Cardiac arrhythmias are an important and life-threatening condition for emergency department admittance, and for this reason, cardiology guidelines advise health care professionals to obtain and interpret electrocardiograms (ECGs) as soon as possible (Zhang & Hsu, 2013). Because ECGs and patient monitoring are usually performed by nurses, the health care providers who first realize risky events are nurses (Doğan & Melek, 2012). Therefore, the ability of nurses to correctly interpret ECGs and identify arrhythmias that may be life threatening is an important step in the early initiation of appropriate treatment for these patients.
As is expected, the accuracy of ECG interpretation improves with time and practice (Hoyle et al., 2007). Studies related to the ECG interpretation accuracy of nurses demonstrated that they need more education and training in this area (Goodridge et al., 2013). It is not possible to discuss a single teaching method as the most effective one for improving ECG interpretation skills (Fent et al., 2015). However, Atwood and Wadlund (2015) introduced the Cardiac Rhythm Identification for Simple People (CRISP) method as an algorithm designed to teach cardiac rhythm interpretation to nurses in an easy and simple way (Atwood & Wadlund, 2015). This algorithm allows nurses to evaluate the rhythm in three steps: whether QRS complexes are present, whether P waves are present, and whether QRS complexes are wide or narrow or there are more P waves than QRS complexes (Atwood & Wadlund, 2015).
The aim of the current study was to assess the effects of the CRISP method for primary cardiac arrhythmia interpretation by nurses.
This was a prospective study that was conducted in a training and research hospital between June 1 and December 31, 2019 after receiving approval from the local ethics committee.
Nurses working in the emergency department, intensive care units, and inpatient departments of a training and research hospital were included in this study. Nurses were contacted through the head nurse responsible for in-service training. With the approval of the hospital management, nurses were instructed on arrhythmia interpretation using the CRISP method during this training program, which was organized every month regularly with different nurse groups. The head nurse divided all nurses in the hospital into four groups. The nurses were invited for CRISP training, which was held over 4 months. Participation in the study was voluntary, and participants signed an informed consent form, which explained the purpose of the study. Participants were asked to use a pseudonym on the test forms; thus, their confidentiality was ensured.
All nurses who were interested in proper ECG interpretation and who wanted to receive education on this topic were included in the study. Nurses who were on vacation or on duty during the study period were excluded.
This study used a pretest–posttest design. The aim of the study was to assess normal sinus rhythm (NSR) and primary cardiac arrhythmias, which were ventricular fibrillation (VF), ventricular tachycardia (VT), asystole (A), sinus tachycardia (ST), sinus bradycardia (SB), supraventricular tachycardia (SVT), atrial fibrillation (AF), atrial flutter (AFlu), first-degree atrioventricular block (1st AVB), second-degree atrioventricular block - Mobitz I (2nd AVB Type I), second-degree atrioventricular block - Mobitz II (2nd AVB Type II), and third-degree atrioventricular block (3rd AVB) by using the CRISP method.
First, participants were asked to complete the study forms, which included descriptive data such as age, gender, department, professional experience, education level (university/high school), and postgraduate education on ECG interpretation. All kinds of training activities, such as in-service training and courses regarding ECG interpretation completed by the nurses after their graduation from nursing school, were considered as postgraduate education.
The nurses then completed the pretest. The study test included 15 ECGs related to primary cardiac arrhythmias. Participants were asked to interpret the rhythm and write the answer under the relevant ECG on test forms within 15 minutes. To ensure that the study would be as accurate and scientifically rigorous as possible, each participant answered the test questions individually.
Immediately after the pretest, nurses were instructed on arrhythmia interpretation using the CRISP method (Atwood & Wadlund, 2015). The first part of this educational program was lecture based, and it was given by the researchers, who were emergency physicians with at least 3 years of experience. Initially, the characteristics and normal values of each duration and intervals of normal ECGs were mentioned, and then the CRISP method was discussed.
The CRISP Method
This method was described by Atwood and Wadlund (2015). It is a three-step algorithm. The first step is the interpretation of QRS complexes; if there are no QRS complexes, the rhythm is VF or A. If QRS complexes are present, the nurse should proceed to step two.
The second step is the interpretation of P waves, and based on the answer, nurses should proceed to step three. If the answer to the second step is “no” and there are no P waves, nurses progress to the third step and should evaluate the width of the QRS complexes. If the QRS complexes are wide, the rhythm might be VT; if the QRS complexes are narrow, the rhythm might be SVT, AF, or AFlu.
If the answer to the second step is “yes” and P waves are present, nurses should interpret whether there are more P waves than QRS complexes in the third step. If the answer is “no” and there are not more P waves than QRS complexes, then the rhythm might be SB, NSR, ST, or 1st AVB; if the answer is “yes” and there are more P waves than QRS complexes then the rhythm might be 2nd AVB Type I, 2nd AVB Type II, or 3rd AVB. A summary of the CRISP algorithm is shown in Figure 1, and this algorithm was distributed to participants as training material. With the CRISP method, instruction on how to differentiate the specific rhythms (e.g., the difference between SB and 1st AVB) was also provided. This part of the lecture took 90 minutes.
Summary of the CRISP algorithm. Note. VF = ventricular fibrillation; A = asystole; NSR = normal sinus rhythm; SB = sinus bradycardia; ST = sinus tachycardia; 1st AVB = first-degree atrioventricular block; 2nd AVB Type I = second-degree atrioventricular block - Mobitz I; 2nd AVB Type II = second-degree atrioventricular block - Mobitz II; 3rd AVB = third-degree atrioventricular block; VT = ventricular tachycardia; SVT = supraventricular tachycardia; AF = atrial fibrillation; AFlu = atrial flutter.
After this initial lecture, the researchers led small-group discussions on ECGs to increase the practice skills of the nurses. This part of the education took 30 minutes. At the end of this educational program, participants completed the posttest. The questions on the posttest were the same as those on the pretest but were in a different order. Participants completed the posttest using the CRISP algorithm. This educational program was repeated for different nurse groups four times.
Statistical analyses were performed using SPSS® (version 22.0). After assessing normal distribution using the Shapiro–Wilk test, all variables were described in terms of mean ± standard deviation or median and interquartile range (IQR) (25% to 75%). To determine the statistical differences between the groups, the Student's t test was used to analyze parametric variables, and the Mann–Whitney U test was used to analyze nonparametric variables. An ANOVA test was used to analyze the differences in test scores among nurses from different departments and with different professional experience. The Wilcoxon signed-rank test was used to analyze the differences between the pretest and posttest scores, and the McNemar's test was used to analyze the unique differences between the answers of pretest and posttest questions. Values of p < .05 were considered statistically significant.
Of the total 218 nurses who were invited, 150 were included in the study. The median age of the participants was 40 years (IQR = 34–43), and 82.4% of the participants were female. Half of the participants had postgraduate education on ECG interpretation. The other characteristics of the participants are summarized in Table 1.
Characteristics of Participant Nurses (N = 150)
There were no differences between the pretest scores of the participants in terms of gender, department of work, professional experience, or graduation status. However, there was a significant difference between the nurses who had postgraduate education on ECG interpretation and those who did not (p = .002). The most incorrectly answered questions on the pretest were AF, 3rd AVB, and 2nd AVB Type II, respectively, and the most correctly answered questions on the pretest were NSR, A, and SB, respectively. Correct recognition rates of fatal rhythms (i.e., VF and VT) were remarkably low (26.7% and 22%, respectively).
The posttest scores were analyzed, and there were no differences between the posttest scores of the participants in terms of department of work, professional experience, graduation status, or having postgraduate education on ECG interpretation. Only a significant difference was found in terms of gender among the posttest scores. Female participants had higher scores than male participants (p < .05). The results for the pretest and posttest scores are shown in Table 2.
Analyses of the Pretest and Posttest Results Within the Groups (N = 150)
Pretest Versus Posttest
There was a significant increase in the test scores after the educational program. The median test score increased from three correct answers of 15 questions (IQR = 2–5) on the pretest to seven correct answers of 15 questions (IQR = 5–9) on the posttest (p < .001). We grouped the test questions into three sets as normal sinus rhythm and fatal arrhythmias, atria-ventricular blocks, and other arrhythmias, and we analyzed the frequencies of correct and incorrect answers for every question on the pretest and posttest. The success rate decreased after education for the questions on normal sinus rhythm and did not change for the questions about SB and first AVB and the second question about third AVB. There was a significant increase in the correct answers for all other questions after the educational program. In general, participants failed the questions about heart blocks, whereas they were most successful with questions about fatal arrhythmias after education. All the results are summarized in Table 3.
Comparison of the Pretest (n = 150) and Posttest (n = 150) Scores
This study demonstrated that the accuracy of cardiac rhythm interpretation of nurses was remarkably low and that the identification of the most important fatal rhythm, VF, was only 26.6% on the pretest. There were no differences in the pretest scores in terms of gender, department of work, professional experience, or graduation status, but there was a difference between the pretest scores of nurses who had postgraduate education on ECG interpretation and those who did not. The study also showed that the CRISP method was an easy and simple method for effective ECG education and accurate ECG interpretation by nurses. The posttest scores of the participants, especially for accurate interpretation of fatal arrhythmias, increased significantly after the educational program.
Most of the participants in the study were female because of the higher prevalence of female nurses than male nurses in Turkey, like in other parts of the world (Kouta & Kaite, 2011). Our hypothesis was that nurses working in the emergency department and those with more experience would be more successful with ECG interpretation because they encounter more ECGs in their daily practice. There are publications supporting this hypothesis. Hoyle et al. (2007) demonstrated that there was an improvement in ECG interpretation accuracy with advancing years of emergency medicine training. In contrast, Coll-Badell et al. (2017) showed that the level of ECG knowledge was not influenced by experience but rather by training courses on ECG interpretation, and this finding was similar to those in our study.
There is no established evidence-based standard for teaching ECGs; however, the main learning activity in the literature is a lecture format supplemented by small-group practical teaching with ECG interpretation practice, as we did in our study (Breen et al., 2019). The step that we did differently was teaching how to use the CRISP method during ECG interpretation. To our knowledge, this is the first study to evaluate the effect of the CRISP method on ECG interpretation, and our opinion is that it is an effective, simple, and easy way to accurately interpret ECGs. The significant increase in the posttest scores after only a 2-hour educational program demonstrated the success of this method.
In one study, nurses' accurate identification of NSR was approximately 60%, and accurate identification of arrhythmias was approximately 30% (Üzel & Ulupınar, 2011). In our study, accurate diagnosis of NSR was 73.3% on the pretest but decreased to 49.3% on the posttest. This might be because nurses were focused on finding pathologies during ECG interpretation training. In general, studies have demonstrated that nurses had difficulty recognizing tachyarrhythmias and heart blocks and were better at recognizing bradyarrhythmias (Keller & Raines, 2005; Varvaroussis et al., 2014). Our results were similar to those in the literature. In the pretest, the most incorrectly answered questions involved heart blocks and AF, and the most correctly answered questions involved NSR, A, and SB. After the training program, success rates for fatal tachyarrhythmias (i.e., VF and VT) increased significantly. Nevertheless, questions on heart blocks remained the most missed questions on the posttest. The CRISP method provides a structured ECG interpretation strategy for basic arrhythmias, but additional teaching might be necessary to progress beyond the simple approach and accurate rhythm description to more precise identification, especially for specific arrhythmias, including heart block.
Rapidly and accurately assessing primary ECG rhythms during cardiac rhythm monitoring is an important skill for nurses, and it is associated with decreased mortality (Pothitakis et al., 2011). Nurses should use the CRISP algorithm in their daily practice to improve their ECG interpretation skills. Another important point of ECG training is retention of the knowledge. Studies have demonstrated that skill retention and competence in ECG interpretation were intermediate (Brooks et al., 2016). Therefore, periodic postgraduate education programs with ECG training should be organized to maintain and improve nurses' ECG interpretation skills because this is an important component in improving patient care.
This study had some limitations. First, we aimed to evaluate the effectiveness of the CRISP method on primary cardiac arrhythmia interpretation, but we did not compare this method with a different method or have a control group. Second, we did not evaluate the retention of the knowledge. We should have repeated the posttest after more time had passed, but that was difficult because the nurses participating in the study were working in different departments and shifts. Therefore, it would be nearly impossible to reunite the same group on the same day after a certain period.
This study showed that the primary cardiac arrhythmia interpretation accuracy of nurses was remarkably low, especially for tachyarrhythmias and heart block. The success of ECG interpretation was not affected by variables such as gender, department of work, professional experience, or graduation status, but it was affected by having postgraduate education on ECG interpretation. The CRISP method is an effective, simple, and easy method for accurate ECG interpretation by nurses. The posttest scores of the participants, especially for accurate interpretation of fatal arrhythmias, increased significantly after training.
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Characteristics of Participant Nurses (N = 150)
|Median age (years)||40 (34 to 43)|
| Female||122 (82.4%)|
| Male||26 (17.6%)|
| Emergency department||19 (12.9%)|
| Intensive care unit||38 (25.9%)|
| In-patient departments||74 (50.3%)|
| Other (e.g., dialysis unit)||16 (10.9%)|
|Professional experience, n|
| ⩽ 5 years||15 (10.3%)|
| 5 to 10 years||22 (15.2%)|
| 10 to 15 years||26 (17.9%)|
| 15 to 20 years||35 (24.1%)|
| ⩾ 20 years||47 (32.4%)|
|Graduation status, n|
| University||120 (83.9%)|
| Health vocational high school||23 (16.1%)|
|Postgraduate education on electrocardiogram interpretation, n|
| Yes||72 (50.7%)|
| No||70 (49.3%)|
Analyses of the Pretest and Posttest Results Within the Groups (N = 150)
|Variable||Pretest Score||Posttest Score|
|Score||p Value||Score||p Value|
|General test score||3 (2 to 5)||7 (5 to 9)|
| Female||3 (2 to 5)||7 (5 to 9)|
| Male||3 (2 to 4)||6 (5 to 7)|
| Emergency department||3 (2 to 4)||8 (5 to 9)|
| Intensive care unit||3 (3 to 5)||7 (5 to 8.75)|
| Inpatient departments||3 (2 to 5)||6 (4 to 8.75)|
| Others (e.g., dialysis unit)||3.5 (2 to 6)||5 (3.5 to 9)|
| ⩽5 years||3 (2 to 3.5)||8 (5.75 to 9)|
| 5 to 10 years||4 (3 to 6)||6 (5 to 9.25)|
| 10 to 15 years||3 (2 to 5)||7 (5 to 8)|
| 15 to 20 years||3 (2 to 4.25)||7 (4 to 10)|
| ⩾ 20 years||4 (3 to 5.5)||6 (4.25 to 8)|
| University||3 (2 to 5)||7 (5 to 9)|
| Health vocational high school||3 (2 to 4)||6 (4.25 to 8)|
|Postgraduate education on ECG interpretation||.002||.122|
| Yes||4.32 ± 4.92||7.15 ± 6.02|
| No||2.99 ± 3.38||6.32 ± 4.78|
|Most incorrectly answered questions||1. AF [F: 143 (95.3%)]||1. 3rdAVB [F: 138 (92.6%)]|
|2. 3rdAVB [F: 140 (93.3%)]||2. 1stAVB [F: 123 (82.6%)]|
|3. 2ndAVBTypeII [F: 138 (92.2%)]||3. 2ndAVBTypeII [F: 116 (77.3%)]|
|Most correctly answered questions||1. NSR [T: 110 (73.3%)]||1. A [T: 145 (97.3%)]|
|2. A [T: 109 (72.7%)]||2. VT [T: 120 (80.5%)]|
|3. SB [T: 83 (55.3%)]||3. AFlu [T: 106 (71.1%)]|
Comparison of the Pretest (n = 150) and Posttest (n = 150) Scoresa
|Variable||Pretest Score||Posttest Score||p Value|
|Normal rhythm and fatal arrhythmias|
| Normal sinus rhythm||110||40||74||76||<.001|
| Ventricular fibrillation||40||110||104||46||<.001|
| Ventricular tachycardia||33||117||121||29||<.001|
| First-degree atrioventricular block||17||133||26||124||.094|
| Second-degree atrioventricular block - Mobitz Type I||19||131||45||105||<.001|
| Second-degree atrioventricular block - Mobitz Type II||12||138||33||117||.001|
| Third-degree atrioventricular block, one||10||140||55||95||<.001|
| Third-degree atrioventricular block, two||17||133||11||139||.161|
| Sinus bradycardia||83||67||76||74||.244|
| Sinus tachycardia||37||113||65||85||<.001|
| Supraventricular tachycardia||29||121||84||66||<.001|
| Atrial flutter||13||137||107||46||<.001|
| Atrial fibrillation, one||17||133||46||104||<.001|
| Atrial fibrillation, two||7||143||39||111||<.001|