

Dependent Variable: Myerburg et al9 Derived Score

Variables not in Model

Variables in Model

F-Enter

Coefficient

Standard

Error

t Value

Constant

12.89

3.11

4.14

PFR

3.64

-1.93

0.88

— 2.19t

PaC02

2.52

-0.06

0.04

-1.59

Age

0.90

Pa02

0.18

Clinical score

0.12

LVEF

0.10

PER

0.01

*r squared = 0.22. tp<0.05.

Table 7—Stepwise Selection and Model Fitting Results for Atrial Arrhythmias Expressed as AFC per Hour* 

Dependent Variable: Myerburg et al9 Derived Score

Variables not in Model

Variables in Model

F-Enter

Coefficient

Standard

Error

t Value

Constant

12.89

3.11

4.14

PFR

3.64

-1.93

0.88

— 2.19t

PaC02

2.52

-0.06

0.04

-1.59

Age

0.90

Pa02

0.18

Clinical score

0.12

LVEF

0.10

PER

0.01

*r squared = 0.22. tp<0.05.

Dependent Variable: APC/h

Variables not in Model

Variables in Model

F-Enter

Coefficient

Standard

Error

t Value

Constant

687.63

210.64

3.26

PaC02

3.05

-4.24

1.72

-2.461t

PaO*

3.79

-7.06

3.01

— 2.34$

LVEF

0.42

PER

0.34

Clinical score

0.25

PFR

0.24

Age

0.02

*r squared = 0.31.
t p<0.02.
$ p<0j05