Nigerian Journal of Cardiology

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 17  |  Issue : 1  |  Page : 37--41

Electromechanical dyssynchrony and short-term outcomes of readmission and death, among heart failure patients in Aminu Kano teaching hospital, Kano State, Nigeria


Bashir Garba Ahmad1, Muhammad Sani Mijinyawa2, Mahmoud Umar Sani2,  
1 Department of Medicine, Aminu Kano Teaching Hospital, Kano State, Nigeria
2 Department of Medicine, Aminu Kano Teaching Hospital; Department of Medicine, Bayero University, Kano State, Nigeria

Correspondence Address:
Dr. Bashir Garba Ahmad
Department of Medicine, Aminu Kano Teaching Hospital, Kano State
Nigeria

Abstract

Background: Cardiac dyssynchrony refers to a difference in the timing of contractions in different chambers and/or segments of the heart. Left ventricular (LV) dyssynchrony is frequently seen in patients with heart failure (HF) and is a poor prognostic marker if left untreated. The impact of cardiac dyssynchrony among HF patients in Nigeria is unknown. We set out to assess the role of electromechanical dyssynchrony in short-term outcomes in terms of readmission and 6-month mortality among HF patients in our hospital. Methods: We conducted a prospective observational study among adult HF patients in our hospital. Electrical and mechanical dyssynchrony were measured using electrocardiography and echocardiography, respectively. Data on the outcome of readmission and death within 6 months were collected. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 16 software. Results: A total of 100 participants were recruited for this study. Electrical dyssynchrony (Duration of QRS complex on ECG > 120ms) was found in 11%, 8 (73%) of them had QRS width between 120 and 150 ms, while in three, the QRS width was >150 ms. The prevalence of interventricular dyssynchrony (LV preejection interval – right ventricular preejection interval ≥40 ms) was found to be 79%, while that of intraventricular (septal to posterior wall motion delay >130 ms) was 75%. Nineteen percent of the study participants were readmitted with worsening HF symptoms, while up to 37% died within the 6 months follow-up period. Electrical dyssynchrony was a significant predictor of short-term readmission and death. There was also a statistically significant difference (P < 0.005) between all forms of dyssynchrony and death. Conclusion: The presence of electromechanical dyssynchrony is associated with a poor short-term outcome of readmission and death. More studies are needed in our country to fully define the burden of dyssynchrony among HF patients in our environment.



How to cite this article:
Ahmad BG, Mijinyawa MS, Sani MU. Electromechanical dyssynchrony and short-term outcomes of readmission and death, among heart failure patients in Aminu Kano teaching hospital, Kano State, Nigeria.Nig J Cardiol 2020;17:37-41


How to cite this URL:
Ahmad BG, Mijinyawa MS, Sani MU. Electromechanical dyssynchrony and short-term outcomes of readmission and death, among heart failure patients in Aminu Kano teaching hospital, Kano State, Nigeria. Nig J Cardiol [serial online] 2020 [cited 2020 Aug 15 ];17:37-41
Available from: http://www.nigjcardiol.org/text.asp?2020/17/1/37/288640


Full Text



 Introduction



Heart failure (HF) is one of the major causes of hospital admission globally and a major driver of hospital costs. HF is associated with shorter life expectancy, greater morbidity, and impaired quality of life than most common diseases. About 30% of people die within 3 months of the diagnosis of HF. Annual mortality is 10% thereafter. Those with severe HF have an annual mortality of >50%.[1],[2],[3]

Cardiac dyssynchrony refers to a difference in the timing of contractions in different chambers and/or segments of the heart. The role of dyssynchrony in the pathophysiology and outcome of HF has been shown by many studies in the developed world.[4],[5],[6],[7] Despite the very high burden of HF in Nigeria and Sub-Saharan Africa, there is a paucity of data on the prevalence and outcomes of dyssynchrony in HF in these parts of the world. Patients with cardiac dyssynchrony have been shown to benefit from cardiac resynchronization therapy (CRT) with improved symptoms, reduced hospitalization, and improved mortality in HF.[8],[9],[10]

In this work, we set out to assess the role of electromechanical dyssynchrony in short-term outcomes in terms of readmission and 6-month mortality among 100 HF patients presenting to our hospital.

 Methods



We conducted a prospective observational study among adult HF patients in our hospital. Electrical and mechanical dyssynchrony were measured using electrocardiography and echocardiography, respectively. A total of 100 patients with HF New York Heart Association (NYHA) functional Class II–IV were recruited consecutively through the emergency unit, medical outpatient clinic, and medical wards of the hospital. HF was diagnosed using the Framingham criteria. Twelve channel Schiller electrocardiogram (ECG) machine was used to obtain ECG tracing for all patients in the ECG laboratory of the hospital.

Echocardiography was done using the Sonoscape SSI 8000 cardiac ultrasound system. It was done in the left lateral decubitus position using parasternal, short-axis, and apical four-chamber views. Two-dimensional (2D), M-mode, and Doppler echocardiographic evaluation were performed. Using the 2D-guided M-mode approach, left atrial, left ventricular (LV), and other cardiac chambers dimensions were determined.

Echocardiographic parameters of interest included LV pre-ejection interval (LPEI), right ventricular pre-ejection interval (RPEI), and septal to posterior wall motion delay (SPWMD). LPEI and RPEI were defined as the distance measured from QRS onset to the beginning of aortic and pulmonary Doppler flow velocity curves, respectively. The difference between LPEI and RPEI was computed, and where found to be ≥40 ms, 2 standard deviations (2SD) above the mean of normal controls it signifies interventricular dyssynchrony. SPWMD was measured as the time interval between the maximal outward displacement of the interventricular septum and the LV posterior wall, a value of >130 ms 2 SD above the mean of normal controls were considered as the presence of intraventricular dyssynchrony.[11] In patients with difficult to identify systolic peaks of the LV posterior wall or akinetic interventricular septum, intraventricular dyssynchrony was defined as LPEI ≥140 ms.[11]

Data on the outcome of readmission and death within 6 months were collected. Data were analyzed using the Statistical Package for the Social Sciences (SPSS for Windows, version 16.0. Chicago, SPSS Inc.) version 16 software. Chi–- square test was used to check for an association between categorical variables and Binary logistic regression analysis was used to test the strength of the relationship between dyssynchrony and short-term outcomes of readmission and death. The level of statistically significant difference between those with and without dyssynchrony was determined, and in the whole analysis, P < 0.05 was considered as statistically significant.

The study was approved by the hospital's ethics committee, and written informed consent was obtained from each of the participants.

 Results



A total of 100 participants were recruited, and each of them was followed up for 6 months. All the participants were Nigerians with a mean age of 41.95 ± 16.07 years, 67% were female, 13% were traders, and 85% were married. Fifty-four (54%) had some informal education, and 51% resides in urban areas.

All the participants complained of productive cough, 71% reported frothy white sputa, 22% mucoid, whereas 7% had associated hemoptysis. Palpitation was reported by 42% of the study population, it was intermittent and unprovoked in 29 (69%) of them, occurs with activity in 10 (24%), and was continuous in 3 (7%).

The grouping of the participants according to the NYHA functional classification of HF symptoms is as shown in [Figure 1]. Majority (71%) falls within NYHA Class III, but only 14% were in NYHA II [Figure 1]. There was no statistically significant difference observed between the degree of dyssynchrony and NYHA functional class. In all the different forms of dyssynchrony, the difference was not statistically significant, as shown in [Table 1].{Figure 1}{Table 1}

Results of echocardiography demonstrated a mean LA dimension of 46.76 mm for men and 49.16 for women, with SD of 8.5 mm and 10.2 mm, respectively. LV end-diastolic diameter, LV ejection fraction (EF), and LV mass index were all measured and reported as means with SD as shown in [Table 2].{Table 2}

Electrical dyssynchrony (QRS ≥120 ms) was found in 11%, 8 (73%) of them had QRS width between 120 and 150ms, whereas in three, the QRS width was >150 ms. The prevalence of interventricular dyssynchrony (LPEI – RPEI ≥40 ms) was found to be 79%, while that of intraventricular (SPWMD >130 ms) was 75%.

Thirty-four percent of the study participants were recruited while on admission for symptoms of cardiac decompensation, and the median length of hospital stay was 10.5 days. However, no statistically significant relationship was observed between dyssynchrony and duration of hospital stay.

A total of 19 patients were readmitted in the study. There is a statistically significant association (P = 0.032) between electrical dyssynchrony and readmission within 6 months in HF patients, as obtained in this study. The findings were different with mechanical dyssynchrony and readmission [Table 3]. Thirty-seven patients (37%) died during the study period. All the three forms of dyssynchrony were significantly associated with increased mortality [Table 4].{Table 3}{Table 4}

 Discussion



LV dyssynchrony, or previously known as myocardial nonuniformity of ventricular activation, is a prevalent feature in HF patients.[11],[12] Studies aimed at understanding the natural history of this condition pointed to the importance of the QRS width as an independent marker for death. Specifically, individuals with wider QRS widths and/or left bundle branch block patterns have a worse outcome compared with those with normal conduction.[13],[14] Patients with QRS widths >120 ms had a 15% increase in mortality when compared with patients with QRS widths <120 ms independent of age, EF, severity, or etiology of HF.[15] Many theories have been forwarded to explain this observation, but the most acceptable is the concept of ventricular dyssynchrony.[16]

We found no significant statistical relationship between the degree of dyssynchrony and NYHA functional class. Finding from a recent Swedish HF registry highlighted the relationship between QRS prolongation and worse NYHA outcomes.[17] The possible reason for this difference could be attributed to the power of the study, with about 13,423 patients studied in the Swedish registry. Severe LV dyssynchrony was found to be associated with NYHA III more than NYHA II functional class in another study by Atchley et al.,[18] but the technique of assessing dyssynchrony was different from ours. This may be responsible for the observed difference in results.

Nineteen percent were readmitted with worsening HF symptoms of cough, dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and body swelling. This value was higher than 7.4% readmission rate among acute HF patients in the sub-saharan africa survey-HF (THESUS-HF) registry,[19] perhaps because THESUS-HF considered the end point of readmission through the period of only 60 days, while we considered readmission through 6 months in this study. Our readmission rate was higher than 30 days but lower than the 1-year readmission rate for HF patients in Ontario province, Canada.[20]

We found a statistically significant association (P = 0.032) between electrical dyssynchrony and readmission within 6 months among HF patients in this study, but none was observed between mechanical dyssynchrony and readmission. Electrical dyssynchrony was a significant predictor of readmission and death at 6 months among our HF patients in this study (P = 0.033, odds ratio (OR) = 1.220, 95% confidence interval [CI]), and (P = 0.0430, OR = 1.48, 95% CI), respectively. Our findings are in agreement with the findings of another study that observed electrical dyssynchrony to be associated with adverse outcomes.[21]

We found that 37 of 100 participants (37%) died within the follow-up period. Our value was higher than the 17.8% 6-month mortality from THESUS-HF[19], and even higher than 29.6% 1-year mortality among HF patients in Canada.[20] Death from cardiovascular diseases is on the rise in Nigeria due to epidemiologic transition taking place across much of Africa. Causes of death in HF are many, including progressive pump failure, arrhythmias, electrolytes disturbances, major organ failures, or other factors unrelated to the HF, but endemic to the region. Patients with QRS width >120 ms had 15% increased risk of death when compared with QRS width <120 ms, regardless of age, EF, severity, or etiology of HF.[15],[22] Failure to manage HF patient on goal-directed optimal medical therapy is an indication for device therapy, including CRT.[17],[23] Device therapy for HF is very rare in Nigeria, despite the benefit associated with it in the appropriate patients.

There was a strong relationship between electrical dyssynchrony and intraventricular (LV) dyssynchrony (P < 0.01), but no statistically significant association was observed with interventricular dyssynchrony (P = 1.00). This finding resembles that of Gyalai et al., when they performed an echocardiographic evaluation of HF patients with reduced EF.[24] Our finding is in some agreement with the work of Behaghel et al., where they found a relationship, although weak, between electrical and both interventricular and intraventricular dyssynchrony.[25]

Death among HF patients within 6 months was significantly associated with all forms of dyssynchrony in this study, and the relationship was strong. The relationship between prolonged QRS and poor outcomes among HF patients was also observed in the works of Iuliano et al.,[15] Naqvi,[26] and even among patients with HF and preserved EF.[4] Bader et al.[5] in 2004 also documented the association between intraventricular dyssynchrony and worse cardiac events in HF. LV dyssynchrony was also noted to be a harbinger of poor outcomes among patients with myocardial infarction.[6] Dyssynchrony between ventricles or within segments of the left ventricle will lead to the progressive decline in resultant myocardial contractile strength, decrease stroke volume, and subsequent decrease in effective circulating blood volume, hence HF with attending morbidity and mortality consequences. Resynchronization of the asynchronous chambers and/or segments of the heart (CRT) has been proven to result in the improvement of symptoms and quality of life, and the reduction of complications and death. CRT is therefore recommended for patients with systolic dysfunction and cardiac dyssynchrony who have moderate or severe HF and who are in sinus rhythm (Cardiac Resynchronization-HF).[7]

 Conclusion



The presence of electromechanical dyssynchrony is associated with the poor short-term outcome of readmission and death. More studies are needed in our country to fully define the burden of dyssynchrony among HF patients in our environment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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