Prognostic Value of Heart Rate Variability, QT interval dispersion, and Late Diastolic Potentials in Patients with Congestive Heart Failure
Hazem Abd El-hameed Ramadan Elakabawy;
Abstract
Background:- Ventricular arrhythmia frequently occur i n patients with congestive heart & failure (CHF) and were reported to underlie many cases of sudden cardiac death (SCD). !£ Participation of the autonomic nervous system in the genesis of ventricular tacharrhythmias and &: SCD has been well documented in acute myocardial infarction (MI) and CHF. Depressed heart & ra te variability (HRV) may reflect a decrease in vagal activity directed to the heart, which leads
to dominance of sympathetic mechanisms and to cardiac electrical instability. QT dispersion is g supposed to be the electric expression of an underlying re-entrant arrhythmogenic substrate & with nonhomogeneous repolarization. Signal-averaged ECG used for detection of late
potentials as an indicator of slower fragmented ventricular contraction. The present work aims & at studying the prognostic value of non-invasive tests - HR.V, QT dispersion and SAECG - in & a population of patients with CHF due to ischemic cardiomyopathy in relation to the natural
course and ultimate outcome. 8:
Met/rods :- In twenty-five patients with CHF (NYHA class lito IV), including 19 males and 6 & females; mean age of 57± 9.19 yrs., we studied HRV indices by 24-hr ambulatory ECG S: moni toring, SAECG using the same electrode of the ambulatory holter, QT i nterval dispersion
measured manually using standard 1 2-lead ECG at 50 m m/s and Bazzett's formula for rate &
correction, and Ejection fraction assessed by echocardiography prior to discharge. All pts were &
followed up for 4-6 months searching for any cardiac events such as major VA, total mortality 8:
and SCD. We assessed HRV time-domain indices, including :- (1) SD of all filtered RR &
intervals over 24-hrs (SDNN}, (2) Mean of SD of all filtered RR intervals for all 5 minute
segments (SDNN-1), (3) SD of the means of all filtered RR intervals for all 5 minute segments g (SDANN-1), (4) Square root of the mean of the sum of the sq uares of differences between & adjacent filtered RR intervals (r-MSSD}, (5) Percentage of differences between adjacent
filtered RR intervals that are > 50ms for the whole analysis (pNN50). &
Results:- During the !-!ospi tal course (mean 10±3.78 days), theincidenceofcomplexVA
demonstrated significant drop from 64% on admission to 32% at the day of discharge.(p-value g
= 0.047) Compared to those with no VA, patients with complex VA at discharge had &
significantly lower Mean RR (600.75±65.89 versus 694. 82±93.79 with p-value = 0.02), lower &g
SDANN-1 (34.09±11.5 r versus 55.18±21.64 withp-value = 0.02 ) and higher QTc dispersion & (95.1 3±15.42 versus 66.53±23.07 with p-value = 0.004). For complex VA prediction at & discharge, both SDANN-I and QTc dispersion showed a sensitivity of 75%, specificity of 82%
and 88% respectively, positive predictive value of 66.5% and 75% respecti vely, negative &
predictive value of 87.5% and 88% respectively, and a diagnostic accuracy of 80% and 84%
respectively. On the other hand, ambulatory SAECG demonstrated statistically insignificant &
differences. A combination of non-invasive parameters, such as HRV indices, QTc dispersion, &
late diastolic potentials (LDP), and left ventricular EF"/o could increase their predictive value.
During the follow u p period of 4-6 months, there were 4 cardiac deaths, including 3 SCD. IS:
Compared to survivors, non survivors had significantly lower SDNN (42.13±13.37 versus &
76.37±23.49 with p-value = O.OS),Iower SDANN-1(29.25±3.84 versus 54.65±19.13 withp-
value= 0.02), and higher QTc dispersion (99.5±35.08 versus 71.15±20.29 withp-value = 0.03). &
Conclusion :- In patients with CHF, predischrge non-invasive tests - HRV and QTc &
dispersion -singly or in combination with other non-i nvasive parameters such as LDP and left
ventricular EF% could predict complex ventricular arrhythmic even ts and identify those at high 8 risk of cardiac death. They are also recommended as routi ne tests in all patients admitted in
cardiac care units with CHF.
to dominance of sympathetic mechanisms and to cardiac electrical instability. QT dispersion is g supposed to be the electric expression of an underlying re-entrant arrhythmogenic substrate & with nonhomogeneous repolarization. Signal-averaged ECG used for detection of late
potentials as an indicator of slower fragmented ventricular contraction. The present work aims & at studying the prognostic value of non-invasive tests - HR.V, QT dispersion and SAECG - in & a population of patients with CHF due to ischemic cardiomyopathy in relation to the natural
course and ultimate outcome. 8:
Met/rods :- In twenty-five patients with CHF (NYHA class lito IV), including 19 males and 6 & females; mean age of 57± 9.19 yrs., we studied HRV indices by 24-hr ambulatory ECG S: moni toring, SAECG using the same electrode of the ambulatory holter, QT i nterval dispersion
measured manually using standard 1 2-lead ECG at 50 m m/s and Bazzett's formula for rate &
correction, and Ejection fraction assessed by echocardiography prior to discharge. All pts were &
followed up for 4-6 months searching for any cardiac events such as major VA, total mortality 8:
and SCD. We assessed HRV time-domain indices, including :- (1) SD of all filtered RR &
intervals over 24-hrs (SDNN}, (2) Mean of SD of all filtered RR intervals for all 5 minute
segments (SDNN-1), (3) SD of the means of all filtered RR intervals for all 5 minute segments g (SDANN-1), (4) Square root of the mean of the sum of the sq uares of differences between & adjacent filtered RR intervals (r-MSSD}, (5) Percentage of differences between adjacent
filtered RR intervals that are > 50ms for the whole analysis (pNN50). &
Results:- During the !-!ospi tal course (mean 10±3.78 days), theincidenceofcomplexVA
demonstrated significant drop from 64% on admission to 32% at the day of discharge.(p-value g
= 0.047) Compared to those with no VA, patients with complex VA at discharge had &
significantly lower Mean RR (600.75±65.89 versus 694. 82±93.79 with p-value = 0.02), lower &g
SDANN-1 (34.09±11.5 r versus 55.18±21.64 withp-value = 0.02 ) and higher QTc dispersion & (95.1 3±15.42 versus 66.53±23.07 with p-value = 0.004). For complex VA prediction at & discharge, both SDANN-I and QTc dispersion showed a sensitivity of 75%, specificity of 82%
and 88% respectively, positive predictive value of 66.5% and 75% respecti vely, negative &
predictive value of 87.5% and 88% respectively, and a diagnostic accuracy of 80% and 84%
respectively. On the other hand, ambulatory SAECG demonstrated statistically insignificant &
differences. A combination of non-invasive parameters, such as HRV indices, QTc dispersion, &
late diastolic potentials (LDP), and left ventricular EF"/o could increase their predictive value.
During the follow u p period of 4-6 months, there were 4 cardiac deaths, including 3 SCD. IS:
Compared to survivors, non survivors had significantly lower SDNN (42.13±13.37 versus &
76.37±23.49 with p-value = O.OS),Iower SDANN-1(29.25±3.84 versus 54.65±19.13 withp-
value= 0.02), and higher QTc dispersion (99.5±35.08 versus 71.15±20.29 withp-value = 0.03). &
Conclusion :- In patients with CHF, predischrge non-invasive tests - HRV and QTc &
dispersion -singly or in combination with other non-i nvasive parameters such as LDP and left
ventricular EF% could predict complex ventricular arrhythmic even ts and identify those at high 8 risk of cardiac death. They are also recommended as routi ne tests in all patients admitted in
cardiac care units with CHF.
Other data
Title | Prognostic Value of Heart Rate Variability, QT interval dispersion, and Late Diastolic Potentials in Patients with Congestive Heart Failure | Other Titles | دراسة علاقة تغير معدل نبض القلب وتشتت زمن الكيوتي والجهد الانبساطي المتأخر بتطور حالات الهبوط الاحتقاني لعض القلب | Authors | Hazem Abd El-hameed Ramadan Elakabawy | Keywords | Congestive Heart Failure Heart Rate Variability Late Diastolic Potentials QT Interval Dispersion | Issue Date | 2000 |
Attached Files
File | Size | Format | |
---|---|---|---|
Hazem Abd El-hameed Ramadan Elakabawy.pdf | 2.42 MB | Adobe PDF | View/Open |
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