Diastolic Dysfunction in Persons with Hypertensive Heart Failure: DISCUSSION
The assessment of LVF was initially accomplished using cardiac catheterization and radionuclide angiography. These earlier techniques have the disadvantage of being invasive and therefore not suitable for very ill patients. There is also the risk of radiation exposure with the radionuclide method. However, with the emergence of Doppler echocardiography, a noninvasive assessment of LVF can now readily be done. It is easy to perform, results are reproducible, and the technique compares favorably with other techniques of cardiac function assessment.
Because of the high cost of echocardiographic examination and the poor state of our economy, the facilities for this valuable assessment are still lacking in this part of the world. This accounts for the paucity of comprehensive literature on this subject in our area of clinical practice. Viagra Online Canadian Pharmacy
Figure 1. Doppler mitral inflow velocity tracing in two of the patients showing diastolic dysfunction characterized by higher A wave than E wave velocities with a reversal of E/A ratio (E/A < 1.0).
The mean age of the patients in this study is 52.6 ± 12.01 years. This is in agreement with the studies by Falase et al., Akinkugbe et al., and Danbauchi et al., who reported that most of their patients were in the fifth decade.
Diastolic dysfunction is a continuum. It begins with impaired relaxation and progresses through pseudonormalization to the restrictive pattern, which is said to be the worst form of diastolic dysfiinction. This pattern is clearly demonstrated in this study with all forms represented in various proportions. A high proportion of the patients were in the restrictive pattern group. This is partly due to late hospital attendance of these patients who when seen were already in New York Heart Association III or IV. pharmacy uk
Figure 2. Doppler mitral inflow velocity tracing showing pseudonormalization in one of the patients. The E/A ratio was 2.0; the deceleration time (DT) was more than 150 but less than 200 msec. E = Peak E wave velocity due to early/rapid/ ventricular filling in diastole; A = Peak A wave velocity due to atrial contraction in late diastole; note: DT is time taken for the peak E velocity to come down to baseline.
A combination of ignorance and poverty makes them seek medical attention very late. As seen in this study, isolated diastolic dysfunction was associated with heart failure in 12.6% of patients, combined diastolic and systolic dysfunction in 24.2%, pseudonormalization in 6.3%, and restrictive pattern in 26.3% of the patients. This brings the overall prevalence of diastolic dysfunction to 69.4%. A similar study in Ife, western Nigeria involving 30 patients put the prevalence of isolated diastolic dysfunction at 30%), reversed E/A ratio at 53%, and restrictive pattern at 10%. The reversed E/A ratio in our study was 36.8%, and the differences in these figures may be a reflection of the difference in the spectrum of sample and size. The restrictive pattern is seen more in our patients than theirs, while impaired relaxation was higher in their subjects than ours—a reflection of the timing of hospital attendance. Balogun et al. reported a prevalence of 46% in both hypertensives and hypertensive heart failure. Prevalence of diastolic dysfunction in adult hypertensive Nigerians reported by Ike et al. from the eastern part of Nigeria is over 80%, while that of Kingue et al. from Cameroon was 67% in black African hypertensives. Our prevalence seems to be higher because only patients in heart failure were considered in the study, though this is similar to reports from Cameroon. An early detection of cardiac failure (i.e., in the form of diastolic dysfunction alone) does not require the use of ionotrophic drugs, like digoxin, but drugs that will enhance diastolic relaxation of the ventricle in the form of beta-blockers and calcium channel blockers. Though drugs used for reducing pulmonary hypertension and diuretics are common to both diastolic heart failure and systolic heart failure, the prognosis of patients with diastolic heart failure is less ominous than of systolic heart failure. Whether treatment of asymptomatic diastolic dysfunction confers any benefit has not been examined. The annual mortality for diastolic heart failure is 5-8%, whereas that of systolic heart failure is 10-15%.
Figure 3. Pulsed-wave Doppler mitral inflow velocity tracing seen in one of the patients showing a restrictive pattern. It shows a very tall E wave and a very small A wave (E wave »A wave). The E/A ratio was >2.0 and DT <150 msec. E = Peak E wave velocity due to early rapid ventricular filling in diastole; A = Peak A wave velocity due to atrial contraction in late diastole
Despite the differences in these studies, one message stands out clear. That is, a significant proportion of Nigerians with hypertensive heart failure have diastolic dysfunction. This is in agreement with reports from other countries of the world. Further studies are required to confirm this hypothesis.
In conclusion, the 69.4% prevalence of diastolic dysfunction in this study is quite significant. Isolated systolic dysfunction was seen in 30.5% of the patients, isolated diastolic dysfunction in 12.6%, and combined systolic and diastolic dysfunction in 24.2%. Pseudonormalization and restrictive pattern were seen in 6.3% and 26.3%, respectively. The significance of these findings is that two-thirds of our patients have diastolic dysfunction, and half of them are within the pseudonormalization and restrictive pattern that carry poor prognosis. Thus, diastolic dysfunction is the most common ventricular functional abnormality in hypertensive cardiac failure in our group of patients. Since early diagnosis and therapeutic intervention may improve diastolic function, a routine Doppler echocardiographic evaluation is recommended for all hypertensive and hypertensive heart failure patients. The results of such evaluation will aid the physician to prescribe appropriate treatment.